Originally Posted by
1967brutus
On request of Rob.M, first flight vid of his rendering of Chris' throttle body design.
https://www.youtube.com/watch?v=d3z5-EGyYXw
He has, in the mean time drilled a 1,1 mm airbleed port according Chris' drawings, and reports a very much improved idle in flight: Without the airbleed hole he saw an irregular idle in flight, the airbleed hole stabilized that.
Personally, I am a bit confused by that, because Dave way back when he converted his Boxer had issues trying to use the airbleed that was OEM present in the carb of his engine, and in earlier experiments of mine, the airbleed adjustment also was problematic and that was putting it mildly. My experiments back then were pre-solenoid admittedly, but Daves tests were WITH the solenoid.
Whatever the case, to me this sounds like a pretty good running engine, and according to Rob, top RPM in level flight has remained the same (12K) but throttle response improved in that it is more accurate and predictable (and it was allready pretty good previously if you ask me).
SO great to see another one in the air - It even sounds similar to the ST 45 (different from glow) -
I am glad Rob reports improvement with the Air bleed - I think the success with this is simply a function of bringing the idle pulse width back into a better range for consistent metering...
Is Rob on a Hans or Dave controller?
On the Carb production - I think this would be a tough Game to get into with all the variables - I built custom rotor heads for mikado helis for a while and it was a very time consuming process that ate up a lot of hobby time. The limited production is an issue as it falls in that gap between a pure custom (we need too many) and a mass produced piece (we don't need this many) - When the busy summer is over I can probably do up some custom ones for Bert and others to play with to "advance" the tech. Its really not a complicated piece but still the issue would be the custom "fits and adapters" needed for so many engines.