RE: Low Wing Skimmer 400 w/not fly
Well put Matt - I forgot to mention the "magic up stick".
I apologize for the math error - at 1:2 thrust to weight you need perhaps 11oz for a 22oz plane (not the 16 I calculated from a 32oz plane) - and for a sailplane you might get away with a bit over 8oz.
Another way of looking at the power issue, is to use the old rule of thumb - 40W/lb. Your 1.4lb plane needs something like 56W. Allowing for voltage drop under load your 6-cell NiMh pack might be giving 6.0-6.5v - that means more than 8.5A draw to get the required 56W - and the simple fact is that 6x3 folder can't pull that much at such a low voltage. If you go to 8.4v or 9.6v (~8-9v respectively under moderate load) you can see how the math gets better - so you only need to pull 6-7A. On 8-9v a 6x3 folder can certainly do that with a decent pack - on 7-cell KANs I've pulled 12.0A and 80W, and on 8-cell KANs, a ridiculous 13.6A (100W) [though even that still only gets you 10oz thrust!].
Indeed, direct drive 400's are only good for very small, fast, slippery planes. The best way to power a big sailplane is to use a geared motor and a big folding prop - lots more thrust at much lower amp draw.
Cheers, Phil