Originally Posted by
Cat 1
Dave - Cant wait to see that clock (or Tach)..
.
Got out flying tonite and as Bert predicted things are different in the air - I am still seeing the hotter cylinder 1 than 2 but only about 15 deg C at max diff.(full throttle) Most of the time they are quite close. Ambitent temp was a balmy (for spring in Canada) 28C. I could get 145C only after a long push of full throttle (+1 minute). On my "typical" flying with lots of twists and turns and vertical I rarely saw 140. Engine was running great tonite and club members out all loved the sound.. RPM telemetry verified that the "skinny" prop is not enough bite as its getting close to the "danger zone" on wind up low passes . I like how it preforms on this smaller one but don't want rods sticking out of the block..
I did find one anomaly that I didn't notice last time - After a long vertical pull and a throttle back after a hammerhead - the engine goes very rich (as expected with tank pressure decay delay) but tonite a couple of times it actually cut out - it did coast though and relight on all but one of the occasions but one time I really pushed the issue and it went dead stick. Will play with a few settings (no shortage on this setup
) to see if I can minimize this one.. other than that it ran great.
Chris
Those numbers at that ambient temperature really sounds quite good. It also means your engine is pretty well broken in.
A slightly heavier prop and I'd say you really are good to go.
The hammerhead thing, I think that is something that basically approaches the limits of the working principle, and I don't think it has to do much with your "forced tank pressurizing".
I have long since adopted the habit of reducing throttle to about half a second or so before kicking it over with rudder, and pulling it back all the way about when the fuse has turned 90 degrees, because my set-ups also have that tendency a bit. Reducing power at the end of the upline, maintaining a bit of rudder pressure but letting the tank pressure bleed off in part while still in nose-up attitude allows the system to bleed off the pressure before the fuel in the tank closes off the tank vent (which prolongs the duration of bleeding off that pressure). Unless you can find settings that manage to recognize the specific situation of an upcoming hammerhead, I would just pull back on the throttle a little bit earlier. It shortens the upline by a marginal bit, but IMHO the turn at the top is executed a bit smoother and nicer to the eye too...
I guess, at these small scales we simply cannot have it all...
