Originally posted by rcign
Two different charts, rcfaq and ThrustHp
Webra 120, 18-6 MA prop, 9100 rpm from rcfaq, 25.3 thrust from ThrustHp chart
RCS 1.8, 20-8 prop, 6800 rpm from RCS,21+ thrust from same chart
Something wrong with this picture.....
And the RCS is heavier than the Webra....
Thrust charts are fine, but 9100 with and 18-6 on a Webra. Sure.......
My webra flew best on a 16-8 APC turning 8800 and according to ThrustHP that is 14.79 lbs of thrust. This was on 10% nitro. We tried 15% 20% and the engine was never reliable. I was told this was because this engine was made for the European Market and as such was not designed for high nitro content. Whether it is or not I do not know. I loved the engine for its ease of start and reliability and would buy another in the future. But the reality was that "the motor I had" never pulled the Pitts very well in the up lines.
How about the RCS 1.8? Are the numbers that they list on rcfraq and on the rcshowcase real? If so this might be the engine and its a gas burner. What would be a good three blade if ground clearance is and issue?