The Wizzard
Well Known Member
Here is the case. Whirlwind 200RV prop, IO-375-M1B.
2350 RPM, 70% power 164KIAS @ 3000 msl FF 11.3 GPH
2000RPM, 63% power 160KIAS @ 3000 msl FF 9.2 GPH
The operating limits on prop are 2050-2300 no continuous operation but nobody ever talks about 2000 or 1900. An email was sent to Jim the main engineer at Whirlwind and his explanation is there has not been any testing done in that range but he operates his prop routinely around 2200 RPM.
This prop has very low drag and my thoughts are if you can take the biggest bite then why not? Any thoughts on the above? Not good for the engine, to hard on the prop governor, bad for the prop? Help! I'm listening, the fuel saving outweigh the speed lost but what am I missing.
Dave
2350 RPM, 70% power 164KIAS @ 3000 msl FF 11.3 GPH
2000RPM, 63% power 160KIAS @ 3000 msl FF 9.2 GPH
The operating limits on prop are 2050-2300 no continuous operation but nobody ever talks about 2000 or 1900. An email was sent to Jim the main engineer at Whirlwind and his explanation is there has not been any testing done in that range but he operates his prop routinely around 2200 RPM.
This prop has very low drag and my thoughts are if you can take the biggest bite then why not? Any thoughts on the above? Not good for the engine, to hard on the prop governor, bad for the prop? Help! I'm listening, the fuel saving outweigh the speed lost but what am I missing.
Dave