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Re: Let's talk propellers
Originally Posted by
Subsonic
So here's an idea I have. There is a sensenich M74DM7 63 inch for sale right now cheap with only 300 hours on it. What do you think about having it repitched to 62 inches for use on my PA-22-150? What I have read in the TCDS requires it to be able to static a minimum of 2150 RPM. Please comment. My goal is to get all the practical speed I can out of my plane.
Here is the TCDS specs...
Propeller (with Lycoming O-320-A2A or O-320-A2B engine) - Fixed pitch metal Sensenich M74DM Landplane: Static r.p.m.: Not over 2480, not under 2250. Diameter: Not over 74 inches, not under 72.5 inches
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Re: Let's talk propellers
I finally tested my static RPM and I am at 2400 rpm. I have the 74 inch prop with 60 pitch. Im want ting to go to 58 . best I have is 500 foot take off and I want to try to shave as much as possible off that. I also want better climb on hot days. The plane does great at sea level on cool days . I also need to have it dynamically balanced. I called a guy yesterday and He is going to do the balance. According to Him its best to balance it before its re-pitched. Ummmm sounds fishy. I would think the opposite .
And, what are people paying for a re-pitch ? Im in SoCal so your price x 2.5 sunshine factor tax should give me a good Idea of what the cost will be
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Re: Let's talk propellers
Originally Posted by
sierrasplitter
I finally tested my static RPM and I am at 2400 rpm. I have the 74 inch prop with 60 pitch. Im want ting to go to 58 . best I have is 500 foot take off and I want to try to shave as much as possible off that. I also want better climb on hot days. The plane does great at sea level on cool days . I also need to have it dynamically balanced. I called a guy yesterday and He is going to do the balance. According to Him its best to balance it before its re-pitched. Ummmm sounds fishy. I would think the opposite .
And, what are people paying for a re-pitch ? Im in SoCal so your price x 2.5 sunshine factor tax should give me a good Idea of what the cost will be
I would check your tach first. If you are actually getting 2400 RPM, you are only 80 RPM away from the limit with the M74DM prop, Maximum static RPM is 2480 RPM with that prop. If you're not worried about "legal" that's up to you, but I would think from my experience it is unlikely you are actually getting 2400 rpm with a 60" pitch prop. Long ago, I ran a 53" pitch prop on a TriPacer. That airplane would really get out, and it was a 160 HP. I think is still was only about 2500 RPM static with the 53" pitch prop.
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Re: Let's talk propellers
[QUOTE=dgapilot;130746]I would check your tach first.[/QUOTE
Concur. I found my old mechanical tach was off considerably, to the optimistic side. Replaced with EI digital and all of my previous measurements were now out to lunch. That's why I stopped posting on this string. All my previously stated numbers were off.
Then I repaired the static system and watched my airspeed indicator stabilize and indicate slower.
Then had my prop overhauled and found it measured close to 58" but was stamped 61. So, I bought a brand new 74DM60 from Sensenich.
With these changes I now have a much better idea of what the real speed is.
Once again I relearn Garbage In,....
-Subsonic
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