Electric And Hybrid Vehicles Design Fundamentals Pdf File

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Scheme of a proton-conducting fuel cell A fuel cell is an that converts the from a fuel into electricity through an reaction of with oxygen or another. Fuel cells are different from in requiring a continuous source of fuel and oxygen (usually from air) to sustain the chemical reaction, whereas in a battery the chemical energy comes from chemicals already present in the battery.

Fuel cells can produce electricity continuously for as long as fuel and oxygen are supplied. The first fuel cells were invented in 1838. The first commercial use of fuel cells came more than a century later in space programs to generate power for and. Since then, fuel cells have been used in many other applications. Fuel cells are used for primary and backup power for commercial, industrial and residential buildings and in remote or inaccessible areas. They are also used to power, including forklifts, automobiles, buses, boats, motorcycles and submarines.

There are many types of fuel cells, but they all consist of an, a, and an that allows positively charged hydrogen ions (protons) to move between the two sides of the fuel cell. At the anode a catalyst causes the fuel to undergo oxidation reactions that generate protons (positively charged hydrogen ions) and electrons. The protons flow from the anode to the cathode through the electrolyte after the reaction. At the same time, electrons are drawn from the anode to the cathode through an external circuit, producing electricity. At the cathode, another catalyst causes hydrogen ions, electrons, and oxygen to react, forming water. Fuel cells are classified by the type of electrolyte they use and by the difference in startup time ranging from 1 second for (PEM fuel cells, or PEMFC) to 10 minutes for (SOFC). Individual fuel cells produce relatively small electrical potentials, about 0.7 volts, so cells are 'stacked', or placed in series, to create sufficient voltage to meet an application's requirements.

In addition to electricity, fuel cells produce water, heat and, depending on the fuel source, very small amounts of and other emissions. The energy efficiency of a fuel cell is generally between 40–60%; however, if waste heat is captured in a scheme, efficiencies up to 85% can be obtained. A related technology is, in which the fuel can be regenerated by recharging.

The fuel cell market is growing, and in 2013 Pike Research estimated that the stationary fuel cell market will reach 50 GW by 2020. Sketch of William Grove's 1839 fuel cell The first references to hydrogen fuel cells appeared in 1838.

In a letter dated October 1838 but published in the December 1838 edition of The London and Edinburgh Philosophical Magazine and Journal of Science, Welsh physicist and barrister wrote about the development of his first crude fuel cells. He used a combination of sheet iron, copper and porcelain plates, and a solution of sulphate of copper and dilute acid. In a letter to the same publication written in December 1838 but published in June 1839, German physicist discussed the first crude fuel cell that he had invented. His letter discussed current generated from hydrogen and oxygen dissolved in water. Grove later sketched his design, in 1842, in the same journal.

The fuel cell he made used similar materials to today's. In 1939, British engineer successfully developed a 5 kW stationary fuel cell. Thomas Grubb, a chemist working for the Company (GE), further modified the original fuel cell design by using a sulphonated polystyrene ion-exchange membrane as the electrolyte. Three years later another GE chemist, Leonard Niedrach, devised a way of depositing platinum onto the membrane, which served as catalyst for the necessary hydrogen oxidation and oxygen reduction reactions. This became known as the 'Grubb-Niedrach fuel cell'. GE went on to develop this technology with NASA and McDonnell Aircraft, leading to its use during.

This was the first commercial use of a fuel cell. In 1959, a team led by Harry Ihrig built a 15 kW fuel cell tractor for, which was demonstrated across the U.S. At state fairs.

This system used potassium hydroxide as the electrolyte and and oxygen as the reactants. Later in 1959, Bacon and his colleagues demonstrated a practical five-kilowatt unit capable of powering a welding machine.

In the 1960s, Pratt and Whitney licensed Bacon's U.S. Patents for use in the U.S. Space program to supply electricity and drinking water (hydrogen and oxygen being readily available from the spacecraft tanks). In 1991, the first hydrogen fuel cell automobile was developed. Was the first company to manufacture and commercialize a large, stationary fuel cell system for use as a power plant in hospitals, universities and large office buildings. In recognition of the fuel cell industry and America’s role in fuel cell development, the US Senate recognized 8 October 2015 as National Hydrogen and Fuel Cell Day, passing S.

The date was chosen in recognition of the atomic weight of hydrogen (1.008). Types of fuel cells; design [ ] Fuel cells come in many varieties; however, they all work in the same general manner. They are made up of three adjacent segments: the, the, and the. Two chemical reactions occur at the interfaces of the three different segments.

The net result of the two reactions is that fuel is consumed, water or carbon dioxide is created, and an electric current is created, which can be used to power electrical devices, normally referred to as the load. At the anode a oxidizes the fuel, usually hydrogen, turning the fuel into a positively charged ion and a negatively charged electron. The electrolyte is a substance specifically designed so ions can pass through it, but the electrons cannot. The freed electrons travel through a wire creating the electric current. The ions travel through the electrolyte to the cathode. Once reaching the cathode, the ions are reunited with the electrons and the two react with a third chemical, usually oxygen, to create water or carbon dioxide. A block diagram of a fuel cell The most important design features in a fuel cell are [ ]: • The electrolyte substance.

The electrolyte substance usually defines the type of fuel cell. • The fuel that is used.

The most common fuel is hydrogen. • The anode catalyst breaks down the fuel into electrons and ions.

The anode catalyst is usually made up of very fine platinum powder. • The cathode catalyst turns the ions into the products like water or carbon dioxide. The cathode catalyst is often made up of platinum or platinum-group metals and it can also be made of non-platinum metals such as iron. A typical fuel cell produces a voltage from 0.6 V to 0.7 V at full rated load. Voltage decreases as current increases, due to several factors: • • Ohmic loss ( due to resistance of the cell components and interconnections) • Mass transport loss (depletion of reactants at catalyst sites under high loads, causing rapid loss of voltage).

To deliver the desired amount of energy, the fuel cells can be combined in to yield higher, and in parallel to allow a higher to be supplied. Such a design is called a fuel cell stack. The cell surface area can also be increased, to allow higher current from each cell.

Within the stack, reactant gases must be distributed uniformly over each of the cells to maximize the power output. Proton exchange membrane fuel cells (PEMFCs) [ ]. Main article: In the archetypical hydrogen–oxide design, a proton-conducting polymer membrane (typically ) contains the solution that separates the and sides.

This was called a 'solid polymer electrolyte fuel cell' (SPEFC) in the early 1970s, before the proton exchange mechanism was well understood. (Notice that the synonyms 'polymer electrolyte membrane' and 'proton exchange mechanism' result in the same.) On the anode side, hydrogen diffuses to the anode catalyst where it later dissociates into protons and electrons. These protons often react with oxidants causing them to become what are commonly referred to as multi-facilitated proton membranes. The protons are conducted through the membrane to the cathode, but the electrons are forced to travel in an external circuit (supplying power) because the membrane is electrically insulating. On the cathode catalyst, oxygen react with the electrons (which have traveled through the external circuit) and protons to form water. In addition to this pure hydrogen type, there are fuels for fuel cells, including, ( see: and ) and chemical hydrides. The waste products with these types of fuel are and water.

When hydrogen is used, the CO2 is released when methane from natural gas is combined with steam, in a process called, to produce the hydrogen. This can take place in a different location to the fuel cell, potentially allowing the hydrogen fuel cell to be used indoors—for example, in fork lifts. Condensation of water produced by a PEMFC on the air channel wall. The gold wire around the cell ensures the collection of electric current. The different components of a PEMFC are • bipolar plates, •, •, • membrane, and • the necessary hardware such as current collectors and gaskets. The materials used for different parts of the fuel cells differ by type.

The bipolar plates may be made of different types of materials, such as, metal, coated metal,, flexible graphite, C–C, – composites etc. The (MEA) is referred as the heart of the PEMFC and is usually made of a proton exchange membrane sandwiched between two -coated. Platinum and/or similar type of are usually used as the catalyst for PEMFC.

The electrolyte could be a polymer. Proton exchange membrane fuel cell design issues [ ] • Cost. In 2013, the Department of Energy estimated that 80-kW automotive fuel cell system costs of US$67 per kilowatt could be achieved, assuming volume production of 100,000 automotive units per year and US$55 per kilowatt could be achieved, assuming volume production of 500,000 units per year.

Many companies are working on techniques to reduce cost in a variety of ways including reducing the amount of platinum needed in each individual cell. Has experimented with a catalyst enhanced with carbon silk, which allows a 30% reduction (1 mg/cm² to 0.7 mg/cm²) in platinum usage without reduction in performance., uses as a. A 2011 published study doi: 10.1021/ja1112904 documented the first metal-free electrocatalyst using relatively inexpensive doped, which are less than 1% the cost of platinum and are of equal or superior performance. A recently published article demonstrated how the environmental burdens change when using carbon nanotubes as carbon substrate for platinum. • Water and air management (in PEMFCs). In this type of fuel cell, the membrane must be hydrated, requiring water to be evaporated at precisely the same rate that it is produced. If water is evaporated too quickly, the membrane dries, resistance across it increases, and eventually it will crack, creating a gas 'short circuit' where hydrogen and oxygen combine directly, generating heat that will damage the fuel cell.

If the water is evaporated too slowly, the electrodes will flood, preventing the reactants from reaching the catalyst and stopping the reaction. Methods to manage water in cells are being developed like focusing on flow control. Just as in a combustion engine, a steady ratio between the reactant and oxygen is necessary to keep the fuel cell operating efficiently. • Temperature management. The same temperature must be maintained throughout the cell in order to prevent destruction of the cell through. This is particularly challenging as the 2H 2 + O 2 ->2H 2O reaction is highly exothermic, so a large quantity of heat is generated within the fuel cell.

• Durability,, and special requirements for some type of cells. Typically require more than 40,000 hours of reliable operation at a temperature of −35 °C to 40 °C (−31 °F to 104 °F), while automotive fuel cells require a 5,000-hour lifespan (the equivalent of 240,000 km (150,000 mi)) under extreme temperatures. Current is 2,500 hours (about 75,000 miles). Automotive engines must also be able to start reliably at −30 °C (−22 °F) and have a high power-to-volume ratio (typically 2.5 kW per liter). • Limited tolerance of some (non-PEDOT) cathodes. Phosphoric acid fuel cell (PAFC) [ ]. Main article: Phosphoric acid fuel cells (PAFC) were first designed and introduced in 1961 by and.

In these cells phosphoric acid is used as a non-conductive electrolyte to pass positive hydrogen ions from the anode to the cathode. These cells commonly work in temperatures of 150 to 200 degrees Celsius. This high temperature will cause heat and energy loss if the heat is not removed and used properly. This heat can be used to produce steam for air conditioning systems or any other thermal energy consuming system. Using this heat in can enhance the efficiency of phosphoric acid fuel cells from 40–50% to about 80%. Phosphoric acid, the electrolyte used in PAFCs, is a non-conductive liquid acid which forces electrons to travel from anode to cathode through an external electrical circuit.

Since the hydrogen ion production rate on the anode is small, platinum is used as catalyst to increase this ionization rate. A key disadvantage of these cells is the use of an acidic electrolyte. This increases the corrosion or oxidation of components exposed to phosphoric acid. Solid acid fuel cell (SAFC) [ ]. Main article: Solid acid fuel cells (SAFCs) are characterized by the use of a solid acid material as the electrolyte. At low temperatures, have an ordered molecular structure like most salts. At warmer temperatures (between 140 and 150 degrees Celsius for CsHSO 4), some solid acids undergo a phase transition to become highly disordered 'superprotonic' structures, which increases conductivity by several orders of magnitude.

The first proof-of-concept SAFCs were developed in 2000 using cesium hydrogen sulfate (CsHSO 4). Current SAFC systems use cesium dihydrogen phosphate (CsH 2PO 4) and have demonstrated lifetimes in the thousands of hours.

Alkaline fuel cell (AFC) [ ]. Main articles: and The alkaline fuel cell or hydrogen-oxygen fuel cell was designed and first demonstrated publicly by Francis Thomas Bacon in 1959. It was used as a primary source of electrical energy in the Apollo space program.

The cell consists of two porous carbon electrodes impregnated with a suitable catalyst such as Pt, Ag, CoO, etc. The space between the two electrodes is filled with a concentrated solution of KOH or NaOH which serves as an electrolyte. H 2 gas and O 2 gas are bubbled into the electrolyte through the porous carbon electrodes.

Thus the overall reaction involves the combination of hydrogen gas and oxygen gas to form water. The cell runs continuously until the reactant's supply is exhausted. This type of cell operates efficiently in the temperature range 343 K to 413 K and provides a potential of about 0.9 V. Is a type of AFC which employs a solid polymer electrolyte instead of aqueous potassium hydroxide (KOH) and it is superior to aqueous AFC.

High-temperature fuel cells [ ] SOFC [ ]. Main article: (SOFCs) use a solid material, most commonly a ceramic material called (YSZ), as the. Because SOFCs are made entirely of solid materials, they are not limited to the flat plane configuration of other types of fuel cells and are often designed as rolled tubes. They require high (800–1000 °C) and can be run on a variety of fuels including natural gas. SOFCs are unique since in those, negatively charged oxygen travel from the (positive side of the fuel cell) to the (negative side of the fuel cell) instead of positively charged hydrogen ions travelling from the anode to the cathode, as is the case in all other types of fuel cells. Oxygen gas is fed through the cathode, where it absorbs electrons to create oxygen ions.

The oxygen ions then travel through the electrolyte to react with hydrogen gas at the anode. The reaction at the anode produces electricity and water as by-products. Carbon dioxide may also be a by-product depending on the fuel, but the carbon emissions from an SOFC system are less than those from a fossil fuel combustion plant.

The chemical reactions for the SOFC system can be expressed as follows: Anode Reaction: 2H 2 + 2O 2− → 2H 2O + 4e − Cathode Reaction: O 2 + 4e − → 2O 2− Overall Cell Reaction: 2H 2 + O 2 → 2H 2O SOFC systems can run on fuels other than pure hydrogen gas. However, since hydrogen is necessary for the reactions listed above, the fuel selected must contain hydrogen atoms. For the fuel cell to operate, the fuel must be converted into pure hydrogen gas.

SOFCs are capable of internally light hydrocarbons such as (natural gas), propane and butane. These fuel cells are at an early stage of development. Challenges exist in SOFC systems due to their high operating temperatures. One such challenge is the potential for carbon dust to build up on the anode, which slows down the internal reforming process. Research to address this 'carbon coking' issue at the University of Pennsylvania has shown that the use of copper-based (heat-resistant materials made of ceramic and metal) can reduce coking and the loss of performance. Another disadvantage of SOFC systems is slow start-up time, making SOFCs less useful for mobile applications.

Despite these disadvantages, a high operating temperature provides an advantage by removing the need for a precious metal catalyst like platinum, thereby reducing cost. Additionally, waste heat from SOFC systems may be captured and reused, increasing the theoretical overall efficiency to as high as 80%–85%. The high operating temperature is largely due to the physical properties of the YSZ electrolyte. As temperature decreases, so does the of YSZ. Therefore, to obtain optimum performance of the fuel cell, a high operating temperature is required. According to their website,, a UK SOFC fuel cell manufacturer, has developed a method of reducing the operating temperature of their SOFC system to 500–600 degrees Celsius. They replaced the commonly used YSZ electrolyte with a CGO (cerium gadolinium oxide) electrolyte.

The lower operating temperature allows them to use stainless steel instead of ceramic as the cell substrate, which reduces cost and start-up time of the system. Main article: (MCFCs) require a high operating temperature, 650 °C (1,200 °F), similar to. MCFCs use lithium potassium carbonate salt as an electrolyte, and this salt liquefies at high temperatures, allowing for the movement of charge within the cell – in this case, negative carbonate ions. Like SOFCs, MCFCs are capable of converting fossil fuel to a hydrogen-rich gas in the anode, eliminating the need to produce hydrogen externally. The reforming process creates CO 2 emissions. MCFC-compatible fuels include natural gas, biogas and gas produced from coal. The hydrogen in the gas reacts with carbonate ions from the electrolyte to produce water, carbon dioxide, electrons and small amounts of other chemicals.

The electrons travel through an external circuit creating electricity and return to the cathode. There, oxygen from the air and carbon dioxide recycled from the anode react with the electrons to form carbonate ions that replenish the electrolyte, completing the circuit. The chemical reactions for an MCFC system can be expressed as follows: Anode Reaction: CO 3 2− + H 2 → H 2O + CO 2 + 2e − Cathode Reaction: CO 2 + ½O 2 + 2e − → CO 3 2− Overall Cell Reaction: H 2 + ½O 2 → H 2O As with SOFCs, MCFC disadvantages include slow start-up times because of their high operating temperature. This makes MCFC systems not suitable for mobile applications, and this technology will most likely be used for stationary fuel cell purposes. The main challenge of MCFC technology is the cells' short life span.

The high-temperature and carbonate electrolyte lead to corrosion of the anode and cathode. These factors accelerate the degradation of MCFC components, decreasing the durability and cell life. Researchers are addressing this problem by exploring corrosion-resistant materials for components as well as fuel cell designs that may increase cell life without decreasing performance. MCFCs hold several advantages over other fuel cell technologies, including their resistance to impurities. They are not prone to 'carbon coking', which refers to carbon build-up on the anode that results in reduced performance by slowing down the internal fuel process. Therefore, carbon-rich fuels like gases made from coal are compatible with the system. The Department of Energy claims that coal, itself, might even be a fuel option in the future, assuming the system can be made resistant to impurities such as sulfur and particulates that result from converting coal into hydrogen.

MCFCs also have relatively high efficiencies. They can reach a fuel-to-electricity efficiency of 50%, considerably higher than the 37–42% efficiency of a phosphoric acid fuel cell plant. Efficiencies can be as high as 65% when the fuel cell is paired with a turbine, and 85% if heat is captured and used in a (CHP) system. FuelCell Energy, a Connecticut-based fuel cell manufacturer, develops and sells MCFC fuel cells.

The company says that their MCFC products range from 300 kW to 2.8 MW systems that achieve 47% electrical efficiency and can utilize CHP technology to obtain higher overall efficiencies. One product, the DFC-ERG, is combined with a gas turbine and, according to the company, it achieves an electrical efficiency of 65%. Electric storage fuel cell [ ] The electric storage fuel cell is a conventional battery chargeable by electric power input, using the conventional electro-chemical effect.

However, the battery further includes hydrogen (and oxygen) inputs for alternatively charging the battery chemically. Comparison of fuel cell types [ ] Fuel cell name Electrolyte Qualified (W) Working temperature (°C) (cell) Efficiency (system) Status Cost (USD/W) solution 0! >-20 (50% P peak @ 0 °C) Aqueous alkaline solution 39! 90–120 Research Polymer membrane (ionomer) 100! 1 W – 500 kW 125! 50–100 (Nafion) 120–200 (PBI) 60%! 30–50% Commercial / Research 50–100 Liquid electrolytes with shuttle and polymer membrane (Ionomer) 1000!

1 kW – 10 MW Research Molten (H 3PO 4) 999999! With fuel cell propulsion of the in dry dock Power [ ] Stationary fuel cells are used for commercial, industrial and residential primary and backup power generation. Fuel cells are very useful as power sources in remote locations, such as spacecraft, remote weather stations, large parks, communications centers, rural locations including research stations, and in certain military applications. A fuel cell system running on hydrogen can be compact and lightweight, and have no major moving parts. Because fuel cells have no moving parts and do not involve combustion, in ideal conditions they can achieve up to 99.9999% reliability.

This equates to less than one minute of downtime in a six-year period. Since fuel cell electrolyzer systems do not store fuel in themselves, but rather rely on external storage units, they can be successfully applied in large-scale energy storage, rural areas being one example. There are many different types of stationary fuel cells so efficiencies vary, but most are between 40% and 60% energy efficient. However, when the fuel cell's waste heat is used to heat a building in a cogeneration system this efficiency can increase to 85%. This is significantly more efficient than traditional coal power plants, which are only about one third energy efficient. Assuming production at scale, fuel cells could save 20–40% on energy costs when used in cogeneration systems. Fuel cells are also much cleaner than traditional power generation; a fuel cell power plant using natural gas as a hydrogen source would create less than one ounce of pollution (other than CO 2) for every 1,000 kWh produced, compared to 25 pounds of pollutants generated by conventional combustion systems.

Fuel Cells also produce 97% less nitrogen oxide emissions than conventional coal-fired power plants. One such pilot program is operating on in Washington State.

There the Stuart Island Energy Initiative has built a complete, closed-loop system: Solar panels power an electrolyzer, which makes hydrogen. The hydrogen is stored in a 500-U.S.-gallon (1,900 L) tank at 200 pounds per square inch (1,400 kPa), and runs a ReliOn fuel cell to provide full electric back-up to the off-the-grid residence. Another closed system loop was unveiled in late 2011 in Hempstead, NY. Fuel cells can be used with low-quality gas from landfills or waste-water treatment plants to generate power and lower. A 2.8 MW fuel cell plant in California is said to be the largest of the type.

Cogeneration [ ] Combined heat and power (CHP) fuel cell systems, including (MicroCHP) systems are used to generate both electricity and heat for homes (see ), office building and factories. The system generates constant electric power (selling excess power back to the grid when it is not consumed), and at the same time produces hot air and water from the. As the result CHP systems have the potential to save primary energy as they can make use of waste heat which is generally rejected by thermal energy conversion systems.

A typical capacity range of is 1–3 kW el / 4–8 kW th. CHP systems linked to use their waste heat for. The waste heat from fuel cells can be diverted during the summer directly into the ground providing further cooling while the waste heat during winter can be pumped directly into the building. The University of Minnesota owns the patent rights to this type of system Co-generation systems can reach 85% efficiency (40–60% electric + remainder as thermal). Phosphoric-acid fuel cells (PAFC) comprise the largest segment of existing CHP products worldwide and can provide combined efficiencies close to 90%. Molten Carbonate (MCFC) and Solid Oxide Fuel Cells (SOFC) are also used for combined heat and power generation and have electrical energy efficiences around 60%. Disadvantages of co-generation systems include slow ramping up and down rates, high cost and short lifetime.

Also their need to have a hot water storage tank to smooth out the thermal heat production was a serious disadvantage in the domestic market place where space in domestic properties is at a great premium. Delta-ee consultants stated in 2013 that with 64% of global sales the fuel cell micro-combined heat and power passed the conventional systems in sales in 2012. The Japanese ENE FARM project will pass 100,000 FC mCHP systems in 2014, 34.213 PEMFC and 2.224 SOFC were installed in the period 2012-2014, 30,000 units on and 6,000 on. Fuel cell electric vehicles (FCEVs) [ ].

Fuel cell vehicle Automobiles [ ] As of 2015, two have been introduced for commercial lease and sale in limited quantities: the and the. Additional demonstration models include the, and.

As of June 2011 demonstration FCEVs had driven more than 4,800,000 km (3,000,000 mi), with more than 27,000 refuelings. Demonstration fuel cell vehicles have been produced with 'a driving range of more than 400 km (250 mi) between refueling'.

They can be refueled in less than 5 minutes. Department of Energy's Fuel Cell Technology Program claims that, as of 2011, fuel cells achieved 53–59% efficiency at one-quarter power and 42–53% vehicle efficiency at full power, and a durability of over 120,000 km (75,000 mi) with less than 10% degradation. In a Well-to-Wheels simulation analysis that 'did not address the economics and market constraints', General Motors and its partners estimated that per mile traveled, a fuel cell electric vehicle running on compressed gaseous hydrogen produced from natural gas could use about 40% less energy and emit 45% less greenhouse gasses than an internal combustion vehicle. A lead engineer from the Department of Energy whose team is testing fuel cell cars said in 2011 that the potential appeal is that 'these are full-function vehicles with no limitations on range or refueling rate so they are a direct replacement for any vehicle. For instance, if you drive a full sized SUV and pull a boat up into the mountains, you can do that with this technology and you can't with current battery-only vehicles, which are more geared toward city driving.' In 2014, Toyota introduced its first fuel cell vehicle in Japan, the Mirai, at a price of less than US$100,000, although former European Parliament President estimates that Toyota will initially lose about $100,000 on each Mirai sold. Hyundai introduced the limited production.

Other manufacturers that announced intentions to sell fuel cell electric vehicles commercially by 2016 included General Motors, Honda, Mercedes-Benz, and Nissan, but by 2017, most of the automobile companies developing hydrogen cars had switched their focus to battery electric vehicles. Criticism [ ] Some experts believe that hydrogen fuel cell cars will never become economically competitive with other technologies or that it will take decades for them to become profitable. Elon Musk stated in 2015 that fuel cells for use in cars will never be commercially viable because of the inefficiency of producing, transporting and storing hydrogen and the flammability of the gas, among other reasons. Professor Jeremy P. Meyers estimated in 2008 that cost reductions over a production ramp-up period will take about 20 years after fuel-cell cars are introduced before they will be able to compete commercially with current market technologies, including gasoline internal combustion engines. In 2011, the chairman and CEO of,, stated that while the cost of hydrogen fuel cell cars is decreasing: 'The car is still too expensive and probably won't be practical until the 2020-plus period, I don't know.' In 2012, Lux Research, Inc.

Issued a report that stated: 'The dream of a hydrogen economy. Is no nearer'.

It concluded that 'Capital cost. Will limit adoption to a mere 5.9 GW' by 2030, providing 'a nearly insurmountable barrier to adoption, except in niche applications'. The analysis concluded that, by 2030, PEM stationary market will reach $1 billion, while the vehicle market, including forklifts, will reach a total of $2 billion. Other analyses cite the lack of an extensive in the U.S. As an ongoing challenge to Fuel Cell Electric Vehicle commercialization. In 2006, a study for the IEEE showed that for hydrogen produced via electrolysis of water: 'Only about 25% of the power generated from wind, water, or sun is converted to practical use.'

The study further noted that 'Electricity obtained from hydrogen fuel cells appears to be four times as expensive as electricity drawn from the electrical transmission grid. Because of the high energy losses [hydrogen] cannot compete with electricity.' Furthermore, the study found: 'Natural gas reforming is not a sustainable solution'. 'The large amount of energy required to isolate hydrogen from natural compounds (water, natural gas, biomass), package the light gas by compression or liquefaction, transfer the energy carrier to the user, plus the energy lost when it is converted to useful electricity with fuel cells, leaves around 25% for practical use.' , the author of (2005), devoted two articles in 2014 to updating his critique of the use of fuel cells in cars. He stated that FCVs still had not overcome the following issues: high cost of the vehicles, high fueling cost, and a lack of fuel-delivery infrastructure. 'It would take several miracles to overcome all of those problems simultaneously in the coming decades.'

Most importantly, he said, 'FCVs aren't green' because of escaping methane during natural gas extraction and when hydrogen is produced, as 95% of it is, using the steam reforming process. He concluded that renewable energy cannot economically be used to make hydrogen for an FCV fleet 'either now or in the future.' 's analyst reached similar conclusions in 2014.

In 2015, Clean Technica listed some of the disadvantages of hydrogen fuel cell vehicles. Another Clean Technica writer concluded, 'while hydrogen may have a part to play in the world of energy storage (especially seasonal storage), it looks like a dead end when it comes to mainstream vehicles.'

The world's first certified fuel cell boat (), in /Germany The world's first fuel-cell boat used an AFC system with 6.5 kW net output. Iceland has committed to converting its vast fishing fleet to use fuel cells to provide auxiliary power by 2015 and, eventually, to provide primary power in its boats.

Amsterdam recently introduced its first fuel cell-powered boat that ferries people around the city's canals. Submarines [ ] The of the German and Italian navies use fuel cells to remain submerged for weeks without the need to surface. The U212A is a non-nuclear submarine developed by German naval shipyard Howaldtswerke Deutsche Werft. The system consists of nine PEM fuel cells, providing between 30 kW and 50 kW each. The ship is silent, giving it an advantage in the detection of other submarines.

A naval paper has theorized about the possibility of a nuclear-fuel cell hybrid whereby the fuel cell is used when silent operations are required and then replenished from the Nuclear reactor (and water). Portable power systems [ ] Portable power systems that use fuel cells can be used in the leisure sector (i.e.

RVs, cabins, marine), the industrial sector (i.e. Power for remote locations including gas/oil wellsites, communication towers, security, weather stations), and in the military sector. SFC Energy is a German manufacturer of for a variety of portable power systems. Ensol Systems Inc.

Is an integrator of portable power systems, using the SFC Energy DMFC. Other applications [ ] • Providing power for or • • are a type of fuel cell system, which may include lighting, generators and other apparatus, to provide backup resources in a crisis or when regular systems fail. They find uses in a wide variety of settings from residential homes to hospitals, scientific laboratories,, • telecommunication equipment and modern naval ships. • An ( UPS) provides emergency power and, depending on the topology, provide line regulation as well to connected equipment by supplying power from a separate source when utility power is not available.

Unlike a standby generator, it can provide instant protection from a momentary power interruption. • • •, pairing the fuel cell with either an ICE or a battery. • for applications where charging may not be readily available. • Portable charging docks for small electronics (e.g. A belt clip that charges a cell phone or ). •, laptops and tablets. • Small heating appliances •, achieved by exhausting the oxygen and automatically maintaining oxygen exhaustion in a shipping container, containing, for example, fresh fish.

•, where the amount of voltage generated by a fuel cell is used to determine the concentration of fuel (alcohol) in the sample. •, electrochemical sensor. Fueling stations [ ]. In 2013, reported that there were '10 hydrogen stations available to the public in the entire United States: one in, eight in Southern California and the one in '. As of December 2016, there were 31 publicly accessible in the US, 28 of which were located in California. A public hydrogen refueling station in Iceland operated from 2003 to 2007.

It served three buses in the public transport net of. The station produced its own hydrogen with an electrolyzing unit. The 14 stations in Germany were planned to be expanded to 50 by 2015 through its Now GMBH. By May 2017, there were 91 hydrogen fueling stations in Japan. As of 2016, planned to build a network of hydrogen stations between the major cities, starting in 2017. Markets and economics [ ]. Main articles: and In 2012, fuel cell industry revenues exceeded $1 billion market value worldwide, with Asian pacific countries shipping more than 3/4 of the fuel cell systems worldwide.

However, as of January 2014, no public company in the industry had yet become profitable. There were 140,000 fuel cell stacks shipped globally in 2010, up from 11,000 shipments in 2007, and from 2011 to 2012 worldwide fuel cell shipments had an annual growth rate of 85%.

Expanded its manufacturing facilities in 2011. Approximately 50% of fuel cell shipments in 2010 were stationary fuel cells, up from about a third in 2009, and the four dominant producers in the Fuel Cell Industry were the United States, Germany, Japan and South Korea. The Department of Energy Solid State Energy Conversion Alliance found that, as of January 2011, stationary fuel cells generated power at approximately $724 to $775 per kilowatt installed. In 2011, Bloom Energy, a major fuel cell supplier, said that its fuel cells generated power at 9–11 cents per kilowatt-hour, including the price of fuel, maintenance, and hardware. Industry groups predict that there are sufficient platinum resources for future demand, and in 2007, research at suggested that platinum could be replaced by a gold- coating, which may be less susceptible to poisoning and thereby improve fuel cell lifetime.

Another method would use iron and sulphur instead of platinum. This would lower the cost of a fuel cell (as the platinum in a regular fuel cell costs around US$1,500, and the same amount of iron costs only around US$1.50). The concept was being developed by a coalition of the and the. Cathodes are immune to monoxide poisoning.

In 2016, 'decided to drop fuel cell-related business projects, as the outlook of the market isn't good'. Research and development [ ] • 2005: researchers used to raise the operating temperature of PEM fuel cells from below 100 °C to over 125 °C, claiming this will require less carbon-monoxide purification of the hydrogen fuel.

• 2008:, used as a. • 2009: Researchers at the, in Ohio, showed that arrays of vertically grown could be used as the in fuel cells. The same year, a nickel bisdiphosphine-based catalyst for fuel cells was demonstrated. • 2013: British firm developed a fuel cell that it said can run for 10,000 hours in simulated driving conditions. It asserted that the cost of fuel cell construction can be reduced to $40/kW (roughly $9,000 for 300 HP).

• 2014: Researchers in developed a new method for regeneration of hydrogen sulfide contaminated PEFCs. They recovered 95–100% of the original performance of a hydrogen sulfide contaminated PEFC. They were successful in rejuvenating a SO 2 contaminated PEFC too. This regeneration method is applicable to multiple cell stacks. See also [ ].

Hello everyone this is my first Instructable but I am excited and eager to share with all of the great people on here how to design and build a remote control airplane. Aviation has been a passion of mine all my life, and has led me to pursue my aerospace engineering degree. As a engineering student I know that I still have much to learn, but that there also a lot that I can teach since I have been flying, building, and designing airplanes for about 10 years. To design any airplane the first task is always to define what its mission will be.

This will be the guiding force behind all research that is conducted and all design choices that will be made. For me I choose to design a fighter styled after the great piston engine fighters of WW2. Therefore my research began with finding various parent aircraft to look at for design inspiration. These included the P-51 Mustang, BF-109, P-40, Spitfire as well as several WW2 fighters turned racers. These aircraft were all designed in different environments worlds apart and yet were effective in their mission through unique solutions.

This Instructable will go through the design process as applicable to many different airplane configurations, and the trade offs associated with different designs. I will then show how I built my airplane showcasing the many different wood working and fiberglassing techniques required to build a similar airplane. From this Instructable you will see all of the techniques used and the challenges overcome to build a beautiful airplane.

This Instructable should therefore be considered a reference of various building techniques, that will allow a moderately experienced RC enthusiast to design and construct a custom RC airplane. I hope that this will provide the knowledge and serve as a guide to anyone designing and building a custom airplane. 9-13-2015 UPDATE I have finally had to opportunity and the nerves to fly the airplane. I have linked a video of the maiden flight in the last step, and am please to say she flew beautifully. Thank all of you for your support and kind reviews of this instructable. In Regards to the Epilog VI Contest This Iinstructable is entered in the Epilog VI contest to win a laser cutter.

If I were to win a laser cutter it would provide me with the ability to expand my craft and share it with others. Designing and building has always been a passion of mine, and a laser cutter would allow me to turn my ideas into reality very quickly. A laser cutter would be my most prize piece of equipment in my toolbox. In Regard to the Remote Control Contest The macbook and the GoPro would go a long way in ensure this airplane will reach its full potential. Just think how awesome it would be to have a GoPro mounted on the wing of this airplane cruising around at 80mph. It would complete this airplane. Step 1: Mission Planning.

• Configuration • Conventional- Wing produces the entire lift for the airplane plus the lift required to balance out the negative lift being produced by the tail. Efficient because the larger main wing is more efficient than the smaller tail at producing lift • Canard- Both the wing and the canard produce the lift for the airplane. The canard will often stall before the main wing, and will therefore require a larger wing than a conventional wing since the wing will not be able to reach its highest lift coefficient before the canard stall. • Delta-efficient for high speed flight. The wing can reach higher lift coefficients since a vortex will roll over the leading edge, this occurs at high angles of attack.

• Flying wing- The tail is integrated into the wing. This is achieved by means of using reflexed airfoils to counter the airfoils nose down pitching moment. Yaw control can be obtained through use of a drag rudder or through wing tip rudders if the wing has sufficient sweep.

Flying wings are very sensitive to the location of the center of gravity. • Wing- All wing characteristics are considered with no wing twist. Wing twist will change the lift distribution across the wing, and also the stall characteristics • Rectangular- Easiest to build since it will have the same shape along the entire span. This wing shape is very forgiving and will stall from the root outward.

• Tapered- A slightly tapered wing will be more aerodynamically efficient than a rectangular wing. It may be more challenging to build based on the desired taper.

This wing will stall from the midsection and move in towards the root and out to the tip. • Elliptical- Planform of minimum induced drag(drag from lift). Fabrication is difficult since all ribs are different sizes and do not uniformly change in size. Complex curves will develop on the aircraft skin that will be difficult to cover. Just think how few commercial and military airplanes have use this planform. This wing will stall violently all at once.

• Double or triple tapered wing- Used to increase the efficiency of a tapered wing by making its lift distribution closer to that of an elliptical wing. Stalls similar to an elliptical wing. • Tail • T-Tail- Raises the tail above the downwash of the wing, and away from possible ground hazards.

This type of tail requires a reinforced vertical stabilizer since it must take the loads from the horizontal stabilizer as well as the rudder • Cruciform tail- Raises the tail partially above the base of the vertical stabilizer for many of the benefits of the T-tail but with reduced structural loads. • H Tail- Excellent for twin boom configurations or for when increased vertical stabilizer area is required.

• V Tail/ Inverted V- Less efficient than a conventional tail since lifting forces are pointing in a direction other than the desired on increasing drag during maneuvers. • Conventional tail- The standard for most airplanes. Efficient and light this is a good choice in most applications Step 5: Construction Techniques. • Composite- constructed from materials such as carbon fiber, Kevlar, or fiberglass this allows for very strong and very light airplanes to be fabricate. However the time and cost to produce a one of a kind airplane can be restrictive.

Furthermore this technique will require specialized tools and processes for constructing molds and parts. Radio interference even with modern 2.4 ghz transmitters can be in issue for aircraft utilizing carbon as a primary building material. • Traditional wooden- Requires only basic tools for a basic airplane. Material cost can be reduced along with time since the material is easy to work with and commonly available. Additionally since the required techniques have been used for many years an abundance of information exists on the subject from build to covering the model. • Foam- Fast to build and durable, however the airplanes are generally heavier since the foam requires substantial reinforcements to to be able to with stand the flight loads of a substantially sized airplane.

Step 6: Sizing. The sizing of the airplane depends on the objective of the airplane design. This can include construction techniques, transportation to and from the flying site, flight capabilities such as range, ability to handle wind, runways (water, grass, paved, hand launched.).

These are just among the factors that will set the size of the aircraft. From this point sizing becomes an iterative process of working with the components for which the weights are known, ie electronics, and then working to take a first guess of what the airframe will weigh. This can be difficult to do so it is best to itemize the components and then work to build up an entire airplane. For example the weight of the wing could be approximated by approximating the weight of the material that will be used to make the spar, then guessing how many sheets of balsa it will take to build the wing ribs, and cover the wings. Additionally components such as the leading edge and possibly a drag spar must be considered.

It is best to have some of the materials on hand at this stage because it will allow for accurate measurements of weights. Step 7: Stability. To have a successful airplane it is paramount to calculate a few stability terms to ensure that the airplane will be stable and thus flyable. They are a fast to check and are worth calculating rather than just eyeballing the design. I have provided the values I calculated for the airplane I designed. • The first term is the to be found is the mean aerodynamic cord (MAC). It can be found geometrically by adding the root cord in front of and behind the tip, and also by adding the tip cord infront of and behind the root.

These points are then connected to make an X. The cord length at the intersection of the X is the MAC. • The aerodynamic center of the wing section is simply 0.25 times the MAC. • The aerodynamic center must be found for both the wing and tail surfaces. • The neutral point of the aircraft must be found next. It is used to determine the location of the center of gravity of the airplane, and is calculated with the aerodynamic center.

• Next the static margin of the airplane must be determined. The static margin is a measure of stability of the airplane, the higher it is the more stable the airplane, and the lower the less stable. However if the airplane is too stable it will not be maneuverable and thus not controlable, and if it is too unstable then it will be to maneuverable to be controllable by a human. Therefore for most aircraft it ranges between 5 and 15 percent. • Lastly the tail volume coefficients should be calculated. These terms are used to compare the effectiveness of the tail in reference to the size of the wing and the distance the tail is from the wing. • The tail volume for the vertical tail generally ranges between 0.35 and 0.8 • The tail volume of the horizontal tail generally ranges between 0.02 and 0.05 Step 8: Electronics.

• Transmitter- The controller held by the pilot and used to broadcast the radio signals to the receiver on the airplane. • Receiver- Receives the signals sent from the transmitter and relays them to the servos and esc. • Electronic Speed Controller(ESC)- Controls the power going to an electric motor(throttle). • BEC- Reduces the voltage from the flight pack to a safe level for the receiver and other radio equipment to operate on.

• Flight pack- The main battery pack used to power the motor and possibly the BEC • Receiver Pack- A battery pack separate from the flight pack that is used only to power the receiver and servos. It adds a level of safety rather than using a BEC built into a ESC which could fail if the ESC fails. • Motor • Brushless- most commonly used on remote control airplanes.

These motors has increased efficiency over brushed motors do to reduced friction and increased electrical efficiency. • Brushed- Older type of motor, commonly used on cheaper beginner airplanes and in very small applications such as micro helicopters • Servos • Analog- Cheaper and sufficient for all but the most extreme cases • Digital- By using a faster frame rate these servos are able to provide increased speed, torque, and accuracy. However this comes at the price of a higher current draw, and the BEC or receiver pack must be carefully sized for the number and size of servos being used Step 9: Weight Estimation. This is a critical step in the planning of your build.

It will tell you if the design and sizing is feasible or if the design needs to be revised. I recommend making a spread sheet to aid in this step since it will allow the design to be iterated quickly(My spreadsheet can be found on the my design process step). First begin with components that are fixed in weight for the airplane such as servos and receivers. Then begin estimating the weight of either the entire airplane and then try to break that over down into the weight of the wing, tail, fuselage, gear, and power system. At this stage the mission of the airplane will determine how much power is required and therefore the weight of the power system. If at this point the airplanes weight has resulted in an excessive wing area then it is time to reevaluate the design, sizing, and fabrication techniques.

Additionally at this stage it is important to verify that the take off speed will be acceptable. To do this use the lift equation below and either enter Cl max for the airfoil or a conservative value of Cl which would be in the ballpark of 1.1. L=1/2*rho*v^2*s*Cl Step 10: Power System Design. Designing a light and efficient power system is a must for any aircraft to take to the skies. For an electric powered model the best setup that is available is a brushless motor with a lipo battery.

However, there are a thousand possible combinations leaving us with the question of where to start. • Determine the level of performance that you desire out of the airplane. From here there are general guidelines for how many watts of power per pound are required. Check out the link below for the most common rule of thumbs • • Once the power required is found the next step is looking for motors that are capable of putting out that much power. While comparing it is important to look at the current and power limit to ensure that you will stay within the Spec.

• Brushless motors speed are measured by kv. Kv stands for rpm per volt, so a high kv motor will spin faster than a low kv motor. High kv motors are often limited to smaller models and ducted fans.

Lower kv motors will produce higher torque but will spin slower, to compensate these often run a a higher voltage. As a general statement to produce the same power a high kv motor will spin a smaller prop faster while pulling a higher current(higher current=lower battery life) compared to a low kv motor that will spin a larger prop much slower and with a much lower current draw but at a higher voltage. The final motor setup is a trade off between efficiency and battery size.

• I highly recommend using a motor calculator to find the performance of the motor prior to buying it. Ecalc is a easy to use subscription web app that contains many motors and propellers and allows you to essentially try different combinations before ever buying one. This will also tell you the current draw of the setup you have chosen as well as thrust measurements. • • An ESC must be selected that can handle the desired voltage and current of the motor. Additionally if the airplanes electrics will be powered off of the BEC built into the ESC, then it is important to ensure that it is capable of providing sufficient current for all of the servos.

Be sure to oversize the ESC by at least 20% to provide a safety margin for operation. • Lastly the battery must be selected. Selecting too small of a battery for the application is dangerous and will result in damaging the batteries cells on the of best days. Lipo batteries come rated by the number of cells in series, ie higher 'S' count the higher the voltage. The capacity of the battery is rated in mah, and the discharge rate in C.

To find the max current able to be extracted from the battery take the capacity in mah divide by 1000 and then multiply by the C rating. Be sure to add a margin of safety in the discharge rate because some batteries are 'overrated' and as cells age performance is lost. Lastly never over discharge a lipo battery and always 'break in' a new battery by being gentle during the first 10 flights. Step 11: Tools.

From the outset I knew that I wanted to design a warbird that was different from all those that came before it to make it one of a kind. I also knew that I wanted to make it fully sheeted with balsa and fiberglass, because I love the look of wood. Additionally, I wanted to include retractable landing gear to not only reduce drag, but also to make the airplane look more complete in the air.

From the outset these requirements made it the hardest but most rewarding airplane that I have ever designed and fabricated. I encourage anyone who has been flying to try to design and build at least one airplane of your own, whether it is simple or complex it is a great learning experience. Below is the preliminary steps I took to design the airplane. • Sketch the airplane- First I drew my preliminary design sketch on graph paper without any dimensions. This allows you to scale the sketch to any size that you want and will allow the wing area to be found for different wingspans.

• Weight estimation- Once the preliminary wing area was found I then started making a weight build up of all of the major components. This stage was very much a reality check. My initial plan was to have a 45 inch wingspan however with the components, and the weight of the wing sheeting I quickly found that the airplane would have too high of a wingloading. Therefore I re-scaled my preliminary drawing to have a 60 inch wingspan (Wing area=630in^2) not counting the wingtips.

This proved to be a much more sound design and have attached the preliminary weight build up spreadsheet to this step. As you can see I measured the weight of the materials that I was using with the following averages listing below. These allowed me to estimate the weight of the various components. For example the weight of the balsa sheeting was found by multiplying the wing area times 2 (for the top and bottom of the wing) by the weight of balsa per square foot. This same method was used on the rudder and elevator.

For the fuselage I found the side area and added it to the top area of the fuselage, then multipled that by 2 and then by the weight per square foot. • Basswood.24oz/in^3 • Balsa 1/32'.42oz/ft^2 • Balsa 1/16'.85oz/ft^2 • Stability-After I estimated the weight I calculated the stability criteria as describe in the stability section to validate that my airplane would be stable and that they tails were adequately sized • Airfoil selection- Choosing the correct airfoil for the airplane being built will ensure the airplane will fly exactly how you would hope it would. Below is a link to a very simple to use airfoil analysis tool. For the planform that I have designed tip stalling could be an issue since the tip chord is half of the root chord. If at all possible bad tip stalling characteristics should be designed out of the airplane, since tip stalls will result in the wingtip dropping rapidly with no way to regain role control until airspeed is raised.

I have achieved this through the use of washout (twisting the wing tips down) and through careful selection of root and tip airfoils. At the root I have selected the S8036 it is 16 percent thick meaning that the wing thickness will be 16 percent of the chord. This will allow for a large spar for increased strength and also for landing gear to easily fit inside of the wing. For the wing tip the S8037 was selected. It is also 16 percent thick.

It stalls at a higher lift coefficient and also at a higher angle of attack than the S8036 at the same Reynolds number (Reynolds number is a fluid mechanics term used to compare specimens that in our case are different sizes. The higher the Reynolds number the larger the chord), this means that the root if at the same Reynolds number (same chord as tip) would stall first and thus the airplane would maintain role control. However since the root is twice the chord of the tip it will have twice the Reynolds number, and increasing Reynolds number tends to delay stall. Therefore I twisted the wing tips down so that they will stall after the root.

Once I had the design completed I wanted to validate the design before putting the time to build one from balsa. To to this I scaled down my plans to half scale.

Using this new plan I made a glider version of the airplane out of foamcore. I began by cutting out the side view of the fuselage and then elevator. I then cut a slot into the fuselage for the tail to slide in.

Note that the tail is mounting with the leading edge below the trailing edge ie. At a negative angle of attack. For a conventional configuration airplane with a wing in front of the tail this is critical for stability. To hold the two wing halves together I glued some small pieces of wire into the wing and slid them into the other wing half.

Then i put the airplane together with packaging tape and added a ball of clay to the nose to get the CG at the desired location. To test the airplane I threw it around outside beginning with simple tosses to see how it flew and trimmed. Then i began testing to see how it would recover from stalls, for stability the airplane should nose down and pickup airspeed. The scale model flew well even through it did have a high wing loading, and only a flat plate for an airfoil. With this in mind i proceeded on to constructing the full size model. Step 14: Parts Listing.

I have tried very hard to present this Instructable in a clear and logical order. However, you may notice that some pictures that I reference may be further along than described to that point.

This has been done to allow similar construction processes to be grouped together since when building an airplane it is very difficult to build the entire wing, and then build the entire fuselage and have them magically bolt together. Therefore the steps my be slightly reordered to maintain a nice reading flow.

So be patient and keep reading, the later steps will cover anything that may seem missing including how to finish the surfaces with fiberglass. Step 16: Wing Structural Design. The wing must be designed to be able to support the weight of the airplane plus the additional forces caused by maneuvering. This is generally accomplished through the use of a central spar which is made up of spar caps, that are the upper and lower flanges on the beam, and the shear web, the thin sheeting that connects the spar caps. Although the shear web is thin it will greatly increase the wings bending strength by unifying the structure.

Also very common are smaller drag spars in front of the trailing edge. These can take bending loads as well as serving to increase the torsional rigidity of the wing. Lastly the leading edge may be sheeted back to the spar creating closed cross section beam, this is called a D-tube and it is designed to very efficiently take the torsional loads generated by the wing.

Shown are a few very common spar designs. • The top wing has a I-beam spar, with the shear web located in the center of the spar caps, it also has a sheeted leading edge called a D-tube. The D-tube is designed to increase the torsional rigidity of the wing, and can be added to any of the other spar designs, as well as extended to the trailing edge to create a fully sheeted wing. On this wing the trailing drag spar is simply a vertical support. It also has a simple top hinged control surface, which is easy to fabricate. • The second wing has a C-beam spar, with a stronger drag spar which is better able to handle the drag loads placed on it.

It has a centered hinge, this hinge reduces the gap and thus the drag as compared to a top hinge. • The third wing has a tube spar, these are usually made from carbon tubes, and are very convenient to build with, if the carbon tube is unidirectional/pultruded then wing twisting can be an issue, but this can be managed with the addition of a D-tube.

Furthermore the drag spar is a C-beam which would greatly increase the rigidity of the wing. The hinge is a rounded control surface with the pivot point in the center point of the circular leading edge to minimize the hinge gap and to have smooth edges.

• The fourth wing has a fully boxed spar with shear webbing on both the front and back of the spar. The hinge features the same control surface as the previously discussed wing, but has fairing on the top and bottom of the wings trailing edge to close the hinge line. All of these are common ways to built the spar and make the hinge line on a RC airplane. These are by no means the only ways to do it, and the various spar designs and hinge types can all be exchanged to create the desired wing. Step 17: Wing Structual Design Continued. For the airplane that I am building I chose to use a wooden C-beam spar with a solid leading edge and a simple vertical drag spar. The entire wing is sheeted in balsa for torsional rigidity and for aesthetics.

Wood was chosen over a composite tube because the airplane is designed with 2 degrees of dihedral and the joint in the center of a composite tube wing would difficult to make strong enough to withstand the bending load. The I-beam was also less favorable than the C-beam since it would be much more difficult to fabricated, since a slot would need to be made running the length of the spar for the shear web to be installed into.

This added complexity is not made up for by a noticeable increase in the strength to weight ratio of the spar. The box beam was not chosen because of the increased weight, however this would not have been more difficult to build and would also have been stronger. The simple vertical drag spar combined with the hinge fairing was selected since the entire wing is sheeted and would be strong enough without any additional supports. • Spar- The wing spar is designed to carry the bending load created from the lift being generated by the wing. It is not designed to support the twisting caused by aerodynamic forces on the wing, that load is instead carried by the wing skin.

This load sharing allows for a light and very efficient structure since each part is supporting the load that it is most efficient at handling.• The spar caps are made from ¼ x ½ x 24” pieces of basswood. Basswood was chosen for the since it is a hardwood with a very straight grain, furthermore it is very strong for its weight. Convenient sizes can be readily purchased from craft stores which was important due to my lack of sufficient tools to cut strips of a wood from this hard of a material. • The shear web is made from 1/32” thick basswood sheeting, and is glued between the upper and lower spar caps to join the structure.

Shear webbing is absolutely necessary in a wing since it dramatically increases the rigidity and strength of the wing for very little weight. • The trailing edge / drag spar is made from 1/16” thick balsa sheeting, it helps add to torsional rigidity while also unifying the wing ribs to allow the control surfaces to be mounted to the back of the ribs. Step 18: Designing Wig Ribs. Creating ribs for a tapered wing can be challenging. A few methods are prevalent the first is cutting out a template for the root airfoil and the tip airfoil.

These are then stacked at end of a pile of airfoil blanks and bolted together the whole stack is then sanded. This method is exceptionally good for creating straight wings. However the amount of taper that is achievable using this method is limited because of the angle that is created between the two templates grows with quickly with the difference between root and tip cord.

This large angle will make it difficult to assemble the wing later on due to the large amount of excess wood and sharp angles on the edges of the ribs that will need to be removed. Therefore the only method that I had available to me was to make my own templates for each rib and then cut and sand each rib until it was the perfect fit.

This is exceptionally challenging on this airplane since the root airfoil is not the same as the tip airfoil so all the airfoils in between those are a combination of those two. Additionally since the wing is fully sheeted the rib shape must be adjusted to compensate for the thickness of the sheeting.

Below I present the method that I used to create my ribs templates, it is done using Autodesk Autocad 2012 Student Addition which is my preferred CAD software for designing RC airplane plans in, since I learned it in high school and have used it through out college. The pictures in this step are all labeled with the step that they go along with. • To import an airfoil into autocad the fastest method that I have found has been to open the airfoil text file with excel so that it will organize the data(these files for many airfoils can be found on the UIUC airfoil database). Then insert a column between the x and y data and fill each box with a comma, and verify that the first point and the last point are in the same location so the the program creates a closed object. Then copy this data back into the txt file and save it. Once it is saved go back and highlight all of the data making sure not to include any headings.

Then in Autocad launch the “spline” command and paste when it asks you for the first point. Hit enter and until the command prompt finishes the command. Airfoil data is generally formatted such that the cord is 1 unit as such it is very easy to scale the airfoil to the appropriate size simply by using the desired cord as the scaling factor. • Draw the airfoils and align them as dictated by the planform. Note that the wing tip(the little airfoil) is set at 2 degree nose down in comparison to the wing root. The leading edge and spars must be carefully sized in the drawing since the end product will be the sheeting on the wing, therefor the the spars must be drawn narrower than they are.

It is preferable to make the spars and the leading edge taller than required to make the drawing go smoother. Also the spar notches are located such a way that the entire spar will fit in the rib while remain square.

• Here the airfoil sections are shown at each end before they are lofted together to form the intermediate airfoil sections. • The wing spar and the sub leading edge are lofted to allow them to be subtracted from the wing later on. • Now the airfoils are lofted creating the shape of the wing while also having the location of the spar and sub leading edge visible. • The spar and sub leading edge have been removed using “subtract” leaving the outer shape of the wing, minus the leading edge which is not part of the ribs. • The wing is then hollowed out using “solidedit” and then selecting “shell”.

The wing tip and root were then selected as the faces to remove, and what is left is the wing skin. Therefore the inner wall of the wing skin is the rib shape. • Now using the “section plane” button at each of the wing rib locations a cross-section of the wing will be generated.

• Then under “section plane” select generate section. With this command the cross sections at all of the stations already made can be displayed by generating a section for ever rib. To aid in aligning the wing ribs during construction I highly recomend drawing a horizontal line from the trailing edge of the wing through the leading edge. This will allow you to correctly align the wing if it is being build with twist and will also help in making the wing straight. • Again since these templates are actually the wing skin the inside of the innermost line is the correct one to cut on. • Now with the ribs all labeled using the 'text' command they are ready to be printed.

Around each page of ribs I have made a print box to allow for easy repeatable printing. The box will not print since it is in a separate layer that is turned off from printing but is still displayed on the screen. I will be printing out all of the smaller ribs on resume paper since it is a heavier stock it will make for a nicer template. The larger airfoils will be printed on regular paper and then reinforced before the ribs are cut Step 19: Wing Fabrication: Cutting Non-structural Wing Ribs. All of the non-structural wing ribs are made from 1/16' thick balsa wood with the grain running in the cordwise direction to provide rigidity from the leading edge to the trailing edge. I printed the templates that were made in CAD onto resume paper since it is thinker and produces a very nice template. I then put double sided tape on the back of the templates and cut them out, this ensures that double sided tape covers the entire backside and prevents having to cut the tape and wood at the same time with a razor.

Once the first wing rib is cut put double sided tape on to the back of it and then stick it on to another piece of 1/16' balsa and cut out another rib, this will yield both the right and left rib. With the ribs for both wings still stuck together and with the template still attached sand the ribs to the innermost line on the template. I recomend sanding across the grain or in other words through the template, or else the template will tend to roll up or bend instead of sanding. Sanding both the right and left wing together ensures a symmetric wing. With the rib sets all stacked together it is easy to see why sanding between the root and tip ribs would produce issues.

The steep angles made by the tip cord compared to the root cord would leave angles along all of the ribs with the worst being left at the leading edge and trailing edge. This would reduce the accuracy of the airfoil and also cause headaches when trying to build the wing since those angles would need to be sanded smooth across all of the ribs Step 20: Wing Fabrication: Landing Gear Ribs Stage 1. The ribs that support the landing gear must be very strong since they will be required to withstand the full weight of the airplane, and likely many times that weight if the airplane lands rough. As such balsa would not be able to support the loads experienced by these ribs, so instead this ribs are made from 1/32' thick basswood and 2oz fiberglass to make a composite plywood that is incredibly strong and much less brittle than craft ply wood.

The process that is being used to apply the fiberglass called a wet layup since the resin is being used to wet the fibers. These ribs will experience a large load in front of the spar however very little behind it, therefore to keep the airplane as light as possible the front of the rib will be much more heavily reinforced than the rear. Below is the first stage of building the reinforced ribs. • First cut the rib shape from from 1/32' basswood and sand the rib as done on the previous ribs. • Trace the wing rib shape onto 2 oz fiberglass leaving about 1/2' around the outside of the ribs as shown in the photos. It is important to have the fiberglass weave running from the leading edge to the trailing edge and from the bottom to the top of the rib.

This maximizes the strength of the part by allowing for continuous fibers along the length of the part. • Prepare a working surface by taping down a sheet of painter plastic to apply the fiberglass and resin on. • Next prepare the surfaces which will be in contact with the parts as the cure. Here wax paper is covered with packaging tape to create a very smooth and nonporous surface. Then apply release wax to the packaging tape with a paper towel according to the packaging instructions. As a personal preference, I use Megular's Mirror Glaze Mold Release Wax, it works very well with the Z-Poxy finishing resin that I use and once cured the parts very easily separate from any smooth surface where the wax was applied.

It also does not leave very much residue on the parts once separated. • Now that all the surfaces are prepared make sure that there is plenty of ventilation, and that extra gloves and squeegees are easily available.

I like to use either playing cards or the plastic from old clam shell packaging as a squeegee because they are either cheep or free and also disposable to avoid the harsh solvents required to clean a reusable squeegee • Mix the resin which you will be using to laminate the wood and fiberglass with. • Pour some resin onto the wood and use a squeegee to evenly spread it across the surface. Then remove any excess with the squeegee.

This will aid in the fiberglass cloth laminating to the wood. • Pour some resin onto the fiberglass cloth and use the squeegee fully coat the cloth. The cloth will change from white to a translucent color as it absorbs the resin. • Squeegee off all the excess resin from the fiberglass cloth, being sure to only run the squeegee with the grain of the cloth. • Now gently pick up the wetted piece of cloth, the squeegee may be needed to help peel it off of the working surface and place it on the rib blank.

• Squeegee the cloth again this will help to adhere the fiberglass to the wood, again you will see a change in color as the glass bonds to the wood. • Now pick up the rib and place it fiberglass down on the waxed surface.

• Repeat the wetting process to the rib and to the fiberglass cloth and apply to to the other side of the rib. • Once all the other ribs have been given similar treatment lay a second waxed sheet on top of the ribs. At this point you can use your hands or a dry squeegee to remove any air bubbles between the waxed surface and the ribs. • Place something flat on top of the ribs, in my case it was a piece of foam core. Then place as much weight as you can onto the ribs. This will help to adhere the the fiberglass to the sub-straight, as well as squeezing out any excess resin.

• Let the resin fully cure, per the manufactures specs. • Remove the weight and pull off the waxed surface. If the waxed sheet is not damaged it can be saved to use again. • Wipe down the fiberglass with rubbing alcohol to remove any wax residue.

• Excess fiberglass around the edges can often be first cut with scissors. • With gloves, a respirator, safety glasses and plenty of ventilation the remaining fiberglass can be sanded back to the size of the wooden rib. Additionally the entire surface of the rib should be roughed up so that more layers of resin will be able to adhere to the surface. Congratulations if you have made it this far, you have just completed your first wet lay up, but there are more required to finish this airplane. Step 21: Wing Fabrication: Landing Gear Ribs Stage 2.

The next stage of reinforcing the landing gear brackets is reinforcing the front of the rib from where it attaches to the wing spar forward to where it attaches to the sub leading edge. This is accomplished by adding more layers of wood and fiberglass to turn the rib into a very solid piece of fiberglass reinforced plywood. • Cut out the pieces of wood which will be laminated on. In my case I added a layer of wood with the grain running vertically and then a piece of wood with the grain running in the cord-wise direction on both sides of the rib. This makes the front 5 plys of wood thick with 6 layers of fiberglass. • Next cut out the plys of 2oz fiberglass that will be needed for the laminate sandwich.

• Prepare the working surface as before with painter plastic and if reusing the waxed sheet apply a new layer of wax to it for good measure. • Mix and prepare the resin. • Coat the leading edge of the rib with resin and squeegee off the excess.

• Coat the wood with the grain running vertically with resin and squeegee the excess. • Wet the fiberglass and apply to the to side of the wood with the vertical grain. • Apply the vertically grained piece of wood to the rib blank ensuring that there is resin on the wood block being added to ensure proper lamination.

• Apply the fiberglass to the block just added to the rib and squeegee off any excess resin. • Wet and apply the wooden block with the grain running in the cord-wise direction to the rib. • Apply a layer of fiberglass onto the to of the cord-wise grained block.

• Place the fiberglassed side down on the waxed sheet. • Repeat steps 5-11 to the other side of the rib and to all remaining ribs. • Apply waxed sheet onto the top of all of the ribs.

• Compress the laminate as done previously. • Allow the resin to cure and then removed from waxed sheet. • Clean surfaces with rubbing alcohol. • With the appropriate safety precautions remove the excess from the ribs. A coping saw can help to get close to the rough shape. It is also possible to carve the excess away with a very sharp razor.

Sand to the final shape and rough the surface to that it can be written on easily. • Using the rib templates determine the correct placement of the spar notches and cut them out using a razor saw, once cut a razor can be used to finely adjust the fit.

• Determine where the cross member must be placed to mount the landing gear on. Be sure to leave enough room for the landing gear to retract fully, as well as enough room in front of the spar to allow the wheels to not hit when retracting.

Also it is important to take into account if the wing had dihedral since the gear will then either have to not extend 90 degrees or it will need to be mounted at an angle in the wing, in my case it is mounted in the wing at an angle. • Once the location is determined a starter hole can be made with a small drill bit in my case 3/16' since the cross member running between ribs are 1/4x1/2'. • After the starter holes are drilled the rest will likely need to be done again with a very sharp razor. This will be time consuming but be patient since these must support the weight of the airplane and be carefully aligned so that the gear will retract into the wing and extend and be straight. The landing gear ribs are now complete.

Step 22: Wing Fabrication: Building the Center Wing Ribs. The center rib along with the rib on either side of it are reinforced to support the mounting bracket for the fuselage. These ribs are build using a similar technique to the landing gear ribs. They are made with 3 plys of basswood with the center ply having the grain running in the vertical direction.

The outer plys have the grain running in the chordwise direction. • Cut out the rib blanks out of 1/32' basswood with the grain running in the chordwise direction leaving them slightly over sized they will be sanded to final size in a later step. • Since basswood does not come in wide enough sheets to have the chord length fit with the grain running vertically through it, strips must be joint to create these sheets. Glue strips of 1/32' bass wood together to make a strip as long as the rib with the grain running vertically. • Cut out the 2oz fiberglass cloth with excess to cover the ribs. • Prepare for the wet lay up the same as was done for the landing gear ribs • Lay up the fiberglass on both sides of the rib blank and then place on the waxed sheet. • Next adhere the vertically grained core onto the the rib blank.

• Apply a ply of fiberglass to the layup stack. • Apply the other rib blank to the stack being careful to align the rib with the one of the bottom since there will not be much margin. • Use the same procedure for the remaining ribs. • Cover with a waxed sheet. • Compress with weight and allow to cure. • Remove from the waxed sheet and clean. • Using the appropriate safety measures cut and sand the ribs to match the template.

• Cut the spar notches using a razor saw. • Place the ribs on a scrap piece of wood and then drill through them to make holes to run the servo wiring through. Make sure the holes are large enough to fit the standard servo plug through. At last all the ribs for the wing are made and it is time to begin assembling the wing. Step 23: Wing Fabrication: Wing Spar. The wing spar is the key structural element of the wing. The spar is the critical load path for the airplane, all loads generated from the fuselage are transmitted through it.

As such it is of the up most importance that the wing spar is strong enough to withstand the loads it will be subjected to. Driver Hp Scanjet G3010 Xp. The weakest point of any structure is a joint, do not take shortcuts to make it easier at the cost of strength. Therefore I will show how to build joints on the wing spar that will be as strong as the surrounding wood to ensure the integrity of the finished wing.

These joints are called scarf joints. • Make a jig to hold the spar stock while cutting. • Line up two of the strips and the cut the angle the desired angle. You should use at least a 5 to 1, greater if possible) for the angle.

The longer the angle the stronger the joint will be. • Once the angles are cut then alight the cuts as shown to make the spar a perfect fit for the slot. • Now use the wing jig to cut the scarf into the ends of the spar caps that will be joined. • Check the joint of the joint to ensure that the boards do not twist along the joint. If needed correct the joint by carefully sand it down.

• Once the joint fits perfectly then mark the alignment of the joint with a pencil. • Lay down a sheet of wax paper on a flat table. • Pull the two haves apart and apply thick CA to the joint, then align the marks. • Repeat as necessary for the rest of the joints in the spar. Step 24: Wing Fabrication: Upper Spar Cap Dihedral Break. The dihedral break must be the strongest joint in the airplane because it is in the center of the wing.

Therefore the scarf joint should be longer. It is also easy to make it longer because the joint is simply cut at the angle that you want the diheral to be. Note that the angle that is cut may not be the same for the top and bottom of the wings because if the wing is tapered the thickness of the airfoil is reduced. Therefore I recommend waiting until the wing is built to build the other spar cap. • Using a ruler mark where the cut must be made to get the proper angle. • Then cut along the line with a razor saw.

• Check the fit of the joint and mark the alignment. • Put a piece of wax paper done on a flat table. • Using thick CA glue the two pieces together. Step 25: Wing Fabrication: Attaching Non Structural Ribs. Now the that upper spar cap has been made it is possible to being attaching the wing ribs onto the spar to make the wing. To make this process a lot easier I drafted a simple wing plan using autocad to build on. The drawing includes the wing spar, drag spar, subleading edge, trailing edge, as well as the location of each rib.

While this is not the only way to do this, it does beat drawing a plan by hand or measuring as you go. By printing out the wing plan full size I will have a blue print to build on, which makes building a straight wing much easier. Note: Wing twist is achieved by mounting the ribs onto the spar at the desired angle, the spar cap does not twist at all. • Lay out the wing drawing, making sure if you printed it in segments as I did that they are all properly aligned and that the spacing is correct. • Lay the top spar cap upside down on the drawing using spacers to support it along its length and especially at the center. • Now transfer the horizontal line from the rib templates to the leading edge of the ribs.

This is to allow you to build the wing with the desired amount of twist. • Apply woodglue to the spar notch of the outermost rib.

Then using the trailing edge and the mark on the leading edge mark align the rib so that the mark and the trailing edge are the same height above the working surface. In my case this alignment would give me the 2 degrees of washout that I desired.

Once the elevation of the rib is set insure that it is square with the surface of the table, and that it is mounted in line with the ribs on the wing plan.• Repeat for the other side of the wing • Apply the inner most non reinforced rib similarly to how the outermost rib was installed. • Repeat for the other side of the wing By gluing these two ribs on each wing it is now possible to align the ribs angle of twist without the need to measure the height off of the table.

T • This is done by applying wood glue to the spar notch of the rib and then setting the rib square to the table with a triangle. • Then verify that the rib is lined up with the wing plan. • Now that the ribs is in position move to the end of the wing and look down the wing in such a was that the trailing edge of the wing tip is aligned withe the trailing edge of the root rib. • Now adjust the rib that you are positioning so the its trailing edge is also aligned between these two ribs. • This is an iterative process so check to verify that the rib is still square with the table, then aligned with the wing plan, and aligned between the root and tip trailing edge.

• Once the alignment is perfect allow the wood glue to set up. Although this may seem like a tedious process it goes rather quickly since while one rib is setting up you can do a rib on the other side of the wing Step 26: Wing Fabrication: Attaching Structural Ribs. Spine Stabilization Program.

Since the structural wing ribs on this airplane are a composite laminate of materials, wood glue would be a very ineffective way to attach them to the spar. This is because wood glue is a water based adhesive and would not be able to penetrate the resin to form a secure mechanical bond. Therefore different adhesives had to be used to attach them. Here I will describe how the center wing ribs were attached and then how the landing gear ribs were fitted to the wing. • Verify the fit of the wing ribs on the spar, these ones can be difficult to fit since the material is so hard.

• Once the proper fit is achieved put on gloves and ensure that you have sufficient ventilation.• Mix a small batch of 5 minute epoxy. Only a few drops will be needed for each spar notch.• Apply a small amount of epoxy to the center wing rib and align it on the spar as done previously.• The remainder of the structural ribs can be done at this point with the exception of the landing gear ribs.

The landing gear ribs must be fitted to ensure that they operate correctly on the airplane. In my case since the landing gear were retracting towards the center of the wing I had to remove material from the inner ribs to allow the landing gear to retract.

I recommend waiting until this stage to do this because with the wing starting to come together it is possible to see if the landing gear must be angled inside of the wing. In my case it had to be because the wing had dihedral and my landing gear extends a full 90 degrees, therefore if they were not they would be bent outwards when extended. To do this I retracted the landing gear and repeated trying laying it into the slot that I was cutting until there was sufficient room for it to retract with a about 1/16' of an inch surrounding the landing struct. This was done to ensure that if the gear was damaged or moved during flight it would still be able to open or close. Once happy with the positioning of the wing ribs and landing gear cross members the ribs can be epoxied in place. Step 27: Wing Fabrication: Lower Spar Cap.

The lower spar cap can be challenging to install since it must fit into all of the spar notches in the wing with out being such a tight fit that it actually twists the wing, after all the effort was spent ensuring that it was constructed with the desired twist. The lower spar cap is installed as two separate pieces and is joined in the wing unlike the upper spar cap that was was installed as one piece. Below is how to install and join the two halves of the lower spar cap. • Make sure that the wing is still being well supported and is not sagging in the center or along the span, if so add a few more supports under the wing.

Improper alignment will result in undesired wing twist. • Test fit one half of the spar cap.

Note that I am leaving enough overhang of this spar cap over the center of the wing to attach the other half of the spar to. Things to look for include very tight ribs,very loose ribs, and that the spar cap is fully enclosed by the spar slot in the rib. It cannot be allowed to stick above the ribs otherwise it will show through the wing sheeting.• Adjust the fit of the lower spar cap by carefully removing material or by adding in shimming material to the ribs until it is a perfect fit. • The most challenging part of installing the spar cap is that since it is rigid it must be glued in all of the slots at one time. With that many joints its is impossible to hold and support all of them at one time by yourself. Therefore creative means had to be found to hold it in place as the glue set.

To do this I positioned pieces of electrical tape and masking tape underneath the wing that were long enough to wrap up and around the top spar cap to firmly secure them in place while the glue set. • All of the non structural wing ribs should be glued to the upper spar cap with wood glue while the center ribs and landing gear ribs must be glued in with epoxy.

While doing this I recommend using a paint brush to paint the wood glue into the spar notches and then mix the 5 minute epoxy and apply it to the reinforced ribs, since the wood glue will take longer to set. • Once glue has been applied to all of the joints insert the spar cap.

Then secure it in place with the tape, and wait for the glue to dry.• Begin test fitting the other side of the spar cap, in addition to checking and fixing its fit with the wing ribs. It is vital that the joint between the two halves of the spar cap is made to fit as closely as possible because as with the upper spar cap the center of the lower spar will be heavily loaded during flight operations. • Once satisfied with the fit prepare to glue the spar cap in by placing the tape at the desired locations • Apply the glue as before, for the connection between the two halves of the spar cap at the center of the wing use epoxy and once the rest of the tape is applied, hold or clamp this this joint until it has set. Step 28: Wing Fabrication: Sub Leading Edge. The sub leading edge is a 1/4' think piece of balsa that is attached to front of the ribs.

Its purpose is to be something for the sheeting to be attached to since sheeting would not be able to make the curve around the leading edge of the wing. It also provided the required thickness to allow the leading edge of the wing to be sanded to the shape of the airfoil. • Sand the tips of the ribs very gently with a bar sander such that they all have the same angle and are perfectly straight in respect to one another. • Next cut out an over sided strip of 1/4' balsa from a sheet. To make cutting a long strip of any material easier with a razor simply put double sided tape on the back of the straight edge and it will make the task incredibly easy since the edge will not move while cutting. Also do not try to cut through the material in one pass, because it increases the chances of splitting the wood.

Instead make a few light passes to cut the whole way through. • Use thick CA to glue the sub leading edge to the ribs. I found it is easiest to apply the glue to the end rib and then align the strip with the center rib. Once the glue has dried then apply glue to the next few ribs. Be careful to not bend the ribs that the sub leading edge is glued to while gluing it to new ribs. The shear web is made of 1/32' thick basswood and is glued to the top and bottom spar caps, as well as the wing ribs.

It is very important that the material used for building this is stiff because it will be compressed when the wing is under load. This allows the spar caps to form a beam rather than being small sticks. • Cut sheets of basswood with the grain to be slightly wider than the spacing in between the wing ribs.• Cut the bass wood strips to be slightly larger than the distance between the outside surfaces of the spar caps.• Sand the side of each piece of shear web until it fits snugly between the ribs on either side. • Glue the shear web onto the upper and lower spar using thick CA. • Use a course sanding block to sand, that is narrower than the space between ribs, to sand the shear web down to the height of the top of the spar.

Step 30: Wing Fabrication: Landing Installation. Fitting the landing gear proved to be challenging due to the the wing being rather thin. To add to the challenge the shear web was installed on the leading edge of the wing, this had its own pros and cons. While it did produce a smooth surface for the landing gear to ride on if the alignment is off, it also reduced the size of the already small space it was being installed in.

Furthermore I had mis-measured the space required for my landing gear so I had to adjust the size of the landing gear cross members that connected the landing gear to the ribs. • Set the landing gear inside of the gear rails to see which ribs need to be hallowed out to allow the wheels to retract fully. • Cut the required ribs so that the wheels are able to fully retract into the wing.

Now determine the angle the landing gear will be mounted at.• The gear can be mounted so that if looked down upon looks like it is slanted toward the front or back of the wing. However doing this will require the angle of the wheel to be adjusted or else the wheels will either point inwards or outwards when extended. • Once the correct position is found mark one of the mounting holes and drill using the appropriate drill bit being careful to support the end of the wings so that the end ribs are not crushed.• Place a bolt through through the landing gear into the drilled hole and then drill the remaining holes using the gear as the guide.• Now that all of the landing gear bolt holes are drilled the landing gear must be shimmed such that is parallel to the ground and thus perpendicular to the ground when extended. This is critical since mounting the landing gear so that it is angled in or out increase the stress on the gear when landing and thus the chances of the gear collapsing.• Using a piece of basswood carve it down into a wedge to and then sand it until it is the perfect angle to mount the gear straight.

• Once the angle is correct use thick CA to glue the wedge in place. • Flip the wing upside and drill through the back side of the mounting holes to put a hole through the wedge.• Bolt the landing gear into the landing gear bracket.

On the back side attach the gear with a washer and a nylon lock nut to ensure that the nut never comes off since it would be very difficult to replace and also could get stuck in the landing gear mechanism. Step 31: Wing Fabrication: Drag Spar and Aileron Construction. To build the ailerons it is easiest to build them while the end of the ribs which will be used to make them are still attached to the wing.

The flaps are not being constructed this way since the ribs in that section of the wing are the reinforced ribs that were made for the landing gear. The flaps will be constructed later on. Once the ailerons are constructed the trailing edge will be installed on the rear of the ribs. Lastly the hinge fairing is installed on the upper rear trailing edge.

• Square the wing off on the wing spar in such a way that it will stay. • Measure from the leading edge back to where the trailing edge/ flaps will begin and mark it on the tip rib and the innermost rib on the flap. • Place a ruler between the marks and then mark all of the ribs, additionally make the location of the center of the radius being made for the hinge.• Now use a square to mark the trailing edge of all of the ribs from the bottom to the top, and the mark for the radius of the hinges.• Cut off of the trailing edges off of the ribs that will not be part of the ailerons or the root section.• Sand the the beginning of the ailerons so that they will fit tightly in the fairings, look at the photos for an example of what this may look. Note that the sanding continued passed the hinge center point to make covering easier • Using thick CA glue the 1/32' balsa sheeting to the aileron ribs. All sheeted surfaces on this model are covered in 1/32' thick balsa wood.

Since I am leaving the wood grain exposed when the model is finished it is important to match the grain and color of the board to the piece next to it. Furthermore it is important to make the seams as smooth tight as possible because wood filler will show up after finishing. • Select the sheets of balsa that will be joined on the edge. Important considerations are the curve in the edge since no boards are actually cut straight, the wood grain, wood color, and hardness. • If the two board needing to be joined have edges that do not perfectly match because the edges are not straight or are wavy use a long bar sander to very carefully sand them to fit each other, while maintaining a square edge on the sheets.

• Lay down a sheet of wax paper and tape it down to the work surface • Lay a piece of packaging tape on the wax paper. This is to prevent the glue joint from sticking because CA will glue to wax paper.• Lay the boards being glued face down on the the working surface with the edge being joined over the packing tape.• Put on a pair of gloves and ensure there is adequate ventilation.• Apply a thin bead of thick CA on the first 8 to 10 inches of the joint and hold the pieces together being sure to keep them flat on the table.• Two alternate methods can be used at this point. • The first option is to bend the remaining portion of the sheeting back and apply another bead of thick CA approximately the same distance and align. • Hold the boards flat on the table and hold the seam together. Then apply a few drops of thin CA to the section being held. Be careful to not apply too much or else it will soak into the surrounding wood.

• Repeat this as needed until enough strips have been jointed together to cover one side of the the wing surface.• Sand the sheet with a sanding block with between 120 and 180 grit sand paper on it to level out the surface where the joints are and to remove excess glue. Patience is needed while sanding or else the sheet can shatter. • Determine how to position the grain of the wood on the wing. The wood will only be able to bend perpendicular to the grain. In my case I ran the grain along the leading edge, this will leave the center of the wing with a V where the grains of the wood come together, however since this will not be seen I can accept this.• Lay the balsa sheet over the wing and with a pencil mark where excess can be cut away with a sharp razor to make the sheet more manageable.

Leave at least an inch of excess around the edges. • Lay the sheeting over the wing slightly ahead of the leading edge.• Apply a line of Thick CA along the top of the sub leading edge and then carefully move the sheeting over the leading edge and work from the center out applying pressure to adhere it. Be careful not to 'pull' or 'push' the wood or else the sheeting my become wavy further back on the wing.• Gently lift the sheeting up being carefully to not bend it to far and crack it. Then apply a bead of Thick CA to the the front half of the rib in front of the spar. Next fold the sheeting back over the glue making sure that it adheres smoothly without wrinkles.• Repeat the previous step now going up to the wing spar.• At this point you can proceed two ways.

• Keep lifting and applying thick CA to the ribs until you finish the wing.• Flip the wing over and while supporting the skin from underneath use small drops of thin CA along the joints to glue the sheeting on. • Trim away any excess wood from the edges with a sharp razor.• Sand the sheeting at the center rib at an angle to allow a scarf joint to be made along it.• Fit the other wings sheeting and trim off the extra.• Continue dry fitting until the edge of the new sheet comes to end of the scarf joint on the sheet on the other wing. • Place the root end of the sheeting on the edge of a table and sand in the scarf joint to match the one on the wing.• Apply the sheeting to the second half of the wing using the same technique used on the first half. Step 33: Wing Fabrication: Finishing Ailerons. Now that the shells of the ailerons are completed, the control linkages and hinges must be build into the aileron and into the wing. Since I have choosen to use the rotatory drive system to move the control surface the ailerons will not have any visible control horns but instead will have a slot in side of them where a bent wire will rotate to move the control surface.

In this step I will describe how I made the slots, installed the hinge pockets and hinges, as well as how the leading edge was installed on the ailerons. Additional information on rotatory drive systems can be found at the link below. • The rotatory drive system that I purchased did not include a set of pockets so they had to be fabricated. First i cut 6 sheets of 2oz fiberglass large enough to make make pockets for all of my control surfaces from. • To prepare for the wet layup tape a waxed sheet to the working surface. • Mix the epoxy and work it into the the first ply of fiberglass, once it is thoroughly wetted place it on the waxed sheet.• Wet the next sheet of fiberglass and after squeegeeing out the excess epoxy place it onto the previously placed fiberglass ply.

Then squeegee the plys together to remove any air bubbles. Repeat this until all of the plys are stacked together.• Place a waxed sheet on the top side of the laminate stack and squeegee out any air bubbles to ensure that a flat smooth surfaces is created.• Wait for the resin to cure.• Using a razor saw strips out of the fiberglass plate approximately 3/4' of an inch wide. These will form the inner surfaces of the pocket that the drive shaft will rotate in.• The pockets need to be large enough to allow the drive shaft to rotated freely within therefore I made mine 2.5' long. Again I cut the fiberglass with a razor saw.• While wearing the appropriate protective equipment rough up what will be the outside of the pocket and also the outside 1/4' inch on the inner surface, this will allow the fiberglass to be glued while keeping a smooth inner pocket.• Glue a 1/16' thick basswood backer to the back of the fiber glass liners.

• Now the gap must be set between the two plates I used a piece of 1/4x1/8' bass wood to make the spacer for the drive shaft. First glue the spacers onto the inside of once of the fiberglass spacers with thick CA.• Sand the spacers and then place the other pocket halve on the spacers and check the fit with the driveshaft. The fit should be tight, but not to tight as to where it does not rotate freely and smoothly.• Once the desired fit is achieved glue the top piece of fiberglass onto the lower assembly to make the pocket.• Glue thin strip of balsa onto each side of the pocket till it is the thickness of the opening in the aileron. When using a rotatory drive system to move the control surfaces the servo installation is much more critical than for a traditional control horn and pushrod setup. • Depending on the surface being moved the angle of the bend in the drive shaft will vary. In this case it is close to 45 degrees.• The servos are installed on a shelf in between the ribs made from 1/16' balsa with 1/8' inch balsa strips around the edge to reinforce it.• Drill the necessary holes to allow the drive shaft to exit out the trailing edge.

• Test fit the shelf with the ailerons installed. The angle and vertical height of the shelf is vital for smooth operation. Once the ideal location is found mark the location and then glue it in place with thick CA.• Test fit the servo again with the aileron to verify that the shelf position is correct. If it is off a spacer between the shelf and the servo may be required.• Reinforce the hole the driveshaft exits the trailing edge of the wing through by drilling a slot through a small piece of fiberglass plate. It is good for the shaft to have play in the vertical direction, however lateral motion should be minimized. Once the plate is aligned glue it in place with CA.• Using sand paper rough up the side of the servo that is being glued in.• Mix epoxy to glue the servo in place.

Step 35: Wing Fabrication: Hard Point Installation. Hard points are installed on each of the wings just outside of the flaps. They are designed to allow any payload to be securely held in place with a pin and then be released when the pin is pulled. The blue block is an 1/8' thick block that fits inside of the mount.

With the hole aligned with the pin • Reinforce the rib that will be supporting the hard point with 1/16' thick balsa, being sure to attach it securely to the spar. • The pocket is also build using 1/16' inch bass wood with the edge of the bracket being supported with 1/8' inch basswood. • Once the bracket is complete use it as a guide to drill the hole in the wing rib for the pin to go through • On the center rib a small shelf is made for the release servo from 1/16' balsa with the edges being reinforced with 1/8' inch balsa, just like the aileron shelves • Epoxy the servo onto the self. As a side note I originally set this mechanism up with a GWS pico fast ball bearing servo, but the gears stripped after operating only a few strokes. As a result I replaced it with a Futaba S3114.

• Thin carbon rods are run through the wing ribs to the pin pull. Step 36: Vertical Stabilizer & Rudder Fabrication.

The vertical stabilizer is fabricated very similar to the wing but is much simpler and faster to fabricate. This is because it is • Using the same technique used to make the wing rib templates draft the rudder rib templates (NACA0010).• Print out and use double sided tape to attach the templates to the 1/16' inch balsa stock.• Cut out the ribs and then sand to the final shape. • Cut the spar notches.• Draw the blue print to build on and then cover with wax paper.• Cut the rudder spar made from 3/16x1/8 basswood to length. Then place the rudder spar on the blue prints being sure to prop the tip up so that the center of the rudder is horizontal.• Glue on the ribs, while verifying that ribs are square with the table.• Once the ribs are all installed dry fit the other spar half making sure it will not twist the rudder. Once the fit is correct glue in the other spar cap.• The shear web is made from 1/16' balsa. Cut and install it as done on the wing.• Sand the leading edge with a straight edge to properly angle the ribs for the installation of the sub leading edge.• The sub leading edge is 1/4' thick over sided balsa strip that can be glue on to the ribs with thick CA.• Use a razor to get the sub leading edge close to following the angle of the ribs.

Once the shape is close use the tape technique that was used on the wing to protect the ribs as the sub leading edge is sanded.• Mark on the vertical stabilizer where the rudder will begin then glue one side of the sheeting on to the part that will be the rudder.• Sand the trailing edge of the sheeting as done on the ailerons and then glue the sheeting on the opposite side.• Cut the rudder off of the vertical stabilizer using a razor saw. • Attach the drag spar and sand as was done of the wing.• Attach the leading edge of the rudder as done on the aileron.• Sheet the first side of the vertical stabilizer using one of the methods used on the wing.• The leading edge of the rudder and hinge pockets are fabricated exactly they were on the ailerons.• Build a servo shelf as was done for the wing and fit it.

• Check that is is properly installed for smooth operation and then epoxy in the servo.• Drill a hole down through the ribs to allow the servo wire to exit out the bottom of the vertical stabilizer.• Cover the other side of the vertical stabilizer by slowly working your way from the leading edge back, by bending the sheeting up and applying thick CA to the ribs. Step 37: Horizontal Stabilizor & Elevator Fabrication. Once again this control surface is constructed very similar to the wing. The main differences are that the servo is set up to use a control horn and push rod setup rather than a rotary drive system, this was done because the elevator is equipped with a standard size servo for increased reliability and control authority. Additionally the elevator is solid rather than being build up as all of the other control surfaces were, this was done because there elevator is very thin at the tips and the difficulties in building a build up elevator that would be strong enough is not worth the weight savings. • Using the same technique used to make the wing rib templates draft the horizontal stabilizer rib templates (NACA0010)• Print out and use double sided tape to attach the templates to the 1/16' inch balsa stock • Cut out the ribs and then sand to the final shape.

• Cut the spar notches.• Draw the blue print to build on and then cover with wax paper.• Cut the elevator spar made from 3/16x1/8 basswood to length, note that this spar is 4 pieces and that they will come together in a V. Then place the stabilizers spar on the blue prints being sure to prop the tip up so that the center of the stabilizer is horizontal.• Glue on the ribs, while verifying that ribs are square with the table. Do not install the center rib at this time. • Once the ribs are all installed dry fit the other spar half making sure it will not twist the elevator. Once the fit is correct glue in the other spar cap.• The shear web is made from 1/16' balsa. Cut and install it as done on the wing.• The two sections must now be joined together with a structural carry though.

To accomplish this I cut and sanded three pieces of basswood that would be large enough to completely fill the gap between the upper and lower spar cap. These pieces not only replace the shear web in this section but also serve to unify the right and left wing.

• Now cut the middle rib so that it can be installed in two pieces on the spar.• Sand the leading edge with a straight edge to properly angle the ribs for the installation of the sub leading edge.• The sub leading edge is 1/4' thick over sized balsa strip that can be glued on to the ribs with thick CA.• Use a razor to get the sub leading edge close to following the angle of the ribs. Once the shape is close use the tape technique that was used on the wing to protect the ribs as the sub leading edge is sanded.• Since the stabilizer is swept the leading edge will need to cross as done on the wing. • Mark where the elevator will begin on the ribs and then cut off the excess rib material with a razor saw.• Attach the drag spar and sand as was done of the wing.• Note that the structure of the elevator is made mounting points must be installed before the stabilizer is sheeted. I chose to install two brackets.

The front bracket is made to connect to the upper and lower beams on the truss in the fuselage. The aft mounting bracket mounts only to the upper beam since the lower beam does not extend the entire length of the fuselage. They are both made from 1/8' thick hobby plywood.• Sheet the first side of the vertical stabilizer using one of the methods used on the wing.• Hinge pockets are fabricated exactly they were on the ailerons.• Cover the other side of the horizontal stabilizer by slowly working your way from the leading edge back, by bending the sheeting up and applying thick CA to the ribs.• The wingtips are made from solid pieces of 1/4' balsa stacked together to be the thickness of the surface.• Once the balsa pieces are stacked to form the tips, cut out the top view of the tip into them.

Trace that view onto the other tip and cut it out. • Glue the tip blanks on to the stabilizers tips.• Use a razor to thin down the tips until they are close to the desired shape.• Use progressively finer sand paper to finalize the shape of the tip. The elevator on this airplane is split by the fuselage, but is only articulated with one control rod. To allow the motion to be transmitted between each side a dowel rod was added onto the solid wood elevator blank.

At this point I recommend drilling the hing holes in the elevator blank in case they do not come out well very little work will be lost. Begin carving the elevator blank into a streamlined shape that follows the curves of the stabilizer. Once the elevator is sanded to shape the center section can be cut out so that it will clear the fuselage.

Additionally on the control horn side the balsa is cut back further to allow a piece of basswood to be installed. This basswood is to provide a solid material that a slot can be cut into to mount the control horn into. Step 38: Fuselage Design. This fuselage is designed to carry flight loads through a truss, like a bridge. Therefore most formers are not designed to take any load. The formers are simply attached to the truss to allow a streamlined fuselage to be build over the truss. The fuselage had been preliminary designed in CAD as a side view.

From this I had to determine the cross-sectional shape at each location along the fuselage. To do this I printed out the side view from CAD and then taped it onto a sheet of foam core. Then using poster board I began cutting out every other cross section, from there I cut out the intermediate cross sections. Then I was able to use the model to size the fuselage truss. I was able to do this by laying a ruler along the length of the fuselage and using that to determine the height of the truss, then I measure what the maximum width of truss could be to fit inside on both ends. By dividing the difference in size by the number of formers that were between the end points I was able to check to see if the truss would fit in the remaining formers. You can see the final truss design marked out on the fuselage cross sections as boxes.

It is a two part truss with the joint near the middle of the cockpit. This allowed me to maximize the size of the truss and thus strength, while also minimizing the number of joints between truss sections. Step 39: Fuselage Fabrication: Building the Truss. Building the structure of the fuselage as a truss proved to be a rather fast and easy process, that produced a light yet very strong framework. To save time constructing it I had purchased strips of 1/2x1/16x36' hard balsa to make the corners out of, however it was challenging to find enough straight pieces.

The vertical members of the truss were made from strips of hard 1/4x1/16' balsa, while the diagonal members were the same size but made from a lighter and softer balsa. • Lay down wax paper over the working surface and apply a strip of packaging tape along the length of it to protect it from glue. • Use double sided tape to stick a long straight edge to the wax paper. This will be used as a guide while gluing the two pieces together into the beam. • Stand one strip of balsa upright in front of the straight edge and then lay down the second piece flat on the table to hold the other piece in place. • Hold the two pieces tightly together and with the joint over the tape.

Work from one end to the other applying thin CA to the joint to bond the two pieces together. I have tried making beams like this previously with wood glue and have found it to be a headache because the water in the glue will swell the wood along the joint which will bend the beam. From there it is luck as to whether it will return to being straight once both the wood and then glue have dried thoroughly. • To make assembling symmetric trusses easier, I drew a quick side view of the truss in Autocad which showed the location and spacing of the truss members when looked at from the side. Note that you will need a different drawing for each side since they are mirror and not a copy of each other. • With the drawing printed out and taped on the working surface and covered in wax paper, apply double sided tape to hold the long corner members of the truss in place.

• Start installing the vertical members, which are made from the harder balsa, following the template. • Once all the vertical members are installed then install the diagonal members. The easiest way I have found is to sand one end of the strip into the required shape so it fits in the first corner by the vertical member and then line the strip up to pass through the opposite corner.

Then cut it diagonally across with a razor saw and sand to fit the second corner. • Now that the sides of the truss are formed they must be joined. To prepare for this I drew a very simple blue print on poster board that shows the correct taper to mount the trusses.

• Carefully align the trusses with the blue prints, and again double sided tape can be used to help hold them in place.• Starting from the bottom install the horizontal members between the vertical members on the side and then install the diagonal members.• Once the bottom is finished, flip the part over and do the horizontal members. Once a sufficient number are in place the truss can be moved into a more convenient position to fit the diagonal members. Do not forget to leave areas to allow access into the fuselage for batteries and electronics.• To join the truss sections together I first tacked them together with CA, then installed a balsa doubler inside the truss at the joint between the sections. Step 40: Fuselage Fabrication: Installing Formers and the Firewall. The formers are basically the ribs of the fuselage, they provide the base shape to attach the balsa sheeting too. They are all made from 1/16' balsa, with the exception of a few structural ribs that are made from 1/8' plywood.

Two of these structural formers are located at back of the canopy for the rear wing mount, the other two are located in front of the wing mount where the fuselage is connected on both sides in between the canopy cover and the engine cover. The firewall is a fiberglass reinforced plywood that the motor mounts onto. It must be extremely stiff or else vibrations from the motor can cause it to flex which will cause the vibrations to grow until either something breaks or the throttle is reduced.

Additionally the firewall must be attached very well to the fuselage truss so that it can pull the airplane through the air as well as withstand any vibrations. • Using the templates made from the plan cut out all of the formers out of the desired material.

The balsa formers are made in two halves and then glued together while the plywood ones are cut out as one piece. • Dry fit all of the formers to ensure they fit the truss well since the marks on the template are really just an approximation of the parts that were actually made. • Once all of the formers fit appropriately begin by installing the solid plywood formers from the widest point on the fuselage to the narrowest using wood glue.• Install the remaining formers to the fuselage one half at a time. A drop of thin CA can be used to join the two halves together in the center. Note: because of the orientation of the grain in these pieces they can be very fragile. If any break during the build they can simply be glued back together with CA since they are not carring any load and are hidden.• The firewall is made from a fiberglass reinforced plywood that is made from 8 layers or 1/32' basswood with a 2oz ply of fiber.