Model Boat Mayhem - Forum

Technical, Techniques, Hints, and Tips => Other Technical Questions... => Topic started by: tigertiger on January 17, 2008, 03:47:12 PM

Title: trickey rudder problem
Post by: tigertiger on January 17, 2008, 03:47:12 PM
I am trying to plan how to attack my next build. However I have a problem with the rudder.

The rudder tube runs outside the transom and there is a tiller arm.
How do I attach the rudder to the servo?

Any suggestions greatly appreciated
Title: Re: trickey rudder problem
Post by: Martin [Admin] on January 17, 2008, 04:56:07 PM
What about a closed loop (pull- pull) cable system like they use on aeroplane rudders?
I've used them successfully on a couple of fast Offshore power boats.
A lot less friction than I was expecting!!


http://www.shopatron.com/index/101.0.5161.5186.0.0.0
Title: Re: trickey rudder problem
Post by: tobyker on January 17, 2008, 06:01:28 PM
On the hoy I fitted a short tiller at right angles to the proper one, with a ball joint to compensate for the rudder shaft angle, and ran the link from a hatch, just above the deck. There is no reason you couldn't run a similar arrangement just below the deck if you want to hide it, but who's going to see it when she's sailing?
Title: Re: trickey rudder problem
Post by: Martin [Admin] on January 17, 2008, 06:22:51 PM
Here's how I did it......
Title: Re: trickey rudder problem
Post by: John W E on January 17, 2008, 08:55:29 PM
hi there TT

I have solved a similar problem on a model Air Sea Rescue Launch 2564 - the only difference being there are two rudders slung over the transom.   The tiller arm goes through two slots cut in the transom, the slots in the transom are very thin only about 3mm-4mm wide and about 10mm-15mm long.

If you have a look at the drawing you will see an extension arm, which has a slot cut into it.  The pin that goes through this slot, which is connected to the 'dummy tiller arm' has to be pretty 'neat' to stop 'side-slop movement'.

On one of the drawings you will see I have drawn the pin mid-way in the slot, when the rudder is facing fore and aft.   This is 'technically wrong' the pin should actually be very close to the top of the slot next to the servo - I have only drawn it like that to illustrate it for you  :o

The other thing is, the material that you use to construct the extension arm, with the slot in, try and use aluminium, brass or a very hard material.   Try and avoid using plastic, as my original one was made from plastic and after a number of outings - it snapped .

This is an idea for you anyway my friend. Gives you food for thought.  O0 O0   

I did try and take a photograph of the Air Sea Launch but, they are actually mounted right against the stern, and a little difficult to photograph through the hatch, I will give it another try though and see if I can

aye
John e
Bluebird
Title: Re: trickey rudder problem
Post by: John W E on January 17, 2008, 09:05:04 PM
hi again, with the aid of a mirror  {-) {-) {-) I do hope you can make this out.

aye
john e
bluebird
Title: Re: trickey rudder problem
Post by: DickyD on January 17, 2008, 09:14:30 PM
Brilliant idea, rubbish photos  {-)
Cleaned me glasses three times before I realized your photos were blurred canny lad . 8)
Title: Re: trickey rudder problem
Post by: John W E on January 17, 2008, 09:20:02 PM
Dicky BONNY LAD  :) :), yer all lucky that you lot didnt get a 'mug shot' of me -  :D :D {-) {-)

ever tried, holding the camera in one hand, mirror in the other and trying it all in focus and hey I was damned if I was going to clean the mirror - or is that there dust on the boat........  ::) ::) ::) last time she was in the water to get a wash it was the Mayhem bash  ;) :)

aye
john e
blueblirdie
Title: Re: trickey rudder problem
Post by: DickyD on January 17, 2008, 09:29:41 PM
Ah this is the one thats been in the water then ?
Title: Re: trickey rudder problem
Post by: longshanks on January 17, 2008, 10:16:16 PM
Hi TT,

How about using the actual tiller arm above deck. Using perhaps braided dacron, led at 90' to each side and led down below deck much as you would feed a sail sheet. Hope thats clear? Imagine you were lashing the tiller in a fixed position but in fact your 'lashing' moves.
Regards
Title: Re: trickey rudder problem
Post by: tigertiger on January 18, 2008, 01:21:12 AM
Thanks chaps,

I now have a clearer idea of how to fix this.

Longshanks
You idea would work, but I would need to try and rig up a drum to feed the sheet in and out. As the arm would give a problem of varyig tension due to angle of arm.

Bluebird
Your idea will work well. have you ever had any water ingress?

Martin
I like your idea as space is an issue. Can I get a push pull in the UK?
I will be in uk soon.

TT
Title: Re: trickey rudder problem
Post by: tigertiger on January 18, 2008, 01:44:21 AM
Bluebird

I have held up servo to the plan and I have very little room to do this. Also the slot would be close to the waterline.

How much do you think the servo can be angled to the horizontal.

You see the angle of the transom on the model is as steep as in the diagram. LOL

Title: Re: trickey rudder problem
Post by: tigertiger on January 18, 2008, 01:58:09 AM
Martin

I can sort of picture it. But it is new to me.


With the pull pull systems listed on the website you mentioned.

Would I need one or two of these items #517?
http://www.shopatron.com/product/part_number=517/101.0.5161.5186.0.0.0

Would I be better going for the complete system #881 http://www.shopatron.com/product/part_number=881/101.0.5161.5186.0.0.0
Title: Re: trickey rudder problem
Post by: John W E on January 18, 2008, 08:30:35 AM
Hi there TT

Water ingress?   You will only get when you go full astern at High Speed - well, that is the only time I get water ingress.   To solve the problem of water ingress you could make small bellows up out of an old piece of balloon glued to the inside.  You can get a mini servo as well, which is half the size of a standard servo or you could extend the arm and move the servo further into the model.

Servo to be angled to the horizontal?  Could be quite a bit, because, if you wanted too, you could bend your extension arm to suit your angle that you desire.

aye
john e
bluebird
Title: Re: trickey rudder problem
Post by: chas on January 18, 2008, 10:42:17 AM
HI TT, I'm going to have a similar problem myself soon, but didn't fancy having the tiller moving all by itself. I was going to see if anyone had put a figure in a model, hand on tiller with a servo inside working the arm. It sounds tricky, but would look good. Anyone any ideas?
 Chas
Title: Re: trickey rudder problem
Post by: DickyD on January 18, 2008, 11:05:15 AM
Why not put the servo below the deck working the tiller and have the figure being worked by the tiller ? :-\
Title: Re: trickey rudder problem
Post by: tigertiger on January 18, 2008, 11:07:31 AM
HI TT, I'm going to have a similar problem myself soon, but didn't fancy having the tiller moving all by itself. I was going to see if anyone had put a figure in a model, hand on tiller with a servo inside working the arm. It sounds tricky, but would look good. Anyone any ideas?
 Chas

Beat me to it DicktD
All you need is a 'universal joint' on the arm. Many action figures have these.
Then as uyou say, the tiller works the arm.
Title: Re: trickey rudder problem
Post by: chas on January 18, 2008, 11:25:45 AM
Nice idea, but........ Oh God, I'm going to play with dolls.
 Chas
Title: Re: trickey rudder problem
Post by: Jonty on January 20, 2008, 08:38:02 PM
  Have a look at this:

  http://navi.modelisme.com/article7.html

  And click on 'Barrotage et commande'