A Prop Pitch Speed Calculator

A Prop Pitch Speed Calculator

Prop Pitch Speed Calculator


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wwwThis calculator requires the use of Javascript enabled and capable browsers. This calculator is designed to give any missing value from the 5 variables needed for marine propeller calculations. They are engine RPM, prop gear ratio (normally for 1.5 to 3.0), prop pitch (the distance that a propeller would move forward in one revolution), prop slip (the efficiency of the prop, lower at high speed, but perhaps very inefficient at low speed) and the boat speed in mph. Enter any 4 variables and the 5th variable will be calculated. Our defaults are set up so that boat speed is the missing variable; however, you may clear any of our defaults and insert your own values. .To determine how fast your propeller can theoretically push or pull you through the air at a given rpm and pitch, multiply your propeller's pitch in inches (usually measured at 75 percent of the prop disk radius) times the RPM. Then multiply that figure times .000947 which gives you your speed in miles per hour. Then multiply this figure by .85 if your aircraft is reasonably aerodynamically clean or by .80 or .75 if your aircraft is somewhat "draggy". This last operation compensates for propeller slippage and some aircraft drag. The end result should be a reasonably accurate estimate of your aircraft's airspeed potential. Use this process to help determine the amount of propeller pitch you need for your particular aircraft. Use the Theoretical Speed Calculator below.

Please Note: The calculation of pitch speed does not account for real-world environment variables such as aircraft weight and aerodynamics, wind or air density nor prop slip. Pitch speed is therefore only an estimate and actual flight results may vary. Real-time flight-speed is best calculated either by radar on the ground or a telemetry system onboard the aircraft. (Source: www.headsuphobby.com)



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