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Old Jun 28, 2012, 08:27 PM
flieslikeabeagle is offline
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Joined May 2004
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Quote:
Originally Posted by JohnsPop View Post
Here's an article that discusses watts per pound for an airplane: http://www.rc-airplane-world.com/watts-per-pound.html If your AUW is 1670 grams (3.7 lbs) I'm thinking at 910 watts, you're either going to tear your wings off or you're going to have so much flutter in the control surfaces that the control rods are going to be quickly ripped out of the control horns at WOT.
JohnsPop, the very high power numbers are because Jake's model is extraordinarily heavy for its size.

Coroplast is a very heavy corrugated plastic sheet, but it's cheap and durable, so some creative soul started building (glow) RC planes out of the stuff many years ago.

Jake's plane is built out of this same material, but he wants to go electric.

Incidentally, Jake's model is just one more example showing that "watts per pound" rules of thumb frequently just don't work. Jake's model is unusually heavy for its size, and the "watts per pound" rules fail miserably, suggesting far too little power for this particular plane.

In fact, the watts/lb rules of thumb don't work with small models, they don't work with very light models, they don't work with very slow models, they don't work with very fast models, and they don't work with very heavy models!

Back in 2004, someone showed me those "watts/lb" rules of thumb, and I very quickly found out they were pretty much useless. That's actually what drove me to find a better way - and that better way eventually turned into WebOCalc.

-Flieslikeabeagle
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