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Author Topic: Cat Turn Fins ?  (Read 2704 times)

John Mk2

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Cat Turn Fins ?
« on: November 16, 2010, 02:07:21 PM »

My App/cat tend's to spin out when turning at speed {:-{ Not a great deal of rudder angle being used 25 degree's (Ish) Would turn fins help ?
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pompebled

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Re: Cat Turn Fins ?
« Reply #1 on: November 16, 2010, 09:31:05 PM »

Hi John,

You can't expect a fast cat to behave like an Eco, fast turns need to be wide, if you want to make them narrower you'll have to slow down to give the hull more grip on the water.

Turnfins are a sure way to make it flip at speed.

If you try it anyway, make a video, please.

Regards, Jan.
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John Mk2

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Re: Cat Turn Fins ?
« Reply #2 on: November 16, 2010, 09:55:47 PM »

Thank's Jan :-)) Had an Eco turned like a house fly  %) Have to back off a bit then when turning then ok2 So no fins or video  %)
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martno1fan

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Re: Cat Turn Fins ?
« Reply #3 on: November 16, 2010, 10:32:44 PM »

Turn fins are for monos and hydros what you need is a skegged strut by the sounds of it.
Mart
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martno1fan

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Re: Cat Turn Fins ?
« Reply #4 on: November 16, 2010, 11:11:32 PM »

Also i would suggest re-balancing the boat ,i remember talking to you about balancing hulls before and seem to remember yours is very far forward ? that would explain the spin outs at speed.
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John Mk2

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Re: Cat Turn Fins ?
« Reply #5 on: November 17, 2010, 08:37:27 AM »

I can move the ballast about  ok2 Have to have a play with the C of G  :-)) It's 40% from the transom @ the moment. Any more back & she ride's very dry & take's to much air Try's to flip if i don't back off :o
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50mm

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Re: Cat Turn Fins ?
« Reply #6 on: November 17, 2010, 08:52:47 AM »

try a longer skeg strut and rudder , or change to twin prop setup back off the throttle when making the turn, apply the power upon being half way through,all should be done in 100th of a second , so throttle to neutral as you turn, just as you move the rudder stick apply the power, ( the pistol grip controllers work better for fast electrics as you can get the power on and off far more efficiently, hopefully thats what your using, if not change to one)

As someone said already you cannot treat a cat like a mono also sounds silly check you CG and ballest is correct use a spirit level to check the left/right trim.

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John Mk2

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Re: Cat Turn Fins ?
« Reply #7 on: November 17, 2010, 09:33:37 AM »

It's the first cat I have owned  %) Had Mono 1 , Mono 2 , Eco's ect  :-) So I think this call's for a whole new driving technique  {:-{ Not sure about the pistol T.X part ! never used one !
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50mm

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Re: Cat Turn Fins ?
« Reply #8 on: November 17, 2010, 11:13:30 AM »

ask any race boy who drives fast electrics or nitro they will tell you that a pistol grip controller give you that edge to control your boat better, i assure you its the way to go when running a boat at great speeds  :-))
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John Mk2

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Re: Cat Turn Fins ?
« Reply #9 on: November 17, 2010, 11:24:20 AM »

Might be worth thinking about ! Will have try one first. Nobody where i run use's one :embarrassed: All on stick's for fast leccy , scale & the o.m.r.a guy's when they are testing (Out of season)
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HS93 (RIP)

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Re: Cat Turn Fins ?
« Reply #10 on: November 17, 2010, 11:31:06 AM »

ask any race boy who drives fast electrics or nitro they will tell you that a pistol grip controller give you that edge to control your boat better, i assure you its the way to go when running a boat at great speeds  :-))

that may be the case in the USA but NOT in the uk twinsticks has always been used , some buggy drivers use pistol grips .

It would also  be interesting to know how Many of the offshore boys use pistol grips as some of the top racers are on hear I think. different type of boat but people tend to flit between different types of boating

Peter
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martno1fan

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Re: Cat Turn Fins ?
« Reply #11 on: November 17, 2010, 11:42:54 AM »

COG at 40% is way too far forward it needs to be no more than 34% tops the rest is all down to trim adjustments and prop choice,im no expert on cats but a skegged strut will help no end with smoothing out the turns.The guys running cats with the zenoahs at 70-80 mph all seem to shoot for a cog of arround 32-34%,with stock engines it needs to be further back .Its no different with leccy the more power you have the further forward the cog should be but def no further than 34% in my opinion.As with any boat cog is critical to how the boat handles.Then again perhaps you have too much power in that little boat  :}
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John Mk2

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Re: Cat Turn Fins ?
« Reply #12 on: November 17, 2010, 11:53:28 AM »

Yes i have been told she is overpowered  :embarrassed: On Lipo 4s but the e.s.c is FROM 4s to 8s wont even start up on 3s ! So maybe a smaller prop ? 35 mm bronze set high @ the moment.
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tjones27

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Re: Cat Turn Fins ?
« Reply #13 on: November 28, 2010, 05:49:13 PM »

Hi,
sorry to tag a question on this thread, but turning fins. i know this sounds silly, but what do they actually do? or how do they work, and how should they be set up?
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martno1fan

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Re: Cat Turn Fins ?
« Reply #14 on: November 29, 2010, 09:35:37 AM »

Turn fins enter the water as the mono hull leans over in a turn,the fin acts like a pivot allowing the hull to turn smoother thats the best i can describe it anyway  ok2.They are fixed to the transom on the outer corner at 90% to the bottom as in this pic.Heres a pic of a mono hull with one turn fin,most races are clockwise so some only add one to that side,most sports boaters add one either side,they only enter the water when turning once the boats on plane.
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