Model Boat Mayhem
The Shipyard ( Dry Dock ): Builds & Questions => Navy - Military - Battleships: => Topic started by: Bob K on February 23, 2016, 12:33:34 pm
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Gunfire
Not sure if anyone has tried this, or even whether it’s street legal, but I am looking into attempting simulated gunfire. Obviously pyrotechnics are out unless you have all the necessary licenses, and even firing blanks is not permitted in public spaces.
I am looking at adapting a low power BB airsoft firing mechanism from a toy RC tank, together with artificial smoke, and a 2 second sound file (which I have). The mechanism to be housed in the RH side of a twin 15” gun turret, operated by remote control. The LH gun to have a ‘recoil’ mechanism and powder smoke. Thus it will appear that the LH gun is firing, even though the BB pellet comes from the RH barrel. Gun elevation and turret rotation by conventional means.
A spare gun mechanism is only £9.99 on E-Bay and looks both slim and compact. Actual firing would only be “out to sea” with a range of 25 meters. Simulated fire (with the BB part disabled) no problem.
Any thoughts ?
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Sounds interesting Bob, I'd like to see what you do with that, one of my Grandson's was round at the weekend who said when looking at the turret on my Coventry "wouldn't it be good if you could fire a tiny bullet out of it" my reply to him was "don't think I haven't thought of it" %%
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It is for my HMS Abercrombie Monitor. Just one huge twin turret, so its not like trying to fire a dreadnaught broadside. The recoil should be straightforward, a light coil spring in the barrel with a servo operated cam.
Sound: https://www.audioblocks.com/stock-audio/distant-big-gun-sound-effect.html (https://www.audioblocks.com/stock-audio/distant-big-gun-sound-effect.html)
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How about "firing" flour or talc using the airsoft mechanism?
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I thought I'd stumbled on a thread about my favourite military alchoholic tipple !
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:}
Bob, Geoff who is building Iron Duke (also in this room) is also trying out ideas for a gundfire system for his Battleship, so it might be worth seeing what he is trying to do and wether any of it would be of use for Abercrombie.
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There is a group that specifically model "firing" warships and engage in battles and try to sink their opponents.
Details of guns mechanisms etc were on their website.
Cant recall the group name, but Google should come up with it.
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Those henglong or taigen bb units are horrifically unreliable m, I would avoid.
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I have been following his Iron Duke with great interest. I was just thinking of a simple soundcard.
Note: The gun firing mechanism is NOT in any way a ship combat type, but low pressure air firing a plastic airsoft pellet, from a toy tank suitable for children. I have never seen a recoil mechanism on a model warship but thought it would look visually realistic. Can talc be used for repeated firings? Probably, as when I was likkle I had a toy Sherman that puffed talc from its gun.
The only working guns I have seen on ships use gunpowder. So was seeking a more street legal effect.
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https://youtu.be/opugmmhGfTw
https://youtu.be/Yf2mCXqf-u0
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Very interesting video clips Martin, especially the recoil mechanism inside the tank turret.
I am trying to find the video clip I saw last week of an early battleship gun firing. Fast recoil with slow return, and huge amounts of cordite smoke.
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https://www.youtube.com/watch?v=hnxYMic7xG0
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Hullo Bob.....this is an interesting action to simulate, however it is relative to science being the speed of light >>>> to the speed of sound >>> then to what the human mind can accept
In older photography of ordinance firing [of the period your are contemplating] are we really sure what we perceive?
a. we see the flash
b. we hear the sound
c. we see the barrel return as a function of the return from recoil
What I am trying to say is with [a.] & [b.] occurring at such a close visual/audio perception in time, that we don't really see the barrel retract into recoil, however we do see [c.] the secondary motion of the barrel returning from recoil
The video of the Henlong tanks look impressive during the firing, however viewing the real tanks firing offers a somewhat different perception in that the barrel retracting post firing is literally a milli second action
Good luck........ Derek
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Bob...here is a link to 16" guns on a US Iowa Class Battleship...
BTW...the puff of smoke exiting the barrels @ 3:25 minutes after the firing is termed as the 'air blast', which blows/expels combustion gases from the barrel prior to opening of the breach...naturally this eliminates or stops the same gases from entering the gun house ....... Derek
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https://www.google.com.au/url?sa=t&rct=j&q=&esrc=s&source=web&cd=6&cad=rja&uact=8&sqi=2&ved=0ahUKEwjngYjEjI_LAhXJp5QKHU_RApUQtwIIKjAF&url=https%3A%2F%2Fwww.youtube.com%2Fwatch%3Fv%3DdVvEPTYrcXA&usg=AFQjCNGX0S4MG7wRegWhRyMGfAGzU3W9dg&bvm=bv.114733917,d.dGo
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That was the clip Derek, I could not easily re-find it as the actual firing is a long way into it.
The recoil is virtually instantaneous, allowing for the sound / light effect as you say.
What it interesting is that the barrel dips shortly after firing, probably starting to return to its loading elevation. The sheer scale of the flash and smoke would be difficult to reproduce without pyrotechnics.
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https://www.youtube.com/watch?v=43gBsxijkU4
http://www.pmbdt.co.uk/HOMEPAGE.html - maybe these guys can explain what is involved with the pyro aspect, license etc
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C-3PO: That is the Portsmouth Model Boat Display Team, I have watched many of their awesome displays.
However they do use live pyrotechnics, and have all the relevant licenses for gunpowder and public displays. Incredibly professional and 'must see' if you get the chance, but definitely comes under the caption "Do not try this at home."
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I would generally concur that the recoil happens quite fast but believe it would be visible with a gun that weights about 100 tons. As has been reported the puff of smoke afterwards denotes on British guns the breach has been opened and a jet of compressed air used to blow the remaining smoke and fumes out of the barrel.
The gun then returns to its loading position. In general it was quite possible to load at any angle but the cycle for loading was typically 30 seconds or so for a big gun and it proved easier to bring the gun back to a fixed position to reload.
On British ships this was all controlled by hydraulics basically working off a pressurised ring main which was in turn pressurised by hydraulic pumps in turn driven by reciprocating steam engines supplied by steam from the main engine boilers.
In terms of simulating this in model form I have always felt the increased complexity of a recoil would outweigh the reliability particularly as 30 feet away you really can't see it. Fun to do but in my opinion not necessarily conducive to creating the simulated effect we are all seeking on a repeatability basis.
With Iron Duke the concept is simple enough, plastic box with smoke generator, pump the smoke out the barrel. In the adjoining barrel use a very bright LED and all connected to speakers for the sound.
The devil is in the detail but I have a number of experiments on going to validate the system for Iron Duke. I have built a number of similar test systems and they all worked to an acceptable degree so the theory is valid, but they all leaked smoke everywhere which is the problem.
It sounds easy to say just put a valve in but the actual construction of airtight valves of say 8mm (for the gun barrel) and 40mm (for the PC fan) is proving challenging. If you move to compressed air (Air gun propellant) then there are other issues such as flammability and making/breaking high pressure air pipes and the volume for the air reservoir. It adds complications in different directions. I'm a believer in simple rugged systems that work all the time, every time.
One of the problems is that you can only get so much gas flow (smoke) through an 8mm" tube and beyond a certain unknown pressure there is no advantage in going higher. Does the design of the neck of the gun pipe make any difference? This is part of the reason I've decided to fire 5 shots at a time in a proper salvo. A single shot may not produce the volume of smoke but pretty sure 5 at a time will be effective!
A conservative estimate with ID is that I can fire 40 salvo's so basically 200 shots which means I can fight all day!! Ye ha!! I only need fog fluid and battery capacity to continue all day.
If anybody knows of a source for 40mm very powerful PC/server fans and/or has any ideas of how to make airtight valves do please share on the forum as if I'm successful it would be my plan to publish a "how to" so we can all do it!
I've tried flap valves and even a ping pong ball in a tube which was very promising but used too much air pressure. I liked the ping pong ball idea as it was fully automatic - I may give it another go maybe stacking the fans to increase the static pressure rather than increased airflow.
Most valved have a very positive action and need a fair amount of force to seal/unseal. I had event thought of a diaphragm valve (like a camera) - yes lets see someone make one of those! And then we have the problem of how to operate the valve - solenoid perhaps etc. This is all where it gets both interesting and challenging at the same time. Hours of work to find there is a fundamental problem in what you were building - more stuff in the junk box!!
I'll keep at it as I'm convinced the method is sound
Sorry, long post here but its an interesting topic
Cheers
Geoff
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Geoff: I greatly appreciate your taking the time for such an interesting and constructive description, and in hearing about your research work on getting the smoke effect. That's about 30,600 yards further than I've got O0
Silly thought, but how about a 1" dia syringe type piston to push the smoke through the barrel.
I will continue to watch your Iron Duke build with even greater interest
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No thought is silly, I had thought about a syringe but for the volume it needs to be about 8" long and 1" or 2" wide plus the plunger and the drag to push it in and out plus the engine and gearbox to move it.
This is both the problem and fun in trying to develop this system, sometimes the practical engineering side intrudes!
The reason I went for the fan solution is that I can suck as much air in as I need and don't have to store it anywhere so no pressure vessels.
I have thought about using one larger fan linked by tubing to all of the turrets as a possible solution but haven't got to the point of developing a prototype. It has some advantages as one large fan will be easier to construct and more efficient than five smaller fans, also one valve etc.
Please keep the ideas coming!
Cheers
Geoff
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Fair enough Geoff. I am sure you looked at countless possible scenarios. Good luck with your gun trials - most interesting :-))
On recoil distance, the British 15" Mk I is stated to be 46 inches, or 12.5 mm at 1/96 so is enough I believe to be visually worth replicating if I can.
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I've heard of some people simulating the recoil on a crank, like a piston in an engine if that makes sense. The speed can be adjusted by the voltage.
Good luck
Cheers
Geoff
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Geoff, for your valve, maybe a rotary device would be acceptable, they can be leak-proof and require low energy to operate, think of model aircraft throttle bodies, or a higher pressure application as on a tap-loading air rifle , in both instances this design of valve has high reliability. For shifting more air than cooling fans, would a suitably sized and regulated EDF unit be suitable? Good luck with your scheme, it's always fun experimenting!
Trevor
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The best smoke effects could only be produced by a chemical reaction such as black powder detonation and or another reaction just to create smoke, and as both of you have mentioned requires a liscense for the former, while the latter is illegal due to the compounds required.
If only you could remember the make and provenance off your toy Sherman Bob, this might have provided prototype systems to back engineer.
The issue with syringes of such size though similar in scope to model sub flotation chambers, is where to put them. While both hulls are quite capacious due to their shape, there is competition for that space with drive train, power and control systems.
I wondered when hearing how tinny the digitised sound can be wether the speaker could be muffled with some foam to remove the higher frequencies of sound and add a bit if base to what is to be the sound of very large guns firing!
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R&D evolution. Well, it was worth a try for under ten Quid. However the 'replacement' toy tank firing mechanism is far to big and bulky to adapt into a 15" turret at 1/96. No dimensions on web page, so was a shot in the dark based on size of tank.
(http://i1143.photobucket.com/albums/n626/bobkiralfy/HMS%20Abercrombie/gun-mechanism_zpsj5hjuml9.jpg) (http://s1143.photobucket.com/user/bobkiralfy/media/HMS%20Abercrombie/gun-mechanism_zpsj5hjuml9.jpg.html)
Next up was the sound file. The usual small speaker proved nowhere near adequate for this low frequency high air volume sound. To do it justice a big bass speaker with corrugated cone base (to shift max air volume) might be needed, but they are far too big for a model ship.
Tried blowing cigarette smoke down a suitably sized brass tube. Not bad effect. I wonder if a motorised syringe with a flap valve to draw and expel might work? ( He is getting desperate here ! )
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As a thought whilst it may not fit inside a 15" gun turret would it fit inside the barbette below the turret and pipe the smoke out?
With real ships there were several levels within the barbette which rotated with the turret so it follows full time practice.
Any chance of taking it apart so we can see what's inside?
Cheers
Geoff
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What about all these new e cigarettes units - any good for source of smoke
Don't know the first thing about them but just a thought
C-3PO
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What about all these new e cigarettes units - any good for source of smoke
Don't know the first thing about them but just a thought
C-3PO
I'm playing with one of these at the moment.
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Musical e-cigarettes - amazing
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The best smoke effects could only be produced by a chemical reaction such as black powder detonation and or another reaction just to create smoke, and as both of you have mentioned requires a liscense for the former, while the latter is illegal due to the compounds required.
Disco smoke machines use smoke fluid. You can get this on Amazon, maybe even Maplins.
You could consider building a smoke machine in the bowels of the ship, and then generate smoke in some kind of chamber, maybe pressurised.
You could then consider running pipes to each gun barrel and using a system of RC of valves to allow the smoke to escape on demand.
Just thinking out of the box.
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That's exactly what I'm doing with Iron Duke, but the devil is in the detail! Have a look at the ID thread and there is a picture of a working prototype.
Cheers
Geoff
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Next up was the sound file. The usual small speaker proved nowhere near adequate for this low frequency high air volume sound.
Have your tried building a base box?
Sorry if you already know this. Try putting your small speaker onto the front of a cardboard box, and hear the difference. Also for a bit more base, try mounting the speaker backwards.
Give these a go. If you get a more pleasing result you can build a sound enclosure into your hull. Something like this,https://www.youtube.com/watch?v=WHV0KgqpXPc but smaller obviously.
Or this, cut in half.https://www.youtube.com/watch?v=PpCwoYOZi2o
You can also buy small speakers for iPhones that are single speakers with huge base response. Like this one. http://www.amazon.co.uk/Kinivo-ZX100-Portable-Rechargeable-Resonator/dp/B004HHICKC/ref=sr_1_5?ie=UTF8&qid=1456485759&sr=8-5&keywords=mini+speakers (http://www.amazon.co.uk/Kinivo-ZX100-Portable-Rechargeable-Resonator/dp/B004HHICKC/ref=sr_1_5?ie=UTF8&qid=1456485759&sr=8-5&keywords=mini+speakers)
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E2V,
Re e-cigarettes - How do they work - is it as simple with these things that the liquid is "burnt" on a hot element or atomised and the liquid is bought into the burning/atomising chamber when you suck on the cigarette?
If so would it be possible to remove the device and place in a gun barrel perhaps?
C-3PO
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Thanks all. :-))
The problem with big bass speakers is they need a large aperture to move air waves outside, constrained inside a model ship most of the effect gets baffled out.
The turret platform on a low draught big monitor is at the top of a very tall barbette to contain all the gun and munitions handling. Too much weight high up is a problem.
The e-cigarette element still needs to be 'drawn' then expelled to generate vapour.
I shall keep beavering away, hoping the magic light bulb will appear above my head. O0
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Thanks all. :-))
The e-cigarette element still needs to be 'drawn' then expelled to generate vapour.
I shall keep beavering away, hoping the magic light bulb will appear above my head. O0
I was thinking of some kind of bellows that draws the "smoke" in then then forces it out
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Re e-cigarettes - How do they work - is it as simple with these things that the liquid is "burnt" on a hot element or atomised and the liquid is bought into the burning/atomising chamber when you suck on the cigarette?
If so would it be possible to remove the device and place in a gun barrel perhaps?
C-3PO
I find this bloke great viewing! - https://youtu.be/H5QtGerJ_tI
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I was thinking of some kind of bellows that draws the "smoke" in then then forces it out
A suggestion I have nicked from a fellow member building a 1/6 scale Mk1 Tank. Use the speaker box as your bellows...
It is not perfected yet though ok2
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Same guy Martin suggested but a different video
https://www.youtube.com/watch?v=iC878A2puH0
I think this looks promising. All you would then need is a electronic device to trigger the sequence - an Arduino could flash/flicker an LED / kick a servo to simulate recoil / trigger mp3 sound and turn on/off the e-cigarette & pump all to the timings of your choice
C-3PO
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Thank you Martin for both the recoil servo link video, and the e-smoke instructional video.
Thanks also to C-3PO for the second video (was an 'up next' from Martin's) showing a possible solution using a micro pump. Food for thought !
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I think there are some very good ideas here but think the problem with the air pump may be two fold:
1) They appear to work on 240 volts rather than 12 volts - can you get a 12v version?
2) The volume of air they pass seems to be quite low so the smoke may just kind of drift out the barrel rather than shoot out.
Item 2) is one of the issues I have with my design for Iron Duke. If you then use a higher pressure air pump you get back flow but I'm very interested to see how this works
Cheers
Geoff
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Here's a picture of the prototype system for ID using a PC fan as the air pump.
Cheers
Geoff
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Pump is 6volt - the guy states that he only uses it a 2v
It may be that the sequence needs to be turn on e-cigarette and then some microseconds later when it's started smokin the pump kicks in at 6v then reduced quickly to 2v so you get a plume of smoke.
Search eBay "Vacuum Pump Small DC" - may be aquarium pumps would also be worth investigating
C-3PO
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What - not enough smoke :)
https://www.youtube.com/watch?v=8iDJAhVrdA8
Only draws 150-300 amps according to video spec
C-3PO
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Eeem, we're only trying to simulate gunfire, not the sinking of HMS Indefatigable at Jutland.
Extreme overkill, as quoted in The Italian Job . . . "You're only supposed to blow the bloody doors off!"
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You can't have too much smoke to simulate gunfire! That would be about right for a full salvo at 1/96 scale!
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Can you actually believe a human would want to do this to themselves
On a different note - if the 6vdc pumps are worth investigating you could always chain a few together with Y adapters to get more airflow - although the video guy suggests running at 6v was to much - not exactly sure why - maybe just thin smoke
C-3PO
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Many thanks for all the positive and helpful responses. I am going for a change of plan on this.
I am dropping the pellet firer, too large, and it's the effect I am more after.
I love the simple servo actuated recoil on the video clip Martin posted.
The second video link from C-3PO showing vac pump and E Cigarette looks to have significant possibilities, and is compact. I bought a couple of slim disposables to run trials with.
Can I fit a small 'ultra bright' wide angle LED in the barrel without interfering with the smoke?
Good luck with the fan system Geoff. They do blow Misters very effectively but not sure how they would work in a 'closed' chamber system.
More news as trials progress.
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How about these for recoil - video seems to use a 12volt one but I found Solenoid 5volt £5
https://www.youtube.com/watch?v=azZ3yuNLfj0
https://www.youtube.com/watch?v=4GhIPVjKwX0 - this one includes free sounds effects :) - would be great for a machine gun - mount a sounding board behind the solenoid!
More kick than a servo
RE THE SMOKE
This video shows the strange behaviour of the smoke in a cup at about 2minutes 30 seconds in ( https://www.youtube.com/watch?v=nQ6oISHtRAA ) etc. It might be possible to start smoke production into a holding chamber, then switch on the air pump(s) at 6v to get a quantity of smoke to be expelled in a burst , the air pump then drops to 2 volts to give a slower supply.
Would be neat if you could fit and RGB led in the barrel - you could then have a blue or white or yellow or, or, or what ever you want flash. You can power an LED with a PWM signal (not receiver PWM signal) so you can vary the brightness in the sequence as well.
Bob what is the likely internal diameter of your gun barrel?
C-3PO
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Bob what is the likely internal diameter of your gun barrel?
C-3PO
4 mm at 1/96. May have to make it a tadge larger. Hopefully the recoil can be made to generate some 'pulse' pressure.
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Maybe fibre optic cable to get illumination near the end of the gun barrel?
Maybe you could also get away with adding some discrete very high intensity LEDS disguised near the gun - the eye may not be able to determine the fact that the flash did not come from the gun barrel - especially across the water.
C-3PO
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I think its easier than that, Given that any turret has two guns and would typically fire one at a time you can put a very bright LED in one barrel and use the other for the smoke ejection. Again what I plan to do with Iron Duke.
From any distance the brain will see a flash, a cloud of smoke and hear a bang and add it all up to gunfire.
Fibre optics are a good idea if you can't get the LED at the end of the barrel, or use acrylic barrels as the light transfer medium.
Geoff
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Some months ago there was a thread where a bloke in Holland used the works from a disposable camera to produce a very clean flash and a sharp crack. I saved the photos (See below) but can't seem to find the thread.
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Found the thread but further back than I thought. 1st post on Warships R&D on 1st Dec 2013. Photos/plans missing as are the YTube films but it may be worth a search further if the text whets your interest.
Tony
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If the LED were mounted in a piece that also acted as a diffuser in the muzzle then you would kill two birds with one stone Bob. The diffuser/mount could also be used to route the wires away from the vapour and possible moisture issues with shorting.
Re the fluid used in E Cigarettes, you can get non nicotine solutions for those who are on the last leg of their giving up smoking and just have the residual 'Habitual act of smoking' to give up after the need for nicotine has abated sufficiently.
I reckon the E-Vaping mechanism is the safest and most effective creator of mist for its size and weight. It just needs sufficient draw and a method of projection to make best use of the vapour before it condenses toomuch to be of use.
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take a look at mrrcsound website. I have the v4.1 soundcard, fitted in a model P51 Mustang, its utterly amazing, with engine start up, shut down, throttle sensitive, then, hook ups on the board for gunfire, linked to flashing leds, and so on.
What you will want to look at are the speaker replacements, called TT25 transducers. They attach to the body of the plane, or boat hull, and this becomes the speaker, so no bulky magnets etc. Do a bit of googling, youtube etc. He does soundcards for boats, tanks etc, but primarily its for planes, with a load of engine choices. Not cheap, but you get what you pay for. Extensive thread on rcgroups, under vendors. I have a couple of sound units in boats, and would definitely use the TT25's in place of speakers if I did it all again
http://test.mrrcsound.com/
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take a look at mrrcsound website. I have the v4.1 soundcard, fitted in a model P51 Mustang, its utterly amazing, with engine start up, shut down, throttle sensitive, then, hook ups on the board for gunfire, linked to flashing leds, and so on.
What you will want to look at are the speaker replacements, called TT25 transducers. They attach to the body of the plane, or boat hull, and this becomes the speaker, so no bulky magnets etc. Do a bit of googling, youtube etc. He does soundcards for boats, tanks etc, but primarily its for planes, with a load of engine choices. Not cheap, but you get what you pay for. Extensive thread on rcgroups, under vendors. I have a couple of sound units in boats, and would definitely use the TT25's in place of speakers if I did it all again
http://test.mrrcsound.com/ (http://test.mrrcsound.com/)
Wonder if the TT25 would work with the Action P100?
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Wonder if the TT25 would work with the Action P100?
Sadly not
The P101 Amplifier requires an 8ohm speaker and these are 4
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Transducer/Exciter - http://y2u.be/j2SqHMZ2Dao
MrrcSound transducer image looks very similar to this £3.59 https://proto-pic.co.uk/2w-4-ohm-electrodynamic-exciter/ - only £2.10 from Kitronic
Think the first 2 items are 8 ohm https://proto-pic.co.uk/search.php?search_query=surface+transducer
This is an alternative https://www.youtube.com/watch?v=4qxakHiJ7CM
https://www.kitronik.co.uk/catalogsearch/result/?q=exciter
I wonder if this has any detrimental effect on glued joints after a period of time?
C-3PO
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Wow. I thought my initial query would bring up some existing / proven methods for achieving this without pyrotechnics such as gunpowder. Instead it has become a Think Tank for many exciting ideas and possibilities. Thank you everybody. So much to consider.
With two close fitting barrel tubes I am sure a 12.5mm recoil could be arranged on the outer which briefly exposes the diffuser mounted LED 'bulb' in the inner. How much that would restrict the smoke flow is subject to trial of course, but could be significant without high pressure.
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Hi Bob,
Indeed a good collection of inspiration - sure it stirs up some long lost boyhood stuff to do with smoke, flashes and bangs!
Another link for your development melting pot - This company "TCS Micropumps" seem to make "real" pumps compared to eBay items. Not cheap but proper engineering - I found an Air pump 680ml per minute at 12PSI working at 3-6volts weighing just 30grams 'ish - I think ( based on nothing else but gut feel) that sounds quite a good spec (assuming I have read it correctly which is always a danger)
http://www.micropumps.co.uk/TCSD200range.htm
I have just ordered some of the sound transducer/exciters so I post my experience with them on here at some point
C-3PO
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While cheap cigar smoke would provide a drier and therefore more stable smoke, a nicotine free vapour fluid would be useable indoors should you have the urge to display it on the stand :} My concern with fog oil is wether it would leave an oily residue? Mind you, cheap cigar smoke will leave nicotine stains, so vapour fluid seems to tick the boxes.
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DIY nicotine free vapour fluid
https://youtu.be/MTI0CuPvOB0 (https://youtu.be/MTI0CuPvOB0)
https://youtu.be/4Xe4mXnvej4 (https://youtu.be/4Xe4mXnvej4)
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That's an interesting thought, Wonder if I could use one of those e-cigarette things as an exhaust smoke unit in my lifeboat? Would be quite easy to rig up a small fan to blow through it occasionally to produce a puff. Wonder how long they would last?
Craig.
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As an observation, whilst the e-cigarette fluid produces a significant cloud of smoke which is ideal for what we are looking for we should consider that in practice this is mixed with the air in your lungs (several litres worth I think) before its exhaled in the smoke cloud.
This was the basis, albeit using fog fluid, for my experiments with Iron Duke - the need for a mixing tank to mix the vapour/smoke with air to create the volume we are looking for and then pump it out the barrel.
It may be that this process is unnecessary if we assume the "raw smoke" is mixed sufficiently with air after/as it leaves the barrel.
Accepting that maybe a fish tank air pump can force it out the barrel which would add to the volume. I guess only practical experimentation would work.
Anybody out there with a e-cigarette they can try putting it into a narrow tube and blow very gently from the other end to see how the "smoke" behaves?
I have used fog fluid for many years and don't really find any residue on the model after usage - be warned though even though is "fog" it will set of fire alarms as a certain community centre will testify many years ago!!
I'm in the process of building some sample guns to see how they respond to production of fog in a confined space rather than a large space and will report back.
The bottom line is we need to produce a significant volume of smoke and eject it from the barrel.
Very interesting topic.
What other air pumps are available?
Cheers
Geoff
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"What pumps are available?" I am going to try my spare 'Sparkfun' 12V vacuum pump, not sure if this is the right model (looks the same) https://www.sparkfun.com/products/10398 (https://www.sparkfun.com/products/10398)
(You can get them in the UK if you google Sparkfun air pump)
It is quite powerful and shifts a lot of air / min. I use it to blow out the ballast tanks on my semi submersible HMS Polyphemus. Less than a minute to blow 2 x 1.3L side tanks.
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Bob,
Sparkfun pump - nice one spec 0-32psi, free flow 12-15 LPM - possibly branded as "Airpo" that should do it!
C-3PO
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C-3PO: It does have "Airpo" on its ID label, although I got it from Sparkfun. Shifts a heck of a lot of air at quite reasonable pressure.
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Guess it's one of these
http://www.alibaba.com/product-detail/Mini-D2028-12v-dc-air-pump_354079276.html
I was going to paste the manufacturers link but it contains the word j e s u s (without the spaces). If you type the jxxxx word on Mayhem and save it automatically changes it to LORD when you save
Give it a go - it's really quite funny
C-3PO
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Geoff's point about flow rate is the key I reckon to any successful system.
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I was going to paste the manufacturers link but it contains the word j e s u s (without the spaces). If you type the jxxxx word on Mayhem and save it automatically changes it to LORD when you save
Give it a go - it's really quite funny
C-3PO
Same happened to me when I typed in t o s s e r , as in bunting "idoit" - it auto changed to bunting idiot. (if you try it, you will find the word idiot has been spelled incorrectly as "idoit" {-))
Regards,
Ray.
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....and it's just happened again. Seems the only way to avoid this is to copy C-3PO and put spaces between each letter.
Sorry for jumping in on your thread Bob K.
Back on track now %)
Regards,
Ray.
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Transducer/Exciter - http://y2u.be/j2SqHMZ2Dao (http://y2u.be/j2SqHMZ2Dao)
MrrcSound transducer image looks very similar to this £3.59 https://proto-pic.co.uk/2w-4-ohm-electrodynamic-exciter/ (https://proto-pic.co.uk/2w-4-ohm-electrodynamic-exciter/) - only £2.10 from Kitronic
Think the first 2 items are 8 ohm https://proto-pic.co.uk/search.php?search_query=surface+transducer (https://proto-pic.co.uk/search.php?search_query=surface+transducer)
This is an alternative https://www.youtube.com/watch?v=4qxakHiJ7CM (https://www.youtube.com/watch?v=4qxakHiJ7CM)
https://www.kitronik.co.uk/catalogsearch/result/?q=exciter (https://www.kitronik.co.uk/catalogsearch/result/?q=exciter)
I wonder if this has any detrimental effect on glued joints after a period of time?
C-3PO
Ordered a couple for testing purposes with the P100 & P101 combination.
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Ordered a couple for testing purposes with the P100 & P101 combination.
E2V - excellent - we can compare notes - I went for the little 2w one and the big 25w one
Should arrive on the door mat today
C-3PO
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E2V - excellent - we can compare notes - I went for the little 2w one and the big 25w one
Should arrive on the door mat today
C-3PO
I went for the 2W and the 10 so should be interesting
Mine are going into this:-
(http://www.oldmodelkits.com/jpegs/Lindberg%20814%20Constsld.JPG)
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It may be possible that you can find threaded, refillable Co2 canisters and regulator from a paint ball gun.
This and a bit of creative plumbing and a Clippard MAV-3 valve at a servo could fire a burst of air.
Also a small can of "air duster", for computers could supply air pressure for your gun.
As for a talc or cornstarch gun, it just needs a "powder" reservoir to puff the air into to
agitate the powder. An exit hole and tubing to your gun barrel will give you a nice burst of "smoke".
However, I can't say how much of that talc or powder will settle onto your model.
Here is a quick assembly using an old rx bottle and small 3mm brass tube.
https://www.youtube.com/watch?v=ssX893soYXI (https://www.youtube.com/watch?v=ssX893soYXI)
:-)
.
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That looks pretty neat
C-3PO
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Thinking about, ... if you turn the "air" can upside down, you will get a burst of the
liquified gas, and that might work for a burst of smoke also. :-))
As for the talc gun (https://www.youtube.com/watch?v=ssX893soYXI) it might work better if I didn't have the air supply directly below the outlet.
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Gun Firing Control System
In development electronic trigger sequencer/timer to trigger events - concept working just needs polishing! The sequence is triggered from a spare channel on your rc kit.
C-3PO
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Talk air gun........
Umi......that is a most realistic visual representation :-))
It would appear that the can of propellant air/gas could be mounted lower down in the hull & connected to the talk venturi gun/s mounted in the turret via small bore flexible nylon tubing
Gun Firing Control System
C-3PO.. this looks impressive, although my take on the sequence is as per post #13 and is based on the speed of light over the speed of sound over the human minds ability to perceive what they do or don't see/hear
1 = flash
2 = sound [bang]
3 = return form recoil
The timing for adding smoke from the explosion is subjective dependent of the ordinance WW1 gun mounts being considered.....could be before or during the recoil
I have seen relatively modern warships fire live 5" projectiles at night, however this is a rather different scenario to the 15" projectiles of some 100 years ago ;D........Derek
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Hi Derek,
You may well be correct with the sequence in the real world.
The sequence here is being driven by a microprocessor running at 16,000,000 instructions per second. I have no idea exactly how many instructions are needed to step between "recoil" and "bang" but it's in the single 10's. Unless I introduce an intentional delay here my logic was to get the relatively slow electro mechanical recoil mechanism moving cause in a few nanoseconds after this the "bang" sound would be triggered as it's electrons would be racing down the cable to trigger the sound file.
At the end of the day as the sequence is software based you can cut, slice and dice the solution to do what you want.
I'll see if I can upload a video somewhere when it's a bit more polished.
C-3PO
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C-3PO........please understand I was not attempting to be critical in any sense :P.......when we view those 80 year old films of gunfiring ... I restate is all about our human minds ability to perceive what they do or don't see/hear
So when we scale this down, the time signature or time window is also reduced
There are certain functions or processes that defy a correct visual perception if correctly scaled
One of these is the rate of fire.... if scaled correctly these 15" scale turret barrels would be behaving like a Gatling gun in the rate of fire <*<.............
That is possibly one aspect that you may need to consider in some sort of time delay sequence
My mind has difficulty in even considering one or two instructions per second, let alone 16M instructions in the same period {-)
Please keep us posted with your work..... it is enlightening .......... Derek
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Using a phrase from one of my favourite blues musicians
"It goes something like this" - https://youtu.be/wC2MIffSL6I
Rough timings, in a repeating loop so you can see what's happening. Currently switching relays but final solution in the main will switch components directly
C-3PO
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Gun Control Firing System - Second rework
https://youtu.be/cC4vUqXaoWY
C-3PO
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Hi Bob have a look on the chapman steel and Hutchinson web site they produce very large scale square riggers such as hms suprise if you follow the links theres a chap called meatbomber who came up with a firing system which allowed it to fire full broadsdes, regards pete
p
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Hi Petesubman: I have been trawling links on the page, and indeed site, but so far not found reference to the 'meatbomber' article you mention. I will keep looking.
Bob K
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Meatbomber is active in the model waterplane world, you might find him on RCGroups.com waterplane pages. His nick-name derives from his profession as a pilot for parachutists.
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Sorry bob, try hms surprise fires her guns, regards pete
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Goodness.....that certainly is impressive :-)) .... however the sound is more like a current day weapon.... being a loud high pitched crack, whereas Bob is after a lower pitched earth shattering blast noise...........Derek
______________________________________________________________
https://www.google.com.au/url?sa=t&rct=j&q=&esrc=s&source=web&cd=5&cad=rja&uact=8&ved=0ahUKEwiWpf7XtK_LAhXDHZQKHehHCVIQtwIIKTAE&url=https%3A%2F%2Fwww.youtube.com%2Fwatch%3Fv%3Dz0uqJWeUP48&usg=AFQjCNHAFXkV16FunDMFvLpMoGJkOqpIOA&sig2=oX-zz_ZqdfHo2iO0zrMzIg
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Very impressive indeed. However, that definitely looks like black powder to me, and alludes to the same in the text near the end of the clip. I need to simulate gunfire, not replicate it with gunpowder.
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I believe I may have solved the problem of simulated gunfire. Pictures to follow.
Geoff
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Rather a long post here but hopefully the pictures will also speak for themselves.
Over the weekend I tried a number of experiments regarding simulating gunfire. The basics are quite simple using a home-made smoke generator (Nichrome wire wrapped round a wick resting in a small bath of fog fluid) and blowing air and smoke/fog out of a barrel. Fundamentally this follows the principles I have been working on with Iron Duke but I wanted to re-validate the proposed system and process to see if there were areas for improvement.
First experiment.
Single barrel with a small container not much larger than the barrel containing the smoke generator – air supply is just blowing gently down a tube. The concept was to see if such a simple arrangement would produce a smoke cloud. Could it be that simple that vaporising the fog fluid in a relatively confined space would work? When it exits the barrel would it immediately mix with the surrounding air and provide the volume needed? I blew down the tube and smoke certainly exited but the volume was disappointing. A longer heat time did not improve matters.
Second experiment
Basically the same as the first but this time with a larger smoke container something in the region of three times the volume. The results were a significant increase in smoke volume so this would seem to be the way to go and may be sufficient to contain all within the turret structure. If the turret was airtight the whole interior of the turret could be used? This has some possibilities?
Third Experiment
I used the barbette under the turret itself as the smoke container which has greater volume still and this produced the volume of smoke as shown in the picture which I believe is adequate to simulate gun fire. I used a 15mm copper elbow feeding into a 15mm/8mm adaptor which was taped to a plastic barrel. The barbette is sealed and air blown through plastic tube. The pressure required is not high and may well work with a fish tank air pump.
I deliberately did not put any valve at the base of the gun. I wanted to see if this was really needed as maybe the smoke would stay inside until blown out. My conclusion is a valve is required as otherwise before firing the smoke tends to drift out which would spoil the effect.
Conclusions:
1) I think this is a viable approach and produces sufficient smoke and sufficient shots.
2) A puff of air is better than a gentle blow – the effect is more sudden.
3) A valve of some kind is needed at the barrel to stop smoke drift.
4) Current consumption is 5 amps on 12v. Three generators = 15 amps.
5) I need a single smoke generator on for about 8 seconds to generate sufficient smoke
6) Whilst the current consumption is quite high this needs to be set against 3,600 seconds in an hour so nominally 450 shots! (Assuming the battery can discharge at 5 amps). It’s not that simple in practice due to efficiency losses but the potential numbers are certainly attractive.
7) The smoke definitely needs space to form properly in the consistency needed but importantly the volume needed is nowhere as large as early trials had suggested, which means it can be smaller.
8) The barbette is about 3” wide by 2” high – plastic drain pipe connector.
9) After firing about 10/12 times the copper elbow was hot to touch, so more heat than anticipated, but I think this is manageable and no damage was caused to the plastic barrel which remained cool during the experiments. I think the copper was hot as it was directly over the element.
10) Using the barbette as the smoke container meant I could have a 15mm hole off center for the smoke to exit. Condensation on the copper proved negligible although some drops were formed at the end of the barrel. If the barrel is elevated then this may be reduced and just run back into the fog fluid bath.
One of the problems is to design an efficient valve that will seal at very low pressure and be easy to operate and sufficiently small. I have tried sliding valves (A plate with a hole in it which slides sideways to permit smoke flow through) and disc valves (A circular disk with a hole such as it rotates it aligns with a hole and again permits smoke to flow through). These worked to a degree but were complex to manufacture and prone to leakage and installation problems.
I have now decided to go a piston valve route – basically a brass tube with a hole drilled through one side to the other with another brass tube inside. If the inner tube is slid it will open a passage for the smoke to pass through. Experiments with this show they should be easy to build and operate and be quite gas tight.
The plan is to build a shared smoke tank underneath “A” and “B” turrets, one under “Q” and the other under “X” and “Y” with the piston valve(s) at the top of all three tanks all of which will be fixed to the underside of the deck thus simplifying smoke transfer to the rotating turret and barrel. Air supply will be through a single powerful fan blowing into a distribution pipe through ½” diameter plastic pipe to each of the smoke boxes again with a piston valve to prevent back flow.
Some thought will show this has to be an entirely separate part and installed in the hull albeit this will depend on the particular ship characteristics. The air connectors will be cone shaped and push through latex sheet with a hole in it thus providing an air tight seal to the smoke box. This method means only a single more powerful fan will be needed which could be easily modified dependent on system characteristics.
Operation will then be:
1) Smoke units on for 8 seconds
2) Open fan valve and switch on fan
3) Simultaneously switch off smoke generator and open gun valve for 2 seconds to eject puff of smoke from all five turrets, so a proper broadside.
4) Switch of fan and close both valves
5) Repeat as required.
I plan to use a slow cam to operate various micro switches in sequence and believe the whole system to be fairly simple to build and maintain.
Simplistically if I have three generators working at once they will draw 15 amps. Assuming the battery can supply this current drain how many shots will it give us? If I have a total battery capacity of 15 amps/hour this is 15 amps for 1 hour or 1 amp for 15 hours. 15 amps per hour = 3,600 seconds. Divided by 28 (3 generators x 8 seconds = 24 seconds equivalent duration) = 150 broadsides. If battery capacity is doubled then we get 300 broadsides. Again simplistically if we then times this by 50% for loss of efficiency etc we get 75 broadsides or 150 broadsides respectively. Modern batteries should readily be able to provide the current requirements – for those of you who are better at batteries do please comment if this is generally correct. “Single” shots from “A & B” and “Q” and “X & Y” could extend the effect considerably.
I hope to have this ready for Iron Duke for Wicksteed Park in May if all goes well.
The end point is to create a system which can be readily built and operated with no pyrotechnics and importantly can produce a high number of shots.
Sorry, a long post here but thought the gunfire developments may be of interest.
Cheers
Geoff
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Eureka Geoff! I read your paper (well that is what it is) on the experiments and thoughts leading you to this effective conclusion and the effect is very satisfying visually.
Without particulates I do not think brown cordite colouration will be possible, and this would need another mechanism alongside the smoke generator. But as it goes, your system looks to provide as good a non chemical cloud as I have seen.
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Wow Geoff. I had to read this through very carefully several times, but I believe you are on to a winner.
In my case I have just one twin turret, in a taller barbette. To be able to repeat the effect more than once is enough for me. No need to lay a sustained bombardment. I trialled the air pump on an e-cigarette but not much smoke was sucked through. Maybe the recoil mechanism could double as a shut off valve.
Thank you O0
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Looking for something different but related to model ships, I found this link http://www.modelshipmaster.com/products/modern_navy/ (http://www.modelshipmaster.com/products/modern_navy/) with a turret and smoking guns! I am trying to find more information for you from it.
Fair enough, they are a commercial concern and understandbly would keep this development for the benefit of their customers but the image dose show the plumbing and some wiring.
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Thank you for your comments and thoughts. I have seen the pictures of the Bismark turrets and yes its a commercial secret but shows it can be done in a small scale.
I'm convinced if we all share our knowledge we can come up with a workable system as we all know different parts so if we can work together we can figure it out for the benefit of us all.
I'll update as the experiment continues!
Cheers
Geoff
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Geoff,
This looks really good - very impressive. Can I ask what power source/battery you are using? Also do you just wind the coil or are you winding it do give a calculated resistance?
C-3PO
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I was using a 12v 7ah battery (gell cell) so nothing special. I used nichrome wire from an old hair-dryer and really the length was a guestimate. It depends on how thick the wire is but you want to aim for glowing red like an electric fire. Any hotter and it will oxidise and burn out. Longer and thinner is better as you have more heating area. No more than 5 amps current as otherwise it can get unmanageable in terms of battery capacity.
I don't think its possible to generate brown smoke without using pyrotechnics which defeats the whole point of this experiment. I also am not convinced we can ever get the sudden ball shaped cloud of smoke as this is really the result of very high pressure gasses exiting the barrel. We could probably get something close if we used compressed at at about 200psi to blast the smoke out but I'll leave that for others to try!
None of the proposed components are too critical or too difficult to engineer. A lathe is always useful but is not necessary.
Next steps:
I'm planning on building a sample box to fit under "A & B" turrets to see how it all performs pumping smoke out of two barrels. I'm anticipating it will work fine as the smoke box will of necessity be larger. I'll report back soonest
Cheers
Geoff
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Geoff,
Some additional info to chuck in the pot - might be some useful bits
It seems that it's hip in the vaping crowd to wind your own coil to get the maximum cloud. single, double, staple.....
Have a look at this - http://www.stealthvape.co.uk/wire/kanthal-sample-pack and what a selection of wire! http://www.stealthvape.co.uk/wire
They have an online coil calculator - http://www.steam-engine.org/coil.asp?testreferer=StealthVape
And loads of these on Youtube - this is just one example - https://www.youtube.com/watch?v=E-sjzc_DahA
So you may be able to enhance the coil for more smoke. On the other hand depending what liquid you are heating maybe just a quicker fire!
C-3PO
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Thank you, I'll have a look and digest.
Now a question does anybody know of the best (read loudest) sound generator as I need to develop something for the gunfire sound. Cornwall Model Boats have a sound module for a 16" salvo which can be operated by a micro switch so seems ideal but the speaker is only 2" so I am uncertain of the sound volume.
Does anybody have any experience with this module, or similar, and how loud, or any other suggestions.
Thanks
Geoff
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Meant to add I have the space for two speakers up to 4" diameter.
G
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Geoff,
Do you want an off the shelf sound or would you want to load your own?
Also do you want to be able to trigger bang 2 whilst the bang 1 is still sounding? ie you fire another gun quickly after the first and both sounds play out to their end
C-3PO
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Off the shelf should be fine but it depends on the difficulty as my IT skills are limited. I intend to be firing broadsides of 5 guns at a time so ideally a staggered rippling blast lasting say 2-3 seconds would be best but a single blast would probably suffice.
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Of preference I would prefer a 'standard' smoke generator element, rather than trying to make my own which could be more dangerous than gunpowder (ship aflame or infinite current). I am still not sure if the two part tubular sleeve valve is for the barrel exhaust, inlet to the barbette, or both.
I have a replacement 'Sparkfun' air pump on order as the 'spare' I trialled may have been water damaged. Maybe I can get the e-cigarette idea a stage further. If I suck on it then blow it down the tube it seems quite effective.
If rotary 'petal' valves were not successful it could be very tricky getting the turrets to rotate and guns elevate whilst still retaining reasonable internal pressure?
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Making your own element as its just the same as used in the commercial smoke units - it really isn't an issue as you use a non flammable wick which sits in non flammable fog fluid - it basically boils it off creating the smoke. If the element gets too hot it just brakes without any drama. If there was a direct short for some reason this is protected by an in line fuse.
Fire could be caused if you used any type of oil rather than fog fluid and years ago that was a problem. To the best of my knowledge none of the commercial units uses anything other than fog fluid even if its called "smoke oil".
I have used this system of smoke generators in a number of models for years and never had any problems. If the container is made of plastic card its necessary to use an alloy heat shield over the top of the element but otherwise its really no problem.
My solution of the two part tubular valve would be one at the base of the gun and the other just outside the fan, The concept being the fan valve opens the fan kicks in and pressurises the whole system (we are talking very low pressure here) and then the gun valve opens and the smoke is ejected in a puff.
The valves can be located in any convenient location but the gun one must be between the barrel and the smoke box.
Experience showed that when I used a PC fan into the smoke box smoke was forced back past the fan hence the need for a second valve to stop this.
Hope this clarifies.
Geoff
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Home made Smoke Oil
Does this make sense - any comments? - Found this on instructables - so I is not me it's the author :)
What you need
- Glycerol, Glycerin or Glycerine (same thing)
- Distilled water
- Measuring jug
- Container to store solution
Step 2: Where to get your ingredients from
Gylcerol, Glycerine and glycerin are the same thing. It is easily and cheaply obtainable from your local chemist. Either behind the counter or on the shelf, you will find it next to the throat medicines as this is one of its uses -- eases discomfort from harsh coughing. It will also make you more than regular if you drink too much of it!
Distilled water should be easy to come by. Places like Halfords (England), or outlets which sell car consumables should sell this. At a push you can get away with dionised water. The aim here is to get a water that is about as free from lime and other impurities as possible.
Step 3: Method
For high density smoke...
Make a solution of 30% glycerol. The remaining 70% is made up with the distilled water.
For medium density smoke...
Make a solution of 20% glycerol. The remaining 80% is made up with the distilled water.
For low density smoke...
Make a solution of 15% glycerol. The remaining 85% is made up with the distilled water.
-------------------------------------------------------
For purposes of clarity, should I want to make a solution of high density smoke fluid I would simply pour all of the glycerol into my container. I would then fill the empty glycerol bottle with water and pour that into my container. I would then do this a second time to achieve (roughly) a 30/70 mix of glycerol to water. You don't have to be exact with this.
-------------------------------------------------------
Once you have poured the required amount of each liquid into your container, shake for a few minutes to ensure that the two have completely mixed. You now have your own smoke fluid at a fraction of the cost of commercial smoke fluid.
Step 4: Preservation
You may find that you want to keep your smoke fluid for a period of time. If your container is clean, and your smoke machine doesn't already have traces of mould in it then you should be ok for about a month. Less if you have made up a solution that is less than 30% glycerol.
Anything past a month and you may want to add a preservative (antibacterial agent) to extend its life. Given that this solution will eventually be aspirated and breathed in, it is important that you don't add too much of something, or the wrong thing for that matter!
I would recommend simply adding 2-3 drops of bleach to every litre. This will keep any chance of infection down and will still be safe to people in the concentrations given out when it's used.
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That looks like what 'Big Clive' on Youtube was using to make vaping fluid. You have the benefit of not needing to worry about the flavour additives that can have wick damaging oil in it. Glycderine is cheaply available from chemists like Boots.
https://www.youtube.com/watch?v=MTI0CuPvOB0
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I think I will have a go and report back on my findings - all experiments will be conducted outside so currently rain stops play!
Regards
C-3PO
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Geoff,
Have a look at this - is this the type of thing you would like to achieve - https://youtu.be/t9P3ZJBE53g
In this example there are 5 separate sound files each individually triggered. Up to 14 files can play simultaneously. You might just be able to make out the previous bang has not finished as the next one starts.
The final sound file needs some echo/reverb added as it ends very abruptly. Sorry the quality isn't great partly YouTube compression but also the fact that I fried my little amp earlier - this sound is recorded playing through non bass friendly headphones.
C-3PO
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Close but a little sharp as I need more of a rumble. Google Iowa firing 16" gun and there is a u-tube video of a salvo of three - almost perfect!
Cheers
Geoff
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Ram in the US make a 16" gun sound unit:
http://www.ramrcandramtrack.com/ramdemos/ram81/ram_81demo.html
I think they are marketed as Admiralty Electronics in the UK, available here:
http://www.model-dockyard.com/acatalog/Admiralty-Electronic-Accessories.html
http://www.cornwallmodelboats.co.uk/acatalog/admiralty_sounds.html
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Geoff,
Have a look at this - is this the type of thing you would like to achieve - https://youtu.be/t9P3ZJBE53g
C-3PO
Very impressive!
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These are exactly the ones that I'm most interested in because I can trigger them with a micro switch but they only have a 2" speaker. Does anybody have any experience as to how loud they actually are? For example could you hear it at 50 feet away on the pond?
Thanks
Geoff
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They are pretty loud, but you could always put a bigger speaker on if you have the space (just make sure the impedance is the same). I have the 16" gun sound in my Yamato and the destroyer whooper in my Solebay.
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Geoff,
Very happy to be proved wrong but I would suggest you would be underwhelmed by the sound for a couple of reasons. The 2" speaker just won't move enough air and also the sound file I listened to doesn't seem to have much dynamic range- more whoosh than thump
I am no expert here but I have played with sound files and boats for several years and even with an efficient 2x20w audio amp into two decent quality 4" speakers unless the sound is ported well to the outside world it can be hard to get the result you want.
You are pushing the envelope with your smoke development - I don't think this solution will sit well with that - sorry!
C-3PO
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The 2" speaker size was my concern as well. On ID I have room for a 4" speaker under the forward superstructure. I have left the back at each side open so sound can get out. I also have room for another 4" speaker under the aft superstructure. The deck for this is wire mesh so should provide room for the sound to get out. I had, to a degree, thought of the problem or porting the sound during construction.
I've also seen some mini Bluetooth type speaker units which seem to give good sound but again I'm somewhat old school and figure large speaker = loud noise but I know with todays technology this is no longer a hard and fast rule.
Thanks
Geoff
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Larger speakers make more noise?
Kind of true but a lot depends on quality and power of the speaker and amp.
Amps being the same, quality of speaker is important.
Output for 50mm speakers available on Amazon is range 0.5W to 5W.
Output from 50x90mm oblong speaker 10W
Output from 100mm speakers varies from 8w to 100w.
Other consideration, will the sound unit put out a pre-amplified signal? If so you can put in a bigger amp.
Other things to consider.
Frequency response, you don't want all tweet or all woof. If you can find a 100mm co-ax speaker it might be a good option. These usually only come in pairs, unless you can find an old car stereo with one duff speaker in the charity shop, or free ads paper.
Weight. Anything from 200-500g for a nice quality speaker in this range. Placement of this weight may be fixed and so the other ballast needs to be planned around it.
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Agree 100% with co-axial - I use these
SONY XS-GTF1027 - About £32 pair on eBAY - IMHO - a great option
And I use this amp - http://www.maplin.co.uk/p/adafruit-stereo-20w-class-d-audio-amplifier-max9744-a54qn or I did until I fried it - another one on order
C-3PO
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Now that seems very interesting, so if I got the 16" gun sound module I could then connect it to the Maplin amplifier and power two larger speakers?
How do I tell if the gun module is pre amp or includes an amp and what difference does it make. If the gun module has an amp why can't I still just connect it to the Maplins amp and boost the signal further? Electronics are not my strong point here!
Thanks
Geoff
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I should have Googled before I posted. The answer of course is an amplified output going to an amp input will overload the input side and fry it so it won't work. does anybody know if the gun sound units are amplified. I can't talk to the seller given the time but may call them tomorrow.
Thanks
Geoff
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Could you use the hull it self as a speaker? I am sure I have seen or heard of flat speakers somewhere. therefore you coulduse the hull which is much larger and might give you some bass quaity to get the deeper tones of large bore guns firing.
Could one of these work? https://www.youtube.com/watch?v=YvQzxcYZuss
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The exciter/transducers do work quite well when attached to virtually anything however anything loose in the boat/ superstructure etc lets you know it's there and can be quite annoying as it rattles away!
In theory the admiralty sound module amplified output could be matched to another amp input but it is not ideal, it may be possible to pick up an output at an earlier stage/lower level of the sound production
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It might be worth asking on an electronics or hifi forum.
OR
Ask one of the guys at your local Maplins (if you have one) if they know a guy who can. Probably worth the investment.
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Google
speaker output to line input
not sure the little sound card will have enough output to drive this type of device.
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not sure the little sound card will have enough output to drive this type of device.
Not well versed in this topic, but.
Isn't that the pre-amplified signal?
Won't the amp then do the work?
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I think Geoff wanted to plug the amplified sound card output into another audio amp
These "speaker output to line input" are a dirty fix to take a amplified speaker level signal and drop it to a line level one so you could plug it into another amp.
Don't really see them much these days they get used where you don't have a line level output only amplified speaker signal on the source device.
"high-level to low-level signal converter designed for devices that do not have dedicated low-level outputs"
eBay have some for a few pounds so may be worth the gamble
C-3PO
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The speaker with the 16" gun sound is 0.2W 8ohm, but it doesn't mention anything in the instructions about amplifiers. The best answer would probably be to ring Ralph at RamRC in the US and ask him (he doesn't do email).
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May I offer a couple of comments, especially having built amplifiers back in the days of Practical Wireless magazine. Do not connect the low Ohm power output into the highly sensitive input of another amp, you could blow it up, probably both of them. Ideally you should look for an amp with the right output, with input suitable for the sound file signal. You can get pre-amps but matching them to power amps can be more complications than you need.
I would avoid using the hull as a 'sound box' as the low frequency vibrations are likely to damage fine detail over time, and could even crack more substantial structures such as ribs or deck mountings. Anyone who has experienced a vibrating motor or worn double U-joints will know what I mean. Having a fine mesh grille in the deck to let speaker sound waves exit the ship will be essential IMHO.
To properly replicate the sound will be a tough call, and probably end up as a compromise. A real Iowa Class broadside will probably be audible for up to 40 miles. Attaining 1/96 of that distance is virtually impossible. Bearing in mind that the vibrations of such a discharge will be more apparent than the actual 'bang'.
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Hullo Bob.....yes...in real life, a firing of the 16" Iowa Class would be a night time visual at the speed of light, however the audible sound at 40 miles away may only just awaken you >>:-( from your sleep
40 miles = 40 x 2240 = 89600 ft
speed of sound = 1126 ft/sec
89600 divided by 1126 = 75.57 seconds after the firing [if you had good ears] :P
Derek
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So the sound audible roughly 75.56 seconds after the flash then. :-))
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Well TT, yes but only in this [non scale] example only...however it highlights previous points that .................
We see the flash.......then we hear the sound......[in that order].........
The calculations of sound pressure level effect to distance is a far more complex
Derek
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My point was, that whilst the aim might be to get a loud(ish) bang from up to 50 feet, there is no way that you can replicate the massive sound pressure wave from a scale 40 miles. The timing does not really come into it as it becomes 'perceived' effect (what the observer might find reasonable to expect from the lake side). ie: an interval of over a minute between flash and bang would be unaccountably long to a lay observer. I would aim for a couple of seconds between flash - smoke to bang, even if the ship were on the far side of the lake.
In practice most might miss the flash, only having their attention drawn by the bang, then seeing the smoke largely dissipated.
It is the perceived effect we are after. The Portsmouth MBC display team have flash / smoke / bang simultaneous, and it looks OK.
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It is the perceived effect we are after. The Portsmouth MBC display team have flash / smoke / bang simultaneous, and it looks OK.
It may be that a delay is not accepted by the brain, which perceives the 50 feet and not the scale distance. The brain can be funny like that.
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Hmmm
40 miles = 40 x 2240 = 89600 ftspeed of sound = 1126 ft/sec89600 divided by 1126 = 75.57 seconds after the firing Derek
I thought there were 5280 feet in 1 mile which would make this closer to 188 seconds
C-3PO
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yes...a monumental calculation cockup with flat batteries using my abacus :embarrassed: ....
The 16"/50 calibre Mark 7 – Iowa Class gun mounts had a muzzle velocity of between 2240 & 2500 ft/second ..depending on the charge loaded
So interestingly :o...a projectile fired from one of those mounts would take approx. 75 seconds to travel the 40 miles and explode, yet, we still would not have heard the gun fire for another 112 odd seconds ....
Thank goodness for the speed of the flash otherwise we would all be asleep {-)...... Derek
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Might be better to stop this nonsense O0....
The American 16"/50 calibre Mark 7 mounts could fire approx. 17 miles, the British 14" BL Mark 8 mounts could fire approx. 14 miles
'So interestingly ...a projectile fired from one of those mounts would take approx. 75 seconds to travel the 40 miles and explode'
Suffice to say lets have the firing with the flash first & the bang sometime later %) ... Derek
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I have found a sound module by "Sense Innovations" ESS ONE. Its not cheap at £80 but appears to give 20 watts output. Perhaps more importantly I have heard and seen one in operation and it is loud! Problem is you download the sound you want and its really designed for trucks and cars so:
1) I'm not sure I can down load a broadside
2) I'm not sure I can operate it just by connecting the power with a micro-switch
More investigation needed but it is really quite small about 5" x 2.5" x 1.5" complete with speaker
Geoff
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Geoff,
Called a Wav trigger i.e. can trigger .wav sound files
Have a look at this product - it plays standard .wav computer sound files.
https://www.sparkfun.com/products/13660
It has an on-board 2w amp or an standard headphone socket audio out which you can plug into an amp
It's a clever bit of kit and can be used in several ways. In simple terms you load your files onto the little SD card and then there are 16 triggers pins. If you want to make sound 5 play you simple make pin 5 +5v (so you could trigger with a micro switch) and the sound will play
This example is a piano - if you consider it's just a set of switches(the keyboard) triggering sound files
https://www.youtube.com/watch?v=UUkcs_XL5x0
C-3PO
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1 x 5 LITRE Vegetable GLYCERINE / GLYCEROL
£18.50 inc delivery from Amazon
Smokin!
C-3PO
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Thought I'd chuck this one in the melting pot
I am currently going for the CO2 option to drive the smoke. Lots of thoughts/concepts already in my head - most will probably not work in the real world!
This product uses a Paint Ball/Soda Stream/Disposable CO2 cylinder and after the regulator has a 12volt solenoid. This may be to big/heavy but interesting none the less. I already have a 12v solenoid valve that works up to 150psi so will use this (paired with a regulator)) in the short term
http://www.co2art.co.uk - based in Milton Keynes
C-3PO
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Very interesting. What are the physical dimensions of the pressure vessel and do you know how many two seconds burst of gas it will provide?
Cheers
Geoff
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My new Sparkfun vac/air pump finally arrived today. These are quite powerful units.
However, after coupling up an e-cigarette to the 'suck' end with heatshrink and applying 12 volts it failed to pump any visible smoke via tubing to the 'blow' end pipe. Rather disappointed really as it only takes a light 'draw' to extract copious amounts of 'smoke' a la normal function.
I was confidently expecting a heavy stream of smoke.
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Bob,
I am awaiting delivery of some kit, having dissected a cheap disposable e-cigarette I am surprised it makes any smoke at all.
I think the solution will be cheap and easy
I'll update you more when I have the result
C-3PO
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For a further update please see the Iron Duke thread.
Cheers
Geoff
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As far as E-cigarettes, It may be a battery issue, but use caution.
E-cigarette explosion.
https://www.youtube.com/watch?v=k1LjSuq0rk8
There's been more than a few occurences of faulty e-cigs.