Syren, Brig, SC&H R/C Square Rigger, 1/24 scale - Page 12 - RC Groups
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Dec 10, 2012, 10:35 AM
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DanL's Avatar

Servo deck almost complete

Just a few details to finish...springs or bungee?, final alignment, rig new braces...
Some pics of test fit of servos.
The existing servo mounting blocks were leveled to serve as a base for this setup.
Next is to check accuracy of drum diameters - Do the drums pull the course and top yards the proper amount relative to each other thruout the full rotation? Does the servo, programmed at the target 4 turns, rotate the yards to the max?
Last edited by DanL; Dec 10, 2012 at 10:44 AM.
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Dec 10, 2012, 07:14 PM
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TBowman's Avatar
Hi Dan


The drums are smaller then I envisioned. Thanks for the continual inspiration.

kind regards
Dec 13, 2012, 09:30 AM
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DanL's Avatar

Brace servo slack takeup system

Went to look for springs to pull on the servos to provide the tension for slack takeup. Thought I would end up just going back to using bungee because all the "pull" type springs were too strong, wrong size, etc
But then the lightbulb went on....use a compression type spring to "push" the servo to provide the tension. And the spring now is completely out of the way and an integral part of the slide system.
Found a spring that just fits over the 7/32 tubes and seems to be about the correct tension. Had to stretch the spring about 10% in length to provide tension over the full servo travel.
Tube slide system is now nice and clean and compact.

Last edited by DanL; Dec 22, 2012 at 10:09 AM.
Dec 13, 2012, 11:20 AM
Registered User
It's a great design for square sails. I'll use it on my upcomming squareriggers. One question: You have two different size drums on the same servo. Is the amount of slack that sliding controls the same for both drums? And if not, how does it affect the system?

Dec 13, 2012, 01:58 PM
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DanL's Avatar
Yalex -
Great observation. On the previous setup, slack comp for the course yards was done with bungee brace pendants and for the top yards it was a combination of bungee to attach the mast blocks and a sliding action of the bungee - back and forth as one side became taught and the other side slack. Called that "trolley blocks". The two systems adjusted slack independently.
On this system, the course brace pendants will be solid line, not bungee, and all slack comp will be done by the sliding servo. For the top braces, the mast blocks will no longer trolley, but the blocks will be attached at the mast with very short lengths of bungee. Again, most slack compensation will be done by the sliding servo, but any small differential between the course and top brace slack development (due to different drum size, yard length, rotation geometry, etc.) will be "trimmed" by the slight stretch of the bungeed mast blocks.
See next post for a vid of the first installed "servo sled".
Dec 13, 2012, 02:43 PM
Registered User
Thanks. That's how I thought it would work. I am a great admirer of your (and others) work on square rigger control systems. I have read and re-read all the square rigger threads numerous times. My own current project, Russian four-master Kruzenshtern, benefited greatly from your experiences. So many, many thanks. I am planning to start my own build log soon, and I am sure you will be able to contribute invaluable incite.
Dec 13, 2012, 03:24 PM
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DanL's Avatar

Servo sled video

Yalex - thank you very much. Anxious to see your project and posts.
Here's the first "servo sled" installed and operating.
Only the course braces are attached. This is the sternmost servo that controls the fore yard rotation.
I replaced the coarse yard bungee brace pendants with solid line, so all slack comp is from the sled. Total travel is only 3/4" from square to fully braced, but since the springs are now on the tubing and take up travel length, about only a bit over an inch of total travel L is available anyway.
Without the bungee pendants, the yard position is very stiff over all the rotation. Very little slop...the spring may be a bit too strong, but that's probably OK.
The new drum diameters are a bit larger than the old ones. With the old drums, almost +/- 2 rotations were needed (almost 4 total servo rotations) for full port to stbd yard rotation. Now only +/- 1.5 rotations are needed (3 total for the servo, which is spec'd at 3.5 rotations)
Operation looks better than the old system - definitely less slop. And more rotation! Old max was about 50 deg if I remember right. Measured a solid 55+ degrees with the new system.
Any observations/.advice appreciated.
servo slide (0 min 52 sec)
Dec 13, 2012, 03:53 PM
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DanL's Avatar

Misc. Tool Info

For re-rigging Syren servo drums and braces, these tools were really helpful.
The mini tubing cutter was used to cut precise-length tubes to make the sleds.
The small ratchet socket is used to tighten the size 2-54 nuts used to anchor the ends of the braces on top of the drums.
The curved mini-forceps are used to handle line, make knots, as a mini marlin-spike, etc. Can't do without them.
The 14" forceps limit my profanity...used pretty much to retrieve parts dropped into the depths of the hull...
The dental floss threaders (at any drugstore) make threading lines and pulling them thru a snap.
Not shown - a magnifier. I can't see much without them....
Dec 13, 2012, 06:21 PM
Damp and Dizzy member
Brooks's Avatar
Thanks for the tool list, DanL. For retrieving stuff, these ear polyp tweezers/forceps (I think of them as alligator tweezers) work nice too. They don't have to held shut as you thread the tool into the hull to the dropped object, which I find helpful. Ditto for tying small knots.,7047.html
Dec 15, 2012, 06:13 PM
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DanL's Avatar

Transmitter and Control setup for Syren

The new setup on a 9 channel Tx is different from the old setup on the 7 channel last used to sail over ayear ago.
The new setup has to include control of 3 new gun functions - select port or stbd guns, advance the multi-gun barrels one at a time, and operate the rotary switch to fire the guns in a rolling broadside.
In the old setup, the right and left sticks were used to rotate the fore and main yards. The control of precise rotation wasn't that great, and the sticks often got bumped or moved (eg, put the Tx down to take a pic) On the new Tx, full rotation pots were added with stiff rotation and knobs that won't get inadvertently moved.
Also modded the right stick - took off the spring and added a ratchet.
The TX allows re-assigning various switches to Tx output channels. Works well, but need to record it all - too easy to forget what's what.....
The setup is shown in the attachments. I use these two forms to plan and record settings for a number of tank and ship models. Servo travels, etc (sections in red) aren't programmed yet - need to finish the model setup first.
Definitely shooting for this spring to sail Syren again.
Dec 15, 2012, 10:01 PM
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TBowman's Avatar
Great info Dan

Thank you for sharing. Even though I'll be using a Futaba, I'd imagine the setup and programing will be similar.

kindest regards
Dec 22, 2012, 10:20 AM
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DanL's Avatar

Slide Servo Update

The slide servos are installed and tested successfully.

A few notes:

Brace tension on the servos causes lateral cocking forces on the "sled" portion of the assembly. That causes high slide resistance of the delrin slide bars on the slide tubes. The delrin blocks that support the servos are thick enough that the edges of the holes cause binding.
Chamfering the hole edges pretty much eliminates the problem (see diagram).

The servo current was measured. Base current for the Rx was 90mA. Max current during rotation for both the fore and mainmast servos was 240mA for each servo So the servos were running at only about 150mA max. for each (at 6.4V fom the SLA battery). They are rated at 2A (I think) and fused at 2A. Will get current under wind load outside when temp gets a little milder.

The spring was stretched to fit, but the spring should be sized to provide pressure on the slide even when it is under minimum brace tension (when the yards are fully braced).

The holes for mounting the frames to the base should not be directly under the slide tubes - makes it tough to get good screwdriver alignment on the screws. Make the holes slightly offset to the inside the slide tubes above.

The drawing shows the delrin travel blocks above the servo mounting tabs. As built, the blocks are under the tabs and the screws put in from the top. The brass slide tubes are then running along the side of the servo body. This makes it very easy to install/remove the servo when necessary.
Last edited by DanL; Dec 24, 2012 at 09:10 AM.
Dec 25, 2012, 10:05 PM
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DanL's Avatar

New Design Gun Ignitors

Big news (to me anyway...)
The guns were always touchy - many misfires and a lot of detail involved in making teh "permanent" ignitiors. Also, loading system was getting better, but still complicated, with flash paper required.
New system has very simple ignitor - #16 silicone RC power wire with nichrome wire simply inserted into the end between the strands. A touch of solder creates a mechanicla bond and seal (solder actually doesnt stick to the nichrome). The other nichrome end just pulls into a slot (or hole) on the grounded barrel.
Drawing shows concept. Other advantage is that the BP ignites from the front -less powder blown out of the barrel, therefor more smoke per amount of powder used.
Going from 2.4V to 4.8V and a bit haevier nichrome (0.012")
Tests very positive. Starting to mod the existing 18 guns. Loading willl be with pre-rolled cartridges. Aprox. 1.3cc BP per load.
More detail later - still tweaks to be made.
Dec 26, 2012, 07:05 AM
Paratrooper's Avatar
Dan, this certainly will make the guns more consistent.

When ramming the charge with the pre-rolled cartridges such as we were doing, how do you get the charge down the barrel? Does each load have to pierce the cartridge somehow?

Pond Sailer will want to modify Surprise for sure.
Dec 26, 2012, 09:09 AM
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DanL's Avatar
'morning , Ray.
Merry Christmas!
Yep - Pond Sailor has been in touch. We'll keep working on the guns.
Not totally sure yet the easiest way to "roll-your-own", but with the wire now heating a loger length alongside the charge, and using double the voltage, the charge goes off very fast. Recoverd foam wads all have a melt line on them along the wire track. No puncturing of the charge seems necessary.
I want to try cigarette paper for the cartridges again. It worked well for making cartrdiges in tests long ago, but always left unburned paper back in the braech area. In the new design, the silicone wire sheds debris and fouling easily vs. the current copper tube design.
More testing today, but so far this seems a big improvement.
Hey, maybe you should build a new "gun platform"!

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