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[mbm999]

Hi all,

Could i have some guidance on what i thought was going to be the simplest part of the build.
The picture shows that the supplied rudder linkage looks to be too long.
What is the rudder link made of - if i need to try and shorten it, i'll have to get some more to have a practice (its pretty thin) - where is a good place to get some?
Or, is there a better method/system to use than the wire? (It's a micro servo with very small holes in the servo arm!).
I've had a look at some model websites but there seem to be a million choices and it's hard to see what would fit my situation.

Appreciate any thoughts,

Mark

[colin-d]

I do not actually know the contents of this kit... but..

As you have mentioned it, and quite truly it is, there are milions of ways to conect the rudder servo to the tiller arm..

Most linkages are made of steal, some use brass, I prefer the harder stuff..
Bike spokes can be used. ..  basically anything you can get your hands on..

Or what ever is in my spares box, for this model I used model helicopter linkages, as it all screws together and the length can be altered without cutting anything..

[mbm999]

Doh!
I forgot to attach the picture.

Mark

PS.
(thanks for the reply)

[SailorGreg]

I don't think I have ever fitted a servo without having to drill out the holes in the arm to take the wire/pin/clevis.  Not sure why they keep producing servo arms with the holes too small!

It would not be unusual for a kit to provide materials which are generously sized.  This allows you to fine tune the length to your particular model.  It also saves the manufacturer some time when putting the kit together.  If the manufacturer tried to produce an exact length, half the buyers would complain it's too short.  Look upon the linkage parts as a set of raw materials from which you will build the linkage.

Enjoy your build!

Greg

[radiojoe]

Hi Mark,, Here's a simple way of getting fine adjustment on a rudder linkage use the brass piece out of a electric connector block to link a rod from the servo and a rod from the tiller arm that way you don't have to be accurate with bending the ends, just line it all up and tighten the screws job done.


Joe

[malcolmfrary]

Without cutting anything, just a pair of nice strong pliers, put a Z bend in the middle of the link.  Make sure that when the rudder is at straight the two arms are both at right angles to the line between the tiller pvot and the servo center.  Tweak the angle of the Z until you get the right length.
Or do it like the railway guys used to do it for points - put an omega ( Ω ) into the wire.
It helps if both can be in the same plane, but rotating the servo so that the swing of the servo arm winds up pointing at the tiller arm makes the best of the job.

[mbm999]

What great ideas - thanks (spoilt for choice now!).

Mark

[timg]

Hi mbm999


In my diva I used the supplied rudder rod and cut it in half then joined it with an electrical terminal block with the plastic cut off  ( like joe's idea) hopefully photo attached
timg

[mbm999]

Hi timg,
Yes i think that will be my preferred choice too, thanks - tho i intend to have a go at the other methods ( i bought some piano wire today) just to have a go.
Did you extend the rudder arm too - i can't quite tell from the picture? If so, why? (not a criticism - just curious).

Mark

[RST]

In your original pic is looks like a laser cut ply rudder arm is supplied? Should be up to the job if they supplied it but on a thin bit of wood I personally would be worried about strength.


Personally I use brass rod mostly.  It's easier to bend in to shape. But as others alluded to you can use chock block contacts but it is better to get it as right as best you can.  In the pic before with the choc block contacts it's on a screwed clevis so there is adjustment at the clevis also.


I don't find I have to enlarge homes in servo arms much. Clevises or ball and sockets work better whenever space allows and are not expensive or difficult to fit. In any case, better the holes on servo arms are too small, which take a few seconds to enlarge, than too big, which just introduces slop.


It's always better to orientate the aero axis with the rudder post if you can. But building small models myself it isn't always possible.  Sometimes you have to get creative with links in the linkage so the servo doesn't try and force the tiller arm up or down as part of the throw. And if you can hear the servo "humming" at either end of the travel I usually take that to mean it's fighting some resistance so the linkage needs adjusting.

[mbm999]

Hi RST,
Yes the rudder arm is laser cut plywood.
It is clamped between 2 locking nuts which i'm not sure is the best arrangement - i think timg has  changed his to something else (maybe a different rudder too).

This is all very interesting info, thanks.

Mark 

[timg]

Hi mbm999


[size=78%]  no problem it is different rudder arm, just a plastic one with a grub screw from my parts box , I wasn't to keen on the wood and 2 x nuts arrangement ( just my opinion) [/size]
[/size][size=78%]Cheers [/size]
[/size][size=78%]Timg[/size]

[timg]

Sorry about the text...

[mbm999]

Thanks timg - my thoughts exactly.
I'm going to have to get myself one of these "spares boxes" - they seem to hold very useful bits and pieces 

Mark