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Old August 6th 07, 06:57 PM posted to rec.aviation.piloting,rec.aviation.homebuilt,rec.aviation.ultralight,rec.aviation.soaring
Orval Fairbairn
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Default Electrically Powered Ultralight Aircraft

In article ,
Orval Fairbairn wrote:

In article . com,
James Sleeman wrote:

On Aug 6, 4:52 am, Larry Dighera wrote:
Electrically Powered Ultralight Aircraft


It's a nice idea, but realisitically there are too many problems, not
the least of which is battery size, weight, cost and safety. I don't
really see batteries as a viable in the near future (I struggle to see
them as viable in the distant future either).


Look at the problem this way: In an all-electric machine, you carry ALL
of your energy supply with you: fuel and oxidizer -- to make electricity.

With any IC engine, you carry the fuel only -- the air is free (20%
oxygen), so, at 15:1 air/fuel ratio, you would need 90 lb of air for
each gallon of fuel.

Therefore, for a nominal 50 gallon fuel capacity (300 lb), you would
have to carry an additional 7500 lb of air.

That is a lot of weight for a 3000 lb aircraft!


DUH! I meant 4500 lb of air! That is still a lot of weight penalty.