henryk
Well-Known Member
=ONLY 250 exemplares!
=NO serial production...
=NO serial production...
Well, by car standards! By aircraft standards that would be pretty good! :gig:=ONLY 250 exemplares!
=NO serial production...
=thru!I personally beleive that electric propulsion in sport aviation is going forward
www.pure-flight.cz
Martin
https://www.youtube.com/watch?v=zd5z0kQCNGQFor a battery electric or hybrid electric, I have a question about countering the wing tip vortices with wing tip propellers turning the opposite direction. What kind of forces are in play here for a 500 kg General Aviation aircraft at 100-300 km/h? Does reduction in span make adding the wing tip propellers worthwhile? It is one of the benefits of electric power I can't quantify. Great discussion.
The tip rotors in that first video seem kind of pointless since the wingtip rudders are going to handle the tip vortexes on their own.
They actually run counter to the vortex and help maintain low pressure on the wing by keeping the vortex in check. At least at low speeds when the Vortex is really bad. Which helps STOL dramatically.Wingtop props don't eliminate drag from tips, they convert some of it into extra thrust. If you can do that twice by having winglets and tip props, even better!
Wingtip engines are vastly more effective. The flying pancake makes everything else look like a joke. Props running counter to the flow of the vortex.The tip rotors in that first video seem kind of pointless since the wingtip rudders are going to handle the tip vortexes on their own.
Yeah, I get what they're supposed to do but the tip rudders already do that. The pancake is a different critter and needs those props because it's such a low aspect wing.Wingtip engines are vastly more effective. The flying pancake makes everything else look like a joke. Props running counter to the flow of the vortex.
The wingtip rudders can only partially neutralize the vortex, which the wingtip engines contain the pressure a magnitude better.Yeah, I get what they're supposed to do but the tip rudders already do that. The pancake is a different critter and needs those props because it's such a low aspect wing.
My point is that unless it's a racer or something, the tip vortexes on a high-aspect wing aren't going to be that bad in the first place, so the tip rudders handle it well enough that we don't need to worry about it.The wingtip rudders can only partially neutralize the vortex, which the wingtip engines contain the pressure a magnitude better.
The pancake requiring them doesnt change that they are more effective. A high aspect wing would also perform drastically better with wingtip engines than with rudders or winglets.
The two are not even in the same league when it comes to the level of improved performance.
L/D is the same up high. There's no energy benefit to flying high. You have to fly faster to stay at best L/D at altitude. That means you need more power than down low. Electric doesn't suffer a power loss at altitude, however. So an electric plane with a reasonably healthy power surfeit for takeoff and climb should fly much higher than a non-turbo gas plane.Random thought. Traditionally, with gas engines, energy is abundant and fairly easy to manage. Therefore, there is a greater focus on a simple airframe and engine reliability.
With electric motors, engine reliability is more "built in", but energy is much more critical. Therefore does it make sense to consider going higher and pressurize the plane so you get a higher TAS with a lower drag for electric planes? Could the new normal be, pressurized to a few PSI for electric planes?
Tim
Maybe I could have stated it better.L/D is the same up high. There's no energy benefit to flying high. You have to fly faster to stay at best L/D at altitude. That means you need more power than down low. Electric doesn't suffer a power loss at altitude, however. So an electric plane with a reasonably healthy power surfeit for takeoff and climb should fly much higher than a non-turbo gas plane.