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Old 12-11-2021, 11:25 PM
av8rrrr is offline
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Propeller or Screw?

How come boat people call it a screw and plane people call it a propeller? I assume, even though air and water are both mediums, the airplane propeller makes lift(thrust) and the boats prop just mechanically screws itself through the water? This leads me to question #2, if the airplane prop does indeed make lift(thrust), is it possible for an airplane to fly faster than the mathematical numbers on the prop x rpm says it should? Just always kinda wondered
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Old 12-11-2021, 11:38 PM
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wrongwayfeldman
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The term Screw came from The Archimedies invention to lift water by means of a pipe and a so called screw
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Old 12-13-2021, 04:07 PM
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With regards to question #2 above, I had an old formula one racer that I regularly radared at 165 mph in straight and level flight. It had a prop that had 6 inches of pitch. In order to reach 165 mph the motor would have to spin approx 29,150 rpm. If I remember correctly the motor would turn around 22,000 rpm and I am also not factoring in prop slippage and drag of the airframe. This leads me to the obvious conclusion that it is possible for an airplane to fly faster than the props pitch alone dictates.
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Old 12-14-2021, 03:31 PM
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Screw propeller...
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Old 12-14-2021, 06:30 PM
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Very insightful.....thanks
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Old 12-14-2021, 09:30 PM
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Airscrew is another term i have heard especially in Europe.
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Old 12-15-2021, 07:21 AM
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They're get'n lower mate.....
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Quote:
Originally Posted by av8rrrr View Post
With regards to question #2 above, I had an old formula one racer that I regularly radared at 165 mph in straight and level flight. It had a prop that had 6 inches of pitch. In order to reach 165 mph the motor would have to spin approx 29,150 rpm. If I remember correctly the motor would turn around 22,000 rpm and I am also not factoring in prop slippage and drag of the airframe. This leads me to the obvious conclusion that it is possible for an airplane to fly faster than the props pitch alone dictates.
This is correct -
The pitch Vs RPM calculation is only somewhat accurate
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Old 12-15-2021, 08:40 AM
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Thanks Rooman....I have always wondered and have been in many conversations about it through the years.
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