prop question

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RonTurner
Posts: 32
Joined: Sun Nov 05, 2017 7:00 pm

prop question

Post by RonTurner »

Open question: I'm currently restoring WR-1. I have the engine running now after going though everything. It's a A65-8-F from a 46 Taylorcraft with a Sensenich 74 X 43 aluminum prop. Static RPM is barely 2000 indicated. Seems that 72 x 42 is the most widely used Piet prop. Sensenich recommended prop is 74 x 44 aluminum or 72 x 42 wood. I don't understand that? Any thoughts?
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taildrags
Posts: 637
Joined: Tue Mar 07, 2017 10:39 pm

Re: prop question

Post by taildrags »

Ron; my airplane, NX41CC, originally made its first flights and most of its test hours behind an A65-8 with a metal prop. I'll have to look through the original logs to see what pitch and diameter metal prop were on it, but it later flew with a wood prop that weighed somewhat less so there is a log entry on w&b after that change as well. I'll let you know what I dig up.
RonTurner
Posts: 32
Joined: Sun Nov 05, 2017 7:00 pm

Re: prop question

Post by RonTurner »

Thanks. Much appreciated! Preparing to put the wings on now. Weight and balance might dictate which prop to use? Metal is 10lbs. heavier.
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taildrags
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Joined: Tue Mar 07, 2017 10:39 pm

Re: prop question

Post by taildrags »

Ron; I went through the logs and although I couldn't find anything indicating what the metal prop was that was on 41CC originally, a log book entry by the test pilot indicated that he was getting 2300 RPM static and that it should be more like 2100-2150 so if you're not even seeing 2000, you're low with what you have on it right now. http://www.flysquirrel.net/piets/NX41CC01.jpg is a photo of my airplane with the metal prop on it (taper shaft prop hub). After the test hours were flown off, Corky swapped out the metal prop and hung a Hegy 72x42 wood prop on it, which worked great on the 65 but when I sold the 65 and put the A75 on it, I went to a Tennessee Props 72x36 to let the engine turn up to its full rated 2600 RPM.
RonTurner
Posts: 32
Joined: Sun Nov 05, 2017 7:00 pm

Re: prop question

Post by RonTurner »

Thanks Oscar. After a long chat with Sensenich tech support I've learned a lot about propellers! Great people and very helpful. He said he was not surprised at my 2000 rpm static as A65's seldom reach more than that? I'm ready to install the wings now and perform W & B then on to some taxi time to see how she feels? Thanks again! Ron. PS Please let me know the shipping cost on the carb heat box so I can send you the money.
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taildrags
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Re: prop question

Post by taildrags »

Ron; I'm ashamed to say that my new responsibilities as president of our company have left me with very little free time, so I have not sent out the carb heat box yet. It is still on the seat right next to me in my Ford Ranger. I just need to box it up and get it sent out!
RonTurner
Posts: 32
Joined: Sun Nov 05, 2017 7:00 pm

Re: prop question

Post by RonTurner »

No rush my friend. Work before play! lol Or work so we can play?
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taildrags
Posts: 637
Joined: Tue Mar 07, 2017 10:39 pm

Re: prop question

Post by taildrags »

Ron: I must add the caution that you should NOT attempt to operate the aircraft in the air without a fully-functional and tested carburetor heat system. This is imperative with carbureted engines like the Continental A65, and I can attest to this by personal experience. Ground operations without carb heat are fine, but my advice is to NOT fly the aircraft without operational carburetor heat that has been tested and proven. I mention this because you said you were preparing to mount the wings onto the airframe.
RonTurner
Posts: 32
Joined: Sun Nov 05, 2017 7:00 pm

Re: prop question

Post by RonTurner »

Thanks I do have a functioning heat box ( new scat tube & cable too ) but it has no way of attaching an air filter. It has only a fine wire screen covering the inlet.
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