Aren't there any dynamos to replaces battery packs?

[darren_uk]

Here's a question that appears in my mind every now and again, and it's just popped in as I was at my PC so I'm posting it here.

Why don't we see dynamos used in radio controlled helicopters (or airplanes for that matter) that are driven from the engine.

Or even trickle chargers to feed the receiver battery pack in flight.

E.g., Maybe the cooling fan and shroud could be modified to generate some current for the servos and receiver? Or, again, to trickle charge the battery if we can't do away with the battery entirely.

[colin]

Ya, like a car alternator..... I'm sure it's possible.

I would guess it's a size to weight ratio thing. The gasser engines of 25cc and up could probably do it as they already have to generate the electricity for the spark.

Same reason we don't see more electric starters on the small engines too. I know the RC cars have them now, but the battery is attached to the car.

Wouldn't wanna completely replace the battery pack, I wouldnt fancy my chances if I had an engine failure or ran out of fuel, although I suppose autogyration would still generate some power for the radio gear,.... Just my two pence worth!!!

It just occured to me that a company, Sullivan, has a generator. Check out this link:

http://www2.towerhobbies.com/cgi-bin...?&I=LXFV20&P=0

Here's an excerpt:

This is the Genesys In-Flight Power System from Sullivan. This revolutionary power system is basically like the alternator in your car. The Genesys will recharge your receiver battery pack in flight while it runs your servos and whatever other accesories you may have. Once the engine is running past a fast idle the Genesys takes over and recharges your battery pack while providing electrical power to the servos and the like. The CCU (central control unit) has five accessory output jacks to plug in such options as navigation lights, strobe lights, rotating beacon, etc... which Sullivan carries specifically for the Genesys.