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Thread: PA-22-160 climb vs cruise prop and speed?

  1. #1

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    Default PA-22-160 climb vs cruise prop and speed?

    Assuming good rigging on a stock pa-22-160, what is the difference in cruise speed that one should expect between mounting a climb prop vs a cruise prop?

    Thx

  2. #2
    RobertC's Avatar
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    Default Re: PA-22-160 climb vs cruise prop and speed?

    Quote Originally Posted by DJ Balla View Post
    Assuming good rigging on a stock pa-22-160, what is the difference in cruise speed that one should expect between mounting a climb prop vs a cruise prop?

    Thx
    I changed from cruise to climb prop on my PA22-160. It did slow me down, but I’ve never actually determined exactly how much. I’m guessing 5-6 mph. It makes engine noise and flies so I’m happy.

  3. #3
    Pacerfgoe's Avatar
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    Default Re: PA-22-160 climb vs cruise prop and speed?

    Quote Originally Posted by RobertC View Post
    It makes engine noise and flies so I’m happy.
    How can you possibly argue with that

  4. #4
    Gilbert Pierce's Avatar
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    Default Re: PA-22-160 climb vs cruise prop and speed?

    Pick your desired pitch and rpm and figure it out

    Pitch x rpm x 0.0009 = miles per hour with no slip. Using my known numbers, 0.90 is a good efficiency number; 10% slip.

    58 inch X 2700 rpm X .0009 = 140.9 x .90 = 127 mph which is what I would see down low.

    Just adjust the pitch and rpm for what you want to do.

    Theoretically at 2500 rpm, 58” prop the math shows I should true out 117 miles an hour.
    That is exactly what I see.

    If anyone wants to see where I got the .0009 I will be happy show you the computation.
    inches x rev per min x 60 min per hour divided by (5280 ft per mile x 12 inches per ft.). The units then cancel to miles per hour. Hope you enjoy this as much as I did deriving it.

    By the way 61 inch pitch would give you 133.4 with the same conditions. An increase of 6.4 miles per hour. My prop is new. That variable 0.90 will change slightly with prop condition. Bear in mind this is theoretical. Your mileage my vary.

    I have doubts about many mph claims. I was getting 135 mph with a 54” prop until I redid my static system and calibrated it with a four course gps flight and some fancy math that camtom12 understands.
    Last edited by Gilbert Pierce; 08-06-2019 at 09:12 PM.

  5. #5

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    Default Re: PA-22-160 climb vs cruise prop and speed?

    Quote Originally Posted by Gilbert Pierce View Post
    Pick your desired pitch and rpm and figure it out

    Pitch x rpm x 0.0009 = miles per hour with no slip. Using my known numbers, 0.90 is a good efficiency number; 10% slip.

    58 inch X 2700 rpm X .0009 = 140.9 x .90 = 127 mph which is what I would see down low.

    Just adjust the pitch and rpm for what you want to do.

    Theoretically at 2500 rpm, 58” prop the math shows I should true out 117 miles an hour.
    That is exactly what I see.

    If anyone wants to see where I got the .0009 I will be happy show you the computation.
    inches x rev per min x 60 min per hour divided by (5280 ft per mile x 12 inches per ft.). The units then cancel to miles per hour. Hope you enjoy this as much as I did deriving it.

    By the way 61 inch pitch would give you 133.4 with the same conditions. An increase of 6.4 miles per hour. My prop is new. That variable 0.90 will change slightly with prop condition. Bear in mind this is theoretical. Your mileage my vary.

    I have doubts about many mph claims. I was getting 135 mph with a 54” prop until I redid my static system and calibrated it with a four course gps flight and some fancy math that camtom12 understands.
    Thx for this!

  6. #6
    Tailwind_Fan's Avatar
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    Default Re: PA-22-160 climb vs cruise prop and speed?

    Quote Originally Posted by Gilbert Pierce View Post
    .... If anyone wants to see where I got the .0009 I will be happy show you the computation.
    inches x rev per min x 60 min per hour divided by (5280 ft per mile x 12 inches per ft.). The units then cancel to miles per hour. Hope you enjoy this as much as I did deriving it.

    I have doubts about many mph claims. I was getting 135 mph with a 54” prop until I redid my static system and calibrated it with a four course gps flight and some fancy math that camtom12 understands.
    Lol you gotta love dimensional analysis!! Even better is when you start working with non-dimensional number... like propeller tip speed in Mach number: ft-sec/ft-sec...

    -Alana
    Last edited by Tailwind_Fan; 08-07-2019 at 12:29 AM.

  7. #7
    Alessandro's Avatar
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    Default Re: PA-22-160 climb vs cruise prop and speed?

    Quote Originally Posted by Gilbert Pierce View Post


    By the way 61 inch pitch would give you 133.4 with the same conditions.
    Is it really 133 mph or 123 mph??

    Thank you.

    Alex.

  8. #8
    Zac Weidner's Avatar
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    Default Re: PA-22-160 climb vs cruise prop and speed?

    A stock PA-22-160 by the book is “supposed” to do 134 mph at 7 or 8,000’, but I can’t get quite that. 130 pretty consistently though.


    Sent from my iPhone using Tapatalk

  9. #9
    Gilbert Pierce's Avatar
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    Default Re: PA-22-160 climb vs cruise prop and speed?

    Quote Originally Posted by Alessandro View Post
    Is it really 133 mph or 123 mph??

    Thank you.

    Alex.
    Alex your right. Thanks for catching that. I corrected it in the original post. It’s 123 mph.

  10. #10
    Gilbert Pierce's Avatar
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    Default Re: PA-22-160 climb vs cruise prop and speed?

    Quote Originally Posted by Zac Weidner View Post
    A stock PA-22-160 by the book is “supposed” to do 134 mph at 7 or 8,000’, but I can’t get quite that. 130 pretty consistently though.


    Sent from my iPhone using Tapatalk
    I am close. You should get 2700 rpm or close at 7500 ft. and a good 61” prop. That would give a 133 mph

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