Thought I'd take this thread out of Orion's Raspberry thread.
I remember a really great article some years ago - unfortunately I can't remember who wrote it, although possibly it was Molt Taylor - that discussed the realities of roadable aircraft design.
The gist of the article was that a practical roadable airplane/flyable car was an engineering possibility, as Molt himself demonstrated with the Aerocar series back in the '50s. Certainly any such vehicle would be a bit of a compromise, somewhat lacking in performance both on the road and in the air, but that a really good engineer (or more likely team of engineers) could probably reduce the compromises to an acceptable level, given the advantages of the entire system.
The major holdup, then, is not engineering, but regulatory. Not only do you have to meet FAA certification standards, but also all the standards for automobiles: front and rear bumper impact and height requirements; side impact standards, airbags, automobile seatbelt standards, luminosity standards for road and brake/marker lighting, roll over, general collision testing... ad nauseum.
Then pile on top of that smog system requirements, CAFE fuel-economy standards for you as a manufacturer, and the like, most of which will probably force you to burn auto gas in the motor, and where are you going to get that at most airports? Do you have to land with enough reserve so you can drive to a gas station? Do you carry around an entirely separate 'flight' motor and fuel system to get around that problem and what about the weight penalty of that?
In short, trying to meet the regulatory standards of two industries is the major problem in roadable aircraft design. It's also one of the reason you've seen a rash of roadable designs with less than four wheels on the 'car' component: anything less than four wheels and the Feds think it's a motorcycle, which has far less stringent 'certification' requirements than a car. But then, if you went that way, all your customers would have to get motorcycle licenses to drive your vehicle...
It doesn't seem to end. :wail:
I remember a really great article some years ago - unfortunately I can't remember who wrote it, although possibly it was Molt Taylor - that discussed the realities of roadable aircraft design.
The gist of the article was that a practical roadable airplane/flyable car was an engineering possibility, as Molt himself demonstrated with the Aerocar series back in the '50s. Certainly any such vehicle would be a bit of a compromise, somewhat lacking in performance both on the road and in the air, but that a really good engineer (or more likely team of engineers) could probably reduce the compromises to an acceptable level, given the advantages of the entire system.
The major holdup, then, is not engineering, but regulatory. Not only do you have to meet FAA certification standards, but also all the standards for automobiles: front and rear bumper impact and height requirements; side impact standards, airbags, automobile seatbelt standards, luminosity standards for road and brake/marker lighting, roll over, general collision testing... ad nauseum.
Then pile on top of that smog system requirements, CAFE fuel-economy standards for you as a manufacturer, and the like, most of which will probably force you to burn auto gas in the motor, and where are you going to get that at most airports? Do you have to land with enough reserve so you can drive to a gas station? Do you carry around an entirely separate 'flight' motor and fuel system to get around that problem and what about the weight penalty of that?
In short, trying to meet the regulatory standards of two industries is the major problem in roadable aircraft design. It's also one of the reason you've seen a rash of roadable designs with less than four wheels on the 'car' component: anything less than four wheels and the Feds think it's a motorcycle, which has far less stringent 'certification' requirements than a car. But then, if you went that way, all your customers would have to get motorcycle licenses to drive your vehicle...
It doesn't seem to end. :wail: