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Old Feb 10, 2014, 09:15 AM
Registered User
United States, NC, Chapel Hill
Joined Sep 2009
252 Posts
Question
One or two float rudders?

Hi all,
just had my first take off (and landing) on water with a .40 Cub.
That was fun. The problem was that when taxiing, I could only turn to the left.
Not an issue when taking off, but after landing makes for some interesting
taxing while trying to move back to shore.
Part of the problem is probably due to the less than perfect flexible linkage (pulls to the left, pushes to the right)
but I was wondering if having only one rudder on the right float contributes to the issue. Anyway, I am planning to put a waterproof servo on the float and getaway
with the linkage, but should I install a rudder on the other float too?
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Old Feb 10, 2014, 12:45 PM
Slip the surly bonds...
Sopwith Mike's Avatar
Christchurch,England
Joined Aug 2004
2,559 Posts
I have the one rudder on all three float planes and have found they work well in both directions. I suspect the push action is not working properly. I like thread PullPull linkages for my rudders.
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Old Feb 10, 2014, 05:55 PM
Seaplane Nerd
JimCasey's Avatar
Joined Jan 2005
829 Posts
yep. one rudder is plenty. As with Mike, I use stranded fishing line to rig a somewhat scale-like (in principle) pullpull. I have never advocated the "Nyrod-Loop-in-the-breeze" rudder actuation 'cause it's so bloody OOGLY. Nyrod is a great control actuator but it loses most of its desirable properties when it is bent much from straight. A nearly straight nyrod from the nose-gear tiller rod back to the rudder tiller will work well.
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Old Feb 11, 2014, 01:07 AM
Art Schmitz
United States, TN, Crossville
Joined Jan 2012
392 Posts
I've had good results using a 1/16 m.w. push rod from a nose gear tiller arm back to the water rudder. using 1" sections of yellow nyrod tied to the struts as fair leads.
One water rudder gets the job done. Can't tell the difference between one or two.
I share Jim's opinion of the looped nyrod set-up.

Another method is to run a m.w. push rod from the air rudder to a fuselage mounted belcrank which then reverses the direction of a second pushrod to the water rudder.
( Jim, you might recall that my old yellow and green TM 400 had that set up )
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Old Feb 11, 2014, 04:29 AM
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Joined Jan 2005
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Lots of ways to skin a cat.
My top2 NOT favorite ways to drive a water rudder are (1) loop of nyrod in the breeze (2) Servo in the float (Loop of servo wire in the in the breeze, leading to a waterlogged servo and a gynormous leak path) Others have done this to their satisfaction. I'll pass.
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Old Feb 11, 2014, 05:42 AM
Registered User
United States, NC, Chapel Hill
Joined Sep 2009
252 Posts
Thank you all for the answers. Looks like the problem is the U bend on the link, which BTW is not a nyrod, but a flexible metal wire in a guide. The wire must wiggle around the guide.
If I install the servo (using a plywood plate glued to the float, no holes into the float), it will be close to the rear strut, so that the wire can be securely tied to the strut.
Or maybe I'll just keep it as is. As long as I can turn one way...
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Old Feb 11, 2014, 03:43 PM
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uniquewon's Avatar
Minneapolis
Joined Jun 2002
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In all my float plane flying, and it's a bunch, I've never installed a water rudder, and also have never not been able to return to where I started....other than when the engine quit. That requires some sort of rudder, but on the rescue craft.

Dispense with all that rudder stuff and learn how to taxi with throttle, rudder and aileron.
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Old Feb 12, 2014, 01:50 AM
Art Schmitz
United States, TN, Crossville
Joined Jan 2012
392 Posts
You'll never see a full scale w/o water rudder (s).
We differ. Peace.
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Old Feb 12, 2014, 06:26 AM
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United States, NC, Chapel Hill
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Quote:
Originally Posted by uniquewon View Post
In all my float plane flying, and it's a bunch, I've never installed a water rudder, and also have never not been able to return to where I started....other than when the engine quit. That requires some sort of rudder, but on the rescue craft.

Dispense with all that rudder stuff and learn how to taxi with throttle, rudder and aileron.
I did notice in the photo gallery planes without float rudders and I was wondering how they go back to the launch point... I suppose you need to build up some speed for the rudder/aileron to be effective?
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Old Feb 17, 2014, 07:57 PM
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Yes it IS possible to taxi without water rudders. I had a video from EAA :"Wonderful World of Floats" that shows the techniques taught to Full-scale pilots seeking their Float certificate. I translated it a bit for RC planes. here:http://www.smilesandwags.com/Floatsi...%20skills.html
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Old Feb 18, 2014, 06:11 AM
Registered User
United States, NC, Chapel Hill
Joined Sep 2009
252 Posts
Interesting.
For now, I just put a bigger horn (and better positioned) on the rudder, so to have better authority on the float rudder. But will try these techniques the next time
I take the Cub out. Right now, it is being refitted with a OS .61 4 stroke.
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