Has anyone noticed a difference in static rpm with the top cowling off (e.g. for carb balancing) compared to with it on as normal for flight?
Had a bit of a problem recently (long story ? best not to ask!) with the exhaust having become displaced from one of the stub pipes that resulted in blow by which caused a significant reduction max rpm and rough running when the top cowl was on but not when it was off. A consequence of which is that an increase in my awareness of max static rpm has ensued and after the problem was resolved it seems as though with the cowling on the static rpm is about 100 rpm lower than with it off (ambient temp 20C/68F, density altitude approx. sea level).
The difference is possibly not unreasonable, since the air temp under the cowling will be warmer than with the cowling off but not having been aware of any difference in the past I wondered if anyone else had similar experience. If not I have more investigating to do!
Alan
Had a bit of a problem recently (long story ? best not to ask!) with the exhaust having become displaced from one of the stub pipes that resulted in blow by which caused a significant reduction max rpm and rough running when the top cowl was on but not when it was off. A consequence of which is that an increase in my awareness of max static rpm has ensued and after the problem was resolved it seems as though with the cowling on the static rpm is about 100 rpm lower than with it off (ambient temp 20C/68F, density altitude approx. sea level).
The difference is possibly not unreasonable, since the air temp under the cowling will be warmer than with the cowling off but not having been aware of any difference in the past I wondered if anyone else had similar experience. If not I have more investigating to do!
Alan