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Field approval paperwork for "Pawnee" prop
Looking to see if anyone has or knows of a 337 for putting the McCauley 1P235 on an O-360. I've seen it done, whether it was "legal" or not I dont know. If anything perhaps I can be educated on the subject.
I'm talking about the 84" prop that was originally type certificated for the O-540, not the 78" one that is type certificated for the O-360.
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Re: Field approval paperwork for "Pawnee" prop
Is it possible that some data already exists in Approved manuals and spec sheets? For example, if you were to compare the crankshaft journals, crank pin and connecting rod dimensions and throw between the 360 and 540 in the Lycoming overhaul manual you may find that they are the same.
As they are probably identical in form fit and function, they could be shown using the FAA blessed PLANK formula to be equal and capable of handling the increased torsional loading of the longer prop.
From the FAA Powerplant mechanics Handbook
The indicated horsepower for a four-stroke cycle engine can be calculated from the following formula, in which the letter symbols in the numerator are arranged to spell the word “PLANK” to assist in memorizing the formula:
Indicated horsepower = PLANK / 33,000
Where:
P = Indicated mean effective pressure, in psi
L = Length of the stroke, in feet or in fractions of a foot
A = Area of the piston head or cross-sectional area of the cylinder, in square inches
N = Number of power strokes per minute: rpm/2
K = Number of cylinders
Then use an approved propeller manufactures pitch calculation data along with the propeller TCDS approved data to show it meets horsepower, rpm and tip speed design of the prop.
Last edited by Vagabondblues; 11-24-2019 at 07:41 PM.
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Re: Field approval paperwork for "Pawnee" prop
The bigger issue with propellers is vibration characteristics for the combined engine and propeller. The propeller TCDS will list engines that have been show to have no vibration issues.
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Re: Field approval paperwork for "Pawnee" prop
Originally Posted by
dgapilot
The bigger issue with propellers is vibration characteristics for the combined engine and propeller. The propeller TCDS will list engines that have been show to have no vibration issues.
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https://www.lycoming.com/sites/defau...%20Drive_0.pdf
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Re: Field approval paperwork for "Pawnee" prop
I know the 1A200 "Borer" prop has an rpm limitation somewhere in the range where your limited on time in that rpm. But it only applies to hollow cranks.
I guess my other question is, what data do I need to compile for this sort of field approval?
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Field approval paperwork for "Pawnee" prop
Originally Posted by
Vagabondblues
? I don’t understand what a SB on mag drives has to do with prop installations. Looking at the TCDS for the 1P235, it is only approved on Lycoming O-540 and IO-540 engines with one 5th and one 6th order vibration damper. It can also be installed on an O-360, but with a maximum diameter of 78”.
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Last edited by dgapilot; 11-25-2019 at 04:28 PM.
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Administrator
Re: Field approval paperwork for "Pawnee" prop
Originally Posted by
dgapilot
? I don’t understand what a SB on mag drives has to do with prop installations. Looking at the TCDS for the 1P235, it is only approved on Lycoming O-540 and IO-540 engines with one 5th and one 6th order vibration damper. It can also be installed on an O-360, but with a maximum diameter of 78”.
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The ground adjustable prop that Sensenich made for the O-200 created a high frequency vibration that effected Slick mags. The combination was used on the Legend Cubs.
The P235 use to be field approved on 180 hp Super Cubs. I would ask this question on SuperCub.org, I know there are a lot of them being run but don't known that the FAA is very receptive to field approvals anymore.
Last edited by Steve Pierce; 11-26-2019 at 07:21 AM.
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Re: Field approval paperwork for "Pawnee" prop
I'll get on supercub.org and look around or ask. I know it flies cause I know of several airplanes that have gone to tbo with the 1P235 on them. Problem is I only know one of the guys and his is "just on there" if you know what I mean. Darn Alaskans.
With what Steve said about the legend cub, I now understand vagabondblues sending the link for the SB. I could have that in my arsenal if needed for approval.
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Re: Field approval paperwork for "Pawnee" prop
With the exception of the “just on there” airplanes, get the N# and order the FAA CD with the airworthiness file. If there is a field approval for that airplane, it will be there.
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Administrator
Re: Field approval paperwork for "Pawnee" prop
Originally Posted by
dgapilot
With the exception of the “just on there” airplanes, get the N# and order the FAA CD with the airworthiness file. If there is a field approval for that airplane, it will be there.
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You find out a lot of things that way. A lot of outlaws out there no matter what they tell you or portray on the internet and in real life.
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