servo turrets

[Kevin Flack 2Participant @kevinflack2]

Early days on HMS Magnificent but I would like to have the turrets able to turn possibly via two servos? A problem i can see or maybe two, how do you get the servos to turn opposite? eg the forward turret turns left the rear right?

Also the turret should ideally have at least 180 degree turn arc and the servos I think have a lesser arc? Could the stops on the srevo be removed?

Comeon chaps I know someone has had these concerns before no doubt.

Kevin

[Kevin Flack 2Participant @kevinflack2]

HMS Magnificent

[Paul TParticipant @pault84577]

Hello Kevin

Do you intend to operate the servos on different channels or on one channel?

With regard to increasing the turn radius this can be achieved by using a basic gearing system simply replace the servo arm with a gear cog and have a slightly smaller gear cog on the turret spindle.

The downside to this method is that it relies upon direct contact between the gears and some moderately difficult engineering to put it together. A simpler system or if you are restricted for space a remote system can be used by replacing the gears with pulley wheels and employing an elastic band as a drive belt. Its basically the same system as used to drive the turntables on the old style record players.

As an alternative you could use a bell crank to increase the turn radius but the geometry can be difficult to work out and if you get it wrong the system will just lock up.

Personally I would use a pulley system as it offerers the greatest flexibility.

Paul

[Paul TParticipant @pault84577]

How big will your model be?

Edited By Paul T on 15/12/2012 09:07:30

[ashley needhamParticipant @ashleyneedham69188]

How about using some of those very small geared motors you can get..directly coupled to each turret via a bit of silicone tube, and obviously having the connection reversed to get the different turn.

Simple on/off/on switch required operated by a servo, and power could be a stand-alone AA battery. ?

Ashley

[Colin BishopModerator @colinbishop34627]

I think Dave Milbourn will be able to suggest something suitable from the ACTion electronics using the Servomorph. You can see a wiring diagram for moving turrets on the Bismarck here:

**LINK**

Servomorph details here:

**LINK**

Colin

[Kevin Flack 2Participant @kevinflack2]

Hi Chaps

Thanks for the feedback I can see now why am am the amateur builder!

The model is the one from Deans and so size is probably not any issue here.

I have a 6 channel Hitech set for this model but have not put much thought into details etc and think at the current rate this model will take a few years to complete! Assuming the two channels left would be for trottle and rudder the right could have the turret controls.

This is really my first multichannel models as all others are on 2x 27Mhz setups, going to the club with a single Tx and a pack of crystals. you can only get so many boats into the car!

The pulley idea seems to be one I could feel comfortable with I had also wondered on the geared idea but was not sure the gears could be purchased locally?

If only a single channel was used how would the one servo be reversed to the other, lead changed?

This build is going to be really a long haul!

Kevin

[Colin BishopModerator @colinbishop34627]

Just mount one of the servos the other way round.

Colin

[Paul TParticipant @pault84577]

Colin

Unless you mount it upside down it will still rotate the same way, do you mean change the polarity?

Paul

[Paul TParticipant @pault84577]

Hello Kevin

Meccano gears and pulleys are very useful and decent second hand ones can be obtained from ebay, or try Maplins as they carry a small range of plastic gears.

Using a pulley system you could operate both turrets with one servo, fitting the pulley cord in a figure of eight layout will enable both turrets to face the same target when the servo is operated. I can draw you a layout sketch if you need one.

Have you thought about having the barrels move up and down as the turrets turn as a fairly simple cam operating against the shaft would achieve this.

If you are going to have rotating turrets you might have to add strengtheners to stiffen the hull and resist the stress of the turning forces.

Paul

 

Edited By Paul T on 18/12/2012 18:27:26

[Colin BishopModerator @colinbishop34627]

Paul,

What I meant was to use the other side of the servo crank. Does that make sense! Looks OK on a diagram i have done!

Colin

[ashley needhamParticipant @ashleyneedham69188]

Kevin. Take a squint at http://www.hobby.uk they have all sorts of goodies there. should have the tiny geared motors I meant, and more gears than you can shake a stick at (why?)

Ashley

[Kevin Flack 2Participant @kevinflack2]

After doing some research I do believe the easiest solution may be the use of sail servo running direct, anyone ever tried this or am I on a wild goose chase?

[Charles OatesParticipant @charlesoates31738]

Hi Kevin, I did much the same thing some time ago. I used a geared motor driving a figure of eight loop aound two pulleys, each of which was mounted on a shaft to the turrets. I chose that method because I wanted the turrets to turn slowly, if they turn quickly it looks silly on a period ship. I aranged a limit swich from a bit of old brass to stop them turning too far. To make the motor work in either direction I fastened two switches one on each side of a servo so that the motor could go each way at the twich of the tramsmiter stick.
I don’t know if this sounds complicated, but it was simple to make and only took a couple of evenings.
However you choose to do it, it is worth the effort, sailing is much more fun with some toys to play with.
Charlie

[Kevin Flack 2Participant @kevinflack2]

Bought as set of Timiya car gears 24T&58T. Placed the larger on the miniservo and the smaller on turret via a 3mm bolt and tried on the turret on the Flyfischen. Works like a dream with aroung a 270 degree action. Only point is to activate slowly to give some sense of realism. Rather chuffed with the setup having activated the 3rd channel on a 2 channel set after noticing the package showed the additional option. All that was needed was a Y connection on the receiver supply and a pot added to the TX. Off to the club today then!

[Dave MilbournParticipant @davemilbourn48782]

P96 ServoMorph will slow down the rotation. Checkout the website under ACTion Electronics
**LINK**

DM

[steve hParticipant @steveh76883]

You could use a servo stretcher, its a tiny unit that plugs inbetween your servo and reciever. I have one on my fairmile , giving 3 guns and a searchlight 180 degrees travel. look on ebay, thats where I got mine from.

[Kevin Flack 2Participant @kevinflack2]

Had to replace the micro servo after it stripped gears. Normal servo copes far better. Have also found a servo speed controller locally (turnigy) to slow down the setup and create a sense of realism.

Also sourced a servo reverser which has solved the dual turret problem noted before. plug and play very easy to use.

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