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Cruise speeds, or why is my -85 so darn slow.
I wonder about all these 100+ Mph cruise speeds talked about on the forum for 85 HP BC12's. I check mine all the time with a GPS and while it indicates a top of about 115 or a little more, it is really only doing 108. Cruise is down in the low 90's. Cruise at altitude (like 8000+) with full throttle (that I never use) is still slightly under 100 GPS.
The indicator problem is the location of the static reference I am pretty sure. The stock static port is inside the left wing and while it gives dead on accuracy at low speeds near stall it gets more and more optimistic as one approaches cruise. Tried 3 different airspeed indicators including the new one in use now on the range variation. Same results. That isn't a problem for me, but I wonder if may be why everyone else is so much "faster" than I am.
This is not unusual performance for just this aircraft, as the other two BC12's that I owned performed similarly considering their engines.
Only thing unusual about this aircraft is the larger 8.00 tires. I can see that changing things 1 or 2 MPH, but not 10.
I do notice that it cruises relatively fast at lower power settings. Around 80 MPH GPS at 2000 RPMs, for example. That implies to me that it is the WING BOSS, THE WING. Fantastic for climbing, but just too much excess lift for going fast. Prop is a metal 7146, pretty much a "standard" prop from my experience.
Bottom line, how come everyone else is so much faster I keep wondering?
Darryl
I wonder about all these 100+ Mph cruise speeds talked about on the forum for 85 HP BC12's. I check mine all the time with a GPS and while it indicates a top of about 115 or a little more, it is really only doing 108. Cruise is down in the low 90's. Cruise at altitude (like 8000+) with full throttle (that I never use) is still slightly under 100 GPS.
The indicator problem is the location of the static reference I am pretty sure. The stock static port is inside the left wing and while it gives dead on accuracy at low speeds near stall it gets more and more optimistic as one approaches cruise. Tried 3 different airspeed indicators including the new one in use now on the range variation. Same results. That isn't a problem for me, but I wonder if may be why everyone else is so much "faster" than I am.
This is not unusual performance for just this aircraft, as the other two BC12's that I owned performed similarly considering their engines.
Only thing unusual about this aircraft is the larger 8.00 tires. I can see that changing things 1 or 2 MPH, but not 10.
I do notice that it cruises relatively fast at lower power settings. Around 80 MPH GPS at 2000 RPMs, for example. That implies to me that it is the WING BOSS, THE WING. Fantastic for climbing, but just too much excess lift for going fast. Prop is a metal 7146, pretty much a "standard" prop from my experience.
Bottom line, how come everyone else is so much faster I keep wondering?
Darryl
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