Electric Hybrid Powerplant - Pipistrel

I know another company stuck an electric motor into a C172 but in only lasts 2.5 hours off a single charge.
 
TK211X said:
I know another company stuck an electric motor into a C172 but in only lasts 2.5 hours off a single charge.
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That's always been the problem. These folks are adding a generator... Looks like.
 
All-electric is not a realistic replacement for a piston engine except in niche applications (like a sweet stealth attack plane! That thing is QUIET!). It probably is more reliable (?) though.

How does a hybrid work in an airplane? Is there an air-driven generator someplace that recharges the batteries in descent or ??
 
MAKG1 said:
A 200 kW generator in a 172?

Will it have a positive useful load?
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That's what I'm thinking. I can't really see an advantage to a hybrid aircraft, other than the fact you can locate the prime mover separate from the propellers.

Hybrid cars lose their advantage at constant highway speeds. Some of the newer hybrid drive trains (Toyota Synergy) use a planetary gearset that effectively locks the engine in direct drive at high speeds.
 
I kind of like the concept of an engine sized for cruise... Maybe even turbo. Then use a booster motor for takeoff, maybe 10 minutes of battery power?

As a bonus, on engine failure, the motor can extend your glide for ten minutes... Make a runway, perhaps.

Paul
 
PaulMillner said:
I kind of like the concept of an engine sized for cruise... Maybe even turbo. Then use a booster motor for takeoff, maybe 10 minutes of battery power?



As a bonus, on engine failure, the motor can extend your glide for ten minutes... Make a runway, perhaps.



Paul
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Always at the expense of useful load. I'll take my chances that the fan doesn't stop and hedge that bet with altitude.


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petrolero said:
All-electric is not a realistic replacement for a piston engine except in niche applications (like a sweet stealth attack plane! That thing is QUIET!). It probably is more reliable (?) though.

How does a hybrid work in an airplane? Is there an air-driven generator someplace that recharges the batteries in descent or ??
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On first blush a 2.5 hour duration electric 172 would seem an economical trainer for a flight school (much less maintenance cost than an avgas engine).

But then what does it take for a student trained on an electric airplane to transition to something else? The systems differences and emergency procedures changes alone would be considerable.
 
SkyHog said:
I dunno - what's the point if you need gas anyway?
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A hybrid plane with a small engine (preferably diesel using jet fuel) set to operate at a constant and highly fuel efficient RPM to drive the generator might be interesting. An electric motor to drive the prop seems perfect given the torque characteristics.

It's probably still going to be range limited though. Batteries are chemical devices and are limited, depending on the specific chemistry, in how fast energy can be input (charging) or extracted from them. Otherwise they overheat and try to melt their way out the bottom of the fuselage - a la Boeing Dreamliner.

Battery chemistry is improving but not by leaps and bounds, so unlikely any breakthroughs that will radically improve range for a given weight of batteries carried on board.
 
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Sac Arrow said:
That's what I'm thinking. I can't really see an advantage to a hybrid aircraft, other than the fact you can locate the prime mover separate from the propellers.



Hybrid cars lose their advantage at constant highway speeds. Some of the newer hybrid drive trains (Toyota Synergy) use a planetary gearset that effectively locks the engine in direct drive at high speeds.
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Well there's some maintenance plusses. It's probably a lot simpler to swap out an electric motor, the prop (and rest of the airframe) isn't subjected to never ending vibration, and the addition of removal of power is very quick, I noticed in the video.

As someone mentions below, sizing the generator for cruise power use plus avionics, lights, and a bit more for a slowish charge / positive power profile seems workable.

One significant problem they probably haven't solved is cabin comfort. Heat isn't going to be plentiful anywhere to use it to heat the cabin, so in cold climates, this thing is a no-go. Heating electrically isn't efficient at all. Cooling isn't either but we're used to not having AC in light aircraft.

GRG55 said:
A hybrid plane with a small engine (preferably diesel using jet fuel) set to operate at a constant and highly fuel efficient RPM to drive the generator might be interesting. An electric motor to drive the prop seems perfect given the torque characteristics.



It's probably still going to be range limited though. Batteries are chemical devices and are limited, depending on the specific chemistry, in how fast energy can be input (charging) or extracted from them. Otherwise they overheat and try to melt their way out the bottom of the fuselage - a la Boeing Dreamliner.



Battery chemistry is improving but not by leaps and bounds, so unlikely any breakthroughs that will radically improve range for a given weight of batteries carried on board.
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Battery tech is the bane of everything electric. None of the breakthroughs have been orders of magnitude better.

I believe you see him starting the small genset when he reaches into the rear cowl there, but I can't really tell. Is it there or is he flipping a remote switch that starts one on the ground out of the frame? I can't tell.

I've always thought the hybrid mix that would eventually need to be done and tried was going to be an electric motor and prop like in the video, but a very small strong turbine turning as lightweight generator as possible while still being relatively reliable. Use some bleed air for the cabin comfort problem and size it appropriately, but it wouldn't have to be massive.

Anyway, interesting that they're trying.

Doesn't that jerkiness of the motor starting up the prop look odd to those of us used to the prop having more mass and being hooked to a traditional piston pounder engine, where it's less obvious it's not spinning evenly during start?
 
denverpilot said:
...Doesn't that jerkiness of the motor starting up the prop look odd to those of us used to the prop having more mass and being hooked to a traditional piston pounder engine, where it's less obvious it's not spinning evenly during start?
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Is that what is actually happening, or is it perhaps a purely visual effect from the frames-per-second of the camera?

An electric motor has infinite torque at zero RPM so I can't see a reason why the start shouldn't be even smoother than a piston engine start. :confused:
 
I'm not sure that this electric aircraft motor technology is truly viable today, but the concept would have been largely unimaginable just 20 years ago. Perhaps this is little more than a proof of concept design? In another ten years, who knows… it just might work!

After all, I currently have a battery powered circular saw, a battery driven angle grinder, and a battery driven hammer drill. A decade ago I wouldn't have thought any of those tools would have been able to run so strongly and reliably on a battery.
 
Unlike cars where the engine operates over a wide variety of ranges and sometimes the car needs to shed energy, an airplane for most of it's flight regime (other than coming down at the end) operates at a pretty high constant power. It's not clear what a hybrid engine is going to provide over an appropriately designed straight engine. Thermodynamics is a beast.
 
flyingron said:
Unlike cars where the engine operates over a wide variety of ranges and sometimes the car needs to shed energy, an airplane for most of it's flight regime (other than coming down at the end) operates at a pretty high constant power. It's not clear what a hybrid engine is going to provide over an appropriately designed straight engine. Thermodynamics is a beast.
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That's my thinking.
 
OTOH, in something like a Pipistrel that is a serious glider in it's own right, this might be really neat.
 
Coloradokevin said:
I'm not sure that this electric aircraft motor technology is truly viable today, but the concept would have been largely unimaginable just 20 years ago. Perhaps this is little more than a proof of concept design? In another ten years, who knows… it just might work!

...
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I assume most folks here are aware of the Airbus electric airplane program, E-Fan? The electric motors in the E-Fan (and the Pipistrel) were developed by Siemens specifically for aviation application.

http://www.airbusgroup.com/int/en/i...us-e-fan-the-future-of-electric-aircraft.html
 
GRG55 said:
I assume most folks here are aware of the Airbus electric airplane program, E-Fan? The electric motors in the E-Fan (and the Pipistrel) were developed by Siemens specifically for aviation application.

http://www.airbusgroup.com/int/en/i...us-e-fan-the-future-of-electric-aircraft.html
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I have to admit that I actually wasn't aware of that particular program. But, as I said before, I've been amazed at the advancements in battery/electric technology in the past decade. Though I probably would have claimed that a practical general aviation electric airplane was impossible if you had asked me the question when I first started flying, I must say that today I'm not so convinced it won't happen.

I think a few of the bigger hurdles that will need to be overcome still include things like the range of flight, and the time to recharge on the ground. These are kind of the same problems that are plaguing the electric car market at the moment… if you want to go cross country it doesn't do you much good if your vehicle (plane or car) only has a 100 mile range, and takes 10 hours to "refuel". But, again, times are changing on this front, and the future may hold some interesting changes to power plants.
 
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