DesertNomad
Pattern Altitude
I had my engine heater on overnight and did a normal run up this morning with oil at 113°F. At 2000rpm I cycled the prop three times as usual and let it fall to somewhere between 1500-1600 before recovering normally. On application of full power for takeoff (11,000' runway) as it came up to speed it went over the 2400 limit and hit about 2520 for less than 2 seconds. I pulled back the throttle to let it fall to about 2000 and tried again, running it to full power where it hit 2500 for less than half a second. We then stopped and exited the runway.
I went back and did another runup and cycled the prop 4 times, letting it fall to about 1500 twice and to maybe 1300 twice. It recovered to 2000 normally. I then did a full power run up where it held at 2390 (where it should be) and did that twice, throttling back to 2000 in between. The takeoff was normal and 5 more takeoffs (after shutting down each time) today were also totally normal.
Lycoming says a monetary overspeed of 10% rated rpm or less for less than 3 seconds requires no maintenance or log entry and can happen when going from idle to full (such as in a go around). I think If I had left it at full power it would have stayed at the low 2500s but would not have comeback to 2400 without me doing something.
My thought is that my original run up did not really get the oil moving enough into the governor to make it limit as it should. It goes into annual Monday (3 hours flying to get there), so obviously I'll mention it to my mechanic. Just looking fore thoughts on the situation.
It has 10 quarts of oil and oil temperature and pressure remained normal.
Thanks.
I went back and did another runup and cycled the prop 4 times, letting it fall to about 1500 twice and to maybe 1300 twice. It recovered to 2000 normally. I then did a full power run up where it held at 2390 (where it should be) and did that twice, throttling back to 2000 in between. The takeoff was normal and 5 more takeoffs (after shutting down each time) today were also totally normal.
Lycoming says a monetary overspeed of 10% rated rpm or less for less than 3 seconds requires no maintenance or log entry and can happen when going from idle to full (such as in a go around). I think If I had left it at full power it would have stayed at the low 2500s but would not have comeback to 2400 without me doing something.
My thought is that my original run up did not really get the oil moving enough into the governor to make it limit as it should. It goes into annual Monday (3 hours flying to get there), so obviously I'll mention it to my mechanic. Just looking fore thoughts on the situation.
It has 10 quarts of oil and oil temperature and pressure remained normal.
Thanks.
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