builder tips

A forum in which to discuss topics specific to the assembly of the RV 4.
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Ronald Sutton
Class G
Posts: 29
Joined: Sun Feb 10, 2013 2:46 pm

builder tips

Post by Ronald Sutton »

Fixed Pitch Prop Formula for miles per hour Air Speed
propeller pitch in inches== 84 X 2700 RPM X 60 minutes
12 inches X feet per mile
example --- full throtle -2700
84 pitch x 2700 RPM X 60 = 13608000
12 inches X feet per mile 5280 = 63360
MPH= to 13608000 divided by 63360 = 214.77272 MPH
What ever you prop pitch is and or RPM can be substituted to calculate your air speed.
One of the examples of this would be to find out what your landing speed would be at say 700 RPM
700 X 84 X 60 =3528000
Divided by 12 X 5280 = 63360
55.681818 miles per hour
Your aircraft stalls at 55 miles per hour.
You ever wonder why your aircraft wants to float down the run way even out of ground effect? Try 650 RPM!
I built a Witman tailwind 1972
i built a RV4 1991
I bought a RV4 2012

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