Prop Pitches are They Correct?

[2fast4u]

I have preached about getting the correct rpm's and prop pitches on your target rpm's. Now for my second sermon. When you are trying to get your rpm's correct you need to know just what prop pitch you actualy have. I have seen almost every brand and type of prop made and none of them are what the Mfg. said they were supose to be. The only way to know what you are dealing with is to put the prop in a pitch gauge and read all three blades both on the trailing and leading edges. There are a lot of good guys out there re pitching props. The tru prop pitch is the only way to start and go from there to get the end results you want. I see on the forum guy #1 has the same mods as guy #2 and has a ??/?? pitch prop and guy #2 try this same ??/?? prop and can't turn the rpm's guy #1 can. Well guess what even though both props have the same pitch numbers on them they are totaly different pitches. To make things worse some guys who re pitch props don't go up on the blade when re ptching as far others do and this also changes rpm's some too. So what is a guy to do? Try to get as close a pitch prop as you can to start with and try to get it repitched even one to three times till you get it correct for your rpm's, if you miss your target rpm's more than 450 rpm's or more you have got the wrong prop for your ski to start repitching on. Another problem for you guys to face is if you add more mods to your ski latter this prop prop is wrong also and usualy will require a different prop again. I just want to let you guys know why we see so many prop questions. Lets pray that everyone get the correct prop the first time! Amen, Tommy Jordan

[BPnta]

Very true. I ordered a 14/25 once and was told later by someone who measured it to be a true 14/23.

[JIM'S PERFORMANCE]

Your not kidding Tommy i hardly ever see the impeller being what the mfg. says it is.

[rossnemo]

Oh so true Tommy, excellent advice, and Bill, your scat is a true 14-25 now, measured with a watcon gauge, with the 25 pitched a full 2 inches up on the trailing edge. Stock it measured a 23..

[305coco]

preaching on saturdays and all gotta love this forum


tommy are you still making the prop gauges?? it would also be nice if one of the prop guru's can make a video on how to pitch props, i think that would help alot of forum members and encourage them to give it a shot, its not that hard..
i know theres a few (how to's) on the forum with pics but a video would be like standing next to your tunner while he pitches your prop.. it would really save you on down time, waiting for props to get back and a few bucks too.

[2fast4u]

preaching on saturdays and all gotta love this forum


tommy are you still making the prop gauges?? .

Sorry I have sold all of them. Tommy Jordan

[beerdart]

Here is a good read.

http://impros.com/store/index.php/tech-info/about-impellers.html

[5001craig]

Great post Mr. Jordan.

Why is it acceptable that the props are not what they are advertised to be? That seems to me to be crazy.

[beerdart]

Great post Mr. Jordan.

Why is it acceptable that the props are not what they are advertised to be? That seems to me to be crazy.

Every manufacture lists there impellers different. Some list them as actual pitch angle and some list them as the distance traveled in one revolution (as in boat props). The only way to compare is to measure yourself and adjust as needed.

[GoFastGuru]

buy prop from dave at impros and he will check it for you

[robk]

I sent my prop to impros (scat 13/23) running 7900rpm. I told them I wanted better holeshot and 300-400 more rpm's on the top end. Its coming back as a 14/19. Will install tomarrow and run Sat.

[RX951]

I have preached about getting the correct rpm's and prop pitches on your target rpm's. Now for my second sermon. When you are trying to get your rpm's correct you need to know just what prop pitch you actualy have. I have seen almost every brand and type of prop made and none of them are what the Mfg. said they were supose to be. The only way to know what you are dealing with is to put the prop in a pitch gauge and read all three blades both on the trailing and leading edges. There are a lot of good guys out there re pitching props. The tru prop pitch is the only way to start and go from there to get the end results you want. I see on the forum guy #1 has the same mods as guy #2 and has a ??/?? pitch prop and guy #2 try this same ??/?? prop and can't turn the rpm's guy #1 can. Well guess what even though both props have the same pitch numbers on them they are totaly different pitches. To make things worse some guys who re pitch props don't go up on the blade when re ptching as far others do and this also changes rpm's some too. So what is a guy to do? Try to get as close a pitch prop as you can to start with and try to get it repitched even one to three times till you get it correct for your rpm's, if you miss your target rpm's more than 450 rpm's or more you have got the wrong prop for your ski to start repitching on. Another problem for you guys to face is if you add more mods to your ski latter this prop prop is wrong also and usualy will require a different prop again. I just want to let you guys know why we see so many prop questions. Lets pray that everyone get the correct prop the first time! Amen, Tommy Jordan

Your not kidding Tommy i hardly ever see the impeller being what the mfg. says it is.

yup. I've seen three impellers brand new out of the box all identical pitches all read different. Also, depending on who it pitching them, that can be a factor as well too. And to add, everyones setup is different.

[2fast4u]

bump this back up to the top for the new guys

[allstar71]

Are the impeller manufacturers at least consistent in their incorrect pitches? I don't really care if the 13/18 impeller I have is actually a 13/20 as long as when I order a 13/19 it is actually a 13/21.....

[mikeFZR]

In my experience the trailing edge for skat is one degree less than what they advertise. IMO any prop will require some tweaking.