170C wrote:Thanks to all who responded regarding dimensions as well as others who had comments, etc. Seems its a bit more complicated than just comparing two props of the same mfg, model, etc. (Nothing in aviation is easy except the FUN & spending $$). And George, seriously, my prop tip width was being compared to an identical prop on a certain "straight wing" 170 that we all know so well! Shucks, I thought maybe I had found a reason why ole pokey was so pokey! Maybe I will have to borrow that "certain" 170's prop, or someone else's, long enough to see if it makes any difference in speed?
It would be interesting to take an accurate hand held tach up in both planes. If your tach reads 2500, but the engine is actually only turning 2350 and mine reads 2500, but is actually turning 2650, that would account for it. These numbers are only examples to show how inaccurate tachs could mislead the situation and the engines could be operating with several RPM's difference with the operators thinking they are running the same.
Don't think a hand held tach would help in George's case though. Maybe an hourglass, no, that wouldn't work either. OH, a sundial would do it.
170C wrote:Shucks, I thought maybe I had found a reason why ole pokey was so pokey! Maybe I will have to borrow that "certain" 170's prop, or someone else's, long enough to see if it makes any difference in speed?
Hey, POKEY!
I always suspected your prop might be the reason Ron and I had to throttle back so you could keep up with us on the way home from Lancaster back in '93! It's too bad I didn't think of that when you were here at the convention.
When my O-300A went south about 3 years ago, I bought a used firewall-forward C-145 up in Reno, and am now running that, mount prop, and all. I still have the MDM7653 from the original that we could have swapped onto your plane to check it out. If you can't find one out in your neck of the woods, maybe I can ship you my spare for a test. It has 5-600 hours since overhaul by Sensenich in '93 and was running smooth when removed. True cruise airspeed was a consistent 117 mph (quite a few antennas and no wheelpants.)
Miles
Miles
“I envy no man that knows more than myself, but pity them that know less.”
— Thomas Browne
Gee Miles, I can't understand why you wouldn't have thought about this during the convention! Especially since you didn't have anything else on you mind. HA! Seriously, I appreciate you offer and I might take you up on it if I don't find other reasonable reasons for ole pokey being pokey. I will sure keep you offer in mind and if we decide to try it I'll be happy to pay for freight both ways + insurance.
Don't think a hand held tach would help in George's case though. Maybe an hourglass, no, that wouldn't work either. OH, a sundial would do it. 
