Freestyle prop pitch industry standard guage?

[masterblaster]

bk..thats what i have found as well on hooker compared to skat,that will be informative to some who read this thread,but im talking about the same larger 148 and up skat prop between skat track direct and impross and watcon or print gauge,the watcon and print guage look the same. Im not concerned with solas or other brand and types of props no one uses anymore.

They do not use or have the watcon gauge for these requests. even harder to understand...

yamanube..kinda the way i feel,its like having 2 diff tape measures at a job that read diff and trying to make something precise using both.If one is metric and one is standard and there is conversion between the 2 thats fine. but to make it Egyptian hieroglyphics for the sake of what matt says?

 

[Big Kahuna]

Did not read that you were talking about the exact same prop same pitch, I just read you bought from different places.

 

[kevbo]

Flatter leading edges improve hookup at low hull speeds. Steeper leading edges work a little better at high speeds. Props willl run smooth as long as the L/E is not much over 10 degrees. They start getting crunchy after that. More power and rpm make is worse.

 

[DAG]

Props willl run smooth as long as the L/E is not much over 10 degrees. They start getting crunchy after that. More power and rpm make is worse.

Is 10 degrees you reference a mesured angle or say a skat 10/19 stamped impeller that mesured 12 degrees?

 

[kevbo]

I always measure it. I never found any corration between published and actual pitch at the leading edge. All modern props are cambered so we don't need two numbers. It just causes confusion. Don't worry about the leading edge too much, every new prop is flat enough except for dynaflys. They are used almost exclusively for racing.

 

[masterblaster]

no large data base needed,no complicated noise. We know the hookers are 3 degrees diff on leading itedge than the swirl,freeride. Seems very sim to swirl and odd but oh well it is what it is. I talked with skat,they said there is only 2 root angles of the swirl,one tall and one compact,all outside radius specs are built from those 2 roots. assuming they are taking the time to bend a custom prop the same every time. we just need to know what a skat swirl or freeride from skat direct and impros reads from them compared to gauge.

Im not surprised a prop guy who does it all the time uses no gauge if he does it all the time,and knows he only needs a degree more. I use gauge to bend first blade from 3 marks on leading and trailing edge made with a marked wire on radius swirl props. then use a marked mounted dowel pin on my drawtite leverage tray to make the other 3 blades match the first one. recheck transition with gauge to verify likeness. im sure their are many ways to do it

 

[lowe0515]

 

[masterblaster]

please do thread chaser...

kevbo..Ive been reading your posts about the efficiency of 155 pumps since way before everyone started running them.This is where 10 pitch props work with our bigger motors.. Even still though,was talking about a punched out 701 to 735 running a 155 with a 13/18 and a really sweet pipe. Why a 10? leading edge and one number.
I can only fit a 148 in my ski or id run larger.. they need around a 14 to 15 LE to work with this motor and pipe setup.

 

[kevbo]

The idea is to prevent flow separation at the leading edge when head pressure is low. We want water to stick to the blades as much as possible when it not being force fed. A steep prop will work fine once underway but tend to vibrate out of the hole and in adverse conditions. A bigger pump with a flatter prop will come to life from a dead stop much faster than a smaller/steeper arrangement.

 

[masterblaster]

interesting concept..how many mph or rpms does the steeper prop have to be turning in the smaller pump to work as well as the flater prop in a larger pump off idle. any further effect on compacting white water and making pressure in the pump come up faster?
I had a 155 mag I was going to run in another hull, I shoulda kept it.

 

[kevbo]

The inlet stream will be moving around 25mph. A heavy couch gets good pressure recovery but a standup pump runs higher so it's not as efficient. If we had rpm reduction units that allowed the use of 10" pumps nobody would be able to hold onto a ski.

 

[masterblaster]

lol um yea id say a 10 inch pump would be tough fit for any ski a 160 pump is only 6.3 inches..The way pumps have gone in the last 3 yrs,makes me wonder what pro level freestyle skis will be using in 5 yrs. It would be difficult for any smaller pump that wasnt huge to work very well with todays motors with a 10 LE