JohnAJohnson
Cleared for Takeoff
- Joined
- Aug 14, 2006
- Messages
- 1,319
- Location
- Orange Beach, AL
- Display Name
Display name:
JohnAJohnson
x-post from red...
Had an interesting problem the other day. Took off, had good power and terrific climb performance, then pushed over at 3000' AGL (3500' MSL) to level off and cruise around a bit. Got up to 140 MIAS quickly, then pulled the prop back to 2200 and MP back to 22, for a 65% cruise.
Banked it over and changed heading from south to west, and when I looked down at the heading during the rollout, noticed the airspeed at 85 MPH. Huh? I verified 22 square and should have been doing 127 MIAS or so. The attitude was slightly nose high, and I turned back to the airport. The airplane was acting as if it were iced up, loaded with a bunch of very fat people, or had a bunch of flaps out. Moving the throttle forward increased the MP of course, and I ran it at 25" till I was on downwind. Funny thing, the prop seemed to fall out of governing range too soon, at anything lower than 22" or so. I thought I might have a governor problem too. Landing was uneventful as I was way high and mostly glided from abeam the numbers in. Uncomfortable feeling believing you've got good power, but are still loosing airspeed.
Was all geared up to troubleshoot a pitot leak, but today, with the cowling off, I found the problem. The B-Nut for the MP Gauge tap-off on the #3 head, (above the intake runner) was completely backed out. Held on by less than a thread. Leaking like a sieve. Makes sense. This caused me to think I was running the engine at a higher power than it actually was running at, and the airplane was in fact moving slow, with the resultant high pitch attitude. Looking at the flight's EDM-700 data dump, EGT for #3 was no higher than normal, so it wasn't enough of an intake leak to cause any abnormal engine behavior.
Had an interesting problem the other day. Took off, had good power and terrific climb performance, then pushed over at 3000' AGL (3500' MSL) to level off and cruise around a bit. Got up to 140 MIAS quickly, then pulled the prop back to 2200 and MP back to 22, for a 65% cruise.
Banked it over and changed heading from south to west, and when I looked down at the heading during the rollout, noticed the airspeed at 85 MPH. Huh? I verified 22 square and should have been doing 127 MIAS or so. The attitude was slightly nose high, and I turned back to the airport. The airplane was acting as if it were iced up, loaded with a bunch of very fat people, or had a bunch of flaps out. Moving the throttle forward increased the MP of course, and I ran it at 25" till I was on downwind. Funny thing, the prop seemed to fall out of governing range too soon, at anything lower than 22" or so. I thought I might have a governor problem too. Landing was uneventful as I was way high and mostly glided from abeam the numbers in. Uncomfortable feeling believing you've got good power, but are still loosing airspeed.
Was all geared up to troubleshoot a pitot leak, but today, with the cowling off, I found the problem. The B-Nut for the MP Gauge tap-off on the #3 head, (above the intake runner) was completely backed out. Held on by less than a thread. Leaking like a sieve. Makes sense. This caused me to think I was running the engine at a higher power than it actually was running at, and the airplane was in fact moving slow, with the resultant high pitch attitude. Looking at the flight's EDM-700 data dump, EGT for #3 was no higher than normal, so it wasn't enough of an intake leak to cause any abnormal engine behavior.
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