greggK

Hello all, 1/4 scale T-Craft w/ SC 46" roundtops. Puttin Ernst water rudders on each float. Im lookin for various ideas on how 2 hook up the control arms on H2O rudders to a servo/rudder horn or another location in nose? Any ideas would be great, thanks gang n enjoy the summer.

JimCasey

My Feedback: (1)

It's a Cub, but a T-Craft has about the same installation.

Wayne22

My Feedback: (2)

pull pull cables work the very best (aka the nice cub above). You'll need some Proctor pulleys and they are a little pricey, but compared to having a plane that will only taxi in ever-increasing circles (BTDT), it is a bargain.....

greggK

Any good ball bearing pulleys or a certain Proctor pulley is best? OR what about puttin a micro servo IN each float and have a NyRod exit the back of the float and connect to H2O rudder control arm?

MinnFlyer

My Feedback: (4)

How fancy do you want to get?

I often just run a flex cable from the rudder to the water rudder

Newc

Here's pictures of two ways that I am currently using. One is as above with a flex cable approach, except I run the flex cable from a rear mounted rudder servo and then - if you are going to use two rudders - I simply link the two water rudders with music wire on the Ernst rudders.


The other way is having a water rudder servo inside the float - either one - and then connecting the two rudders as I mentioned above. The easy thing about this setup is that you can run the servo wire inside the fuselage to the Rx with a regular "Y" extension with the other part going to either the nose wheel and rudder or just the rudder. Then use a through the fuse connector - such as a charging jack bracket - and you are ready to plug in the water rudder servo.


Hope that this helps.

LT-40

My Feedback: (2)

I vote for the pull pull cables. I made my own, and they still work great. I tried the flex tubing stuff, but it was putting too much stress on my servos, and it wasn't even working very well.

LT-40

JimCasey

My Feedback: (1)

Some people will swear that flex-cable works. To slide, there has to be a clearance between the inner rod and the sheath. Put a 180-degree bend on a flex-cable and you're asking for play. OK, if the water rudder is off a little it's not the end of the world. I see water rudders hooked up with flex cables that are off sometimes by 20 degrees because the outer tube slips where it is fastened to the structure. That doesn't mean it can't be done reliably and accurately, but apparently the guys I have actually seen doing this didn't put appropriate care into getting it right. To me, it just looks goofy.

Servos in the float: Floats get wet and so do servos in the float. Plenty of guys swear that the water never gets into the servos. I've seen it happen, but that doesn't mean it will be a problem for you. Servo wire between the airplane and the float looks like a scale set of jumper cables, though.

Since Tower Hobbies is so nice to sponsor this forum I will give you some links to stuff in their site:

I have rigged up a lot of pullpull water rudder linkages. I don't use proctor pulleys. But they are what you would use for a scale plane. (http://www2.towerhobbies.com/cgi-bin...=RF&search3=Go)
I use 2-56 eyebolts. They work just like the guides on a fishing rod. And I use the hi-strength stranded fishing line. http://www.alltackle.com/power_pro.htm for the fishing line,
http://www2.towerhobbies.com/cgi-bin...=RF&search3=Go for the rudder

One water rudder is plenty. If you need more authority your technique is probably off, but use a bigger water rudder instead of two.
It should not stick down far, or it should kick up. You don't want it in the water except when you are in displacement mode. I always put mine on the left, so if it causes drag I will be leading with a little right rudder which is probably what you need on takeoff anyway. http://www2.towerhobbies.com/cgi-bin...L=++&search=Go

greggK

Jim thanks, great idea on eye bolts. Due you not use the Proctor pulleys b/c the friction... the fishing line goes thru the eye bolt easer then the pulley wheel loaded-up? Thanks

Sturtz

My Feedback: (20)

Thank you everyone. Building my first float kit for a kit built plane this week and your pics and suggestions will really help me out. Found a body of water that is crying out for a float plane to fly from it. Just had to try my hand at this wet flying.