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I was in Tucson, AZ for three days of meetings during the week of 06 Feb. It was nice to get away from winter for a few days.

I didn’t get flying the weekend of 11-12 Feb, as the weather wasn’t very good on the Saturday. Sunday was better, but the wind was gusting pretty hard, straight across the runway, and the wind was forecast to increase to 20 kt. I would have probably gone flying if I had slept better on Saturday night, but I had slept poorly, and wasn’t feeling nearly sharp enough to want to face that much crosswind.

I had today off, so I spent much of the day at the airport. The last time I had the RV-8 flying I noted that the indicated airspeed was about 10 kt higher than I would have expected given the altitude and power. There are all kinds of reasons why an aircraft’s performance may deteriorate, but no good reasons why the performance should suddenly improve. So, I suspected a problem with my airspeed accuracy, and the most likely cause was a leak in the static system.

I did a static system leak check this morning, and sure enough it had a moderate leak. The leak was perhaps five times the allowable tolerance given in CAR Standard 571 Appendix B. I started reseating the most likely connections in the static system, repeating the leak check after each one. I found that the problem was in the connection to the analog altimeter, as the leak check was perfect after reseating that connection.

After lunch I did a short flight. I wasn’t sure how high the ceiling was, so I climbed to check out the cloud bases. I hit some light freezing drizzle just below the bottom of the cloud. I got out of the stuff pretty quickly, but still had a fine coating of frozen droplets on the windscreen and wing leading edges. It looked roughly like about 80 grit sandpaper, based on what I could see on the wind screen.

I hadn’t intentionally collected this ice, but now that I had it I was curious to see what the effect on stall speed and stall characteristics was. I did a number of stalls with flaps up and flaps down. The stall characteristics were no different than any other time I have stalled the aircraft. Then I descended down to 1000 ft, which was just below the freezing level, and let the ice melt. I repeated the stall tests and found the stall speed without ice was about 2 kt slower than the stall speed with the light coating of ice. I expect that there would be a greater effect on stall speed if I had collected more ice.

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