Author Topic: Miniature naval guns (Read 2994 times)

KABAR2 · « **Reply #30 on:** August 30, 2009, 06:09:16 PM »

You may want to check with kappullen up in the sale adds he is using a CNC to turn out cannon including a Carronaid,
he should be able to scale it down to your needs. look at his add the last photo is of a Carronaid still in the machining stage,

DanLew · « **Reply #31 on:** August 30, 2009, 06:09:44 PM »

Not stainless steel, 1018.
What is 1018? Does it machine more easily than brass or SS?

I agree with Kaber, about rocket igniters.
Glo plugs are $3.50 and I have some that have at least 75 shots on them and still going strong.
Rocket igniters I've seen are $.50-.75 each and one time use. That would get real expensive. I shoot 9 guns in one braodside, and do that many times on an outing. And igniters would have to be replaced and re-connected every time. I load the guns while mounted on the boat. It already takes too long with the ladle load method. I'm still going to try the cartridg aproach with the glo-plugs.

Also since swab won't work flood the bore with a syrings and then swab
Too much trouble on the boat. Plus I don't want all the mess to get on the model. Again, I really don't have a problem getting off at least ten shots w/o misfire if I use the flash paper "primer" .

Double D · « **Reply #32 on:** August 30, 2009, 06:15:33 PM »

I just looked at that picture again...the sails all look aback! Do they sail or do they have hidden motors?

1018 is a mild steel and machines much easier than brass or SS.

DanLew · « **Reply #33 on:** August 30, 2009, 06:45:37 PM »

Sails are aback. I put on the brakes to fire the broadside across his stern. Ray may have been trying to come about.
They sail - no power. Wind in the sails and rudder is all that's used.

Here's another pic - all 1/24th scale SC&H models - a schooner, a brig and a frigate. We're heading in for a break...

Cannoneer · « **Reply #34 on:** August 30, 2009, 11:23:21 PM »

DanLew,

I really enjoyed the vid of your ship on the water, firing its guns; that's a terrific model.
Last year I tried a black powder substitute called "American Pioneer," and while I'd never use this stuff in my pistol again, it did make thick (more than BP) white smoke, and there was a lot less fouling, but you'd be losing some dB's in the sound dept., its not as loud as BP.

GGaskill · « **Reply #35 on:** August 31, 2009, 12:50:30 PM »

1018 is a mild steel and machines much easier than brass or SS.

12L14 may machine easier than brass but definitely brass is easier than 1018.

DanLew · « **Reply #36 on:** September 02, 2009, 02:30:42 PM »

Here's what I'm going forward with (pic). At this small an internal barrel volume, the approx. 15 grain BP charge, and a soft foam wad, I think it should be plenty adequate. The glow plug will likely be the weak point.
I've found that compressing the powder with the foam wad, and then pulling the wad forward as shown, seems to give quite a bit more smoke than if the wad is left tight against the charge. The foam wad travels only about 5 ft.
I fired my existing test barrel (3/8" sched 40 brass nipple) with a 2X load and a tight felt plug and it was fine. Loud report, but not as much additional smoke as I thought there would be.
So I think I'm in pretty good shape with the new double walled sched 80 barrel design.
Sched 80 materials are ordered. I'll post new gun and firing vid when built.
Thanks for all the input. Got me to a much better place in barrel margin of safety.

dan610324 · « **Reply #37 on:** September 02, 2009, 02:50:54 PM »

that one looks really good

isnt that the reason for all of us to be here , to help and ask questions when we need

just a pity that not anyone so far have been able to help you with a ideas on how to create more smoke

isnt it anyone there who got an idea ??

Cat Whisperer · « **Reply #38 on:** September 02, 2009, 03:11:52 PM »

Quote from: GGaskill on August 31, 2009, 12:50:30 PM

1018 is a mild steel and machines much easier than brass or SS.

12L14 may machine easier than brass but definitely brass is easier than 1018.

12L14 is very easy to machine - BUT - (take a look at the results of the Charpy Notch tests) is NOT a good material for cannons, where 1018 is. One of the criteria you should look at is the ability of the material to flex without getting brittle.

Double D · « **Reply #39 on:** September 02, 2009, 03:43:15 PM »

I don't know about in this small gun application, but in muzzleloaders and especially in muzzleloader made of such weak material like this the leaving of an airspace has been the source of burst barrels.

GGaskill · « **Reply #40 on:** September 02, 2009, 03:48:26 PM »

Probably should conduct multiple firing tests on a prototype before loading the gundeck with copies.

DanLew · « **Reply #41 on:** September 02, 2009, 08:59:52 PM »

DD,
Weak material???
I thought brass was one of the better materials to use for a cannon barrel. What is the measurement test to determine "good" material?
Red pipe brass tensile strength is >6000psi, SS about 7000.
For this short a barrel length and small charge, no projectile, and a foam wad that shoots less than 5ft and is undamaged after firing, I can't imagine that this new barrel design is a problem. I've used single layer sched 40 (thinwall) barrels for two years now with Pyrodex, trip 7 and now BP without incident. The feedback here got me to the double sched 80 (thickwall) barrel, which I feel good about. Now brass is too weak???

GG - I'll definitely build a test prototype before building others.

Victor3 · « **Reply #42 on:** September 02, 2009, 09:18:31 PM »

Just my opinion, but I see your design and load as being very safe.

Rickk · « **Reply #43 on:** September 03, 2009, 03:45:15 AM »

For my BB caliber naval gun I started out with a grade 5 bolt, cut off the head and threaded portion, bored the center and the fuse hole on my drill press,chucked the bolt into the drill press, and started shaping with a metal file.

For what it's worth a grade 5 bolt is only hard on the outside, and soft on the inside, so drilling the bore is pretty easy going.

Double D · « **Reply #44 on:** September 03, 2009, 04:06:03 AM »

Yes weak. You are dealing with material that can generate pressure far in excess of the the pressures your brass pipe can contain. You may not achieve those pressure with your blank loads and that is good. I suggest you do some testing.

Build a gun. mark a line with a felt marker over the chamber. With a micrometer measure the diameter of the barrel over the chamber, the diameter of the barrel right in front of the chamber band and over the muzzle. Also measure the inside diameter of the trunnion ring at 0-180 and 90-270 degrees. On the glow plug make a witness mark and a corresponding witness mark on the back of the barrel.

Now mount the gun as you normally do and fire this gun is say sets of 5. After each five shots measure your the references listed above. Disasemble the gun, clean and repeat the test for 20 shots.

You are looking for dimensional changes; expansion over the chamber, swelling in front of the chamber band, elongation of the trunnion rings, and stretching of the barrel threads allowing the breech plug to turn beyond the witness mark.

I really don't think you are going to have problems with your design. But you do need to test.

I think I would carry this one step further. Number each gun and record each guns measurement. Then after every shooting session check and record every measurement.

I am also a bit concerned about work hardening of the brass.

I only see two possible weaknesses in the design, the copper trunnion ring. Use brass its stronger the copper. The threads for the glow plag can stretch possibly fail.

We often cite "rules of thumb" here on this board, and one we use a lot is "over built is not bad" and steel would be better.

KABAR2 · « **Reply #45 on:** September 03, 2009, 04:06:53 AM »

Quote from: DanLew on September 02, 2009, 08:59:52 PM

DD,
Weak material???
I thought brass was one of the better materials to use for a cannon barrel. What is the measurement test to determine "good" material?
Red pipe brass tensile strength is >6000psi, SS about 7000.
For this short a barrel length and small charge, no projectile, and a foam wad that shoots less than 5ft and is undamaged after firing, I can't imagine that this new barrel design is a problem. I've used single layer sched 40 (thinwall) barrels for two years now with Pyrodex, trip 7 and now BP without incident. The feedback here got me to the double sched 80 (thickwall) barrel, which I feel good about. Now brass is too weak???

GG - I'll definitely build a test prototype before building others.

Traditionaly bronze not brass is used for gun making, brass tends to become brittle and eventually fail, you could test successfully
and have it work for years and on the 100th or 200th shot have it fail.

DanLew · « **Reply #46 on:** September 03, 2009, 07:02:47 AM »

Keeping a log of the barrel dims. is a great idea.
The copper tube is there as a negative bus for the firing circuit on a 9-gun bank of barrels. Pic is of the non-scale model set of firing guns. The other 9 are the model carronades.
The guns shown have probably been fired nearly 20 times. They are sched 40 brass pipe. That's why I appreciate finding this site - time to upgrade the guns! I think I'll be OK with the double layer sched 80 with the specific limited loads used.
Thje new sched 80 barrels should also fit into the scale model resin barrels. I'll work out trunnions on the scale guns when I get the new material in about two weeks.
Note that the scale model carronades, when test fired sitting unsecured on a surface, barely move. Ther is almost no recoil on these barrels when fired. Is that maybe because the barrels are so short?

Double D · « **Reply #47 on:** September 03, 2009, 07:28:25 AM »

Small guns, small charges, no projectile, minimal recoil.

DanLew · « **Reply #48 on:** September 03, 2009, 08:35:19 AM »

Measuring from the pic (taken from another post on this forum), these barrels don't even come close to the wall thickness equal-to-bore "rule of thumb", even at the breech, yet they seem acceptable to a number of knowledgable cannon folks.
So what makes these OK?
Just trying to figure out why there are still so many reservations about my 1/4" bore barrels.

dan610324 · « **Reply #49 on:** September 03, 2009, 08:48:19 AM »

maybe they got reduced chambers

GGaskill · « **Reply #50 on:** September 03, 2009, 09:44:47 AM »

The wall thickness equals the chamber diameter refers to the area that the powder occupies when the charge is fired. Muzzle wall thickness can be much less.

KABAR2 · « **Reply #51 on:** September 03, 2009, 11:29:13 AM »

You know this got me thinking some more.... and your guns are very similar to the squib loads

that are made in movie making where a shot is supposed to hit the door of a car or a wood crate, so a bullet hole appears

they don't use anything this fancy I copied what they do years back for a "D" day event on Long Island

my squibs were made up of clear plastic tubing, 3/8 ID with a rocket igniter hot melt glued in one end, the whole

thing was loaded with 4Fg powder and a card glued over the end. this was hot melt glued in a hole drilled in a sign,

the hole on the front of the sign was covered with Balsa wood and then painted when fired gave a convincing "Bullet hole" afterwords

I recovered the tubes all were still in one piece. with no sign of spliting, they were throw aways but proved sufficient for

the task they were given. With that said Yeah I guess your guns would hold up to their use.

Cannoneer · « **Reply #52 on:** September 03, 2009, 12:05:00 PM »

Quote from: Victor3 on August 28, 2009, 08:36:30 PM

In my opinion, what you show above should be fine. Only possible weak point I see might be in the threaded area if your glow plugs are aluminum. Even so, with blanks, it should be okay. With the small charge you'll be using, you're not likely to experience a catastrophic failure.

If anything, I think you might have the resin underlug break.

Quote from: Victor3 on September 02, 2009, 09:18:31 PM

Just my opinion, but I see your design and load as being very safe.

Allen, sometimes our pal Victor offers up an opinion that simply can't be honed to a finer edge. Sometimes!

thelionspaw · « **Reply #53 on:** September 03, 2009, 01:59:51 PM »

Boy! I hope that's over. The man has a teeny-tiny-toy and not something that is worthy of Krupp's labratory testing. Sometimes we just seem to catch the pass and really run with it.

rc

DanLew · « **Reply #54 on:** September 03, 2009, 02:09:58 PM »

Quote from: GGaskill on September 03, 2009, 09:44:47 AM

The wall thickness equals the chamber diameter refers to the area that the powder occupies when the charge is fired. Muzzle wall thickness can be much less.

Look at the pics. The barrels are the same diameter along the whole length. There is a slight increase in OD at thebreech, but the wall thickness is still nowhere near the bore dia.

Nevermind that. How about this. Victor3 and Kabar have it right I think. I just took a PLASTIC SODA STRAW!!!!!, which is 1/4"ID like my barrels. I pressed in a glow plug (no glue - just press fit). I loaded a standard load - flash paper primer, 15+grains BP and a foam wad. BANG and SMOKE. The straw is still perfectly intact!!!! Not even a sign of swell or heat damage. OK, test same barrel again. This time, lets really jam in a big felt wad. BANG. Straw is still perfect!!!! Third time. Bang. Straw OK. Hmmmmmm.
Dudes, my brass barrels will be fine. The "rules of thumb" don't seem to scale down. Methinks a single schedule 80 pipe with 1/4" ID and max L of 1.75" will be plenty on the safe side for my toy gun.
If you don't believe the above, I can post pics. BTW, I've just found that the Brit model builders use brass tubing, with very thin walls for similar cannons and have no problems.
I appreciate that you must give conservative advice. Thank you.

GGaskill · « **Reply #55 on:** September 03, 2009, 02:18:22 PM »

The wall thickness equals the chamber diameter refers to the area that the powder occupies when the charge is fired. Muzzle wall thickness can be much less.

My above comment was made regarding the barrels referenced in reply #48, not the guns for the sailing ship.

Double D · « **Reply #56 on:** September 03, 2009, 02:49:52 PM »

Quote from: DanLew on September 03, 2009, 02:09:58 PM

Quote from: GGaskill on September 03, 2009, 09:44:47 AM
The wall thickness equals the chamber diameter refers to the area that the powder occupies when the charge is fired. Muzzle wall thickness can be much less.
Look at the pics. The barrels are the same diameter along the whole length. There is a slight increase in OD at thebreech, but the wall thickness is still nowhere near the bore dia.

Nevermind that. How about this. Victor3 and Kabar have it right I think. I just took a PLASTIC SODA STRAW!!!!!, which is 1/4"ID like my barrels. I pressed in a glow plug (no glue - just press fit). I loaded a standard load - flash paper primer, 15+grains BP and a foam wad. BANG and SMOKE. The straw is still perfectly intact!!!! Not even a sign of swell or heat damage. OK, test same barrel again. This time, lets really jam in a big felt wad. BANG. Straw is still perfect!!!! Third time. Bang. Straw OK. Hmmmmmm.
Dudes, my brass barrels will be fine. The "rules of thumb" don't seem to scale down. Methinks a single schedule 80 pipe with 1/4" ID and max L of 1.75" will be plenty on the safe side for my toy gun.
If you don't believe the above, I can post pics. BTW, I've just found that the Brit model builders use brass tubing, with very thin walls for similar cannons and have no problems.
I appreciate that you must give conservative advice. Thank you.

Yes every Fourth of July we see these same and similar statements repeated....

Victor3 · « **Reply #57 on:** September 04, 2009, 12:21:31 AM »

"If you don't believe the above, I can post pics."

No pics required, DanLew.

KABAR2 · « **Reply #58 on:** September 04, 2009, 12:59:42 AM »

Either way If there ever was a failure I doubt anyone would be injured as the models are out away from the user and the general public,
the only real damage might be to the ship where they reside, and like any true fighting ship of the era, it's ships carpenter can make any
damage right. it would just add to the realism of the moment......

I know there is a great amount of time and money that goes into the building of such a fine ship but.........
If I ever got into this hobby more than likely I would rather face an opponent with our guns loaded to cause damage, it may be fun to shoot
blanks, but I would look at it as an experiment to see just what it took to either damage an opponent badly enough to end it or dis-mast their
vessel. the shot of your ship crossing his stern is a classic example of the type of murder and mayhem these ships of war could visit on another,
had that been a real contest you could have cleared a good portion of his gun deck and more then likely damaged his rudder placing him at your mercy.

carronader · « **Reply #59 on:** September 04, 2009, 03:02:16 AM »

hate to agree with a man who reminds me of my latin teacher but I'm with the lionspaw.