ORIGINAL: drksky1056
Ok, I've done the searching, but apparently I'm still too dense to figure it out.
Which needle affects which? High affects low, or vice-versa? Should I adjust the high or low first?
I've been fiddling with my Brillelli 40 and it seems, on the ground, the transition is always good. I had the low needle less than one turn out today and I fear that may be too lean. I did eventually hit a spot where it didn't want to idle any more, and I backed away from that point. At that point, the transition was solid on the ground, but once I got it up in the air things were different. When throttling down on a downline, the engine is still idling well, but sputters when going back up on the throttle. It finally died on one of these manuvers and I had to deadstick it. Am I still too lean on the low?
When tuning, do you make all the adjustments on the ground, or make an adjustment, see how it reacts in flight, land and adjust again?
Thanks in advance.
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Because the timing is controlled by the ignition system, you don't have to worry about running "too lean" as you do with a glow engine.
If the engine will run, the needle is not too lean from a safety standpoint. Throttling response, etc., is another matter and will require finding the best compromise.
High compression, highly tuned two-strokes can "hole a piston" if too lean, but our engines are nowhere near that state of tune when flown in non racing environments.
In flight requirements are what we should base our engine tuning upon. Who cares if it runs great on the ground, but terrible in the air? If the engine won't fly the plane, it is a useless lump of metal.