Bend in a control rod ????

[Peter SykesParticipant @petersykes47234]

[Peter SykesParticipant @petersykes47234]

Hi All,

I'm trying to work out siting a servo for the rudder on my build. I'd like to have as a straight run from servo to rudder. However, it looks like the best I can do is a 15mm step into the 250mm long control rod……. so my question. Do I put the step nearest the servo arm, in the middle or nearest the rudder ??? or doesn't it matter much at all.

Regards

Peter

[Tim RoweParticipant @timrowe83142]

Hello Peter

I have done that a lot for model aircraft. Mechanically I don't think t really matters but I have always put any crank near the servo where in aircraft there is generally more room. It is also then in a location that can be accessed.

Tim R

[Peter SykesParticipant @petersykes47234]

Thanks Tim,

I figured that was probably the case but just wanted a second opinion on it.

Regards

Peter

[ashley needhamParticipant @ashleyneedham69188]

I have been using aircraft slinky control lines for this sort of thing.

Although the inner is flexible, it is supported throughout its length by the outer sheath and the whole lot will curve sinuously around obstacles.

Supporting a bent metal rod can help as well of course.

Ashley

[Malcolm FraryParticipant @malcolmfrary95515]

I usually just go for straight, but arrange things so that a sideways step is needed at the servo end. I use an electrical wiring connector "choc bloc" to do this. The spacing between the two segments is about right, and the screw fixings allow me to sort any tracking adjustments needed.

[Colin BishopModerator @colinbishop34627]

I go along with Malcolm as above. The chock bloc facilitates adjustments. It is vital to ensure that the wire cannot easily bend. One way to do this is to slip close fitting tubes over the longer lengths to stiffen it.

Colin

[Peter SykesParticipant @petersykes47234]

The Choc Bloc idea is clever. I'll bank that one.

Thanks

[Malcolm FraryParticipant @malcolmfrary95515]

A late thought – whatever the route of the rod, the same rules of geometry apply. Both arms need to be at right angles to the line joining the arm pivot points when the rudder is central to keep the response equal both ways. The shape of the (rigid) rod makes no difference.

Things might be different if using a snake. I haven't, so I would be guessing.

[ashley needhamParticipant @ashleyneedham69188]

Snake just the same, keep servo arm/tiller same angle.

Snake allows really long runs to be fitted…about 3 feet in the case of my big destroyer, and they are rustproof and need no lubrication.

Ashley

[Richard SimpsonModerator @richardsimpson88330]

Just another idea for the pot, I like to use the 2mm threaded rods with threaded stainless clevises on the end. The rod is a bit on the heavy side but it does allow you to put a nice offset in it, don’t forget it does not need to be 90 degrees, in fact a shallow angle allows as much adjustment as you need to get it perfect. Then the end can be threaded to suit, giving excellent length adjustment and a very neat and professional bespoke part.

You can buy the rodding, clevises, 2mm die nuts etc and be set up for any connecting rod for some time to come. Don’t forget though to only put a clevis on one end, the other needs to be prevented from rotating.

[Ray Wood 3Participant @raywood3]

Hi All,

Just a word about the most useful tool to have in your workshop are the Z bend pliers which make life so simple, and if your lucky and have a good eye for the position of the second bend you won't need any clevice's and a 45 Deg kink in the rod means you can fine tune the length. aeromodelling tip really but make life so much easier and cheaper   Kink not shown in this picture.

Regards Ray

Edited By Ray Wood 2 on 14/02/2021 09:43:40

Edited By Ray Wood 2 on 14/02/2021 09:44:23

[ashley needhamParticipant @ashleyneedham69188]

I didn’t know there were such things Ray! However, a pair if thin nose pliers does the job for the occasional use that it would get here.

Last few models built have used snake, ball joint and pivoting servo arm connectors as the method due to the need to run the control rod outside the hull but keep the water out.

The big destroyer had such a long run that the snake was the only choice, as I could not support the length of a metal rod sufficiently along the run to stop it bending, being a retro-fit and not having access to half the run under the deck. As received it did have a single piano wire rod,unsupported!

Ashley

[Chris FellowsParticipant @chrisfellows72943]

Just ordered some snakes for my Huntress LC build. Being stern-drive and the motor being in the way I think they will be the best way of dealing with the situation.

Chris

[Ray Wood 3Participant @raywood3]

Hi All,

I use plastic snakes for most of my Aeroplane builds, but before they were available we always used pushrods of hard balsa 1/4"X1/4" or dowel or spruce cross drilled 1/16" and the wire bent 90 Deg and the whole thing bound with threat, I currenty use brass for everthing in a boat where possible and the SLEC nylon clevice's with the brass insert and locking screw.

The issue with snakes is you need something to anchor each end of the outer too, which requires extra internal structures ?

Please excuse the tail of my new build of the Kiel Kraft Mini Super, Snakes on a plane

PS how exciting I just received my new CAA operators number to fly models which was 9 characters last year this year it's 17 !! good job I have a Dymo label maker, don't boaters have it easy .

Regards Ray

Edited By Ray Wood 2 on 14/02/2021 15:28:22

Edited By Ray Wood 2 on 14/02/2021 15:34:32

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