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Looking for wooden prop for Baby Lakes

Shad Bell

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Looking for wooden prop for baby lakes. I currently have a 69-42 but need more rpm for climb. Looking to try a 66-48 or similar. Engine is A-65 with 8:1 compression pistons with flange shaft.
 

tdwrv8

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Shortening the diameter won't help much. You need less pitch.
 

TFF1

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That looks like a cruise prop for a Cub by memory. 69-39 or a bouts should be the climb version.
 

Shad Bell

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Its a Props Inc 69-42. Was repitched once. It helped a little but think chord was reduced a littoo much. I tried a cut down cessna 150 prop was a 66-48. Worked better but eas a little too heavy.
 

TFF1

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The cut down 150 prop probably got the performance from being metal more than the specs as they are counter intuitive. For counting fingers rule of thumbs, one inch less prop diameter but one inch more pitch will load the engine the same. There is a small charge in character if taken far enough. The smaller the diameter the better high speed prop it becomes. The bigger diameter the better short field prop it becomes. Another delima is certified props were not designed for your custom application. But without a half a dozen props to build a data field you have to make educated guesses. If you go all climb, you will climb but hit a wall once you are done climbing. It can act as a brake not letting the plane get to a happy speed. If you are wanting climb, you want the bigger diameter and lower pitch. If you need some speed, you give up some diameter and add pitch. If it's all about speed you want the smallest with the most pitch. With wood you also seem to give up about 2" just because of material; traditional wood props that is. Also this started with load. RPM. If you are overloaded you have to decide if you want to remove pitch or diameter. An inch or two less of either will speed up the engine, you have to pick if you want to keep the pitch or diameter and what speeding up that prop does. The culver props are pretty inexpensive if you can get close to what specs you want. They like all prop manufacturers will have a starting point suggestion. My uneducated guess you want a 67-43.
 

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