the Wasp

My Feedback: (1)

1) as a rule of thumb, if the temperature remains the same but the humidity goes up what shouldn't a motor need, richened or leaned ?? I'm betting richened,,

2) have you noticed, does the MVVS 35 gasser like to be a bit rich on the high needle ??


why I ask,, (if you remember) I got 7400 tuned for flight with a Zinger 20x8,,, then I switched to a 3W 20x8, I had it tuned for flight at 6060 RPM with this 3W 20x8 (it peaked out at 6860), and it pulled fantastic, in fact it pull so good I was surprised to see just how much faster my plane was,,

OK,

the next week (I did NOT touch the needle, temperature was pretty much the same but it was a little bit more humid this week),, I checked the RPM before I flew and it was all-most 7100, yet with the higher RPM it did not pull as well as it did the week before at the lower 6060 RPM,, so I was wondering if this motor just like's it rich ??


thanks guys !!
Jim

pe reivers

Normally, higher humidities call for leaner jetting, because there is less oxigen in the same volume of air. At the same time, the air gets lighter in mass, about the same as when gaining altitude. Dry, cold weather will give the best power. You will get less power and less pull in humid conditions. That is independent of the engine settings.

the Wasp

My Feedback: (1)

OK thanks, that's as I though, it goes along like the temperature,

now what about this motor liking a rich high needle for the nomal ??


Jim

pe reivers

I hope I understand your question well?
All engines for airplanes should be set slightly rich to stay on the safe side of running too hot. If set lean, it will not provide best power in flight. This is the rule for both glow, and gas engines.

the Wasp

My Feedback: (1)

yes, I understand that, I also fly helis,, I was just wondering if the 35 happen's to like it's needle a little extra rich, that's all..

Jim