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[Bob K]

Barbette Outers

The ABS rigid tubing is really nice, although 2.4mm smaller diameter than I had planned for.  After a lot of thought, rather than laminating the above deck portion I would instead use 6mm strips of ABS to line the deck holes with, Araldited in.  I now have a good slide fit for the tubes.   I have cut the tube into 80mm and 40mm lengths, to suit barbettes with gun fire modules and those without.  The super-firing turrets are just mounted higher. 



Turrets
I cannot mount the stepper motors just yet, so I have moved on to the turrets.  Thank you Geoff, I tried B&Q and they had some acceptably thin soldering heat mats.  Carefully cutting the mat to shape I “lagged” the thermistors, securing with thin brass wire.  Gently bending the copper gun barrel inners to a realistic angle I lagged the barrels with cotton yacht rigging, to be sealed with high temperature adhesive.  Barrel outers will be fabricated from aluminium tube.  One barrel will carry the smoke outlet, the other an LED.



Wiring
Tricky this:  Due to the stepper motor being underneath the gun fire module, on its centreline, all wiring has to pass between the module outer wall and the fixed barbette.  Not a lot of room for the thermistors wires, servo lead and LED wires.

More on this later, after I have completed the turret hoods and bases.

T.A.R.G.E.T.

We are gradually approaching the stage where Geoff's gun fire system is to be married up to C-3PO's TARGET gun director control system.  Please keep an eye on that thread too as his development work is coming along superbly.  HMS Agincourt will be the first ship to be equipped with this system, and the Mayhem event at Wicsteed is approaching too fast. 
http://www.modelboatmayhem.co.uk/forum/index.php/topic,56800.msg635813/topicseen.html#msg635813

In the words of Willy Wonka "So much time. So little to do.  Reverse that !"

[Bob K]

Not a lot to report, just spending several day grinding and filing a surplus 4mm from the bottoms of seven turrets.  This fibreglass is good quality, blunts files and is almost 6 mm thick in places.  Anyway, I have to press on as I can't start the turret bases until it's finished.

When this bit is done I can make the gun apertures, then figure how to mount the lagged thermistor assemblies with lagged barrels.  Beside each working gun assembly will be a dummy gun with ultra bright wide angle LED.

[Bob K]

Turrets

Finally finished fettling the turret bases. Fibreglass powder everywhere, but they are now the correct profile underneath.  Now the start on the turret floors.  2mm ply, to be flush with turret base and just inset into the barbette ‘round’.  This meant making a template, then getting out the trusty vibrosaw.  Only problem is where do I put it in this cramped space?  In the end I got out the Workmate, put a ply sheet over it, and used that. 

Filed edges of ply to individually fit turret inner profiles, slight variances due to fibreglass thickness.  Instead of trying to fit numerous small sections of ply inside I decided to use a fillet of Milliput as a support ledge, then lightly pressed the cut ply shapes into it until flush.
The thermistor assemblies will be a close fit inside.



The circular sections will fit onto the barbettes.  Next step will be to drill the gun barrel holes.  It is intended that a single screw will retain the hood for access, after sliding the hood over the barrels.

[ballastanksian]

I'm not sold on fibreglass for smaller items, and not really for hulls either, but it looks like you have got the better of those turrets!

[Bob K]

At four and a half inches long they are almost like a small boat in their own right.   

Fourteen barrel holes drilled, a little green putty on cut edges for minor blemishes, and I am nearly ready to fit thermistor assemblies alloy tube guns and LED's. 

[ballastanksian]

Good show! This is getting exciting Bob 

[Bob K]

Turrets

Apologies for the update delay, this stage took a very long time.  After providing an internal lip for the 2mm ply bases I began on the ply internal structures of the turrets.

It was necessary to make the turret bases in two sections as the turret rears are slightly higher than the circular part.  Quite a bit of fettling was needed to get the joined base sections to lie flush with the lower turret profiles. 

Next bit was fiddly in the extreme.  I used 5mm ply as vertical support structures, to mount the thermistor assembly one side, and the LED barrel and plumbing the other.  An interesting profile based on many Vernier depth gauge readings, plus a step for the two part base.  The fibreglass turrets were each drilled for an M3 stainless CSK screw.

I next fitted M3 stainless nutserts into the top of each divider.  All this virtually blind inside the structure.
At final fit the alloy tubes will be affixed to the lagged barrels using high temp adhesive.

Having the internal structures built it then remained to mount the thermistor assembly inside each, together with the alloy tubes for the barrels.  The plan is to remove the M3 screw, raise the rear of the turret and slide it off the barrels.  Positioning the thermistor assembly is critical as space is extremely tight.  My 12 inch turrets are a fair bit smaller than Iron Duke’s 13.5 inch. 
The fog fluid supply tube goes through the ply, some hot mat padding under the rear of the thermistor assembly, then wire it into position. 



The above should give an idea of the tightness of fit and accuracy needed for ply mounting support.  The turret “shell” just slides over the barrel(s) and is clamped down with the M3 CSK screw.  Next job will be to thread the thermistor wires so they can exit between the fixed barbette and rotating inner,  Very little clearance here for wiring either.

I plan on using thin brass strips down the rotating turret inner, plus thin wires for the LED.  The pump servo cable also has to route between the tubes.  It will be challenging.

The non-firing turrets will be a lot easier, having only alloy barrels and a single LED.

This is all taking time, and Wicksteed is approaching far too fast.   

[ballastanksian]

I make it about seven weeks 


Its good to get awkward things out of the way sooner.

[Bob K]

Kind words always appreciated Iain.   
Only seven turrets too ...  Tee hee !

Seriously, the ship is not even painted yet, no batteries, a lot of superstructure still to build, and the TARGET electronics.

I am indebted to both Geoff and C-3PO and so wanted to have their systems at least working by Wicksteed.

[Geoff]

Bob,

Looking good. As a reminder the holes in the turret should be elongated to allow for the guns to elevate. On a practical basis this will also allow you more clearance when sliding the turret over the guns.

Cheers

Geoff

[Bob K]

Many thank Geoff.  Much appreciated.  Boy, it is a tight fit for 12 inch turrets rather than your 13.5 inch.
I am trying not to do full "U" slots for the gun barrels, but realise that the holes will need to have sufficient vertical clearance to allow the turret hood assemblies to slide over.
When I have the first one operational I will try to post a photo of the gun fire smoke !

The TARGET gun bearing control is being worked on by C-3PO, but that is a brand new development.  Coming along well from what he has shown me.  If I don't have time to complete that I aim to at least have the guns firing, albeit with turrets pointed broadsides. 

I must at least do the spray painting in the time remaining, and get all the batteries on board.

Fingers crossed 

[SteamboatPhil]

Keep going Bob, can't wait to see it in only a few weeks (no pressure then) 

[C-3PO]

TARGET on TARGET


Even if it's just in time for Wicksteed


C-3PO

[Bob K]

C-3PO.  I am very grateful for the wonderful development work you are doing on the TARGET system.  It just seems so much to get working with all the software systems to write and debug.

Separate electronics modules for each turret, each with its own Arduino coding, plus fire control director master and slave units, then the electronic compass (almost like a GPS).  Oh yes, then there are the audio units too - from your diagram.  I reckon about 14 Arduino units including the inter-hull communications units.


From my limited programming experience (yonks ago) It still sounds a heck of a mountain to climb.

I shall press here and aim to have something sailable for Wicksteed, and hopefully operational too 

Many thanks again 

[Bob K]

Turrets

Slow steady progress on the four firing turrets.  The thermistor assemblies are now mounted, secured with brass wire.  Next is the wiring for them, bearing in mind they can draw up to 13A on start-up and space is limited between inner and outer tubes.  I used 0.25 inch x 0.016 brass strip epoxied onto the cylinder wall.  This allowed connection to the thermistor wires using standard spade receptacles.  Thicker wire will be connected onto the strips underneath for connection to the control relay.

The tube supplies fog fluid from the barbette reservoir to the thermistor via servo operated pump.
The alloy spigot is to fill / drain the fluid with turret hood removed.



The servo cable exits down the outside of this cylinder, epoxied in, plus two cores of servo wire will be similarly fixed on this side for the LED’s.  Wiring is roughly equal spacing around the cylinder. 

Next task will be mounting the dummy barrels for the LED’s.  The overall visual effect is a mass of smoke with a bright yellow flash, although only one barrel per turret blast smoke.  The other has an ultra bright wide angle LED at its end.  This should be relatively straightforward compared with the above.

Special battery

As discussed on previous posts weight has become a critical factor, necessitating a very special main propulsion battery to keep the overall displacement from going way over the 29Kg limit.

So I have bitten the bullet and bought a 12V 14Ah LiFePO₄  battery,  Compared to an SLA it weighs in at just 1.9Kg instead of over 5Kg for a similar sized SLA.   Darned expensive, but it has become necessary.  In addition to this battery will be four 12V 5Ah batteries for the gun-fire, one per turret, plus two batteries for all the electronics.  That's eight batteries in all, that otherwise could have totalled around 15Kg.

[Geoff]

Bob,

Its all looking good and yes the wiring is a challenge if not on the centreline, hence my ones have the central tube but of course this does not suit your use of the stepper motors!

All good fun

Cheers

Geoff

[Bob K]

Thank you Geoff, much appreciated.
This kind of construction is not exactly my forte, which makes me admire your barbette construction even more.
However, it is getting there.   

[Bob K]

Smoking Hot

Not fitted the RH barrels yet, but was tempted to see how the LH barrel worked in action. 
60ml of fug fluid pipetted into one barbette module, and a 12VDC supply connected to the brass strips under the module. 
Took just a minute and a half to get the thermistor hot.
Not having the electronics for firing it yet I replicated this with a servo tester and 4.8V battery. 
It moves the internal pump servo arm just using the tester knob.
 My wife kindly took a photo whilst I turned the knob.



Wow !!   Is that smoking hot – or what ?
Thank you Geoff.  Yippee.  It works.  A major build milestone achieved.
After four shots my workshop has a smoke screen.

OK, fun part over.  Back to fitting out the dummy barrels and LED’s.

[Plastic - RIP]

Awesome! 

[Akira]

Wicked nice!

[Geoff]

Bob,


Thank you for posting the pictures and I'm just as pleased as you are that it all worked fine! Its nice to know at some point in time we can shoot at each other!


All we want now are more battleships with firing guns and we can stage a battle.


As a reminder don't forget to seal the end of the barrel with high temperature silicon so any drips don't run back into the barrel and soak the insulation.


I'm very pleased for you


Cheers


Geoff

[Bob K]

Geoff.  Thank you.  Please do not think I was "surprised".  I knew it would work, just like your Iron Duke.
I am just pleased that my implementation hadn't messed up.  SO good to see it work though.  Exciting 

I was thinking of you yesterday. Our family were at Portsmouth making the most of our season tickets. We saw the actual battle ensign of Iron Duke flown at Jutland.  As you know my wife's Grandfather served in her at that time.

Whatever, I am going to Wicksteed, and although Agincourt will be far from completed the guns will be firing.
I need to finish the turrets then think about painting her, and getting the full set of batteries.
Hopefully more will consider building real gunfire systems.  I am following your Invincible with interest.

PS:  Yes, the barrels are sealed with high temp adhesive over the lagging.

Thank you so much for all your help 

[Geoff]

Cheers, Bob,

I have also seen the Jutland exhibition and it was really quite good. I was with a friend and we were wondering if we could sneak out the HMS Canada model past the security guards. It may have been tricky at about 14 feet!

If you Google that model it recently underwent a complete restoration and there are pictures of before and after - quite a difference.

Cheers

Geoff

[Bob K]

Geoff,

Do not bother with the HMS Canada model, however awesome it looked.  The guns don't work 
This is now what now defines a Dreadnaught battleship model.

[Geoff]

Indeed, there are only two types of battleship models, those with guns that fire and those that are targets!!!