Prop Shaft

[gn7]

Pretty sure most the circle boats are seeing those RPM's at the prop most of the time. Not engine RPM, prop shaft RPM. Don't most of them run 50 over or somewhere close to it. Where's Bob?

It would be interesting to see what those shafts do in a hard turn

I asked that same question and I think these guys are concerned with the larger shaft diameter creating more drag in the water.

But theer has to be material to work with to change the profile on a cnc but I thought some props ears were worked, call it bending if that is correct. I guess my point was, I hope that knowledge isn't lost or does the guy making the cnc prop retain the knowledge to make the tweek . If I have prop"A" and say I need more lift for example who does he call to find out what program to run to get that.

Well I guess if someone don't start doing it soon then all V-drive boaters will be without props soon. Why does every other motor sport advance and change for the better and the v-drive industry sit stagnate? Because most of these guys want to keep doing things the same old way.

Circle boats are hard on the props and shafts because they are constantly cycled between max torque and max HP. If you want to break something on the dyno, you do just that. There is a video on You Tube of Mercury testing the 1350 4 cam and that's exactly what they do in the video.
What a shaft does in a turn is a very interesting thought, and assure you, its not pretty. But then anytime the boat exposes the shaft and lands has a similar effect, just upward.
Flats are much worse the GNs because the GNs tend to track the turns more than the flats. Those suckers do some slipping.

Asking how often the shaft sees max RPM is like asking how often it wins. If it isn't hitting max Rs every lap, it isn't winning.
Only the Ks are running gears in the 50s. Pros and some SS in the high 20s low 30s, GNs pretty much the same.

As for knowledgeable tuners......its a dying art form. Harold Kinsvater is tops, but is pretty much in semi retirement. None better than Gibbs in Havasu, but it VERY picky who he will do a v drive prop for. The guy that took over PB props up north I understand does some nice work, as well a guy I Texas, and Florida. My secret weapon guy is truly remarkable. He was doing the props for Ben Morrone's GN 305, and he made "tuned" them up a gaggle of props. He is willing to try anything just to see the results. He just likes working with a known combo he feels is repeatable, and a driver he feels can give him good imput. Bill and him just flat click.
His name is Brent and he goes by Props Works West on PB, and his claim to fame believe it not, is props for RC boats to the rich and famous, like Anton Brown, but he is looking to make a name in circle boat props. He has 4 championships under his belt to date, and he might be doing some work I am not privey to.
How you make a prop provide more or less lift is pretty much a known "shape" of the ear, or more accurately, the fore aft angle (rake)and location of the ear on the hub. Just as moving the whole shaft forward effects the nose lift, so does just moving the blade forward on the hub relatively speaking. Leaning the blade back as opposed to more straight up will raise the nose too.
Where things get really trickey is in the interface area between the blade and hub, and that's where our props get pretty strange. When SFV2RVR was suggesting that the prop under his Schiada would work reasonably well under my GN, he some what right. It would get it up and down the river, and blast across Havasu just fine. It could never be raced under my boat with any success. Been thru waaaay too many props to know that's never going to happen.
Had props that were 2-3 MPH faster, and handled like a kicked football. Ones that handled "reasonably" well, and 5-6 mph slower. And more props than you can imagine, including brand new props from Both Menkins, and Radience, that did nothing right.