Freestyle bending props to the root angle

[masterblaster]

I have some prop gauges and a rig to bend props on a draw tite to get some leverage,vise isnt cutting it. How important is it to bend close to the root angle? kinda hard to get that far back in there with a good size tool. Was talking to Dave about the skat mags and there isnt alot of different root angle casts.One high one low.guess not as important as outside edges? To begin with if you want to pick up a couple hundred rpms would it be better to just bend the trailing edge down a bit and leave the leading edge alone and see how it effects the whole powerband first?

 

[kevbo]

Most modern impellers are very flat at the leading and camber a lot to the trailing edge. Raising the outside trailing edge reduces load significantly. Large hub props are more difficult to work so they need to be close to begin with. Small hubs can be bent a lot at both ends if needed.

 

[masterblaster]

both 144 and 148 large hub skat mag props Im testing look really flat. The 148 has a large spread 11/20 or so.What are the pros and cons of having such a wide progressive span in a prop,I keep seeing people using wider and wider spreads?

 

[Lumpy]

Not many guys I know like a wide spread

 

[Henry Stephen]

...PaDUM pum

 

[kevbo]

both 144 and 148 large hub skat mag props Im testing look really flat. The 148 has a large spread 11/20 or so.What are the pros and cons of having such a wide progressive span in a prop,I keep seeing people using wider and wider spreads?

A low leading edge angle allows incoming water to form a boundary layer and stick to the front surface. This improves hookup at low speeds because the inlet pressure is low. Old straight pitched impellers worked OK at high speeds but would vibrate badly out of the hole because of flow separation at the steep leading edge. You see high pitches needed when there is too much power for the pump. They usually work great once underway but cannot make as much thrust as a larger diameter pump with a lower pitched prop. Size your pump so that it matches the power with a maximum blade angle of 16-17 degrees .

 

[DAG]

. Size your pump so that it matches the power with a maximum blade angle of 16-17 degrees .

Great info here, never though of it in terms of efficiency

Can we start a Kevbo fund, always dropping good knowledge. Wish I had smart people in my riding group haha

 

[naticen]

His posts are definitely ones I take as legit and discard contradicting ones around it for the most part.

I've only bent small hub props and they were to fix problems or match up to other existing products. Like change a 13/18 Solas to a 14/19 or 15/20. It always works well. I use a big adjustable wrench from harbor freight. It reaches all the way in to the root.