Nitro Engine -> Dynamo -> Electric Motor

[Phantasm141]

Anyone ever devised a working electric model that is powered by an alternator/dynamo hooked upto a nitro engine???

[Gary Warner]

Why?

[Comatose]

Gary,haven't you heard how much better fuel economy these new hybrids get? ;)

[Phantasm141]

Why?

Why what? Was just a thought, considering a few points, doesn't the A-10 thunderbolt have electric engines???(the real one that is), and trains use this sort of system...

[Dan Baldwin]

The A/OA-10 is a single place, pressurized, low wing and tail aircraft with two General Electric TF-34-100/A turbo-fan engines

snicker
LOL

Sorry. Couldn't help myself

Dan

[Phantasm141]

lol, well i guess someone has already made an R/C model that works like this, as for the economy...

[lostrider]

converting an energy to other energy;
result is always losing some energy.

nitro motor weight+fuel weight > an a good battery
(nitro motor weight+fuel weight)/performance < (an a good battery)/performance

my 0.02 turkish lira:D

[Gary Warner]

Trains use e-motors because they need tons of torque - it's a 'torque converter' of sorts. E-motors develop maximum torque when stalled. I guess a plane that needed to turn a HUGE prop at very slow speeds could benefit from this kind of energy conversion.

If electric motor driven props were mandated, then the losses of energy could well be worth it, given the energy density of liquid fuel. Again though, it would be a waste if engine driven props were an option.

Also, I could see a military requirement where a drone was to travel a long distance to a target with the engine running then shut the engine down and fly on batteries quietly over a target. This could extend the range of a naturally quite e-powered drone.

Gary
--

[Phantasm141]

Ok so the only advantage is torque, so it would be fairly ideal for a helicopter to have this system?

[Gary Warner]

Ok so the only advantage is torque, so it would be fairly ideal for a helicopter to have this system?

No.

Gearing of an engine multiplies the engine's torque more efficently than a dynamo will.

Gary
--

[50+AirYears]

And don't forget the extra weight you're adding to the airframe.

[sesat]

What if you needed to turn the prop on or off, you need a starter mounted to the engine. This heavy starter, is it not essentially the guts of a dynamo?


Ram.

[MatC]

> Gearing of an engine multiplies the engine's torque more efficently than a dynamo will.
Motors and dynamos can both be > 95% efficient, and more than 90% efficient together. Gears are generally around 90% efficient, so I agree there is not much difference, for any single gear ratio one could name.

However the dynamo/motor combination provides fantastic torque at stopped and extremely slow speeds (the equivalent of an extremely high gear ratio) without losing top end speed. This is roughly equivalent to an infinitely variable automatic gearbox.

[dj2u]

what about EDFs instead of a prop in the nose? :eek:

diego

[TMorita]

Ok so the only advantage is torque, so it would be fairly ideal for a helicopter to have this system?

The alternator + motor will weigh much more than a gear reduction system.

Toshi