Hi all, I'm new to the forum.
I'm flying an RV6A that my Dad built 18 years ago. It has an O320 with a Bernie Warnke 70X74 that was installed during the build. It did not turn up what he thought was enough RPM so it was cut to 68 inches per Bernies recommendation. It gained 100 RPM just like Bernie said it would. It now turns 2300 static. The problem is it will only turn 2300 at 8000'. It trues at about 168 MPH at this altitude. Climb at gross was timed with a stop watch at about 1000 fpm at 1000 feet and 550 fpm at 7000'. 9 minutes 23 seconds from 250 to 7000 feet.
We are curious as to why others seem to get static RPM plus 400 to 500 RPM at altitude. I can get about 2500 RPM at low altitude WOT but I dont fly WOT at low alt so I dont have any numbers for that.
Two weeks ago I flew a 400 mile XC at 7500' ind alt and about 52 degrees at altitude and WOT it burned 8.6 GPH. This was exactly 2 hours at altitude on one full tank so this is an accurate fuel burn. I dont have a fuel flow gauge or manifold pressure so I dont have any real info on what percent power I'm running except fuel burn after the fact.
It seems that the engine is developing enough power but why the narrow RPM range?
Any thoughts on this setup or these numbers?
I'm flying an RV6A that my Dad built 18 years ago. It has an O320 with a Bernie Warnke 70X74 that was installed during the build. It did not turn up what he thought was enough RPM so it was cut to 68 inches per Bernies recommendation. It gained 100 RPM just like Bernie said it would. It now turns 2300 static. The problem is it will only turn 2300 at 8000'. It trues at about 168 MPH at this altitude. Climb at gross was timed with a stop watch at about 1000 fpm at 1000 feet and 550 fpm at 7000'. 9 minutes 23 seconds from 250 to 7000 feet.
We are curious as to why others seem to get static RPM plus 400 to 500 RPM at altitude. I can get about 2500 RPM at low altitude WOT but I dont fly WOT at low alt so I dont have any numbers for that.
Two weeks ago I flew a 400 mile XC at 7500' ind alt and about 52 degrees at altitude and WOT it burned 8.6 GPH. This was exactly 2 hours at altitude on one full tank so this is an accurate fuel burn. I dont have a fuel flow gauge or manifold pressure so I dont have any real info on what percent power I'm running except fuel burn after the fact.
It seems that the engine is developing enough power but why the narrow RPM range?
Any thoughts on this setup or these numbers?