On an earlier post I mentioned the IAS errors which I've encountered in doing prop testing on RVs. Someone told me of a quick check of the static port location and errors. Set your altimeter on the ground, and note, if available, your GPS altitude. Fly down the runway at high speed and note your altimeter and height above the runway, either judged or from the GPS. The one who told me about this said that the altimeter read 50' under the runway when 50' above it; that's a 0.1" error which will give lots of additional IAS errors. BTW; it helps to have someone along to record the data so you can concentrate on flying the plane!