PDA

View Full Version : What is


Tony M
08-27-2010, 06:59 PM
The Correct Way to figure Slip Numbers . :blush5:.
old377guy
08-27-2010, 08:54 PM
Tony, if no one answers here just google the formula to plug in pitch, rpm, etc. I believe that this theoretical speed is measured against actual speed and generates a slip factor. Good luck. - Jeff
Donskihp
08-27-2010, 09:35 PM
Mercury racing web site has a prop slip calculator Address ishttp://www.mercuryracing.com/propellers/propslipcalculator.php
Ratickle
08-28-2010, 10:29 AM
Here it is as a link



http://www.mercuryracing.com/propellers/propslipcalculator.php
Ratickle
08-28-2010, 10:30 AM
Here is Marc's at BAM.....

With the formula above the calculator


http://www.go-fast.com/Prop_Slip_Calculator.htm
Tony M
08-28-2010, 05:46 PM
Thank You ! I Think ? 83gps 30p @17 percent slip on a single guess it not to bad
afr
08-28-2010, 06:37 PM
subscribed
a 26 pitch prop turning one time is pose to go 26 inches
if it only goes 13 inches thats 50 % slip but you can never go more then 26 inches
they are for an estimate IMO just entertainment really
there are no figures for cupping or for the amount of blades they say add one inch for 4 blades etc

so really i would have to put in 27 p for the extra blade and .25 for a 250 rpm cup .50 for a 500 rpm etc
and i worked in a proppeller shop 5 + years
Dad was really good at playing this guessing game so its more exsperance as to how to use the numbers then just throwing in the basic numbers
Donskihp
08-30-2010, 10:54 PM
You ought to be able to do better than 17% on a single engine. I went from 16 down to 10% on my 2 steped hull Donzi. Brett from bblades helped me dial mine in with his propeller test program.
Tony M
08-31-2010, 08:25 AM
You ought to be able to do better than 17% on a single engine. I went from 16 down to 10% on my 2 steped hull Donzi. Brett from bblades helped me dial mine in with his propeller test program.

Brett Got my slip down to 14.5 with full tank of fuel more than likely less after some burn off of fuel .
jeffswav
09-20-2010, 10:27 AM
Try this site. http://www.rbbi.com/folders/prop/propcalc.htm
I have 9.8% slip at 74mph. Maybe you need a nose cone at speeds over 80? Maybe some prop work? What is your drive depth?