Tub mounted turn fin?

[Dan_Cousin]

Anyone tried to mount the turn fin on the tub of an outrigger instead of the sponson?

What was the result and how did it change the turning characteristics of the boat?

This would make it easier the get the fin close to the CG back without a bulky bracket.

Looks like thats one more advantage to Andy style sponsons is the built in turn fin bracket.

 

[Ron Olson]

Some of the European boaters run theirs that way. It could be mounted using the motor mount bolts. I think that it would place less stress on the right sponson also.

 

[Don Templeton]

Some of the European boaters run theirs that way. It could be mounted using the motor mount bolts. I think that it would place less stress on the right sponson also.

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Less stress but also less leverage and holding power. Where do you attach the wires on a control line plane? Not on the fusalage!

Don :huh:

 

[AndyBrown]

The Stock Octura Wing Ding was done that way. Remember Don? But many guys changed the location to the Sponson. There are several advantages to the Tub mounted fin, but there are unfortunately downsides that greatly out way them.

I tried hard to make it work, but it wasn't gonna happen.

I even tried two fins to balance the forces and a leftside only fin as suggested by Gill from Brazil several years ago.

And yes my sponsons where purposely designed for the Fin mounting advantage.

I started with both sides of the sponson curved in like the Wing Ding, but later made the inside straight to eliminate the turnfin Bracket.

 

[gil sonsino]

That's true Andy but I must confess the boat was sometimes very unpredictable in tight turns on choppy conditions.!

Gill

 

[Don Templeton]

Funny story about about my first boat and yes it was a Wingding 60.

I read in a model magazine about an R/C NAMBA boat race in California and then found an Octura add in the same magazine showing the Wingding rigger. Well, I bought the boat kit, hardware, picked up an OS 65 and built it without even knowing we had a club here in Indy. I ran it a number of times with no pipe on a friends lake and it nearly scared me to death. Anyway, a short time later I ran into Fred Mcbroom who was president of IMPBA and joined the Indy Model Boat Club. After running with the guys for one day they talked me into racing in the Indy Unlimited with about 150 boats the very next weekend. A guy named Bob Findley told me to come by his house and he would help me set up the boat. We got the pipe on OK and then he looked down at my solid 3/16 shaft and noticed I was running a thrust bearing hard against the strut and told me to take that off and run the thrust against the U-joint up at the engine.

What he didn't notice was that my shaft ran through a 1/2" brass tube with "NO" support at all. Call me stupid but this guy was one of the top guns in the club and I was going to do what he said.

First heat during launch at about #1 my carb broke off. Bought a new one. Second heat same thing. Bought a new one. Third heat, boat broke in half.

Only good thing about it was the next week I was over at Marty's helping build my new Crapshooter. :lol:

 

[John Finch]

I have tried turn fins everywhare imaginable on riggers. And'y setup is the best. I had an Italian rigger by Fabrizio Medeot that had a bracket off the right side of the tub which put the fin about 2 inches to the right of the tub, and it worked. BUT I later moved it to the sponson. The right sponson lifted too much with it on the tub. Some old three point hydros of the sixtys used to have them under the tub and behing the cg. They worked, but very awkwardly. Stay with what works and work on the angles of the fin.

John