This is my presentation for the Third Annual Electrical Aircraft Symposium at the Hiller Aviation Museum in San Carlos, CA. I have added several links that were not in my original notes, but that I hope will help guide readers to form their own conclusions, and possibly add to the core of knowledge we hope to collectively build.

San Carlos, April 24, 2009 1 This presentation is an expansion of a talk I gave at the 2008 Tehachapi gathering of the Experimental Soaring Association. Dr. Brien Seeley heard that presentation and asked me to do a similar show for the 2009 San Carlos CAFÉ symposium.

San Carlos, April 24, 2009 2 “The many experiments made during this last quarter of the nineteenth century have given considerable impetus to the quest ion of guida ble bllballoons. The cars furni sh ed with propell ers attach ed in 1852 to the aerostats of the elongated form introduced by Henry Giffard, the machines of Dupuy de Lome in 1872, of the Tissandier brothers in 1883, and of Captain Krebs and Renard in 1884, yielded many important results. But if these machines, moving in a medium heavier than themselves, maneuvering under the propulsion of a screw, working at an angle to the direction of the wind, and even against the wind, to return to their point of departure, had been really ‘guidable,’ they had only succeeded under very favorable conditions. In large, covered halls their success was perfect. In a calm atmosphere they did very well. In a light wind of five or six yards a second they still moved. But nothing practical had been obtained. Against a miller's wind-- nine yards a second--the machines had remained almost stationary. Against a fresh breeze--eleven yards a second--they would have advanced backwards. In a storm--twenty-seven to thirty-three yards a second--they would have been blown about like a feather. In a hurricane--sixty yards a second--they would have run the risk of being dashed to pieces. And in one of those cyclones which exceed a hundred yards a second not a fragment of them would have been left. It remained, then, even after the striking experiments of Captains Krebs and Renard, that though guidable aerostats had gained a little speed, they could not be kept going in a moderate breeze. Hence the impossibility of making practical use of this mode of aerial locomotion. “With regards to the means employed to give the aerostat its motion a great deal of progress had been made. For the steam engines of Henry Giffard, and the muscular force of Dupuy de Lome, electric motors had gradually been substituted. The batteries of bichromate of potassium of the Tissandier brothers had given a speed of four yards a second. The dynamo-electric machines of Captain Krebs and Renard had developed a force of twelve horsepower and yielded a speed of six and a half yards per second. With regard to this motor, engineers and electricians had been approaching more and more to that desideratum which is known as a steam horse in a watch case. Gradually the results of the pile of which Captains Krebs and Renard had kept the secret had been surpassed, and aeronauts had become able to avail themse lves o f motors w hose lihlightness increase d at the same time as thhieir power. ” Robur the Conqueror, Jules Verne

San Carlos, April 24, 2009 3 Harpers Magazine, in 1901, published this cartoon, with this telling caption. Often, because no immediate commercial reward can be gained from a new invention, there is no reward or recognition for the inventor. Often, since existing technologies are adequate to dissuade hopeful visionaries from wasting their time in the new field, promising alternatives to the current reality are neglected.

San Carlos, April 24, 2009 4 This book, a compilation of articles from Popular Science and Popular Mechanics magazines of the 1920’s and 1930’s, reflects on the folly of trying to predict the future. Almost none of the predicted marvels in the book came to pass – many are still awaiting an entry in the hoped-for world of the future.

San Carlos, April 24, 2009 5 As with all generalities, my outline is subject to occasional excursions into areas of related interest, if not strict adherence to the categories shown.

San Carlos, April 24, 2009 6 Following a heart attack in April, 2004, I had time to recuperate and engage in leisure reading. On a trip not authorized by my doctor, I had my daughter Beth drive me to a favorite magazine shop in Portland, Oregon, where I purchased the current edition of Quiet Flyer, which featured Rob Honeycutt’s amazing Extra 330L. I was able to deduce that a 28-pound airplane that could hover had to be putting out at least 28-pounds of thrust. It turned out to be better than that, and I was able to conceive that these little model electric motors could power a sustainer power pack for sailplanes. Assuming a 524 pound AUW sailplane with even a modest 25:1 lift to drag ratio, it would require only 20.96 pounds of thrust to maintain altitude at its best l/d speed.

San Carlos, April 24, 2009 7 One has the option to select a single large motor or two or more smaller motor to get the desired thrust. Rob Honeycutt used twin Hacker motors in his successful Extra 330L, using a speed reduction drive to the prop. Hacker followed up with multiple motors in geared drive arrangements – a twin-motor item and a four-motor design that produced 87 pounds of thrust through a 30-inch propeller, and cost $2,995. Because the four motors required four electronic speed controllers and four battery packs, it and the twin-motor system shown above were soon replaced byyg larger, sin gle motor desi gns. http://www.hackerbrushless.com/

San Carlos, April 24, 2009 8 Most model motors in the size ranges of interest in this presentation are brushless, and are either inrunners or outrunners. Inrunners are built like traditional brushed motors, but take their speed control from an electronic speed controller. Outrunners reverse the major parts of the inrunner motor, with the mounted in a fixed, central position, and the spinning around in the outer casing of the motor. The propeller is fastened to the spinning casing, a great deal like the configuration of WWI rotary engines. Taking signals from the speed controller, the motors outer are turned on an off at 120-degree phased intervals. Each time a pole is activated, it draws the rotor toward it. The speed controller acts as the interface between the battery and the motor. Since the battery is always at the same voltage, the controller has to modulate that power to allow the motor to turn at different speeds. A series of MOSFET transistors act as switches in the sppyeed controller and vary the width of the pulses sent to motor.

San Carlos, April 24, 2009 9 Electronic speed controllers (ESCs) must be carefully matched to the intended motor. Brushless motors do not receive electricity directly from the batteries that power them, but have that current modulated by an electronic speed controller. There are several features of electronic speed controllers typically used in model aircraft that we should consider. If the full voltage from the batteries was passed uninterrupted to the motor, the motor would run at whatever speed the available voltage allowed. For determining how to match a motor and propeller, a motor performance parameter, kV, or revolutions per minute per volt, will be helpful. Motors vary in their kV rating, depending on size, number of windings, poles, etc. How do we vary the amount of electricity which passes into the motor? The best control would allow everything from the motor not turning over at all to a full-throttle, full power run. An electronic speed controller (ESC) enables this, with some limitations, usually at lower RPMs. An ESC works as a switch, usinggg high-spp(eed MOSFETs (metal oxide semiconductin g field effect transistors) to switch the current on and off. The motor receives only pulses of electricity that are allowed through by the controller as the MOSFETS turn on and off. The power received by the motor is based on how “wide” the pulse is,

San Carlos, April 24, 2009 10 “The servo signal is a simple digital pulse. It spends most of its time at a logic low (0 V). About every 20mS it goes logi ic highhi h (3 to 6VDC) and then qui ckly kl goes low agai n. It is this tiny window of logic high time, called the pulse width, that gets the attention of the servo. Please refer to the drawing. The period labeled "A" is called the frame rate. In the example it is repeated every 20mS (50 times per second), which is quite typical for most radio systems. Modern servos define center as a 1.5mS pulse width, as shown by detail "B" in the drawing. Full servo rotation to one side would require that this pulse width be reduced to 1.0mS. Full rotation to the other side would requirrequiree the pulse width to increase to 2.0mS . Any pulse width value between 1.0mS and 2.0mS creates a proportional servo wheel position within the two extremes. The frame rate does not need to change and is usually kept constant. The servo will not move to its final destination with just one pulse. The servo amp designers had brilliantly considered that multiple pulses should be used to complete the journey. This little trick reduces servo motor current draw and it helps minimize erratic behavior when an occasional corrupt signal is received. To move the servo, you must repeat th e pu lse every few m illisecon ds, at th e c hosen frame rate. MdModern R/C systems use a 40Hz - 60Hz frame rate, but the exact timing is not critical. If your frame rate is too slow, your servo's movement will become rough. If the rate is too fast the servo may become very confused.” http://www.rc-cam.com/servotst.htm

San Carlos, April 24, 2009 11 Components vary in quality and price. For purposes of this paper and presentation, I’ve decided to stay with equipment that has demonstrated reliability, is made in America or Europe (there are myriad inexpensive Chinese components, but anecdotal evidence suggests lack of reliability and product support for many such motors and controllers – although that situation is improving). Drawing from Hyperion Motors

San Carlos, April 24, 2009 12 Inrunners tend to be more efficient than outrunners, but turn at incredibly high RPMs, requiring the use of a gearbox to reduce propeller speed to required levels. Even with the 6.7 gearbox on this NeuMotor, further reduction would be required. At 70,000 rpm, the output shaft would still turn over at 10,447 rpm! Luckily, the planetary gearbox, made by Maxon, allows stacking a second (or third) gearbox, further increasing torque, allowing a larger propeller, and reducing propeller speed. A second gearbox on this unit would reduce propeller speed to 1,560 RPM, in a desirable ranggge for ultralight use. For some of the lar ger NeuMotors, which turn over at only (!) 30,000 rpm, the speed of the propeller could be proportionally slower. http://www.neumotors.com/Site/Welcome.html http://www.castlecreations.com/products/neumotors/nm.html

San Carlos, April 24, 2009 13 Another inrunner manufacturer, Bob Boucher at Astro-Flight has been involved with solar- powered aircraft such as the Solar Challenger, and pioneered the use of cobalt and other special metals in his motors. He has been involved in the development of the motor Greg Cole is using on the Sparrowhawk, and the 50kW unit currently being tested on the Monnet Sonerai electric project. http://www.astroflight.com/

San Carlos, April 24, 2009 14 Plettenberg has an interesting spinner that completely surrounds the motor, and provides a central hole that cools the motor, a bit like Kurt Tank’s original design for the FW-190. A recent addition is the use of a thrust vectoring servo, similar to what is installed on the A-I- R Atos using Dr. Eck’s motor. Although the Extra is probably too small for the use intended in this presentation, there is the possibility of using two in wing-mounted pusher configuration on something like a Mitchell Wing or Swift. A similar spinner is available for the Terminator and Predator, allowinggg similar configurations with up to 15 hp. http://www.plettenberg-motoren.com/UK/index.htm

San Carlos, April 24, 2009 15 This chart of representative available motors gives some idea of those which fit into the lower range of our survey. Note that peak power is never to be held for more than two minutes with most of these motors (30 seconds for NeuMotors), and that most limit continuous power to half their peak output.

San Carlos, April 24, 2009 16 The DMSV (Deutscher Motorschirm Verbuch e. V. – the German Paramotor Association) gave the first type test certificate for a motor, MP number DMSV-MS-5019-09, to the company LFG [boron man]. The drive unit developed by LFG [boron man] as well as Wolfgang Zankl and the company PAP brought to the production stage one of German Dr. Ing. Werner [Eck’s] developed brushless external runner engine HPDirect 10, which is integrated into the cage of the PAP 1400. The unit is very light, but produces 55 kg (121 pounds) of thrust with a three-bladed propeller on the PAP paramotor. (The above is a rouggygyh translation of the very rough translation afforded by Babelfish.)

San Carlos, April 24, 2009 17 Schulze controllers are recognized as high-quality, high-end units for serious modelers. The unit shown cost over 400 Euros, or about $520. Its light weight is essential in models, and builders of “real” aircraft may want to consider a more robust controller with even more power handling capabilities. Despite that consideration, the Werner Eck motor uses a similar Czech or German controller in its many applications on human-carrying ultralight aircraft. http://www.schulze-elektronik-gmbh.com/index_uk.htm

San Carlos, April 24, 2009 18 Installed on the PAP1400 powered parachute frame, the HPDirect 10 swings a large Helix propeller for greater thrust. In the Swift rigid-wing hang glider, the unit and associated batteries and controller are neatly streamlined, allowing Manfred Ruhmer to note that flight characteristics are not noticeably different from those of the pure glider version. “When I heard of this motor, my interest was aroused immediately. With a weight of 3.75 kg and a number of revolutions of 2,000 [RPM] he is to be propelled in the position large propellers directly. He puts a continuous duty of 8 kW and a short time achievement of over 10 kW problem-free away. As automatic controller… a Czech Jeti Spin 200 is used. This automatic controller is able to carry out with good cooling, 200 [Amps]. The tension (voltage) can amount to up to 60 V. The unit uses battery packs arranged in a sixteen batteries in series, 9 in parallel configuration for 144 cells (A123, LiFePO4). Weighing 12.5 kg. This gives 58 Volts and 20.7 Amp hours. Total added weight on the Swift is 20-22 kg, causing a slight increase in gliding speed and sink rate. http://www.geigerengineering.de/avionik/produkte/ http://www.swift-light.at/

San Carlos, April 24, 2009 19 The A-I-R Mosquito, fitted with the HPDirect 10 with a direct drive to a folding propeller, and Saft lithium polymer polymer batteries gives approximately 10 minutes of running time, enough for an 800 meter climb. Toni Roth notes that the system is not any heaver than a backpack unit with a conventional two-stroke engine. There is some indication that the unit has the possibility of vectored thrust, as indicated in the following: “For … Atos we developed and [built] an electronically steered introduction tail unit, integrated cockpit control members and intelligent servo mechanisms also here automation and avionics for more efficiency and the correct flight feeling.” http://www.a-i-r-usa.com/index.asp?ID=4243 http://www.a-i-r.de/index.php

San Carlos, April 24, 2009 20 This simple operational drawing of a brushed motor’s operation shows the mechanical commutation required to control the motor’s rotation and speed. Mechanical brushed commutation leads to the brushed motor’s biggest drawbacks, inefficiencies caused by the mechanical nature of the system, and wear that requires frequent maintenance. Despite those drawbacks, the most common motors on practical ultralights and light aircraft at this time are brushed motors, mostly Lynch models, but also Perms and those specially built by their creators.

San Carlos, April 24, 2009 21 This diagram, based on the control drawing in the APAME literature, shows the simplicity of the basic motor/controller configuration, in this case for a brushed motor. Note the monitoring of current between the battery and controller and the controller and motor, and the voltage for the battery and motor. Fusing is provided at several crucial points to prevent damage to components, although failures here would probably bring down an aircraft. http://www.apame.eu/AA%20welcome.html

San Carlos, April 24, 2009 22 This cutaway of a shows the compact nature of the design, which has an axial gap arrangement between the coil on the stator and the magnets on the rotor. Lynch motors have excellent power-to-weight ratios, and can be controlled by brushed or brushless controllers. http://www.lemcoltd.com/

San Carlos, April 24, 2009 23 Electravia, following the successful testing of a Lynch motor and 47kg battery pack on their Souricette ultralight, installed the motor on an Alatus AM-12 motorglider. The superior aerodynamics of the motorglider (27:1 lift to drag ratio) allowed over an hour’s flight on a battery pack half the weight of that on the ultralight. Electravia has also flown a trike on this power system, and an ultralight Souricette. The Souricette, although it uses the same motor as the Alatus, is a far “draggier”, heavier machine, and requires a battery pack double the size of that in the Alatus for less duration. The Alatus managggyed 1 hour, seven minutes on its 20 kg battery, the Souricette 48 minutes on its larger pack. http://www.electravia.fr/ANGLAIS/Aindex.html

San Carlos, April 24, 2009 24 Randall Fishman won best new design at the 2007 EAA Air Adventure for his adaptation of the Monnet Moni motorglider with an and controller of his own design. The motor puts out 18hp at full power, but Fishman flies it at about 33-percent power, enabling level flight at 60 mph at .7C battery drain, and with very little elevation of battery or motor temperatures. http://www.electraflyer.com/

San Carlos, April 24, 2009 25 One customer of Fishman’s, Jerry Booker, a farmer and airplane designer in southern Illinois, has mounted his motor on a retractable arm on his Red Tail Hawk motorglider, and is nearing flight testing. He uses the same motor, controller and battery pack as that on Fishman’s Moni, but should have slightly greater endurance because of the lower span loading of his aircraft. A reader of his RTH Yahoo Group, Paul F. Ralph, has designed a 33:1 motorglider, the Mew Gull, and has done a series of estimates for power required with a similar electric motor. He has also created a batteryyygg/fuel chart that is helpful in analyzing weight and expected duration for different power-pack configurations. http://groups.yahoo.com/group/RedTailHawkUltralightSailplane/

San Carlos, April 24, 2009 26 Mark Brierle pulled into Tehachapi, California’s Mountain Valley Airport last Labor Day towing his UltraGull 2000 with a Perm 132 motor and Kelly controller mounted where the two-stroke Rotax or HKS would normally be. He has flown this craft within the last few months, and reports breaking ground in 55 feet, climbing at 270 feet per minute, and being able to stay aloft for 11 minutes on a small lithium battery pack. He reports running at 4.5kW at 55 mph. http://www.thundergull.com/

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San Carlos, April 24, 2009 27 Ken Krueger, engineer for Van’s Aircraft, asked the Lynch Motor Company for assistance in selecting a motor or motors that could power a new, possibly kit-built design for the company. His specifications called for a motor that could produce full power for five to six minutes and up to 50-percent power for at least an hour. http://www.vansaircraft.com/

San Carlos, April 24, 2009 28 APAME and ACV are now working on the two craft shown. The single seat Electro on the right will use a 26 hp Lynch motor while the Duo flying wing will use a 43 hp Lynch unit with belt reduction. http://www.electravia.fr/ANGLAIS/Aproducts.html

San Carlos, April 24, 2009 29 At a greatly oversimplified level, brushless electric motors are controlled through two different means, use of a trapezoidal wave form, or the digitized equivalent of a sinusoidal wave form. The trapezoidal form causes greater motor noise in operation, and less smoothness of running than the sinusoidal form. It is simpler, however, and is resistant to harmonics problems that the sinusoidal motor control can experience. Only one motor in this survey uses this wave pattern – the Yuneec motor from China, used on paramotors and an anticipated twin-motor ultralight aircraft. All other motors use a sinusoidal wave form, with different design approaches to read the back emf or sense Hall effect sensors to determine the rotor position and synchronize the triggering of, usually, MOSFETs to energize the coils in the motor.

San Carlos, April 24, 2009 30 Patrick McLaughlin of Mountain High Oxygen in Redmond, Oregon, is developing a range of controllers independently from other motor projects. He wants to provide a range from 20kW to at least 90kW, and further. These units can be used as servo or stepper controllers if desired. http://www.mountainhighoxygen.com/

San Carlos, April 24, 2009 31 Yuneec, a Chinese company making products imported by Englishman Clive Coote, bases its powered parachute motor on a large outrunner type design. The firm claims 10kW for this motor and is introducing a larger, 12.5 kW unit. With its 66.6 Volt, 30 Ah battery pack, Yuneec claims 25-30 minutes flight time, a good accomplishment considering the high drag inherent in paragliders. It will be interesting to see the run times achieved with two motors on the projected ultralight airplane Yuneec is developing. The motor is part of a package that includes a battery management system, controller (the only one in this presentation running a trapezoidal input to the motor), charger, and a hand-held control interface with an LCD screen and a stick shaker to indicate a low battery charge. http://yuneeccouk.site.securepod.com/paramotor_Tech%20Spec.html

San Carlos, April 24, 2009 32 KLD Energy Technologies, located in Austin, Texas is developing a wheel-hub motor that provides over 55 mph top speed and 0-50 times of 10 seconds for an electric scooter that will be mass produced in Vietnam. Company literate promotes the high frequency nature of the motor, running at 2,500 Hertz, as a result of nano-crystalline materials that replace traditional iron cores. Such “amorphous” materials are being used to promote cooler running and lower saturation losses. http://www.kldenergy.com/ http://www.kldenergy.com/Articles/090419CNNCoverage.pdf

San Carlos, April 24, 2009 33 Light Engineering Motors have amorphous metal and permanent magnets as part of their design, and produce significant torque. Their controllers feature redundant hall sensors and high resolution encoders. http://www.lightengineering.com/

San Carlos, April 24, 2009 34 Apex Drive Laboratories uses a dual stator-single rotor design, with U-shaped core. The dual permanent magnets on the rotor and the patented U-shaped core help produce high torque at low RPM. A dedicated controller can use Hall-effect commutation for high torque at low speed, or sensorless control for high-speed systems. Their DD31w motor weighs 84 pounds and puts out a peak of 46 kW, or 61.7 hp and a continuous output of 31.3 kW, or 46 hp. Its peak torque is of interest, though. With 576 Nm (425 ft-lbs) peak and 157 Nm (117 ft-lbs) continuous, the motor produces this at relatively low RPMs. Recently, the company recently received a $250,000 commercialization grant from the Oregon Nanoscience and Microtechnology Institute (ONAMI) for its patented micro- channel liquid cooling approach. http://www.apexdrivelabs.com/

San Carlos, April 24, 2009 35 Roman Susnik was instrumental in the design of the motor used on the Pipistrel Taurus, a two-seat self-launching sailplane. He has developed a line of 20-, 30-, and 40-kW motors which are large outrunners in concept. He has also developed controllers specifically for these motors. http://www.sineton.com/www/ http://www.glider-one.si/index.php?option=com_content&task=view&id=58&Itemid=87

San Carlos, April 24, 2009 36 “The controller can commutate the motor in two different ways: using Hall effect sensors to determine the core’s position in relation to the coils, or using the motor’s back-EMF to sense rotor position, eliminating the need for Hall sensors. The AeroConversions controller will initially employ a Hall effect sensor-equipped motor, but back-EMF controlling will also be explored to potentially further simplify the AeroConversions motor design. The AeroConversions controller will also provide in-cockpit monitoring of battery power levels to the pilot.” http://www.aeroconversions.com/e-flight/

San Carlos, April 24, 2009 37 Part of ENFICA-FC (Environmentally Friendly Inter-City Aircraft – Fuel Cell) project at the University of Turin, and headed by Professor Ing. Gulio Romeo, the Skyspark project uses a Sicme Motori Valentino motor of 65 kW maximum output in a light wood airframe, the Pioneer 300. The goal is to set a speed record for electric aircraft, first with battery power, and second with fuel cells as the storage medium. The project has an aggressive schedule, with the first proposal in late 2005, and a complete airframe, motor, controller, batteries, fuel cells and hydrogen storage tanks being displayed in Februaryygggy 2009. The plan is to stage a flight test in the late spring or early summer with batteries, establish a speed record (180 km/hr) and then, in the fall, attempt to achieve a speed record on fuel cells only. http://pdf.aiaa.org/preview/CDReadyMATIO07_1768/PV2007_7754.pdf http://www.enfica-fc.polito.it/en

San Carlos, April 24, 2009 38 “Sicme Motori, technological partner of SkySpark, is producing the Valentino engine, which will be propelling the aircraft. This prototype, which stems out of the cooperation with the Electrical Engineering Department of the Polytechnic of Torino, is very light and has a high performance: it only weights 25 kg and features a maximum power of 65 kW at a speed of only 2500 rpm. “Valentino is the crowning jewel of 45 years of industrial experience focused on research and innovation. “Sicme Motori is one of the first companies on the international scene to apply Direct-Drive technology to electrical en gines” states Alberto Sola, Chairman of Sicme. “This has allowed us to do without the gearbox, guaranteeing a maximum energetic efficiency”. Gearless motors reduce maintenance needs enormously, have remarkable environmental advantages, guarantee outstanding performance and absence of noise, even at low power regimes. “Valentino is a Direct-Drive motor (synchronous, with permanent magnets) of a brushless kind. This means that, in contrast with a motor, it does not need electronic switches embedded on the main rotor in order to work. It uses ppyparticularly sophisticated materials , has an external rotor, and is cooled by liquid. “Always active in the field of innovation, Sicme Motori has been one of the first companies to invest in renewable energies. ‘We have been busy with wind power since 2002, well before it became a media hype’ says Alberto Sola, ‘and we are now working on a new generation of electrical engines that will find concrete applications in many important sectors, such as the automobile, to realize highly performing ecological engines’. “ From a SkySpark press release October 20, 2008

San Carlos, April 24, 2009 39 The E-Silence aerobatic has nothing of note I can find at this point that is not on the slide.

San Carlos, April 24, 2009 40 Combining a Rotax 914 with a motor that can be used with the engine at takeoff, or by itself in case of an engine failure, this hybrid is a first of its kind in the light airplane realm.

San Carlos, April 24, 2009 41 Flight Design and Rotax collaborated to produce this motor for this year’s Aero 2009 E- FliFlight ht Expo. It is ins ta lle d on a CTS lightli ht spor t a ircra ft. “Flight Design GmbH, the German creators of the popular CT line of light sport aircraft, used AERO Friedrichshafen to announce details of their work on a new hybrid engine concept. The propulsion package consists of a standard Rotax 914 turbocharged engine to which is mated a 40-hp (30 kW) electric motor. The electric motor is coupled to the propeller hub using a poly-V-belt drive that has no overloading impact on the crankshaft and, thus, allows the motor to transmit its power directly to the point where it's needed. Since the basic Rotax is left mostly untouched, its 130-hppp output, combined with the electric motor's 40 hp, provide for a combined 170-hp output for the hybrid. The electric motor will be used for takeoffs and climbs, and makes use of its full capacity over a maximum five- minute span. In cruise, power comes entirely from running the gas engine at full power. Twenty minutes is required for a full recharge on the 25 kilos of lithium ion batteries that power the electric motor. “One of the features being touted by Flight Design is the added safety inherent with a hybrid. Should there be a failure of the combustion engine, power from the electric motor can supplant a stopped engine and provide sufficient thrust to stretch the aircraft's glide to an emergency landing. Flight Design expects to begin flight testing of its hybrid in one of its existing aircraft by the middle of 2009.”

http://www.avweb.com/avwebflash/news/FlightDesignHybridAero_200078-1.html

San Carlos, April 24, 2009 42 This motor is promising because of its Oxford roots, being designed by graduate students with the intended purpose of selling rights to private manufacturers. Its high power to weight ratio is interesting enough, but further modeling, based on the same factors that led to the demonstrated output shown, suggests that at higher revs, the motor could put out up to 150 kW. http://www.scienceoxfordnetworks.com/news-publications-news-articles/oxford- electric-motor-set-for-track-tests http://www.isis-innovation.com/licensing/3056.html

San Carlos, April 24, 2009 43 Alan Cocconi has built up AC Motors with his highly original solutions to myriad quandaries in electric motors and drives. No longer at the helm of that organization, he is devoting his time to a project called Skybase, a surveillance system using seven separate solar-powered aircraft that will hook up in flight to form a 280-foot wingspan, seven- motored stratosphere cruiser. Each of the seven individual aircraft will use the motor he originally designed for the Solar Impulse project, putting out a maximum 15 kW at takeoff, but slowing to produce 1.5 kW each at cruise. This 10:1 output ratio allows endless cruisinggg, with solar panels producing power during the day, and charging a battery array in each plane for power through the night. He is not in favor of using fuel cells for this mission as they require heating to prevent freezing in the low temperatures at high altitudes, and relies instead on batteries in a central cluster in each airplane. Alan says that batteries provide 90-percent cycle efficiency. His ironless construction reduces inductance losses and allows generation of smooth currents at low sppyeeds. The motors will turn over at only 800 RPM maximum. http://solar-flight.com/solong/index.html http://www.engineering.columbia.edu/news/archive/engnews_s98/cocconi.html http://www.designnews.com/article/3158-The_Quest_for_Perpetual_Flight.php

San Carlos, April 24, 2009 44 One must consider the total cost of batteries, including anticipated cycle life, to fully calculate the cost of powering electric aircraft. NiMH and NiCad batteries may be less expensive than lithium ion or lithium polymer, for instance, but three times as many are needed for an equivalent voltage. LiFePO4 batteries may have slightly lower voltages than straight lithium units, but promise more useful cycles. Any of this may be moot, because there may be a straight lifetime of three years for lithium batteries, regardless of their use. A new battery from Toshiba, the Supercharged Ion Battery, or SCIB, claims a life of 6,000 cycles. Its cost is unknown because Toshiba is releasing it only to OEMs, and its only current use is on the Schwinn Tailwind bicycle.

San Carlos, April 24, 2009 45 Tokyo Institute of Technology students, with a grant from Panasonic, used 160 AA Oxyhydride cells to power a small motor on their adapted HPA, driving the plane to about 5 meters height and 400 meters distance. Calculating a sale price of $5.00 per 4-pack, 160 cells would cost $200. 400 meters = 1,328 feet, or a quarter mile. Flying 1 mile on this aircraft would cost $800. http://panasonic.co.jp/corp/news/official.data/data.dir/en060718-3/en060718-3.html

San Carlos, April 24, 2009 46 From the University of London Press Release:. “Master of Engineering (4th year) ear) project ststudentsudents hav e modified an aircraft to flyfl on electric power, in association with Anglia Sailplanes and AeroElvira Ltd. “The first flights took place on 20/21 September. Test pilot, Derek Piggott, described the modified aircraft as a "delight to handle". “The aircraft was modified by the addition of 8 underwing pylons attached by removable straps. The pylons were fitted with 16 propellers (280 mm in diameter) driven by electric motors and powered by lithium-ion batteries supplied by Ripmax PLC. The motors were activated by a wireless link by the pilot in the cockpit. A permit-to-fly was issued by the British Gliding Association. “The project involved over 3 MEng Project groups over a period of 5 years, including for example the following students (now all graduates): Ross Shepherd, Stefan Wurwal, Mark Saunders, Hamza Baker, Mikel Alonso, Morten Christiansen, Sami Ghamloush, Mehrtash Lotfian, Mohammad Ali Sarkandi, Junaed Wahid.”

News date: 24 September 2008

Graupp$,ner 900’s cost $60 each, so the motor cost was $960.

http://www.pprune.org/aviation-history-nostalgia/343843-edgley-ea-9-optimist.html http://www.qmul.ac.uk/news/newsrelease.php?news_id=1122

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San Carlos, April 24, 2009 47 I’ve chosen to show the classic Pietenpol because it has been the test bed for so many different engines. Originally designed for use with the Model “A” Ford engine, which weighed 244 pounds with magneto, the “Piet” also carried the Ford’s radiator (21 pounds), a propeller weighing 15 pounds, water and oil. The total weight of the powerplant, ready to fly, was thus over 300 pounds. Consider a 43 hp Lynch Motor in place of the Ford, a five-pound controller, and up to 245 pounds of batteries, and one can see the potential. This may be an elusive dream with current technology, though. A takeoff run of 766 feet can get the Piet airborne, and establish a 350 feet-per-minute climb, assuming an 85-percent efficient propeller and the Lynch motor. Weight allowance for batteries would allow about 16kWh, or only about one take-off and a half-hour of cruising before the $24,000 battery pack would be drained (not good for life cycles, either). A full-hour of cruising would require a lighter, more efficient battery and $40,000. This would make 1,000 cycles at $40.00 per flight (plus charging costs), not much better, in terms of cost, than a regular vintage light aircraft. Consider that Pennec and Lucas in France built their Dieselis as a modern homage to the Pietenpp,ol, usin g a modern O pel diesel en gine in place of the Model “A” , and makin g, like the Pietenpol, a light wooden airframe, although far more aerodynamically clean. As a consequence, the Dieselis and its even cleaner outgrowth, the Gazaille, cruise at 90 mph on a little over one gallon of diesel fuel per hour. Both can cruise at 120 on two gallons per hour. Both could be capable, with refinement, of winning the CAFÉ 100 mph/100 mpg prize. Consider also that the weight capacity for power can be used for an efficient electric motor and controller, lightweight batteries, and the dream of a practical, two-seat light sport aircraft can be achieved. Consider also, that the electrification of classic aircraft could be realized, because of their heavy original powerplants.

San Carlos, April 24, 2009 48 In a discussion with Alan Fishman, he claimed that his batteries will last for 1,000 cycles if used carefully, as they have been in test flying. In cruise at 70 mph, the Moni’s batteries are being drained at 0.7C. His battery pack lists at $8,500, meaning that 1,000 flights (around an hour to an hour-and-a-half) would average about $8.50. Adding the cost of recharging to each flight, at .$0.52 per charge (central Florida utility rates) adds up to a direct and indirect battery charge of $9.02 per flight, or around $6.00 per hour if each charge does allow 1-1/2 hours duration. Mark Bri erl e, flflyi ing a t a s im ilar disc harge ra te a t a s lilightly htl s lower spee d in his ultralight Gull 2000, should experience much the same battery life and costs, but with less range per charge because of his slower cruise speed.

San Carlos, April 24, 2009 49 “Axel Lange, Chief Executive of Lange Aviation GmbH, said ‘We use Saft Li-ion batteries in this demanding application simply because we have found them to be the best on the market. The Antares demonstrator LF-20E flew on Ni-MH batteries and performed well. But the extra power available when we switched to the Saft Li-ion batteries has enabled us to more than double the launch height using a battery system that weighs 26 per cent less.’ Battery system “The Antares 20E is equipped with a custom-designed modular battery-system, utilizing Saft VL 41 M Li-ion cell s, th at pack as m uch pow er as possib le into a lig ht we ig ht and space efficient package. The battery system weighs 80 kg, which is around 12 per cent of the sailplane’s typical launch weight (with pilot and ballast) of 660 kg. “The battery system is split into two packs positioned in the leading edges of both inner wings. Each pack consists of 36 cells in series, divided into 12 three-cell modules. Together, both battery packs provide an operating voltage of 212 V to 288 V, depending on the state of charge (SOC). The dedicated battery management system ensures each cell is carefully and redundantly monitored and controlled to ensure that it delivers maximum performance while remaining within its safe operational parameters. “A full nine-hour charge from the onboard charger will deliver the Antares 20E approximately 3000 m above its launch point. It is also possible to use the available battery power for one or more takeoffs and powered climbs. Each extra takeoff costs approximately 100 m final climb altitude. Partial charges and discharges have no adverse impact on the battery life.”

http://www.saftbatteries.com/SAFT/UploadedFiles/PressOffice/2009/CP_20 - 09_en.pdf http://www.lange-aviation.com/

San Carlos, April 24, 2009 50 MMy fri end an d men tor, Mars ha ll Hous ton, prov ide d the fo llow ing to c lose ou t the presentation, thus ending things as we started, with the prescience of Jules Verne. It reflects the optimism and faith in the future that Victorian writers often espoused.

"And what will they burn instead of coal?" "Water," replied Harding. "Water!" cried Pencroft, "water as fuel for steamers and engines! water to heat water!" "Yes, but water decomposed into its primitive elements," replied Cyrus Harding, "and decomposed doubtless, by electricity, which will then have become a powerful and manageable force, for all great discoveries, by some inexplicable laws, appear to agree and become complete at the same time. Yes, my friends, I believe that water will one day be employed as fuel, that hydrogen and oxygen which constitute it, used singly or together, will furnish an inexhaustible source of heat and light, of an intensity of which coal is not capable. Some day the coalrooms of steamers and the tenders of locomot ives will , in stead of coal, be stor ed wi th th ese two con den sed gases, which will burn in the furnaces with enormous calorific power. There is, therefore, nothing to fear. As long as the earth is inhabited it will supply the wants of its inhabitants, and there will be no want of either light or heat as long as the productions of the vegetable, mineral or animal kingdoms do not fail us. I believe, then, that when the deposits of coal are exhausted we shall heat and warm ourselves with water. Water will be the coal of the future."

The Mysterious Island, Jules Verne

San Carlos, April 24, 2009 51 Thank you to Bruce Carmichael for getting me started in making these presentations, and Dr. Brien Seeley for inviting me to this Symposium. Special thanks to David Bettencourt, Patrick McLaughlin, Anne Lavrand, Roman Susnik, Michael Baker, Alan Cocconi, Steve Neu, Manfred Ruhmer, Bob Boucher, Otmar Ebenhech, Edwin Brekke, and Marshall Houston, for guiding my research and testing my conceptual understanding. This presentation is dedicated to the memory of Jocelyn Latka, my late granddaughter, who showed a courage and willingness to test the limits of her capabilities that has been an inspiration to her grandfather and would be to anyone.

San Carlos, April 24, 2009 52