Lead Sled
Sitt'n on the throne...
- Joined
- Apr 1, 2004
- Posts
- 2,066
FyingFisherman...FlyingFisherman said:I'm not sure how 421 motors and the like are geared...but the FW-149D's motor was a Lycoming design made by BMW.
Now...it's geared 'up' meaning that on takeoff, the propeller was turning something on the order of 3600rpm. Do the 421's and other geared motors do the same or are they geared down in rpm?
I've never flown a FW-149D, so I know nothing about them, but never the less, I'd question a motor that "geared up" the propeller to turn faster - it doesn't really make sense. Typically, gearing is provided to allow the motor to turn faster than the propeller allowing the engine to be in its optimal power band while permitting the propeller to be operated at its optimal RPM without the tip speeds going supersonic - their efficiency drops off dramatically after that.
'Sled