To Read Sport Aviation's January 1990 Ed on the ... - Courtesy Aircraft

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·eight, considerably more power - ::e needed than the 85 hp of the Eris calculations worked out, it was ...s t his 2-place flying automobile -eq ire about the same power as a ace lightplane ... 140 to 150 hp. er would have to accept the the cost of the extra power for o having a car capable of flight. -..-,..,..nUllO to Molt, when he and his en- - sat down and began to develop the ::on uration, the Aerocar more or less _:-ed itself. They knew that the public accept anything radically different - car portion, especially with regards to . so the wing had to be positioned so - ,., as as unobtrusive as possible. That, , dictated a high wing mounted as - - as possible. They also felt that the ould object to having to remove the :r:oe er, as was necessary with the Fulton ·an, in order to use the car portion on way, so that plus several other lac- "' ... forward visibility, weight distribution, :x::essive heat in the cockpit, etc .. .. made decide on placing the engine behind :oe seats, almost on the aircraft C. G., and opeller at the end of a long tail cone. -:: ovide adequate prop clearance for rotatake-off, the tail cone would have to :e angled up considerably .. . but, fortui- ,. , in the right direction for overcoming e atural pitching moment of the wing . -- . in turn, dictated the detaching of the arid tail cone as one unit .. . which wed the folding back of the wings and of the flight portion of the vehicle bee car like a trailer. The configuration e tail also more or less fell into place. A entional vertical tail would have caused :::e:arance problems in garaging the Aerocar, s:: a "Y" tail was the logical solution. A wel ::o-:led side effect was the fact that bottom e positioning of the vertical tail served to agel)' offset adverse yaw . . . and was a r in making the Aerocar spirally stable. off, the craft would eventually enter a w turn, then recover on its own . . . insaad of winding up in a classic graveyard • as conventional aircraft are prone to Some earlier roadable aircraft, such as Waldo Waterman's Aerobile, had just 3 wheels, but, again, Molt and his team felt this deviation from normal automotive practice would be a detriment to the acceptance of the vehicle, so they stuck with 4 wheels. Perhaps the most demanding criteria Molt had established was that the car portion had to be sturdy and reliable enough to endure everyday, all weather use just like a normal automobile. Most of the earlier attempts to develop a roadable aircraft had assumed only limited use of the car portion. This meant the Aerocar would have to have adequate suspension travel for both the road and hard landings, it would have to "corner" and steer like a normal car, it would have to have 4-wheel brakes, controls and instrumentation for operation as both a car and an airplane and it would have to have the required lights for both land and sky. It would also have to have a good heater, roll down windows, windshield wipers, both aircraft and auto radios (and antennas), a rear view mirror, turn signals, a jack for changing tires , a horn (that doubled as the stall warner) and much, much more. In retrospect, the engineering solutions the trio came up with to solve the myriad of problems they faced in attempting to cram all the systems and components needed for highway and aerial operation into a single small vehicle were quite remarkable . . . and still are to this day. The Aerocar was, for example, one of the first automobiles to use outer panels made of resin impregnated fiberglass .. . several years ahead of the Corvette. Further, the front wheel drive and 4-wheel independent suspension they designed 40 years · ago is in concept what has only recently come into general use in mass produced automobiles. From an engineering standpoint, as well as that of the operator of an Aerocar, one of the most interesting features of the machine is the fail safe means by which the various controls automatically engage and disengage when the wings and tail are removed for driving . . . and replaced for flying. As the car is backed into the tail cone, the splined end of the drive shaft slips into a larger, similarly splined receptacle . .. and a cluster of little metal pads mounted on the ends of levers butts up against an identical cluster in the other portion of the vehicle. When one of the controls in the cabin is moved, a lever and pad in the cluster moves, pushing its counterpart and moving the elevator or rudder or the ailerons. It is a clever system that requires no fasteners .. . and the engine will not start unless every part of it is matched up and ready to function properly. The mating of the clusters ... for flying ... also shuts off the front wheel braking system, automatically pops the rudder pedals up into position for use (they fall flat on the floor and out of the way when the wings are disconnected) and the control wheel/steering wheel unlocks to permit fore and aft motion for elevator control (it locks for driving when the wings are disconnected). The tail cone and wings are then locked into position by special pins .. . and, again, the engine will not start until every component is properly secured for flight. The drawing shown here indicates the placement and integration of the various auto and aircraft systems, the most obvious element of which is the use of a single engine for both road and aerial operation. (Some flying cars had used two engines, one for road travel and another for flying.) This meant a long driveshaft back to the tail mounted propeller and a second shaft extending forward to drive the front wheels. Front wheel drive, parenthetically, was required because of the need to have the rear wheels, which touch down first in a normal landing, free from suddenly spinning up and possibly damaging the differential and transmission. Transmitting power to each of the driveshafts presented special problems that had to be dealt with separately. <strong>To</strong> smooth out the power pulses of the big 4-cylinder Lycoming 0-320 to the from wheels, Molt decided to use a ''fluid drive" torque converter attached where a propeller would normally go on the engine, with pulleys and four belts running down to drive the shaft extending forward to the front wheels. This shaft, in turn, drove a fan to cool the engine, mounted a manual clutch and a three speed (plus reverse) Crosley transmission and ended up Transmission Universal Joint SPORT AVIATION 15
Molt Taylor's wife, Neil, in an early 1950s Aerocar publicity shot posed in front of a hotel. This is the prototype Aerocar I now owned by the EAA Aviation Foundation. plugging into the lightweight differential for the front wheel drive. The Lycoming, incidentally, had to be derated from 150 hp to 143 hp, largely because of the need to offset the carb intake to clear the driveshaft running up to the front wheels. The car portion was still overpowered, however, and especially over torqued. It was easy to take off in high gear and spin the Crosley wheels on dry pavement at will. There was still adequate power for flight, also, with a 550 fpm rate of climb at full gross (2,1 00 pounds). Potentially, the biggest single problem in the entire development of the Aerocar was dampening out the torsional resonance in the long driveshaft back to the propeller ... because to that point in aviation history it had never been accomplished. The power pulses of a reciprocating engine cause minute "wrap-ups" or twists of even the stiffest of driveshafts and when they get in phase with other vibrations in the system, a broken shaft is the inevitable result. Right after the first flights of the prototype Aerocar, Molt realized he had a problem with his propeller shaft, so he immediately set out across the nation to visit Bell Helicopter and other outfits with products incorporating driveshafts. Every type of vibration damper Molt had ever heard of was investigated and the most promising were tried out on the Aerocar, but nothing worked until, quite by accident, he read in Design News about a device called the Flexidyne "dry fluid coupling", a French invention manufactured in the U. S. by the Dodge Manufacturing Company of Mishawaka, IN. The Flexidyne is a type of clutch that uses tiny steel shot, enclosed in a housing and packed into a nearly solid mass by centrifugal force, to lock up a "wavy plate" on the end of the unit's output shaft to transmit power. The shot provide just enough "give" to absorb the engine's destructive power pulses. The Flexidyne has been used for decades on all manner of machinery to dampen vibration and is built in a wide range 16 JANUARY <strong>1990</strong> of sizes. Molt chose one appropriate for the power of the Lycoming, ran tests on it and found to his immense relief that it worked perfectly. It was a critical piece of the puzzle, the part that made it possible for the Aerocar to ultimately be certified by the CAA . . . and the part without which so many other tail pusher aircraft have been failures. The Flexidyne is still the only such device to have been certified by the CAA!FAA and examples have been operated for thousands of hours on the Aerocars and Molt's IMP series of homebuilts with no problems at all . The only negative is the fact that the Dodge Manufacturing Company has always been adamantly opposed to the use of the Flexidyne in conjunction with anything other than electric motors. One might think the firm would be proud of the fact that their units are so good that they have been certified by the United States government for use in an aircraft, but that is not the case. Another problem Molt had to overcome was the typically rough start-up and shutdown cycles of large bore 4-cylinder aircraft engines like the Lycoming, which auto owners would not like. Fortunately, Bendix was willing to develop shielded magnetos with centrifugal spark advance, which not only cured the start/stop problems but also allowed a slower, smoother, car-like idle. A "vibrator" system to replace the conventional magneto impulse coupler also had to be developed to aid starting .. . and Delco worked with Molt to build a geared starter. Aircraft generators that did not charge until they were turning about 1 ,500 rpm were obviously unsuitable for driving in traffic, so Molt switched to an alternator as soon as those devices came on the market for autos. Using the mixture to cut off the engine was not something car owners would be familiar with, so the Aerocar was shut down with the ignition switch. Some of the features of the Aerocar caused problems of their own and had to be corrected with still more innovation. With the heavy engine located in the rear of the car the front drive wheels were rather ligh tl ~ loaded and this, coupled with the rigidity c the car's frame, resulted in a loss of tractiogoing up steep grades . A '1ork-loc" type c differential pretty we ll eliminated that prot lem in the car only mode of operation, but :. loss of traction still resu lted when the wing; and tail were being towed behind the ca· That was solved by devising a tow hitch wi: the attach point at about the level of the tc: of the car. The geometry involved actua served to shift the weight to the front whee for better traction. The most serious threat to life and lirr that developed during the long certificatir period was a w~ry bad case of aileron flutt ec The origir.dl ailew ns were full span so t ~ = they (;uuld be foldf:d down to reduce the si: load when the wings were being towed t hind the car. They were not balanced and they almost bit Molt during the test fly phase. Of course, new balanced ailercwere substituted after the incident abou be re lated . It all came about because : CAA could not allow its test pilots to fly : Aerocar until it had been flutter tested. l able to afford the services of a for-hire t~ pilot, Molt opted to strap on a parachute c. do it himself. Red line was to have been · - mph, but as he reached 135 mph in a sha dive ... with CAA officials just off his v. in a Stinson 108-3 ... the ailerons sudde- and violently fluttered. Although the C later told Molt the Aerocar was shakin ~ badly that the tail was actually wagging t ~ and forth, the airframe miraculously did come apart before he was able to thr back and get the vibration stopped. His p lems were not over, however. When he tempted to throttle back for landing, th e ter started again. This time he had to SP= up to stop the shaking . .. and therefore - to land the airplane at cruise power! - busy to really be scared while still in the Molt climbed out, walked calmly back tc tail cone . . . and saw that it was crurr:
Page 2 and 3: MOLT TAYLOR'S QUEST FOR A MORE USEF
Page 4 and 5: week or so Molt was back at Long Be
Page 8 and 9: so badly that it was canted a fu ll
Page 10 and 11: airplanes . . . a presey Mustang ,
Page 12: ufacture of power packages for hang

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