[link=http://www.jamesyawn.com/index.html]Recristallised KNO3 and sugar[/link] makes for a great cheap rocket fuel. But I suggest you read through those pages completely before attempting anything. The stuff is basically harmless, but it is still rocket fuel and capable of burning down your house if you mistreat it.
There are also a few nice tips on fuses.
You can give one hell of a boost to your plane with this stuff if you do it right... probably enough to rip the wings of an unmodified sport plane
And the good part is that it is very low cost, so it won't break the bank whe it doesn't work out properly the first time around. (unless you burn your house down of course
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