45 Hydro in a turn

[El Zorro]

I have to agree with David on this. If our turn fins were mounted in the center of the boat we could have some things to agree on. However, our fins are mounted off center to the right of the centerline, causing drag that makes the boat pull to the right. You also have propwalk to deal with, which also causes the boat to go to the right. Sponson angles, sponson toe-in and other things can be adjusted to counteract this which adds up to even more drag on the boat just to get it to go in a straight line. I don't see a deeper, thinner fin working ............been there done that.

Dick Tyndall

 

[John Beardslee]

I have to agree with David on this. If our turn fins were mounted in the center of the boat we could have some things to agree on. However, our fins are mounted off center to the right of the centerline, causing drag that makes the boat pull to the right. You also have propwalk to deal with, which also causes the boat to go to the right. Sponson angles, sponson toe-in and other things can be adjusted to counteract this which adds up to even more drag on the boat just to get it to go in a straight line. I don't see a deeper, thinner fin working ............been there done that.

Dick Tyndall

I've shared this with Terry Keeley a few years back so will share with all now. I once bought a B-Stock Hydro 20 cu.in (Sid Craft) from a guy in Wisconsin named Doc Wilson and the turn fin was on the outside sponson and less than half the size we were running on the inside sponson, the boat was great but I never tried a fin on the outside on any other hull or other classes - ran out of time and money and moved to toy boats. Always in the back of my mind and I will try it on my 20 rigger this year for sure!

John

 

[Brad Christy]

John,

Have fun in your retrieve boat...........

Your weight-to-speed ratio is significantly higher in our models than in full sized boats, and that's all that made it work with the boat you had. The G-forces involved were not enough to overcome the weight of the boat, which is not the case with our toys. The first time you hit the turn with an outrigger with a fin on the outside, it will immediately cartwheel. Most of our current outriggers will immediately flip kiester over tea kettle with much more than a slight left rudder twitch. I would have to think the same would result in a mirrored scenario.

Thanks. Brad.

Titan Racing Components

BlackJack Hydros

Model Machine And Precision LLC

 

[John Beardslee]

John,

Have fun in your retrieve boat...........

Your weight-to-speed ratio is significantly higher in our models than in full sized boats, and that's all that made it work with the boat you had. The G-forces involved were not enough to overcome the weight of the boat, which is not the case with our toys. The first time you hit the turn with an outrigger with a fin on the outside, it will immediately cartwheel. Most of our current outriggers will immediately flip kiester over tea kettle with much more than a slight left rudder twitch. I would have to think the same would result in a mirrored scenario.

Thanks. Brad.

Titan Racing Components

BlackJack Hydros

Model Machine And Precision LLC

Hi Brad,

Have you tried it on a toy boat? If so I'd be interested in the details?

Thanks, John

 

[Brad Christy]

John,

I have not tried a fin on the left side, but I have seen the results when we try and turn left with a fin on the right side: Instant cartwheel. I can't see any reason a mirrored scenario wouldn't produce the same results. I've not discouraging the attempt, I'm just hedging my bet early.

Thanks. Brad.

Titan Racing Components

BlackJack Hydros

Model Machine And Precision LLC

 

[KenOlvis]

Im lost are you talking about trying mounting fin on leftside sponson inside or outside of the sponsons on Right?

 

[John Beardslee]

Im lost are you talking about trying mounting fin on leftside sponson inside or outside of the sponsons on Right?

I'm talking about mounting the turn fin on the left sponson of a model boat as you would look at it from the rear. It will be a lot smaller than anything we've ever run on the right side. It won't have a hook in it to start with and I'll see where the experiment takes me. It's not my first rodeo and it's something I've always wanted to go back and try on a toy boat.

Thanks, John

 

[ChrisCapaldi]

Hi John, I've seen a dual skid fin setup work on a model boat. It was many years ago but Jerry Badgero had the setup on one of his twin 45 hulls. I'm not sure what led to him trying it but I can say it worked quite for him.

Chris

 

[KenOlvis]

Im lost are you talking about trying mounting fin on leftside sponson inside or outside of the sponsons on Right?

I'm talking about mounting the turn fin on the left sponson of a model boat as you would look at it from the rear. It will be a lot smaller than anything we've ever run on the right side. It won't have a hook in it to start with and I'll see where the experiment takes me. It's not my first rodeo and it's something I've always wanted to go back and try on a toy boat.
Thanks, John

Coolbeans

I have a fin with a hook already.the idea behind it is the hook on bottom holds the sponsons down in the turn.appears you have the same idea. Interesting idea tring on otherside please keep us informed on testing. its great to try new things strange or not.

 

[John Beardslee]

Hi John, I've seen a dual skid fin setup work on a model boat. It was many years ago but Jerry Badgero had the setup on one of his twin 45 hulls. I'm not sure what led to him trying it but I can say it worked quite for him.

Chris

Hi Chris,

Jerry had some good running boats, I don't remember his with the dual fins. I remember Tom Daniels had an articulated turn fin that steered with in concert with the rudder. That was on a rigger - most people don't remember that 3D built any fiberglass riggers.

Thanks, John

 

[XtremeRcBoats]

I looked through all of Ian pictures (what a great bunch!) and came across another two that showed similar patterns, although not as clear as the SGX:

https://www.flickr.com/photos/130286344@N07/23989440624/in/album-72157663900856776/

https://www.flickr.com/photos/130286344@N07/24509043342/in/album-72157663900856776/

 

[stan simpson iv]

I looked through all of Ian pictures (what a great bunch!) and came across another two that showed similar patterns, although not as clear as the SGX:

https://www.flickr.com/photos/130286344@N07/23989440624/in/album-72157663900856776/

https://www.flickr.com/photos/130286344@N07/24509043342/in/album-72157663900856776/

The second pic is my 45 JAE...I can blame that on Mark Ham,he was racing her at the Nitro race, lol

Fin is to big,I was off on my turn fin formula by 8.675309 mm. I might even call up Stu because that is the RS CMB 45 he sold me. Crank is out of balance or right hand turning,something.

 

[stan simpson iv]

I looked through all of Ian pictures (what a great bunch!) and came across another two that showed similar patterns, although not as clear as the SGX:

https://www.flickr.com/photos/130286344@N07/23989440624/in/album-72157663900856776/

https://www.flickr.com/photos/130286344@N07/24509043342/in/album-72157663900856776/

 

[Andy Greene]

TTT to easy Martys search ...

 

[Marty Davis]

I'm going thru the ~9000 shots I took at the Winter Nitro Champs in FL and came across a 45 hydro making an interesting wake from it's turn fin, I've not seen this before. I have seen similar wakes from props where the blades strike the water, but not from a fin. Notice the vertical striping in the wake from the fin:

https://flic.kr/p/DgkfdC

I looked at my 67 hydro and sent the image locations to Brian Callahan to look at. He looked at all the images of the riggers and made this comment:

I asked him if the forces were enough to bend and distort the sponson tubes and he replied:

"Simple, the boat is pulling 10+ g so the fin is pulling 10+ times the weight of the boat. Right at the center of pressure is a force 75+ lb!
Does this mean the bending stiffness of the booms matters? Long booms are much more flexible in bending."

Interesting.....

I talked to Andy Brown about this and he made the statement that maybe it was actually a good thing as most race vehicles have some springing and shock absorbers. Might not be totally how he responded but is close.

I have no idea if it is good or bad, but haven't really seen a negative that i could quantify.

Thoughts.....

 

[Ian Inverarity]

These are my opinions:

Boom flex is not a good thing. None of the boats where I have made an effort to improve boom stiffness have had the handling degraded, in some cases it was dramatically better.

Long boom are of course less stiff, a wider boom spacing can help there a bit. A wider sponson stance has other benefits, so as with anything it is a compromise.

In terms of negatives, consider what the hook or inward cant of a turn fin is supposed to do, and consider how effective that is when the booms flex and the sponsons twist relative to the tub as seen in the pictures.

 

[dwilfong]

I know a few have seem my SGX exit a corner more than a few times with no fin in the water at all. riding on the out side sponson.

I call it giving the fin......LOL

I have set up a old SG for my buddy and it has really small boom tubes. In video of this boat running it will pop the fin out of the water in the middle of a turn some times. So much you can see the underside of the boat. If you blink you will miss it. It dose not miss a beat in the corner like it never happened.

SO..................................????????

What really matters............................just the boom tubes and the fin???????????????????

Think not.................it is the whole package.....................

If you are looking for gold in the fin and boom tubes you are fooling your self.......................