Backup Electric Motor

Interesting device. I've always thought some sort of lightweight backup rocket propulsion system would be great in an engine failure.
 
40HP isn't going to get you far, but I suppose it will extend the gliding range. If the engine seizes, I hope it has a propshaft disconnect, otherwise you have a 40HP paperweight that can't turn a prop tied to a seized crank.
 
One downside is that an electric motor drive is another point of failure. Electric motors are generally very reliable, until you start pushing a lot of power through them for their size.
 
As long as it's completely redundant to the original crankshaft and the battery isn't heavy this could be a good thing to have on board.

I assume you will also need to replace the battery every few years regardless of whether you use it or not, curious how expensive that's going to be.
 
SoonerAviator said:
40HP isn't going to get you far, but I suppose it will extend the gliding range. If the engine seizes, I hope it has a propshaft disconnect, otherwise you have a 40HP paperweight that can't turn a prop tied to a seized crank.
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The propshaft is the reactionary for the motor from the looks of it. It's made to operate with a stopped crank.
 
Think the article says the researchers kept the battery small, so as long as it's not buried deep in the engine compartment, wouldn't think it'd be too hard or expensive to replace. But you never know, the world of aircraft pricing is definitely unique.
 
Fredbob711 said:
Think the article says the researchers kept the battery small, so as long as it's not buried deep in the engine compartment, wouldn't think it'd be too hard or expensive to replace. But you never know, the world of aircraft pricing is definitely unique.
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It'll be in the tail most likely for CG purposes.
 
I like the thinking. Neat idea, but I wonder about the reliability and whether there isn't more risk being added than it prevents. My concern is mostly about the clutching mechanism that connects and disconnects the piston engine from the prop. It seems like a potentially hazardous failure point.

I also question the wisdom of allowing the pilot the choice of using the motor as a booster. Who wouldn't want an additional 40 hp on take off? My guess is people will use this all the time and when do a lot of engine failures occur? On take off. This means that you may have diminished your safety device's capability just when you need it most.

I'm not saying this is a bad invention, I do like the idea, but it seems there may be points to work out, particularly if they aim for certification.

Oh yeah, the video's claim of 600 crashes annually between Europe and the US is disingenuous. Only a small percentage of those crashes are due to power failure, so the numbers of crashes and lives they want to save will be much, much less than 600 annually.
 
I'd have just put an extra electric motor in the tail to form a push/pull center line thrust tandem system like a Cessna Skymaster. Electric motors generally don't need any special cooling arrangements when used for short periods during takeoff, so you'd get STOL benefit along with redundancy from a completely different prime mover from the IC engine up front and the advantage of two props vs one in case a prop decides to depart the plane.

During cruise you could continue to run the rear electric motor at a power level the front engine's alternator could supply to avoid windmill drag. Or feather or just lock the rear prop.

EDIT: Oh yeah, forgot to mention that on landing you could in theory run the rear electric motor backward for additional braking action. Not something you'd want to do during any other portion of flight, of course!
 
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Dav8or said:
I like the thinking. Neat idea, but I wonder about the reliability and whether there isn't more risk being added than it prevents. My concern is mostly about the clutching mechanism that connects and disconnects the piston engine from the prop. It seems like a potentially hazardous failure point.

I also question the wisdom of allowing the pilot the choice of using the motor as a booster. Who wouldn't want an additional 40 hp on take off? My guess is people will use this all the time and when do a lot of engine failures occur? On take off. This means that you may have diminished your safety device's capability just when you need it most.

I'm not saying this is a bad invention, I do like the idea, but it seems there may be points to work out, particularly if they aim for certification.

Oh yeah, the video's claim of 600 crashes annually between Europe and the US is disingenuous. Only a small percentage of those crashes are due to power failure, so the numbers of crashes and lives they want to save will be much, much less than 600 annually.
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Sprag clutches smaller handle over 1000hp completely reliably. It's very simple to make a very strong over ride clutch.
 
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