Monday, March 1, 2010

CG & NP For Speedwing

I've added some more information to the Speedwing solid model, and using the neutral point formula in the "basic design of Flying Wing models" website, the NP will be about 8.35" back from the leading edge of the wing root. In reality the NP will likely be farther forward, as the formula assumes the prop cutout space will also be lifting wing surface which is not the case.

Solidworks says the CG will be about 6.4" back, so we're good to go. The 1.94" difference between the two will give plenty of slop to account for paint, fiberglass, etc which may move the CG back towards the NP. As shown in the prototype the CG MUST be ahead of the NP otherwise it will have very undesirable flying characteristics. Below is a screenshot from Solidworks. The pink circle is the estimated CG location, and the vertical dotted line intersects the calculated neutral point.

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