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To all,
 
       I'm by no means an M-14 expert, but spend quite a bit of time behind a geared 1340 Pratt & Whitney. Just wanted to verify a couple of things on reduction gearing and hopefully an M-14 expert may reply. The reduction on the geared 1340 is 3:2 or .667, similar to the M-14, I believe. But the gearing reduces the propeller RPM, not the crank speed i.e. the crankshaft makes 3 revolutions while the propeller makes just 2. This allows the engine to turn a much larger propeller slower (gives a lot more thrust and a heck of a lot less noise on the 1340). While I have never had the nose case off of an M-14 I believe it has a similar type planetary reduction system which reduces the prop RPM similar to the Pratt. This lets it turn that big 3-blader so well. Hope this helps.  

© Dr. Günther Eichhorn
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