Posted by Carl [66.223.182.90] on Wednesday, April 22, 2015 at 15:33:24 :
In Reply to: Interesting, but useless posted by Don in Missouri [97.64.167.2] on Wednesday, April 22, 2015 at 14:49:00 :
Actually an alternator run off from the engine puts a pretty good load on the engine. I was just looking at the specs for a Continental IO520 aircraft engine rated at 285 hp. The alternator robs approx 2% of the power, magnetos and vacuum pumps some more, dropping effective output to around 263+/-.
The alternator mounted in the slipstream robs power by adding drag, the higher the speed the more drag, and the higher the current draw the more drag.
A turbo charger reduces power by restricting exhaust flow, but makes up for it by packing more air-oxygen- into the intake allowing more fuel to be added and burned,more fuel, more air, more power there is no free fuel in the atmosphere.
This method of running an alternator off from the exhaust probably doesn't drop the power too much, as it doesn't restrict the exhaust flow as much as a closed in turbocharger would, but it probably would not turn the alternator fast enough to generate much especially once the load created a drag on the alternator.
A more efficient way to create electricity would be a Seebeck device, or thermoelectric generator
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