RE: Cox PeeWee 020
I have used aluminium foil from a soda can too, but the lifespan was quite short, less than ten tanks. With a slightly thicker brass foil I've done 10+ flight and it hasen't broken yet.
The DDD head I have for the .020 was too high in compression even at its lowest setting, and I've turned down the length of the counter piston to be able to reduce the compression enough. I don't know if this is a general problem with the DDD heads, but it is important to be able to reduce the compression in order to not break the crank pin.
With a well fitted and tight piston/cylinder combo these are very easy to hand start. It just needs a little prime on the side of the piston and it fires everytime.
Another advantage is that it is much less sensitive to the needle setting compared to when it is run on glow fuel. On glow the tank heats up during the run and it would rarely empty the tank, while on diesel it runs full tank everytime even if the needle would a little off.
Here is a short video of mine on the bench spinning a 6x3 prop at about 9500rpm:
[youtube]http://www.youtube.com/watch?v=mMJlI0rgXVo&feature=mfu_in_order&list=UL[/youtube]