All, I know the old airspeed indicators tend to read high. Nothing new there. But I have a particularly flummoxing issue.
To check out my ASI, I took my bird out on a quiet, no wind day and did high speed taxis on all four cardinal headings. We taxied on each heading up to 80 mph indicated, cross checked against the GPS groundspeed, and charted the results. Then, we averaged and interpolated the charts. The charts showed nice straight-line slopes. The error was constant with no curves at all. The airspeed indicator readings were nearly dead-on 10 mph high at all speeds. So, we also extrapolated the speeds up to cruise and charted them also. In short, our calculations indicated that the airspeed would always read 10 mph too high. No problem. But, then, when I got into the air, my airspeed readings on all headings easily varied up to, and over, 20 mph too high. Apparently, something happens once I get off the ground, or maybe out of ground effect. I hesitate to buy a new ASI because my guess is that the problem is not in the instrument itself, otherwise the error would be constant. Anybody have any ideas.or must I fly up to Springfield and harass John Wright for assistance? (Anything for an excuse to fly up and meet you John.) Dave Winters
