pierre smith
Well Known Member
Mornin' everybody.
A friend of mine's -7 has just been signed off and is equipped with a supercharged Subie. Others have told him to fly it with wide open throttle and turn the RPMs back. Apparently the wastegate is set to around 34 inches max. My contention (and I told him this) is that he's asking for extremely high cylinder temps and detonation coupled with short engine life, if not premature failure.
Running an engine with WOT and low RPMs flies in the face of everything I've ever learned about CS prop equipped engines. Since the widely accepted proper technique is to lower manifold pressure FIRST, then RPMs, where is the justification in holding high manifold pressure and lower RPMs with the Eggenfellner engine? One guy told my buddy that he's been running his Subie wide open and lowering the RPMs for the last 300 hours!! I've never flown or operated a Subie but I've owned and operated Cessna 310's, AT6's and several R1340 engined airplanes and many Ag airplanes with CS props and the procedure with all of these has been the same. What am I missing here with the Subie by Eggenfelner?
Pierre
A friend of mine's -7 has just been signed off and is equipped with a supercharged Subie. Others have told him to fly it with wide open throttle and turn the RPMs back. Apparently the wastegate is set to around 34 inches max. My contention (and I told him this) is that he's asking for extremely high cylinder temps and detonation coupled with short engine life, if not premature failure.
Running an engine with WOT and low RPMs flies in the face of everything I've ever learned about CS prop equipped engines. Since the widely accepted proper technique is to lower manifold pressure FIRST, then RPMs, where is the justification in holding high manifold pressure and lower RPMs with the Eggenfellner engine? One guy told my buddy that he's been running his Subie wide open and lowering the RPMs for the last 300 hours!! I've never flown or operated a Subie but I've owned and operated Cessna 310's, AT6's and several R1340 engined airplanes and many Ag airplanes with CS props and the procedure with all of these has been the same. What am I missing here with the Subie by Eggenfelner?
Pierre