Skat-Trak 10-21 Questions?

[BMANN06]

I've never really bothered with aftermarket impellers, I've found the stock setup to work just fine. I've got this skat-trak 10-21 for an rxp. I've read a bit on low pitch better holeshot, bigger pitch more on the top. I'm not quite understanding it all though. Can someone fill me in on what this 10-21 will do in this ski? And what the 10-21 means?

 

[Seadoobuddy]

good question, I'll watching this thread.

 

[red2blue]

While not a prop guru...I have learned a bit....certainly don't mind sharing what lil I do understand.

The numbers...10/21 denote the root angles of the leading and trailing edges, respectively. My understanding has the 13/18 four bladed prop rated for a stock 215 rxp. A 14/19 four blade for a mildly modded 215 rxp. Typically....a 3blade will have a better hole shot while a four blade will have a better top end. Your Skat-Trac is a 3 blade...isn't it? If someone was using it on an rxp...he was perhaps doing some CC racing, where hole shot is much more important than top end. Or maybe...he was surf/wave jumping where again...hole shot is king.

Keeping in mind that water does not compress.

The steeper the leading edge...the more water the prop grabs...the steeper the trailing edge the faster the prop forces the water out of the pump. Your 10/21....doesn't grab as much water as a 14/19 but it gets rid of it faster than than a 14/19. There is a balance or load that will work better for a given motor regarding desired performance.

Hope this helps.

 

[BMANN06]

Thanks man .. starting to make some sense. This 10-21 Skat Trak is actually a 4 blade, I suppose I can just pop it in the pump and see how I like it.

 

[red2blue]

Hmm...I've never seen/heard of a 4blade skat-trac. However...that aside. I wouldn't expect that prop to be tall enough. I would definately be intersted in seeing some results re before/after the prop swap. I have an ....incling of some info that I've been able to garner from one I consider a guru....I didn't/don't want to post it though without some at least small level of corroberation(sp?).

 

[BMANN06]

Here's a couple pics.

 

[BMANN06]

It wasn't included with my recent rxp purchase (that ski has a stock impeller). I got it in a deal with a gtx. I saw this prob was made for the rxp so wheeled it in the deal with gtx. But I'm not sure its going to work ... not a big deal I paid $50 for it.

 

[red2blue]

You've checked the spline count and the dia?

 

[BMANN06]

Your starting to lose me know ... i'm lost on spline count, diameter is easy. I kinda bought this on a whim, while talking with seller he mentioned this prop. I just google it and came to the skat-trak application page. It lists this prop for an rxp without engine mods.

Edit** spline count... Gotcha yes this impeller will fit the 215 driveshaft.

 

[red2blue]

Cool deal then.

If you aren't used to it...write everything down...ie before/after mod....one mod at a time. Base line numbers is what you want...get air/water temps...conditions....fuel load.....ect...ect...heh. With a base line to go by you'll remove "seat of the pants" feel for realistic and actuall gps certainty.

 

[BMANN06]

Sounds good thanks man! I'll give it a try ... i've got the stocker if this doesn't impress.

Appreciate all the help!

 

[red2blue]

Anytime...curious what kinda numbers you're gonna see, myself.