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Author Topic: IRON DUKE 1914  (Read 123180 times)

raflaunches

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Re: IRON DUKE 1914
« Reply #300 on: August 21, 2016, 11:09:19 PM »

I too await with bated breath for the pictures. :-))

Jus two weeks left and I can get back on to the Dreadnought :-)
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Geoff

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Re: IRON DUKE 1914
« Reply #301 on: August 24, 2016, 01:38:41 PM »

I've now upgraded both the funnel smoke generator (by having a "n" shape with the wire in the middle and therefore two long tails in the smoke fluid to increase the flow and
"Q, X and Y" smoke generators have been replaced. Using nichrome ribbon wire from an old toaster so should be stronger.


I hope to be able to try all the guns this weekend.


I have purchased a servo slow from a different source and this only controls the speed and not the throw. The throw being controlled by a plastic gate on the transmitter to limit the joystick throw. The new servo slow (will post details once I can find the site)works perfectly -  asked for a modification 20 - 30 seconds and with this one you just press the button and count the flashes and stop where you want - more flashes = slower rotation. A simpler lower tech solution but works fine.


The big question is will the 12 volt batteries provide 16 amps to work all three smoke generators - we shall see. Worst case is to use one battery per smoke generator which means more re-wiring, again!


I'll report back in due course and hope someone got a picture or two!


Cheers


Geoff




 
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Geoff

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Re: IRON DUKE 1914
« Reply #302 on: August 30, 2016, 01:49:31 PM »

Okay, now for some pictures. It works! To be fair the pictures were taken on an ideal day and in ideal light but they do show the effect quote well. At the time of the pictures only A&B turrets were working.


I have subsequently got "Q" and X and Y" all working and the batteries do provide sufficient capacity to work all three smoke generators. No pictures of that as Saturday was like a gale locally and the smoke was instantly blown away but it was still visible so I'm certainly on the right track. However I was able to fire 30 salvo's at five shots a time so 150 shots in all!


Candidly for the first couple of salvo's the smoke is diminished until the system warms up then its much better. It fires every 12 seconds or so which seems about right for scale effect.


Curiously A&B seem to make more smoke than the aft turrets so I'll need to investigate. It could be that the fan is in the bows and therefore there is a higher pressure surge to start with so again some further experimentation required.


Overall I was very pleased.


Enjoy


Geoff
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Geoff

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Re: IRON DUKE 1914
« Reply #303 on: August 30, 2016, 01:55:58 PM »

I meant to add that the servo slow comes from "modelradioworkshop.co.uk" and works perfectly - Thanks Mike!


Very pleased with this product.


Cheers


Geoff
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ballastanksian

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Re: IRON DUKE 1914
« Reply #304 on: August 30, 2016, 08:03:39 PM »

Given the lack of particulates, that is a pretty good effect you have strived for Geoff. I would be pleased with that result,  and I have been sceptical due to the lack of said particulates to create density.

I expect in real life the gunsmoke would dissisipate quicker in strong winds so everything you are doing is sound.

Hats off to you Geoff, it has been a journey and you are nearly there with the tweaks.

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raflaunches

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Re: IRON DUKE 1914
« Reply #305 on: August 31, 2016, 04:03:16 AM »

Astounding work Geoff! :-))

Considering the effort and the hours you've put into her you deserve a special well done. All you need to do is take a black and white photo of Iron Duke  firing her guns which would certainly create a new old picture from WW1.
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Nick B

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Colin Bishop

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Re: IRON DUKE 1914
« Reply #306 on: September 16, 2016, 05:27:52 PM »

I'm pleased to report that Geoff was awarded a well deserved Gold Medal at the Model Engineer Exhibition currently being held at Brooklands Museum near Weybridge, Surrey.

The model was not displayed to best advantage, I think it came in late yesterday and space was tight but it did not escape the eye of the judges.

Well done Geoff.

Colin
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Geoff

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Re: IRON DUKE 1914
« Reply #307 on: September 16, 2016, 05:34:14 PM »

Wow, thank you, I didn't know! Quite made my day. yes the display area was a little cramped!

Thanks for letting me know!

Cheers

Geoff
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ballastanksian

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Re: IRON DUKE 1914
« Reply #308 on: September 16, 2016, 09:51:53 PM »

Well deserved Geoff. I saw it at Wicksteed and could not keep my eyes off it in and out of the water. The Dukes and KGVs (Super Dreadnoughts) were very attractive ships.
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Bowwave

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Re: IRON DUKE 1914
« Reply #309 on: September 19, 2016, 06:40:15 PM »

Hi  Geoff   great to see you at Brooklands  even though it was towards the close of the event  and a very well deserved Gold   ,a truly outstanding model .   :-)) :-)) :-)) :-)) :-))
Bowwave
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Geoff

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Re: IRON DUKE 1914
« Reply #310 on: September 26, 2016, 01:39:28 PM »

By way of a further update with ID I had used a new servo slow from "Model Radio Workshop"  which was excellent and very easy to use. I believe they can also provide extended "slow" devices upon request.


I was viewing their website and the "twin servo slow" product caught my eye as with ID's turrets linked to a "Y" lead I was getting some disproportionate turning with the turrets not quite lining up to the level I wanted. This product allows you to set the center point and the end points individually so you can tune two separate units (servo's or small sail winches) to match. It also adjusts the speed of the units as well.


Duly purchased and it arrived in very quick time and it works. I found it a little fiddly to get it absolutely right but as I became familiar how the product worked this was soon sorted and its perfect. The return to factory setting proved very useful! The turrets now all turn to virtually 90 degrees each side and return to the center automatically. With ID the small sail winches I used to rotate the turrets have a sizeable "dead band" so there is a little fiddling to get them exactly fore and aft after training but that's down to the winches.


Very happy with this product and the level of service. There are lots of very interesting products on his website. This is miniature electronics at its best - the devices are tiny!


I have also re-vamped the stern smoke generators in "X and Y" turrets as they were not producing enough smoke. Final trials will prove but it looks a lot better in tests. Just got to get it all back together again!


Cheers


Geoff
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ballastanksian

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Re: IRON DUKE 1914
« Reply #311 on: September 26, 2016, 11:42:01 PM »

Your resolve never fails to impress me Geoff! I do hope we can reconvene at Wicksteed next year where all your hard work on the inside will be as visible from the outside.

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Geoff

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Re: IRON DUKE 1914
« Reply #312 on: November 25, 2016, 04:58:41 PM »

By way of an update with ID. All turrets now work and on a calm day discharge a good volume of “smoke” which is certainly visible from a distance. The feedback received has all been the same, nice but where’s the bang! Something I am still working on

I have now fired something like 150 shots in sessions (30 salvos) without issue so the system/process definitely works but like most systems the devil is in the detail.
[/size][size=0pt]However curiously I set fire to my fourth funnel smoke generator which is built along the same lines as the gunfire system (basically a wick in a bath of fog fluid which is vaporised by nichrome wire). The first two caught fire because the plastic top melted and dropped onto the element. The third was less certain and the fourth was a complete surprise because the top and piping was brass and copper so can’t catch fire.[/size][size=0pt]I tried some tests:[/size][size=0pt]1)[/size][size=0pt][/size][size=0pt]Is the fire rope I’m using for the wick actually fire proof or just fire resistant? I put a piece in a gas flame and it wouldn’t burn so obviously fire proof.[/size][size=0pt]2)[/size][size=0pt][/size][size=0pt]Is the non-flammable fog fluid flammable – much to my surprise yes! The same test set fire to the fog fluid despite what the fact sheet says (flash point Not Applicable). The flame was smaller than a candle but even a small flame produces a lot of heat.[/size][size=0pt]3)[/size][size=0pt][/size][size=0pt]Further checking on line revealed that if the fluid is not completely vaporised it can undergo a chemical change and leave a residue. Once the residue reaches a certain concentration it can catch fire if conditions are right (wrong). A guy just put some in a pan on a gas flame and whilst it produced copious amounts of smoke it suddenly caught fire.[/size][size=0pt]4)[/size][size=0pt][/size][size=0pt]My fog fluid was 10 years old so it may have deteriorated anyway and could be a contributory factor.[/size][size=0pt]This has the potential to be a serious problem for obvious reasons however I believe I may have the solution:[/size][size=0pt]1)[/size][size=0pt][/size][size=0pt]The funnels were being used for an hour at a time which creates a very different set of dynamics to the guns which are on for 12 seconds at a time.[/size][size=0pt]2)[/size][size=0pt][/size][size=0pt]I was extracting the unused fog fluid and putting it back in the bottle which is why the liquid took on a yellowish tinge which I then re-used. Inadvertently I was systematically increasing the concentration of residue.[/size][size=0pt]3)[/size][size=0pt][/size][size=0pt]I now only use fresh fog fluid.[/size][size=0pt]4)[/size][size=0pt][/size][size=0pt]A small funnel fire isn’t too serious as it can be put out from above but a fire in a “magazine” is rather harder to control and manage in terms of access.[/size][size=0pt]5)[/size][size=0pt][/size][size=0pt]Redesign of the guns magazine (smoke box) such that the actual smoke generator sits in a draw and can be easily be slid out for inspection and replacement without a major dismantling exercise. This also lets me experiment with alternative heat sources (PTC Heating elements).[/size][size=0pt]6)[/size][size=0pt][/size][size=0pt]Remove the remains of the plastic slide valves as a potential source of burning[/size][size=0pt]7)[/size][size=0pt][/size][size=0pt]Additional alloy heat shields[/size][size=0pt]8)[/size][size=0pt][/size][size=0pt]I purchased some Kapton self-adhesive tape. This is temperature resistant to 350 degrees centigrade – it’s used in 3D printers. I intend to line the roof of the magazines to provide additional protection.[/size][size=0pt]9)[/size][size=0pt][/size][size=0pt]Most importantly a filler tube will now exit above decks disguised as a ventilator. It points directly onto the wick so the fluid absolutely soaks the wick when charged and in the event of any small fire I can pump water down directly onto the source. I could readily set this up for radio control as well.[/size][size=0pt]10)[/size][size=0pt][/size][size=0pt]I’m hoping that only using new fog fluid will cure the problems for the guns but best to be sure I can manage any issues.[/size][size=0pt]11)[/size][size=0pt][/size][size=0pt]More experiments with new fog fluid for the funnel generators.[/size][size=0pt]The biggest puzzle is that the fog fluid is flammable when all the fact sheets say otherwise.[/size][size=0pt]Either way I have decided to pursue the experiments and will report back in due course. The lure of 450/900 shots is too great to ignore![/size][size=0pt]Cheers[/size][size=0pt]Geoff[/size]
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ballastanksian

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Re: IRON DUKE 1914
« Reply #313 on: November 25, 2016, 07:59:54 PM »

Reading your report on progress leads me to think that how ever old the fluid is, it has a potential to catch. Therefore your preventative actions are wise especially given the amount of time you have spent building ID.

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Rottweiler

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Re: IRON DUKE 1914
« Reply #314 on: November 25, 2016, 08:14:13 PM »

Just found this build and messaged you Geoff!
It would be wonderful to have an easier version of your smokers for the firing of my gun barrels in Ramillies,but certainly could not do what you are doing,brilliant as it is!
I was just wondering if a water vapour smoke producer could do the job without the heat of oil? My barrels are made of plastic tube,and the turrets of fibreglass.I would only want two turrets,4 barrels working,and will use ultra bright orange and white leds to simulate the flash.......... or maybe not!
Mick F
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Geoff

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Re: IRON DUKE 1914
« Reply #315 on: November 28, 2016, 02:00:57 PM »

Wow, I don't quite know what went wrong with my update - okay I'll try this again to delete the gibberish!


All turrets now work and on a calm day there is a good discharge of "smoke" which is certainly visible from a distance and leads to the same question, where's the bang? I'm working on it!


I have now fires something like 150 shots in a session (30 salvos) without issues so the system/process definatley works but like most systems the devil is in the detail.


However curiously I set fire to my fourth funnel smoke generator which is built along the same lines - a wick in a bath of fog fluid wrapped with nichrome wire. The first two caught fire because the top cover was plastic and a small piece fell onto the wire. The third was less certain and the fourth a real puzzle as the roof is brass with copper piping to the funnels, so whats to burn?


I tried some tests:


1) Is the fire rope I use for the wick really fire proof or just fire resistant? I put a piece in a gas flame and it wouldn't burn so is fire proof.
2) Is the non flammable fog fluid flammable? - much to my surprise the answer is yes! The same test set fire to the wick with a small flame despite what the data sheet says flash point Not Applicable. It was a small flame but even so a lot of heat is produced.
3) Further checking on line revealed that if the fluid is not completley vapourised it can undergo a chemical change (don't know why) and leaves a residue. Once the residue reaches a certain concentration it can catch fire if conditions are right (wrong). A guy on line put some fog fluid in a pan over the gass and it produced copious amounts of smoke but then caught fire!
4) My fog fluid was 10 years old so may have gone off a bit


This has the potential to be quite serious for obvious reasons however I believe I may have the solution:


1) The funnels were being used for an hour at a time which creates a very different set of dynamics to the guns which are used for 12 seconds at a time.
2) I was extracting unused fog fluid and putting it back in the bottle which is why the liquid took on a yellowish hue which I then re-used. Inadvertently I was systematically increasing the concentration of residue
3) I now only use fresh fog fluid
4) A small funnel fire isn't too serious as water can be dropped down the funnel putting it out but a fire in the "magazine" is rather more serious and awkward to get to.
5) Redesign of the smoke box (magazine) mans the actual unit is now on a tray and can be slid out for inspection and replacement without a major dismantling exercise. This also lets me experiment with alternative heat sources (PTC Heating elements).
6) Remove the remains of the plastic slide valves to minimise combustible material
7) Additional alloy heat shields in the magazine
8) I purchased some Kapton self adhesive tape - this is used in 3D printers and can withstand 350 degrees centigrade to line the roof of the magazine. To be fair I've never seen any signs of burning but better to build in more protection.
9) Most importantly I now have a filler tube which can exit above decks. This places fog fluid directly on top of the wick. I can also pump water down the tube to extinguish any fire. This will be disguised as a ventilator. I also have a drain tube which is accessible when the deck is off.
10) I'm hoping that by using fresh fog fluid the problem will be solved for the guns but with the additional precautions I'm now more comfortable in managing any issues.
11) More experiments with the new fog fluid for the funnel smoke generators.


The biggest puzzle is that the fog fluid caught fire at all when all the fact sheets say otherwise!


Either way I have decided to pursue the experiments as the potential for 450/900 shots is too great to ignore


Cheers


Geoff
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Geoff

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Re: IRON DUKE 1914
« Reply #316 on: November 28, 2016, 02:10:13 PM »

I tried to respond to a PM but got a bounce back so to answer a few questions.


I'm more than delighted if anybody wants to copy my system and if they can come up with some improvements so much the better. For a detailed description of the funnel smoke generators I wrote an article a few years ago on another web site - http://wmunderway.8m.com/cont/smoke/smoke.htm   which give full details. (Model Warships Underway - How to's if the link doesn't work) 


The barrels on Iron Duke are plastic and they remain cool to the touch so the actual heat passed through any piping is quite low. The central pipes within the barbettes are brass for rotational and bearing purposes. The only issue would be if something catches fire.


I tried using the ultrasound smoke generators on ID and has four of them but they interfered with my radio (old 27 set) no matter what I did. Its probably worth experimenting but my thoughts are that its too water based and would cause too much condensation in the guns to be of practical use - insufficient smoke volume but please go prove me wrong!


Cheers


Geoff
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Geoff

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Re: IRON DUKE 1914
« Reply #317 on: January 17, 2017, 02:01:56 PM »

By way of an update, in view of the possible flammable nature of the fog fluid, whilst I have been working to improve the current system with some success I have also been working on a completely new gunnery system for Iron Duke which has proved to be very successful and is completely different from my previous method.


Candidly the possibilities are so broad that it would be possible to "fire" a gun with an external barrel diameter of no more than 3mm which means secondary armament can be "fired" or indeed anti-aircraft guns.


I'm still working out the details and will publish in due course but to date I have built a replica ID turret and barbette and everything fits quite comfortably within.


So far I have had about 20 shots out of the new system and it seems to be very repeatable with good effect with much more of a "blast" effect when firing.


A friend took some camera footage and I hope he will be able to post it on you-tube so I can link it in. As always the devil may be in the detail and at the risk of a boast it is so far advanced over the previous system there really is no comparison. The downside is that I'm unlikely to get anywhere near 450 shots but I anticipate something in the region of 200 so 40 or so full broadsides, which is probably adequate.

Full details to follow shortly

Cheers

Geoff

.[size=78%]  [/size]

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Geoff

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Re: IRON DUKE 1914
« Reply #318 on: January 17, 2017, 02:11:28 PM »

Please see the you-tube link below - hope this works!




https://www.youtube.com/watch?v=qS84P5wSX9U




Cheers


Geoff
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ballastanksian

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Re: IRON DUKE 1914
« Reply #319 on: January 17, 2017, 10:21:43 PM »

That is pretty impressive. You are dealing with a different scale and material than heavy particulate-cordite gasses, but still get a pleasing burst of smoke.

My only concern is the water condensate landing on deck, but if you mainy fire broadsides, this will be less of an issue.
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Geoff

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Re: IRON DUKE 1914
« Reply #320 on: January 18, 2017, 08:34:28 AM »

I think the waste water was partly a function of how cold and damp it was on Sunday, with light rain, but also because of the low temperature the barrel hadn't yet warmed up properly. I get this with the other system as well, I think its just a function of using fog fluid.

There are a number of experiments to continue to work out the best results and it maybe an increase in elevation of the barrel may assist (I doubt it because of the blast pressure) and/or the volume of fog fluid being used for each shot.

The volume can be adjusted but in the test model the stick operated the mechanism inside where in the production model this will be done with a servo which can be adjusted to the optimum fluid volume.

Its more a question or repeatability at the moment and to determine how many shots I can get.

In the video the gun was pointing into the wind. When pointing downwind the smoke effect was greater.

As per my earlier message the great advantage is that everything is contained within the turret and barbette so no large fan powered air supply and no fire risk at all.

I'll report back with developments as I'm in the process of mass producing five guns and equipment to finalise plans to fit into Iron Duke.

Looks like a fairly extensive re-fit coming up!

Cheers

Geoff
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Geoff

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Re: IRON DUKE 1914
« Reply #321 on: January 24, 2017, 08:55:31 AM »

As an update I have now radio controlled the process in the test turret and other than a couple of bits of equipment failure (not unexpected) I successfully fired 90 shots with a 15 second gap between shots. Still some improvements needed but I have definite plans for that.


The battery was a 12 volt 7amp hour  lead acid so nothing special. If I can get 90 shots per turret x 5 = 450 shots I'll be well pleased.


More updates to follow in due course.


Cheers


Geoff
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Re: IRON DUKE 1914
« Reply #322 on: February 03, 2017, 01:59:49 PM »

I'm now building the new system into Iron Duke and will take some pictures of the various components shortly. I have drawn up some schematics of how the process works and how to build it together with a long narrative. I have built all the new guns and controls and am now working on the new inner barbette to contain all the equipment and progress is reasonably good.


As soon as I have the ID system working I'll publish full details so anyone can build and/or modify as they see fit - won't be too long now!


Cheers


Geoff
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Re: IRON DUKE 1914
« Reply #323 on: March 14, 2017, 01:39:44 PM »

Okay, its finished, the new gunnery system. First the narrative - sorry but its quite long, then the pictures and plans, but it all works!
The original gunfire system works reasonably well but still needs some fine tuning and is quite voluminous to install. The blast effect is also limited so it’s really only suitable for calm days. The funnel smoke generators work on the same basis and during these experiments I had several small fires. Investigation showed that under certain circumstances the non-flammable fog fluid can catch fire if it’s not vaporised properly as a residue can form which can catch fire once the concentration reaches a certain level.
 [/size]Gun smoke output can also be a little variable dependent on the nichrome wire crimped connections and the imbalance between units but it was the fire issue that led me to research alternative forms of heating elements and I stumbled on PTC Thermistors. These are used in the chemical and food industries and many of us have them at home keeping coffee warm.
[/size]They are constructed to different voltage and temperature requirements but the fundamental feature is they are self-stabilising so once they reach the designed temperature they will not get any hotter so no feedback circuits are required and no exposed elements to cause a fire.
[/size]These are available on E-bay or Amazon and cost about £4 each so are not expensive. The ones I have are 5cm x 2cm x 0.5cm alloy with two wires supplying the current. On 12 volts they reach 230 centigrade in about 20/25 seconds. Current consumption is about 10 amps but once up to temperature this drops to 3-4 amps dependent on heat loss.
[/size]I researched how real fog generators work and they are based round a block of alloy which acts as a heat capacitor. Once up to temperature fog fluid is pumped into a small cavity inside the alloy and immediately flash vaporises/pressurises and exits via a small hole (2mm I think) under pressure. On contact with cool air it immediately condenses into fog and produces the well-known “blast” seen on stage shows and special effects.
[/size]Experimentation showed this process will work in miniature as you may have seen from the u-tube clip.  [size=78%][/size][size=0pt]https://www.youtube.com/watch?v=qS84P5wSX9U[/size][size=78%][/size][/font][/size]  The heat exchanger/thermal reservoir block is a matching sized alloy block 1cm x 2cm x 5cm. This has a 6mm hole drilled lengthwise but not penetrating all the way through. A smaller 4mm exit hole is then drilled all the way through and a 13-15cm copper tube is a push fit and is used as the inner barrel. A small plug with a 1.5mm exit hole is soft soldered at the very end. The entrance hole has a brass insert pushed in with a 2mm pipe connector. This is then strapped to the PTC Thermistor with the alloy block acting as a heat capacitor. (The production units use a small smear of heat sink compound between the heat exchanger and thermistor to improve heat transfer). A small volume (0.5cc) of fog fluid was then injected into the heat exchanger and it immediately flash vaporised into fog exiting the barrel. Despite reaching 230 C once wrapped in insulation it can be touched when operating but it is hot. I have used plumbers matt from B&Q as the main insulation and tie it all together with very thin copper wire to hold it all in place and this is then strapped down to the turret floor. Loft insulation is then used to pack out any free space in the turret. Obviously the more insulation the less heat loss and the quicker the recovery time and efficiency and lower current consumption.[size=78%]
[/size]The next item was to provide a measured amount of fog fluid on demand. After much thought I designed a long stroke piston pump which would be operated with a micro servo. The throw of the servo can be adjusted (on modern radio equipment) and therefore the volume of fog fluid can be varied to obtain the best effect. The pump itself is not a hard item to manufacture using K&S brass tubes for the barrel and piston and solid brass rod for the body. There are no piston or sealing rings to minimise drag so some leakage occurs but this acts as lubrication and sealing and as the pump sits in a reservoir of fog fluid leakage becomes irrelevant. Either way the pump will pump a consistent volume of fog fluid on demand. The pump valves are nothing more than rust proof ball bearings sitting in the natural drill shape using gravity to seal. I see no reason why the pump could not be made from plastic as pressure is extremely low. In practice the seals are not perfect but are good enough!
[/size]With this system everything can be made to fit inside Iron Duke’s turret and barbette so is very compact and other than batteries is completely self- contained with the lower part of the barbette acting as the fog fluid reservoir. The barbette is 75mm external diameter and 65 mm deep and holds 60 mil of fog fluid. The workings all hang off the turret floor (a working chamber) with the pump immersed in fog fluid. The mini servo is encased in a waterproof container. This structure is also very appealing from a historical structural perspective. As a bonus it also frees up a lot of internal hull space so facilitates a more logical arrangement of batteries.
[/size]A central 12mm brass tube is needed to allow power and servo cabling to exit on the center of rotation. On Iron Duke I winch the turrets round using small sail winches which works well. The attached schematics show the gun concept and detailed design of the pump. Other than the pump all items are easily and readily available and assuming you can drill a straight hole can be made by anyone.
[/size]A final item is the control system. The easy way is to use a servo/micro switch/relay to provide power to the PTC Thermistor and a second channel to manually operate the pump(s) and fire on demand. I am have inserted a high intensity yellow LED in the adjacent barrel and plan for a sound generator to produce the blast noise. The LED is a yellow 5mm 3 volt item from Maplin (cost 29 pence) and is sufficiently bright on an overcast day at 40 feet!
[/size]A more sophisticated control system would use an Arduino. The feature being that it would measure the temperature of the PTC Thermistor and after experimentation would limit the temperature to the most efficient level and only allow the pump to operate once up to temperature to avoid any spitting. It would also operate the LED and trigger the sound module at the right moment thus producing a flash, boom and a cloud of smoke. It could also be set to fire one gun every other second or with the flick of a switch fire a five gun salvo on demand every 15 seconds so should be very flexible.
[/size]Items:
[/size][size=0pt] [/size]-       [/font]If the PTC thermistor is placed vertically the 4mm barrel can be gently bent at a right angle such that it would be quite possible to “fire” a scale 1/96 scale 6” gun turret provided there is adequate depth/space below.-      - [/font][size=0pt]n anti-aircraft gun also works as quick little movements of the pump produces little puffs of smoke – you are limited only by your ingenuity.[/size]-       [/font]The connection from the pump to the heat exchanger is made using high temperature silicon fuel tube and apart from ease of installation this also operates as a safety valve should the exit hole ever become blocked.-       [/font]With Iron Duke the inner barrel is wrapped with string as insulation to keep the outer barrel reasonably cool with a short 5mm silicon tube at the end to prevent wetting of the insulation. The whole turret will also be packed with loft insulation to minimise heat transfer.-       [/font]Soft solder can’t be used as it typically melts at 180/200 centigrade albeit the end cap/nozzle is sufficiently removed from the PTC thermistor so soft solder works okay.-       [/font]The entrance cap in the heat exchanger is an interference fit and has to be pushed in with a vice.-       [/font]The inner barrel is copper to transmit heat and minimise condensation. In practice it was necessary to very slightly flare the inner end and tap in place with a coned drift from the rear to ensure a gas tight seal - Loctite retaining compound is also used.-       [/font]For ID the thermistor sits on top of the heat exchanger as this brings the inner barrel into better alignment with the gun port.-       [/font]I also insulate the floor of the turret with Kapton tape which is proof to 250 C-       [/font][size=0pt]ID has alloy turret roofs so they can readily withstand a degree of heat and can radiate surplus heat to atmosphere[/size]-       [/font]The fog fluid is fed in/emptied through a hole in the turret roof disguised as a hatch.-       [/font]Whilst 10 amps may seem a lot we need to consider this is only on for 25 seconds or so. A standard 12 volt 7amp battery gives a theoretical output of 7 amps for one hour or 1 amp for 7 hours. So notionally 10 amps for 7/10[/font]th[/size] of the time. Now we know we cannot get all the energy out of a battery and it’s not this simple so let’s assume 50% usable power so on this basis we get:
[/size] 7amps x 50% = 3.5ahr x 70% x 60 (mins) x 60 (seconds) = 8,820 usable seconds at 10 amps.[/font]
[/size]              So if each shot takes 20 seconds of energy we get:[size=118pt]
[/size]8,820 divided by 20 = 441 shots overall per 12 volt 7amp battery. This all seems impossibly high so if we discount a further 50% we still get 220 shots which still seems too high so again discount by a further 50% and we get 110 shots.
[/size]The test turret managed 90 shots with a 25 second warn up period and 15 second gap between shots and ran out of fog fluid so it should be capable of 100 shots in practice. With Iron Duke I carry 5 x 12 volt 7amp lead acid batteries so with five turrets we should get somewhere in the region of 450/500 shots which is adequate!
[/size]Barbette fluid capacity is 60mil and I can probably get 90mil as a maximum if required but it’s just as easy to top up if needed if sufficient power is still available. ID has a separate battery per turret to avoid the need to draw 50 amps through any single circuit and mitigate any current draw imbalances (A problem I had with the old system).
[/size]Ultimate reliability and performance is still to be determined but I believe the process/design has been confirmed albeit I would anticipate some further development/fine tuning to achieve the best effect.
[/size]After complete installation with the first proper test firing I achieved something in the region of 40/50 salvos from Q, X and Y but nothing from A and only about 20 from B which then just slowed down and stopped. The test was concluded to examine the fault with A & B and examination showed the mini servo had “fried” on B and was not operating full stroke on A. I don’t know why. These have been replaced with better quality servos so all should now be well. The LED effect is disappointing but may show up better on the pond.
[/size]I have an 8 channel system which is uses as follows:
[/size] 1)     [/font]Throttle[size=0pt]2)[/size]     [/size]Rudder3)     [/font]Train A&B to port/starboard 4)     [/font]Tran Q, X & Y to port/starboard5)     [/font]Switch on all thermistors via 5 separate relays6)     [size=0pt][/font][/size]A & B pump operation/on/off/fire/LED flash7)     [/font]Q, X & Y pump operation/on/off/fire/LED flash
Iron Duke is a complicated ship to work on because of the five turrets. A twin or four turret ship would be easier as most of the wiring would remain in situ without the need to disconnect to get to the interior.[/font]
[/size] I do hope this system may prove to be of interest to other modellers and one day hope to meet another ship which fires back using my system! As always any ideas for improvements will always be most welcome.
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Geoff

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Re: IRON DUKE 1914
« Reply #324 on: March 14, 2017, 01:44:08 PM »

Now the plans: Enjoy. As soon as I can get some pictures of the actual firing I'll post them but the result is a more explosive effect which is audible as a "phwoof" type sound.


The pictures are really self explanatory but show three turrets sideways with the pumps clearly visible. End on view shows the mini servo in a waterproof box as the fluid level reaches the bottom. Top view shows the turret layout the PTC Thermistor is under the insulation. The two lots of pipework. Top left is the filler hole whereas the other pipe comes from the pump to the rear of the heat exchanger.



Cheers


Geoff




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