Large Model Association Forum

The G38 is swinging a menz 19x10 at 6400rpm, are these figures correct for the combination?

Thanks Matt

I would say that that's about what would be expected

On a new engine, yes, that's about right........I'd expect a fraction more on a well run in engine.

Phil

Matt, yes the guys are right & they know these engines! What I would add is the rpm also depends on what the aircraft is that you are flying because the front end shape makes a difference especially if it is flat! I have a 1/4 scale WW1 Se5 which my 38 revs out at 6000 but my 1/5 scale (ish) P51 Mustang it revs out at 6700! Again the SE5 has a 19x8 but the P51 has a 19x10! Figure that one? Yes it's about the frontal aerodynamic shape.
What aircraft have you got your 38 fitted into & why are you expecting more rpm?
Cary

Thanks for the replies..... it's in a practical scale cap 21.Thinking the compression was poor i have changed the ring, lesson learned (compression and rpm are exactly the same). Matt

Matt, the Practical Scale CAP 21 needs a Zenoah 62 not a 38?
Cary

it's been flying on the 38 since at least 1990( I have the entry form from a German comp). I thought a 9kg the engine may be underpowered. The test flight will tell.

Ive flown this plane many times. its a lovely machine the 38 flies it well. scale like loops rolls. if your looking for 3d flying then this not the plane to do it with. it was design for a quadra 32 then the 38. then latter years the 62 was shoe horned in to it. the plane was built by my dear old friend we built two of them at the time. Look after it.

Matt, apologies I only know this model from current website info. As Richard knows and has flown this plane then I think you will be fine!
Cary