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Old Jan 02, 2007, 06:19 PM
Grumpa Tom
Kmot's Avatar
United States, CA, Los Angeles
Joined Sep 2003
22,595 Posts
Mini-HowTo
How to build a rudder and steering arm.

I don't know how to build a rudder and steering arm. I have never made one. So, follow along as we learn together how to make a rudder, and the steering control arm.

I was running my CEN Wave Shark last Sunday and the rudder broke off and went flying. Most likely I hit something submerged. As it turns out, the stock rudder is only connected by a 1/4" of molded material, and then by a short piece of brass tube sticking into the top of it:



The remains of the broken rudder/control arm unit:



I checked into buying a replacement rudder/arm unit and it would have cost me $16 bucks shipped and I would have the same cheaply made piece. So I decided to make a brass rudder that would be more robust.

I knew I wanted a trapezoid shape, but didn't know exactly what shape to choose. I drew out some sketches but was not totally satisfied. I then did a google search for 'trapezoid' and started looking at some shapes. I found a trapezoid I liked. It actually was a diagram of a trapezoidal sailing course. But it was different, and I liked it and so I printed it out and then glued the shape to a piece of .062" brass sheet. Then I cut it out on my band saw, and sanded the edges to the template. I finished it with needle files.

I also needed to make a rudder post. I have various sizes of brass tubing on hand. But it needed to be solid. I do have one size of solid brass rod, but it was not a large enough diameter. My solution was to solder the solid rod inside some tube and make the right diameter. I also had to drill out the 4mm hole in the strut to 3/16" SAE size. After I made the rudder post I slotted the end, and then silver soldered it to the rudder. Here is the result:



And installed in the strut:



Next, I had to make the steering control arm. I looked through my r/c junk box that has bits dating back more than 30 years, and I found a bushing that is either brass or bronze. (Does bronze solder to brass?) I then cut a piece of the brass sheet and soldered the bushing to it:



Then I drilled the holes for the rudder post and link rod. I next drilled and tapped the hole on the side of the bushing for a grub screw. Finally I sanded and filed the arm to a nice looking shape:





And here it is mounted and connected to the Wave Shark:



All that is left to do, is finish sand it and then buff it for some bling-bling.
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Old Jan 02, 2007, 06:27 PM
Boats on the brain!!
green-boat's Avatar
Arnold, Mo.
Joined Jul 2005
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Tom,

A couple of questions, first-How thick is the brass sheet that you used for the rudder.

Second- did you file a flat spot on the rudder post where the setscrew bites into.
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Old Jan 02, 2007, 06:36 PM
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Joined Dec 2006
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don't you think that if you use a longer steering arm you wouldn't need a heavy servo, you will need a longer servo horn too ....well thats the way im doin on my winter project a 48' woodie I do the rudder and the steering arm in aluminium well have fun !!
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Old Jan 02, 2007, 08:27 PM
Grumpa Tom
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United States, CA, Los Angeles
Joined Sep 2003
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Quote:
A couple of questions, first-How thick is the brass sheet that you used for the rudder.
.062"

Quote:
Second- did you file a flat spot on the rudder post where the setscrew bites into.
Si seno'r!
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Old Jan 02, 2007, 08:29 PM
Grumpa Tom
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United States, CA, Los Angeles
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toro-rosso: I am just using the existing servo that was already in the boat, and the steering arm I made is the same length as the original.
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Old Jan 02, 2007, 08:55 PM
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Madison, MS
Joined Oct 2004
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"after I made the rudder post, I slotted the end"

Kmot, how did you do this? How do you accurately slot a fairly small diameter brass rod rudder post? I don't have much in the way of power tools, or access to them.
Bill
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Old Jan 03, 2007, 10:12 AM
Grumpa Tom
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United States, CA, Los Angeles
Joined Sep 2003
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Bill, I used a hand saw. The typical hobby hand saw? I put the post in a mini vise, and sawed a slot into it. The slot was very, very narrow. I used a wedge shaped needle file to open the slot to the size of a flat needle file, and then just filed the slot down to the depth I wanted. No power tools at all were used to make the rudder post. The only power tools used to make the rudder and steering arm itself were a band saw and drill. And in fact, you could use a hack saw instead of a band saw. And a hand drill instead of a power drill.
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Old Jan 03, 2007, 11:01 AM
Is life for real?
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Almere The Netherlands
Joined Sep 2006
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Jeepers, U can use your dremeltool, asuming U have one. I just made mine for the PT a couple of days a go. I use a hollow tube instead of a solid, saves a bit on weight plus U can flatten the ends Ur soldering. Excessive silver can be either sanded or filed (I prefer the latter!) off. Have no, can't take pictures at the moment, the hull is drying and U can't really see the difference in manmade light (that I have that is!) Good posting Kmot!
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Old Jan 03, 2007, 11:24 AM
r/c ships and workboats
bellingham, wa
Joined May 2006
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KMOT, that is the same way I like to make my conetor arms as I feel most of the commercial ones are insufficient to handle the abuse I am going to put them through. Nice job showing how this is done.
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Old Jan 03, 2007, 11:30 AM
"day ain't over yet-"
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Western N.Y. winemaking country
Joined Jun 2005
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Quote:
Originally Posted by keith S
KMOT, that is the same way I like to make my conetor arms as I feel most of the commercial ones are insufficient to handle the abuse I am going to put them through. Nice job showing how this is done.
Ditto on that, Kmot---.
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Old Jan 03, 2007, 11:32 AM
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Bedfordshire, UK
Joined Feb 2006
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Looking at the photos your old rudder seems to be at least partially balanced but your new rudder is unbalanced. The result will be a much bigger load on your servo.

Now I am aware that lots of people run unbalanced rudders but then they also seem to strip the gears on their rudder servos!

The formulae I have used for many years is 1/3rd ahead of the pivot point and 2/3rds behind and I have never stripped the gears on a servo.
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Old Jan 03, 2007, 11:51 AM
no wings any more, just dust!
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stoke on trent
Joined Oct 2004
8,052 Posts
Kmot, an idea, a bent piece if wire going from the hull, then under the rudder, so if you strike something again, the wire acts as a rider, lifing the boat over the obsticle and prevents the rudder striking something and doing some more damage.
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Old Jan 03, 2007, 03:49 PM
3 Blades to the Wind
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Atascadero, California, United States
Joined Oct 2004
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Quote:
Originally Posted by Trevor_G
Looking at the photos your old rudder seems to be at least partially balanced but your new rudder is unbalanced. The result will be a much bigger load on your servo.

Now I am aware that lots of people run unbalanced rudders but then they also seem to strip the gears on their rudder servos!

The formulae I have used for many years is 1/3rd ahead of the pivot point and 2/3rds behind and I have never stripped the gears on a servo.
Two words.... Metal Gears....

I would never use anything short of an MG servo. Have never stripped an MG servo and have put loads on them that would make what Kmot is doing seem like a walk in the park... LOL!

What I find interesting in that standoff setup is that the water pickup is directly in front of the rudder, the widest part of the rudder as well... I wonder if that effects rudder efficiency any... maybe so minor it doesn't matter... interesting.
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Old Jan 03, 2007, 05:32 PM
Grumpa Tom
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United States, CA, Los Angeles
Joined Sep 2003
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Thanks for the comments fella's. Balanced huh? Now you tell me!

Okay, i finished it off today. I slightly changed the profile of the steering arm and then I sanded smooth and polished the works. Here is the bling-bling:







I really like working with metal. If I could get the same warm and fuzzy feeling working with wood I might just start building something from wood.
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Old Jan 03, 2007, 06:27 PM
3 Blades to the Wind
Shaun Hendricks's Avatar
Atascadero, California, United States
Joined Oct 2004
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You don't want fuzzy wood Kmot... it creates things called splinters that really hurt... and get it too warm and you'll discover the ancient ingredients to F I R E...
LOL!

That looks really neat. Nothing like polished brass... now to keep it that way!
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