Even if you only have a fixed pitch prop....

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GAHorn
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Even if you only have a fixed pitch prop....

Post by GAHorn »

...if you ever operate any aircraft with a variable-pitch/constant-speed prop you might wish to know what the following, recently-issued FAA Information Bulletin advises:
Variable pitch prop overspeed ce-10-21[1].pdf
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'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons. ;)
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blueldr
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Re: Even if you only have a fixed pitch prop....

Post by blueldr »

P ponk has a site where you can determine the maximum you can turn a given diameter prop and expect to have efficiency. Most engines can stand some overspeed for a relatively long time. I was always taught to slow the airspeed down to maintain a given RPM and airspeed to mainintain level flight.
BL
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GAHorn
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Re: Even if you only have a fixed pitch prop....

Post by GAHorn »

I agree, bluEldr, however this particular reference illustrates a peculiar anomaly of which some pilots may be unaware.... unless you slow down considerably...maybe even LESS than "best" or "recommended" glide speed... the prop may be at such fine pitch as to produce no thrust. The recommendation in such case is to slow the aircraft still further in order to overcome the peculiarity. (The condition described in the article reminds me of the theory-of-operation of the old Aeromatic props. Be sure to read the article completely in order to understand the concern.)
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons. ;)
hilltop170
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Re: Even if you only have a fixed pitch prop....

Post by hilltop170 »

I find it incredibly ridiculous that a pilot flying an airplane with a constant speed speed prop would crash the plane only because the prop is set in the takeoff position. Unbelievable!
Richard Pulley
2014-2016 TIC170A Past President
1951 170A, N1715D, s/n 20158, O-300D
2023 Best Original 170A at Sault Ste. Marie
Owned from 1973 to 1984.
Bought again in 2006 after 22 years.
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GAHorn
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Re: Even if you only have a fixed pitch prop....

Post by GAHorn »

hilltop170 wrote:I find it incredibly ridiculous that a pilot flying an airplane with a constant speed speed prop would crash the plane only because the prop is set in the takeoff position. Unbelievable!
Richard's comment reminded me of how I felt after learning about the Air Florida 90 crash.... It was pretty difficult to imagine two pilots of any aircraft failing to advance full throttles when the stall warnings commenced.

In this case, I can only imagine that the person failed to corelate the rpm indications with the lack of thrust at regardless of glide speed.
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons. ;)
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