Curved - turn fin

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MitjaJ

Well-Known Member
Joined
Feb 2, 2008
Messages
48
Anyone can help me setting up my turnfin ? I was usualy using a straigth

turnfin on my outriggers but now when the speeds are gone up on my new (my design)

electric outrigger (4S1P, 2200 KV motor, running an Octura X445 or Prather 225).

I'm having problems preventing the boat from flipping in the turns (if I try to

go full throttle) it seems that the inside sponson lifts out of water and the

outside digs in. If the water is choppy the problem is ever worse.

I tried to use a curved turnfin - two bends - was turning better, but I had big

problems keeping the boat going straigth - depending on the speed the boat was

either going straigth or making turns by itself.

For now I will try to make a new longer straigth turn fin, but I would really

like to know how to make the boat run straigth using the curved turnfin.
 
Here are some setup notes from INSANE boats clik on setup and look at the turn fin page.

http://www.insaneboats.com/images/stories/general_pics/setups/Insane%20Hydrofoil%20set%20up%20instructions.doc

You need to make the bends straight and not get the fin rear edge tweeked out at all or it will pull or flip the boat. And the curved fins are mounted at 90 degrees not tipped in.

Insane Hydrofoil Thunderboat & Sport Hydro Turn Fin Set Up Instructions

Picture 1 The bottom of the bracket & the outside edge must be at 90 degrees with the bottom of the boat

Picture 2 The front leading edge must be sharpened with a tapered edge roughly about 3/8th’s of an inch

Picture 3 When the boat is placed on a set up board, the bottom of the turn fin must be set parallel with the water line. “The water line is the set up board”

Tech tip: Using neutral as a best starting point and neutral being parallel. If you raise the front leading edge up a 16th of an inch, that will loosen the boat. If you lower the front leading edge a 16th of an inch that will tighten up the boat.
 
I had problems keeping a consistent radius from front of fin to back if I cut the shape of the fin before bending. You may want to bend it as a square piece of material. Then cut the shape and sharpen.
 
I know this is pandoras' box, but here goes......the bend has almost nothing to do with weather

a fin "pulls down" or "lifts" the sponson in a turn.

Eric Canto
 
I know this is pandoras' box, but here goes......the bend has almost nothing to do with weather

a fin "pulls down" or "lifts" the sponson in a turn.

Eric Canto
OOOOOKKKKKK................I am just going to get me a bucket of popcorn, sit back and watch this one. Should be fun.
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Hey Charles;

I will bring the beer and we both can watch it in Hi Def

Carl
 
I think what Eric means is that the fact that it is curved alone does not create or negate lift ...angle of attack of the fin can contribute to these conditions .
 
I think he's talking about very choppy water conditions compared to smooth water with a curved fin. "Too much" bend could be a real problem in rough water conditions!

Just my 2 cents,

Don <_<
 
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I made a new turnfin adjusted the angle of attack and the boat now turns like on rails.

Thanks for the tips.
 
Don,I hate the smell of cigars but if ya pull out the ole cardtable ill drink with ya!

scott
Scott, come on over & we will "give her a go"
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Don
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Hey...... wait a minute.......that is just not right......why wasn't I invited tooooo?
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Since there is just a little bit of distance between us, maybe we can get together for a conference call and bump the glasses for the toast against the phone.
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Charles
 
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