Editor’s note: Earlier this week Dick Collins shared the long list of airplanes that never made it from dream to reality. In this article, first published in the January 1959 edition of Air Facts, we look at another concept that has never really taken hold–the flying car. Molt Taylor was perhaps the most successful (or least unsuccessful) flying car entrepreneur of the last century, and even delivered a few copies of his Aerocar. In this article, he shared the challenges of creating a flying car that solved the “doorstep to doorstep” problem. Many of the questions he asked are still being asked today about the Terrafugia Transition and other flying car concepts.
What’s With Flying Automobiles?
It has been a long quest.
By M. B. (Molt) Taylor
Ever since the introduction of the airplane, men have sought to make the machine more practical for the routine travel of daily life by making it possible to use the aircraft for the whole trip from doorstep to doorstep. The trouble has always been that it has required another vehicle to take you to the airplane, it required still a third vehicle to take you to the doorstep of your destination.The development of the helicopter was a hoped-for solution to this dilemma, but it too has proven to have limitations which prevent its use as a doorstep to doorstep transportation medium. While it might be possible to land a helicopter on the roof of a few buildings, and in the back yards of a few people, it would be highly impractical to use one for the daily routine personal travel engaged in by most individuals. Accordingly, the air has remained the travel media of only a few who tolerate the limitations of the vehicles presently available for air travel.
As early as 1913 aircraft designers began thinking and experimenting with what appeared to be a more practical solution to the problem of a single vehicle which would serve the needs of doorstep to doorstep travel via the air, and the obvious mating of the automobile to the airplane was attempted at that time. It was obvious that both types of vehicle had much in common and such a dual-use type machine would be practical. For instance, both had engines, seats, wheels, windshields, etc. However, this early trial was doomed to failure due to the state of the aeronautical art and the great weight of the various automotive components then available for such an experiment. The machine barely got off the ground and was highly impractical.
After this, there were few attempts in the late 1920′s, however the idea was more or less left alone and little was heard of “Roadable Aircraft” or “Flying Automobiles” for many years. During the 30′s a couple of bold experiments tried to again achieve a successful mating, but their attempts were similarly plagued with over-weight components, limited engineering skill, and insufficient finance.
Right after WW-II everyone was talking about having an airplane in their garage, and the light aircraft industry was grinding out lightplanes as never before. The huge Consolidated-Vultee organization gathered together all of the talent they could find that had ever experimented with roadable aircraft or flying automobiles and set about to develop an aircraft that could be put in the garage of the average family and provide both air and road transportation in a single vehicle. This program was unhampered by lack of finance or talent, in fact it probably suffered from “too many cooks.”
The resulting aircraft proved to be too complicated and costly, and had inherent limitations due to its use of two separate engines and its inability to take its flight component with it during road operations. However, the machine did fly and resulted in considerable progress towards the development of lightweight components which were required for such a vehicle.
Similarly, the Fulton Airphibian which received widespread publicity all over the world resulted in further acceptance of the “Roadable Aircraft” concept. This project also suffered from financial limitations although it did progress to the state of CAA Certification before its builders were forced to retire from further progress. There were others who laid the finest plans, and some even progressed to the stage of hardware. However, so far as is known by the writer none ever solved the problem of true doorstep to doorstep mobility and practical usefulness for routine daily travel.
This gets us to the AEROCARs with which I have had intimate experience over the past ten years. The AEROCAR project is the result of extensive personal experience with light aircraft by the writer during the 1930-1940 period and the conviction that mass use of the air as a medium of travel only awaited the development of a truly practical personal flying machine. Everyone has dreamed of being able to drive his automobile out to a wide place in the road, pressing a button on the dash to convert it to an airplane, and flying off into the blue. The air would be filled with such machines if they were available.Study of the technical aspects of the problem showed that there were two main difficulties to be overcome. First was the original problem of weight which had licked the earliest experimenters. The other was the matter of a suitable power plant. Until the engines of the post WW-II period were available (100 h.p. and over) there had never been a practical power plant for use in such a machine.
A further fact was apparent, and that was the need of such a machine to be able to fly from point A to point B, then drive to point C and be able to fly back to point A from point C. This meant taking its wings with it during road operations. This capacity lets its owner fly or drive as the situation dictates and does not require that he go back to the point where he stopped flying to retrieve his wings. It permits landing and driving through areas of bad weather and to then fly again when the weather improves. And, it also permits the owner to land and continue on to his destination when it gets dark.
With these requirements of complete road mobility, one other most important fact was obvious and that was the absolute need that such a machine must be as practical for the trip down to the corner drug store as it is for the flight to some distant destination. Thus the machine could not be a “roadable aircraft” which was primarily designed for flying; but rather, it had to be a complete practical automobile that was just as much at home on the highway for weeks on end as it was in the air.
This latter requirement posed some real problems. If the owner was to get the full utility out of this single vehicle he had to have a machine which not only met the safety requirements of a CAA Approved Aircraft, but it had to be one which would go out and operate on the road without excessive maintenance, at a relatively low cost and with the complete flexibility which we have come to expect from a modern motorcar.
This meant that during “car” operation it would have to be capable of moving along with the high speed traffic of today’s freeways, travel in bad weather on rough roads, and embody every known feature of comfort, appointments, ease of driving, etc., of a modern automobile. It had to meet the various requirements of the State Vehicle Codes so that its operation as a complete machine on the highways was legal. And it had to be a good aircraft.
There was obviously little room for compromise. These requirements created tough technical problems and it is now obvious that the lengthy development period of the AEROCAR was largely dictated by the fact that practical solutions necessary for the complete development of the vehicle did not become available until recently. These have included such items as lightweight components (like nickel-cadmium batteries), well developed fibreglas techniques, and resins (which permit light, inexpensive construction), and power plant developments in the light aircraft field so that an aircraft field so that an aircraft engine could be operated in the auto configuration satisfactorily.
The latter problem has necessitated the special development of a suitable generator, starter, and ignition system for the AEROCAR so that auto-like operation was practical. The resulting components have proven so successful that the special starters developed for the AEROCARs are now standard equipment on the Lycoming engines, and the magnetos, with automatic spark advance (like automobile), should soon become standard lightplane equipment. These permit auto-like engine starting and smooth low-speed engine performance without the excessive vibration now apparent in the operation of so many lightplanes. These were just a few of the many technical problems which the AEROCAR designers had to overcome before the vehicle was actually perfected.Probably the most interesting problems which had to be overcome in the design and development of a “Flying Automobile” were the imagined problems which didn’t really exist at all. Among these was the idea that some sort of lever would be included which would permit the owner to convert the car to an aircraft whenever the lever was operated. It was also presumed that something had to be used to convert the engine from flying to driving.
Actually this problem did not exist. The car drive is merely left in “neutral” when you fly. When you attach the wing-tail component it automatically hooks the engine to the propeller. Nothing could be easier.
Similarly, it was imagined that the controls would have to be “hooked-up” for flying and vice versa. Here again the engineers were able to devise simple, fool-proof mechanisms which permit the same steering wheel to be used for flying or driving.
The rudder pedals drop to the floor out of the way for road operations and come up into flying position when the wing-tail is attached. This attachment also results in the steering wheel shaft becoming free for elevator motion of the steering wheel for flying and the entire flight control system engages automatically without any rigging or adjustment. Here again, nothing could be easier or more practical.
Probably the most concerning problem was the matter of the wings being adequately attached so that they couldn’t come off in flight. This too was merely an imagined problem. Tapered attaching pins which are physically impossible to move in flight are driven with a little hand crank. The engine will not start until all of the attaching pins are driven completely. Fail-safe switches at each attachment point, linked with the starter solenoid, provide this feature.
There is one imaginary problem which seems to bother aviation people more than any other. This is the matter of the engine and its dual use for both flying and driving. Many people ask if there are any problems of engine cooling while operating on the ground. Just the reverse is true. This is due to the fact that road operation of the engine requires so little power that the problem is to get the engine to run warm enough for good efficient operation. This has necessitated use of a thermostatic oil radiator control and baffle arrangements together with a cooling fan installation so arranged as to permit completely routine auto operation in either extreme hot or cold weather. The resulting installation is more than adequate to meet the CAA cooling requirements for protracted full throttle running as an aircraft, even on the ground on a 100 degree day.The daily routine auto operation of the engine has proven to be beneficial to the life of the engine. With the thermostatic controls, moisture which normally forms in an engine when it cools after running is evaporated every time the engine is started and does not get a chance to form acids and attack the cylinder walls and exposed internal metal surfaces as it does in an aircraft-only operation where the engine may only be used every week or so.
The usual occasional aircraft-type operation results in microscopic rust forming on the cylinder walls, only to be wiped off by the pistons and circulated with the oil through the bearings and gears when the engine is started. This is entirely eliminated in the flying automobile operation where the engine is started as a matter of routine probably three or four times every day. After ten years of experience and several complete teardowns of engines which have had “Flying Automobile” use, we have ample evidence that the dual use of the engine is actually beneficial for these reasons.
Another imagined problem is the matter of “using up” the life of the aircraft engine for road operations. Here again the beneficial use of the engine for daily road travel enters into consideration. However, many people feel that some sort of set period of life for the aircraft engine is established. This is not true, of course, and many flight operators run their engines up to 1200 hours between complete overhauls. This is common in training activities where the engine is being used every day (as with the flying auto). Other owners find that their engine requires major overhaul at as low as 400-500 hours. These are usually the weekend only flyers.
In AEROCAR operation, where the same engine is used for flying and driving, some sort of accurate determination of how much time is actually put on the engine is required. It would be totally impractical to try to use a written log as one does for flying. The result has been the standard installation of a recording tachometer in each AEROCAR. Similarly, the AEROCARs include a standard automobile type speedometer with recording odometer to show mileage traveled. The gearing of the engine to the wheels of the AEROCARs is such that if one were to go out on the highway and run at 2350 cruise r.p.m. for one hour he would find that he had traveled 50 miles on the road. Accordingly, since the recording tachometer is set to indicate one engine hour for an hour of operation at 2350, it is very easy to use the recording tachometer and odometer together, to determine the flight hours.
For instance, if the odometer shows 500 miles, this is easily transposed into 10 hours of engine time on the recording tachometer. If the tachometer shows 25 hours of total engine time, then one can assume that he has also accomplished 15 hours of flight. Since an AEROCAR will cruise approximately 100 m.p.h. in flight at 2350 and go approximately 50 miles on the road at 2350 in one hour, it is reasonable to figure that the 25 hours shown on the recording tachometer has resulted in approximately 1500 miles of air travel and 500 miles of road travel, for a total distance of 2000 miles.
As a general average, it has been found that a person will drive an AEROCAR about 10 times to every use of the machine as an aircraft. However, records also show that air trips average about 10 times longer than road trips. A recent check of one of the newer AEROCARs shows that with a total of 500 hours on the recording tachometer and about 9000 miles on the odometer, it is reasonable to assume that the machine has provided approximately 41,000 miles of travel. This particular AEROCAR was given a 500 hour inspection at the time and it was found that the engine would still turn within a few r.p.m. of its original power when it was new. AEROCAR propellers are set to turn 2300 r.p.m. full throttle on the ground.As long as the engine will turn this r.p.m. or within a few r.p.m. of this level it is considered that the engine is OK. As the engine begins to near time for an overhaul, the r.p.m. it will turn will drop off slowly, and while there is no real time limit, it is our recommendation that the engine should probably best be overhauled at between 700-800 hours. Thus, you can see that the aircraft engine is not being “used up” to any great degree by the routine road operation, and after all, what you are interested in is miles of transportation provided by the vehicle. Engine teardowns of AEROCAR power plants with 700-800 hours have shown that the reduced wear and less costly overhauls due to the daily use more than make up for any use loss resulting from road operations.
Another problem which is largely imaginary is that of road mileage. We have found that the reduced power requirement for road travel permits you to lean the mixture as far as it will go and still take the throttle smoothly for passing and normal road acceleration. The result is a good healthy 18 miles per gallon fuel economy as contrasted with approximately 12-13 miles per gallon if the mixture is not leaned out. Leaning has the additional beneficial effect of increasing the road operation temperatures and since full lean still does not result in anything more than a good “warm” engine even on a very hot day, we operate all AEROCARs in the full lean condition while on the road. With 100 m.p.h. cruise and 8 gallons per hour fuel consumption at cruise, fuel economy in flight is thus just a bit over 12 m.p.g.
Although experience has shown that automobile fuel is not acceptable for use in the aircraft engine used in the AEROCAR for flight operation, we have used it for road-operation only on numerous occasions when aviation fuel was not available. We then confine operation to driving. These intervals are kept as short as possible and usually only far enough to permit travel to the nearest airport where 80/87 octane aviation fuel is available.
While aircraft type fuel is required for flying, it also works out that its use on the road is no more costly than automobile type fuel since most states sell aviation fuel ex-road taxes. Whenever flying cars get into widespread use, this advantage will disappear. However, it will probably then be possible to get State Highway Authorities to build wide places along the highways for the use of flying automobiles with the road taxes paid on the fuel they use.
When you consider that an AEROCAR will permit you to make a 200 mile trip from downtown to downtown in less than two and a half hours, including time to put on the wings and take them off again and to drive to and from the airport, then the approximately 90 miles an hour average speed for the trip between exact doorstep destinations really makes good economics. This becomes especially apparent when you consider that the national average auto speed for such a trip is only a bit over 40 m.p.h. if you drive. Thus AEROCAR is the only single vehicle that can make the trip between the two points and average a higher speed than an automobile.
While the helicopter can make the trip between special selected destinations, it does not have the flexibility required for the trip between just any two points, and it too suffers from weather, night, and other terminal limitations.
Yes, a “Flying Automobile” does provide the sort of day to day personal transportation we would all like to have. It is truly the airplane at home in the garage. While the present AEROCAR is a long way from the “push button” type we can now visualize for the future, its five minute requirement for taking the wings off or putting them on is not prohibitive. The lengthy development period of the vehicle has permitted engineers to not only perfect its mechanical features, but has also allowed its developers to embody qualities which now make it equal to the dual job it must perform.It remains to be seen whether the public, in its quest for a means of getting from one place to another faster, will now accept this new form of personal transport. If they do, they will fill the sky with vehicles which can truly use the free highways of the air and thus provide thousands of people with a faster mode of personal transport.
The AEROCARs are now fully CAA Certificated and they are available. While the present $15,000 price [$117,000 in 2013 dollars--Ed.] is higher than desired, the utility as well as the point to point transportation capacity of the machine makes even the present price practical. The superb flight characteristics of the AEROCARs make flying as much like driving as is physically possible. This, and CAA approval, eliminates any considerations regarding difficulty of operation or lack of safety.
It now appears that the development of a four passenger version of the AEROCAR would be very desirable. However, a recent study of available engines of the necessary power (approximately 250 h.p.) indicates that none of them lend themselves to the dual flight-road operation conditions. This is due to the problem of engine torsional vibration and balance which are inherent whenever the inertia load of the propeller is removed as it would be for road travel. It appears that a four passenger AEROCAR is going to have to await further development in the engine field. This puts any possibilities a long way in the future.
The present situation for “Flying Automobiles” seems to resolve itself into finding a solution to the problem of making the vehicles available to the public at a reasonable cost. The cars cannot be produced inexpensively unless they are produced in quantity. Quantity production is not warranted until volume demand is indicated. Capital for volume production is not going to be available until the potential market is a proven fact. Thus the old “hen vs. the egg” situation seems to be the only problem at the moment. Only public acceptance will determine the solution.
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Public acceptance never came for the AEROCAR. While Taylor did win some orders, it wasn’t enough to enter full production and the AEROCAR remained a novelty. A total of six were built, and the original one now sits in the EAA AirVenture Museum in Oshkosh, WI. Taylor did design some other airplanes, including the Taylor Coot, before his death in 1995.