mstull
R.I.P.
I'm designing my next plane... an electric powered, fixed wing U/L... using this propulsion system: http://www.electraflyer.com/tech.html
This is a very challenging project. The weight of the propulsion system with batteries is about 111#. So the airframe will have to be very light to be legal. But the motor only puts out 18 Hp. So the plane will have to be very low drag.
This propulsion system lends itself well to motor-gliders, with their extremely low drag enclosed cockpits. But I prefer an open cockpit.
To climb with that much weight and that little horsepower, the plane will have to fly very slowly... so all the power isn't used up fighting drag. My last monoplane wing was as light, high lift, and low drag as I could make. This wing will have to be lighter. But to be lighter, there has to be more flying wires... which add drag.
I think it might be marginally possible to make a wing/plane like that. But I'm starting to wonder if it will be worth the effort. The plane would climb slowly, cruise slow, be a little flimsy, and have very limited endurance. And the complete propulsion system is about $12,000.
If the propulsion system had low power OR high weight, it would be reasonable. But having both would make a lousy airplane. I'll keep going through napkins, hoping for a breakthrough. But it will take a really big one to make this project work.
One big help would be if the FAA ruled that 30# of the battery weight could be counted as fuel, and not included in the empty weight. But knowing the FAA... they'll probably choose not to address the issue.
This is a very challenging project. The weight of the propulsion system with batteries is about 111#. So the airframe will have to be very light to be legal. But the motor only puts out 18 Hp. So the plane will have to be very low drag.
This propulsion system lends itself well to motor-gliders, with their extremely low drag enclosed cockpits. But I prefer an open cockpit.
To climb with that much weight and that little horsepower, the plane will have to fly very slowly... so all the power isn't used up fighting drag. My last monoplane wing was as light, high lift, and low drag as I could make. This wing will have to be lighter. But to be lighter, there has to be more flying wires... which add drag.
I think it might be marginally possible to make a wing/plane like that. But I'm starting to wonder if it will be worth the effort. The plane would climb slowly, cruise slow, be a little flimsy, and have very limited endurance. And the complete propulsion system is about $12,000.
If the propulsion system had low power OR high weight, it would be reasonable. But having both would make a lousy airplane. I'll keep going through napkins, hoping for a breakthrough. But it will take a really big one to make this project work.
One big help would be if the FAA ruled that 30# of the battery weight could be counted as fuel, and not included in the empty weight. But knowing the FAA... they'll probably choose not to address the issue.
