prop slip

[Disturbed]

Here's the math formula that I'm using,

RPM X Gear / (1056/prop pitch) = theoretical MPH

Observed MPH X 100 / Theoretical MPH = % of efficiency

Does this sound right?

 

[73 Sanger Flat]

This is what I use . Plug in the number to the excel spreadsheet .. The prop slip is the actual grip of the prop and not the slip ..It was easier for me to create the formula that way .. So right now it shows .81  so that is 19% prop slip .. So far this is very close to my GPS numbers ..

Once you know the prop slip , change it in that slip column ( cells ) and then it will be close for your formulas ..

And yes you formulas looks correct also .. I am just lazy and created this

 

[Disturbed]

Thanks!!!!!  jump.gif

 

[Drumzilla]

Wow ....  think.gif think.gif ... water goes in mine..water shoots out mine real hard ... boat moves so it's all good...there done.....

                                                              :smile30:

 

[Disturbed]

Wow ....  think.gif think.gif ... water goes in mine..water shoots out mine real hard ... boat moves so it's all good...there done.....

                                                              :smile30:

How's the view from back there?  LOL. 

 

[Drumzilla]

whatever.gif....  wish you would of said that last year ...sure pick on a guy when he's down and running mid 70's mph.... 

                                                                                                    :smile30:

 

[jimsplace]

Wow ....  think.gif think.gif ... water goes in mine..water shoots out mine real hard ... boat moves so it's all good...there done.....

                                                              :smile30:

Jets have so much slip you don't want to calculate it.  Did you ever watch a jet running about 20 mph and think it must be running 50 from the sound.      think.gif

 

[73 Sanger Flat]

It does sound like a jet is going a lot faster than it really is .. Funny how that works ..

 

[Knotty Girl]

Not all of them.  :smile26:

 

[Disturbed]

Not all of them.  :smile26:

Yes, all of them...

 

[KONA77]

Not all of them.  :smile26:

Yes, all of them...

you funny...lol

 

[Disturbed]

Not all of them.  :smile26:

Yes, all of them...

you funny...lol

:smile14:

 

[ChryslerJet]

Not all of them.  :smile26:

Yes, all of them...

you funny...lol

Mine should be fairly quiet under the hood.

Right now its silent lol

 

[Patchman]

There is something screwy about this thread, Oh yea it's a V-drive thread! Next! crazy.gif :smile16:

 

[73 Sanger Flat]

Did not take very long for thsi thread to  get off track ..


Did you try the spreadsheet to get you slip numbers ??
  This was the number I was turning at Tawakoni

 

7100​

16​

1.22​

0.000946697​

131.2046306​

0.81​

106.28​

gps very close

 

 

[Disturbed]

Sure did!  Thanks!  It went 96 at 6700 so, I have around 22% slip.

 

[Disturbed]

There is something screwy about this thread, Oh yea it's a V-drive thread! Next! crazy.gif :smile16:

clap.gif

You're such a punny guy.  crazy.gif

 

[Patchman]

Well I don't have to do some calculus to figure out how to drive my boat! Good thing your son is a genius! :smile16: :smile30:

 

[Disturbed]

It just proves that vdrive drivers are little more intelligent.  :wink:

 

[ChryslerJet]

It just proves that vdrive drivers are little more intelligent.  :wink:

Didn't say we weren't smart just that we didn't need to be. LOL 

Also Patch Did say good thing you have a smart SON. 

whatever.gif