Sonson angles JAE 21 and 45

[DaveMarles]

I made some narrower sponsons (25mm) for my JAE 21 which has improved the stability. Angle on the right is 3.3 degrees and left 3 degrees, which seems to work well. However on my 45 the right sponson is 4.3 degrees and left 3.9 degrees. It is running good at the speed it is at now but are these angles correct? The Ski on the 45 is 2.2 degrees.

 

[Marty Davis]

Dave:

I think that you are probably doing a good thing. I use 3.2 and 3.0 on my boats and get a really stable platform. With more attack angle, the turn fin does not work as well. Doesn't stay hooked up nearly as well. Definitely faster with more attack angle, but it is a "trade off". Knowing you and your driving style, I think you have made a good decision.

 

[RodneyPierce]

Dave, I think the stock angles on the .21 are near 4 degrees or there bouts. The ski is 2*. I want to try a ski at 1.5* on my .21 as I think it would handle the rougher water with a little less ski angle.

 

[SayMikey]

My fronts are nearly 5 on my 20 boat. Ask anyone who has seen it run turns on a dime stays on the water

 

[shoboat]

Fellas,

Sponson angles and strut depth work together.

You can have 4* AOA and run a deep strut for more propeller efficiency.

The lifting propeller will change your final attack angle also.

You have to be able to balance these all out to get the tub ride height that

you desire to run. 4.1 degrees left sponson and 4.3 degrees right works very well.

Keep Testing,

Mark Sholund

 

[RodneyPierce]

Mark, correct. Strut bottom flat on the ski, ski just barely riding above the waters surface, tub level is what I shoot for

 

[eekern]

Mark, correct. Strut bottom flat on the ski, ski just barely riding above the waters surface, tub level is what I shoot for

So if I read your posts correctly your running 2 degree negative on the strut?

 

[Greg Bonahoom]

Mark, correct. Strut bottom flat on the ski, ski just barely riding above the waters surface, tub level is what I shoot for

So if I read your posts correctly your running 2 degree negative on the strut?

I think he is describing the depth of the strut in relation to the ski, not the angle.

 

[RodneyPierce]

Greg correct. But I do have some negative in it. Not sure on how Mich as I have never measured

 

[Buckshot]

Are you guys building the JAE's to have adjustable AOA on the front end? I thought they were built non adjustable.

 

[Steven Bryant]

I've built both of my 21's and my 45 stock without the adjustable fromt end. They run so well stock i haven't bothered to change a thing

 

[RodneyPierce]

No adjustment on mine either.