Looking for one video of Craig Dewald

[Popa97]

Hello racers, last year i started to modify some props and etc. Alot ot people tell me that, there is a video, that Craig Dewald give some basic info about props and after that modify prop with hammer. Do you know anything about that video and also can provide a link to it. Regards!

[rumleyfips]

Is this it ? No banging just talking.

[Popa97]

Thats all i know about the video. Thanks!

[deeougee]

Go check out some the RC videos and information on props. There’s a lot more information with those guys that apply to all props. For example the Barr Cut. That was applied to inboard props in the late 80’s. I’ve seen outboard props with it also. Feedback data proved to be inconclusive. Keep in mind with outboard engines as rpm goes up torque goes down, so thin your blades out as much as you’re comfortable with and your wallet can afford. Also recommend an Adam’s pitch gauge to track where you started and where you change and progress. Also RPM gauge when you are testing, it’s more important than MPH. You want to find the right balance between acceleration and top end.

[Popa97]

Thanks alot for the info. I will be glad if you or somebody else provide like forum links about prop and etc.
Regards!

P.P.- i know alot for the props exacly from RC prop videos.

[ZUL8TR]

Maybe not the exact video you want but Dewald appears at about 4 min

https://www.youtube.com/watch?v=xMTWENDTv8s

Props are definitely part physics but mostly experience and lots of trial and error. My best 2 blade for my 1973 25ss (Avatar) was an experimental blade by Harry Pinner (RIP) he designed for high up engine to get the revs to 7500+ (back in the 1970's no 25ss height rule). The round 2 blade prop had a 7.3" diameter, lots of progressive pitch from LE to TE + cup and very thin blade with flex and 6 degree rake. Worked great top end and acceleration out of turns, then hit something at a race and Harry did a hammer fix on a trailer ball . Worked better after that fix so Harry said leave it alone, how's that for a hammer and trailer ball bang with experience. I learned a lot about props, boat setup and race strategy from Harry, Marshall Eldridge Jr (RIP) and Mark Hauptner OPC Tunnel boat racer.

There are many tech videos on outboard race props on Google just search

Here are articles by Jim Russell

https://www.aeromarineresearch.com/articles.html

Look at list and select Anatomy of Propellers, Propeller Slip and any thing else that you like.
I see at the bottom of the selected article you have to email Russell to get the complete article. That's what I did.

What do you have for measuring blade pitch both overall and local along the arc at a selected radius?