Prop efficiancy.

[birdy]

We all know that the cleaner the airflow to the prop, the more efficiant it will be at converting dead dinosours into moven air, and that we gyro nuts are startn way behind the 8ball with our props follown us, but theres sum little things we can do to improve the airflow.Simple things like streamlining anythn up wind of the prop to minimise turbulance, and keepn everythn as narrow as possable to disturb as little of the flow as we can.And i accidently found anatha thing that, as it turned out, makes a big difference, at any AS.Exhaust gas.I knew that exhaust gas flown through the prop made the prop noiseyer and this effected the efficiancy, but i didnt think it had as much effect as i found yesterday.Id been putn round for bout 4 hours getn sum moos together and pulled up for fuel and other things.But wen i restarted the 912 it sounded like a charff cutter. >One side of my [ home made]

[Russell]

interestin info...........

[Greg Mitchell]

Birdy,My 503 pipe goes straight at the prop on the left hand side and strikes the prop approx a 1/3rd out along the prop. It always leaves a distinctive black oil trace, which is easily wiped off.My Butterfly has always had a slight lean and yaw to the left. No amount of repositioning the spring tang has helped.Side Bar:Having only 6340 eng rpm on take off...to low.I richened up my mix by dropping the clip on the needles to the bottom ring and squeezed 6350rpm up to 6380 and flashed 6400 but settled at 6380rpm. WOT. Thanks for the interesting post. Mitch

[birdy]

Mitch, im not sayn that the exhaust gas is causen the yaw, but it sounds like it ay.Redirect the tail pipe so the gas is either go"n through the prop as near the hub as possable, [ the gas wont wurry the timber, solong as its not too close] or out of the prop disc altogether.