Testing Electric Propulsion Unit For a Light Airplane

Asm109 said:
The question is not can an electric motor generate enough power to make an aircraft fly. Its can an aircraft with enough battery capacity for a useful time aloft, get off the ground.
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Yep, pretty much. Battery energy density is still pretty poor compared to fuel. Currently electric cars are SUPER heavy as a result. This isn't a big deal for cars, since 'heavy' isn't nearly as big of a deal when most of the weight is taken up by the wheels. IN a plane, every pound counts because every pound is 'supported' via the motor via lift.

We either need to figure out how to make the motors so much more efficient that this is made up for (which, for what its worth, is at least part of the way there), OR a way to get higher energy/lb batteries.
 
Takes off on it's own. Flies like a conventional plane. The pilots breath O2 so it can fly at pretty high altitude for efficiency. I would have loved to see it land at Allentown.
Robert
 
rwm said:
Takes off on it's own. Flies like a conventional plane. The pilots breath O2 so it can fly at pretty high altitude for efficiency. I would have loved to see it land at Allentown.
Robert
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Cool! That sounds pretty neat!
 
I have to plead ignorance to most aviation theory. I'm an 82 year old retired Tool & Die maker. My son sells model airplane stuff, scale, rubber powered. (google "Volarè Products) I make balsa props for him, The pitch (angle of attack) is based upon the diameter times 1.3 as the nominal pitch, though it often is varied, usually flattened out, not advanced.

My comment about pitch vs. power is driven by "how flat can it go to continue to increase time" (of the rubber band unwinding).

Probably not an appreciable amount.

Thanks for the explanations. I enjoyed the UTube presentation. Yes, the subtitles helped (made it possible to understand).

Tom
 
wrat said:
Long and short: it's a thread about electric planes, not cars.
I only brought up cars as an illustration of *regulation* not technology.
In order for an electric plane to become Certified, some regulations are gonna hafta change. That's just the reality.
For anyone interested, all the regs are here:
www.faa.gov
What changes that will be, if any, or if ever, I don't know.
Among these regulators is the truism that "no one asked you to fly over them". Meaning when a plane crashes on innocents, it's a really big deal. Much like the big deal made about self-drivers. So the regulators have every motive to not compromise anything for the political expedience (yes it is) of airborne electric power.
In my little world, it's still a very long way off.
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One of the first things that will have to change is fuel reserves.

When flying VFR (bright sunny day), you are required to plan for having 30min of fuel remaining after you land.
When flying IFR (in the clouds), you have to plan for 45min.

The electric planes are advertising 45min to an hour of battery life.
 
T Bredehoft said:
I have to plead ignorance to most aviation theory. I'm an 82 year old retired Tool & Die maker. My son sells model airplane stuff, scale, rubber powered. (google "Volarè Products) I make balsa props for him, The pitch (angle of attack) is based upon the diameter times 1.3 as the nominal pitch, though it often is varied, usually flattened out, not advanced.

My comment about pitch vs. power is driven by "how flat can it go to continue to increase time" (of the rubber band unwinding).

Probably not an appreciable amount.

Thanks for the explanations. I enjoyed the UTube presentation. Yes, the subtitles helped (made it possible to understand).

Tom
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I built the propeller for the Dyke Delta I built.

A propeller is a wing spiraling in a tight circle. Every point along its length is flying at a different pitch, and the pitch changes not just by adjusting the propeller, but by changing the speed that it moves through the air. Twisting the blade to add pitch or slowing the plane down, both cause each rotation to "bite more air". It is very much equivalent to shifting to higher gear. Every motor, electric or gas, has a peak power and a peak torque rpm. The voodoo art is matching a propeller to an engine such that you get the right torque and power at the right times.
 
This is really interesting. I was doing similar work my senior year of college. If the Lindbergh Foundation had secured funding for the project in time, I would have stuck around and made a Masters thesis out of converting a Diamond HK-36. Thanks for posting the video, I'll be glad to follow along!
 
Shotgun said:
One of the first things that will have to change is fuel reserves.
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I'd be awfully surprised if the FAA relaxed fuel reserve regulations for electric aircraft. At least in Pipistrel's case, that advertised endurance includes a daytime VFR reserve.
 
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