In section 3.4.3 it states that the maximum MAP at 5,250 propeller rpm is 28.4 inch Hg with 95 RON fuel and 30.0 inch Hg with 98 RON fuel. These limits are valid for manifold air temperatures up to 122 F.
Previously I had decreased the pitch of the propeller on my RV-12 to less than Van’s Aircraft to ensure that I was running at 5,250 rpm on climb out.
Reviewing the data from the Dynon data logger I see that it is not uncommon for me to have a manifold pressure in the 29 inches of Hg when accelerating for takeoff and on initial climb. The manifold pressure decreases as I climb as one would expect with a naturally aspirated engine and decreases further as I level off and accelerate. This shown in the attached image.
Since I am burning 100LL this meets the specified limits.
The question is if I used unleaded gasoline which typically has a lower octane, would I need to reduce my propeller pitch further or this acceptable since it is a short transient condition?
Thanks.
Brett
