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Post by fascinating on Jul 24, 2018 8:54:39 GMT 1
Electric-powered commercial aircraft are still a long way off, but here's an idea (probably to be shot down in flames) to save weight. A large part of the fuel an aircraft uses is in the take off. Is it possible to have a (ground powered) maglev track and accelerate (smaller, short haul) aircraft to take-off speed?
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Post by jonjel on Jul 30, 2018 15:01:30 GMT 1
Electric-powered commercial aircraft are still a long way off, but here's an idea (probably to be shot down in flames) to save weight. A large part of the fuel an aircraft uses is in the take off. Is it possible to have a (ground powered) maglev track and accelerate (smaller, short haul) aircraft to take-off speed? When you consider that the V1 was sent off in that way, albeit with a rocket assist it is not such a daft idea. At this stage of development however one wold need very light aircraft with enormous wingspans for the solar cell array to be able to cope, so a very long way off in my view. But there were a couple of guys who strapped a lawn mower engine behind a collection of sticks string and cloth not much more than 100 years ago and look where that has gone. Rule nothing out. |
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Post by fascinating on Jul 30, 2018 19:52:55 GMT 1
I wasn't thinking of an aeroplane with a solar cell array, I supposed the power would be from a battery. Of course that battery would be heavy, but maglev on the ground could provide the power to put the plane into the sky. I don't know how long it could stay there, but I am imagining a small aircraft, for travelling the 30 miles from my estate in Kent to the City airport near my villa (I wish!)
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Post by jonjel on Jul 31, 2018 16:48:39 GMT 1
The main hurdle as I see it is that hydrocarbon fuel 'stores' many times the amount of power as batteries in proportion to the weight, so an awful long way to go yet.
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Post by alancalverd on Sept 7, 2018 10:32:17 GMT 1
A large part of the fuel an aircraft uses is in the take off. Depends on the flight duration. For a light plane, consuming about 10 US gallons per hour in cruise, you might burn one gallon during taxi and takeoff and another gallon at full power climb to 5000 ft, then 30 gallons to cover 500 miles to your destination, so the takeoff consumption is negligible. However if you are just going 50 miles, it is indeed a significant fraction. Moral: if there is a good road, don't go less than 100 miles by plane. That said, a decent electric or steam catapult could shorten the runway requirement to, say, the length of a ship....as it does. There is an alternative approach that is finding some favour. An electric motor with a small battery can deliver a lot of power for a short time, so you can use a small (say 100kW) diesel generator to charge the 200 kW / 40 kWh battery, giving you 300 kW available for 6 minutes of takeoff and climb. Having reached cruise altitude, you then deliver say 90 kW to the propellor and 10 kW to recharge the battery. This is overall efficient because a diesel engine works best at constant power output, and a 3:1 ratio between takeoff and cruise power will give you a very short takeoff run with a simple wing. |
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