Freestyle prop pitch industry standard guage?

[masterblaster]

Ive bought a few props from skat direct and impros,custom stuff,or bent my own and sent in for balance and refinish. They are always off by 2 deg or more on the leading edge and dead on with trailing according to watcon gauge or printed adjustable gauge. They say they measure theirs differently? Anyone come up with a standard to compare these "other" type measurements to on gauges that we all have? It would be nice to order a new prop and know what to expect right out of box if you know right what you need on your own gauge from prev testing. A one of real standard would make things much more easy for us all. It would be nice not to have to bend,file a brand new balanced, perfectly clearanced prop

 

[kevbo]

The aft two inches is where all the water ends up and is where all the load comes from.

 

[jo5hi3]

Ive bought a few props from skat direct and impros,custom stuff,or bent my own and sent in for balance and refinish. They are always off by 2 deg or more on the leading edge and dead on with trailing according to watcon gauge or printed adjustable gauge. They say they measure theirs differently? Anyone come up with a standard to compare these "other" type measurements to on gauges that we all have? It would be nice to order a new prop and know what to expect right out of box if you know right what you need on your own gauge from prev testing. A one of real standard would make things much more easy for us all. It would be nice not to have to bend,file a brand new balanced, perfectly clearanced prop

Learn how to read a prop gauge.

 

[masterblaster]

smh...someone that tuned their own ski would be better suited to comment. They state them selves they read different. question is how much diff between the 2 and the watcon gauge.

 

[jo5hi3]

smh...someone that tuned their own ski would be better suited to comment. They state them selves they read different. question is how much diff between the 2 and the watcon gauge.

So who tuned my ski?

 

[masterblaster]

The easter bunny? dont need to hear from a negative nancy post chaser.. would be a better responce

 

[Ducky]

 

[jo5hi3]

ok, just think this over for a second. Can you actually ready the entire leading edge of the prop? Can you read the entire trailing edge?? Maybe, just maybe that has something to do with it.....

 

[masterblaster]

Both these manufactures will tell you they use another type gauge to work with these props and they will not measure the same on the watcon or printed gauge..But cant tell you the degree diff between them because they do not use them. I keep reading people buying props at a listed # and measuring them at up to 3 degree diff on the leading edge,so none of these guys know how to read a gauge? If there is a set standard between the 2 it would be nice to know for custom bent new ordered props.
there is a good thread on green hulk on how to read and bend props on a drawtite for leverage ,wouldnt wana pass along someone elses knowledge here..

 

[snowxr]

Skat, Solas, Nujet, etc. all have slightly different measurements for the same claimed "pitch". Don't expect everyone to use the same " standard" pitch guage. It's just a tool. If your leading edge should be 2 degrees steeper, just tell the shop doing the work to make that change. Simple. Once you have the prop how you want it, you have a baseline to compare other props to with your guage. Simple really.

 

[jo5hi3]

Snow's got it. You order your prop, run it, if its to much you bend it using your gauge to less pitch, opposite if your spinning it. Just like a compression gauge, its a tool to be used for motor health.

 

[masterblaster]

snow.. Thats what im trying to determine for a new order prop,I dont want to bend again or send back to repitch and balance. It seems the diff is more than slight. If there was a listed standard diff between them it would be easy for anyone to order a prop that currently uses one of these gauges avail to us and a known prop in use from the gauge. obliviously dont want to bend a brand new props leading edge up 2 degree or more and file it to fit the ring and re balance,or bend it down and have a larger clearance on the wear ring.

 

[jo5hi3]

Call them and tell them you want it to read x pitch on a watcon or whatever gauge you are using..... Then they will pitch it to your desire.

 

[Ducky]

Buy a prop from each company and order the same pitch, and when you receive them, document the differences and use that for future reference?

 

[Big Kahuna]

Buy a prop from each company and order the same pitch, and when you receive them, document the differences and use that for future reference?

Same prop pitch from Solas and Skat is not the same. Your not gonna order a Skat Freeride 9/15 to be equal to a Hooker 9/15, your going to order a Skat 12/15 or 12/17. This will be about the closest match in peformance to the Hooker. or the Solas Concord you are going to order a 13/17. Prop MFG do not make their props the same as each other. They may be close but there are difference it blade design, shape, Swirl from the hub or clipped like a concord. root angle of the blades coming off the hub. There are many factors that go into play and design. Case in point You can order a Skat slimline that is a 8/16 or a Skat Freeride 12/15. They will both work on a stock SJ. And work pretty good. They will just load the pump differently. Granted, the slimline is much older tech. you are going to want the Freeride.

 

[yamanube]

Snow's got it. You order your prop, run it, if its to much you bend it using your gauge to less pitch, opposite if your spinning it. Just like a compression gauge, its a tool to be used for motor health.

While it may be true, this is stupid. Arguing that there are two ways to measure an angle in degrees is like calling a 144mm pump a 148mm pump because you used a different ruler.

 

[Ducky]

While it may be true, this is stupid. Arguing that there are two ways to measure an angle in degrees is like calling a 144mm pump a 148mm pump because you used a different ruler.

Companies have to keep a competitive advantage somehow.

 

[jo5hi3]

While it may be true, this is stupid. Arguing that there are two ways to measure an angle in degrees is like calling a 144mm pump a 148mm pump because you used a different ruler.

Not saying there is 2 different ways to measure an angle, but since its a progressive pitch prop its going to be different based on where you measure.

 

[DAG]

I think what you are seeking is to start a database. The Watcon, JETTLab, or other brand gauges are the “Standard Gauge”. They are the calculated ratio of “rise” to “run”. I called Scat and Solas about 2 or 3 years ago when I created my first prototype gauge because the reading I took was different than the marking on the impeller. The calculation for how the manufactures derive the numbers they market us is appears to be a trade secret that they are not willing to share that information.

This leaves the pwc community using “standard gauges” as a reference tool to indicate the angle of the outer most edge of the prop around its circumference. Every prop has an outer most edge around its circumference. There for it should be possible to create a database to say a Skat D75 10/18 measures 14/19 using a “standard gauge” across the outer most edge of the impeller and along the leading and trailing linear 2”. However, I don’t see how this database information would be useful to anyone because it does not indicate all the geometry that makes up each and every impeller. It would be interesting to see if everyone’s D75 10/18’s measures 14/19. With my background in stats there will be too much noise in this type of study unless it was performed at the manufacture on the same gauge by the same person on all new props. Good luck setting that up. As of now there is no accountability and no one really knows what they are getting so you just have to trust the manufactures. Who’s going to be the first to come up with a conspiracy theory?


Pitch Gauge tools are best used to confirm all 3 blades leading and trailing edges are the same. Often they are different and need minor truing especially if buying a used impeller. They are also a great tool to use when doing a DIY re-pitch to make sure you move all 3 blades precisely the same about, typically 1 degree up or down at a time from wherever the prop currently indicates.

 

[Big Kahuna]

I have been told, but not seen, and this did happen at the hartwell race, that a racer took his prop to a builder that was there and he does not use a pitch guage, he finds out what you are wanting out of it. More RPM's?, More Bottom?....... Then it picks the part of the blade and tweaks it, measures how much he moved it. does the other 2 and says go test, bring back if need be............ Having a chart for something is not the same as real world tuning. Granted a pitch guage is very usefull to determine if all blades are the same. Then if you are smart enough you use them to repitch your own props by using the guage to determine how much to move them and how much did you move them.