Author Topic: Ideas for a loud cannon or mortar (Read 2886 times)

firebuckeye · « **on:** January 12, 2007, 03:05:01 PM »

Hey guys hopefully this is an easy question. I did search awhile and got some good info but what i am trying is less involved. First of all I have a 4" diameter by 14" piece of brass. What bore and length would give me loudest boom. No projectile at all. I dont know if I want short and big bore or a longer bore better? Or can you direct me were to get info. I am not interested in making it look like a replica at all. I have no lathe skills yet so maybe that will come. Please any info is appreciated.

Brad

Cat Whisperer · « **Reply #1 on:** January 12, 2007, 04:17:08 PM »

Brad - WELCOME to the board!

You've posed an interesting question. There are many of us drooling over that piece of brass. What a cannon it would make!

I would think that it's big enough that it won't make much difference. If you keep the amount of material around the powder chamber at least as thick as the bore (powder chamber) diameter that's a good place to start. Brass isn't as tough or strong as steel would be and you might consider putting in a seamless liner for strength. But for just blanks? When you get up to larger sizes of bores you're burning a LOT of powder. I'd build it with about a 1" bore, just because I think that's a good boom for the buck.

firebuckeye · « **Reply #2 on:** January 12, 2007, 04:23:30 PM »

I live in Dayton and ther scrap yard has a few pieces of this brass. He is cutting me a deal since I am a fireman and its 2.00 a pound. the 4"x14" piece was 50 lbs. Any how I was wondering if money was not an issue on powder what would you do to get the biggest boom. I have had a 1.5 " bore cannon in the past that I after reading here, learned I was WAY OVERLOADING. Nonethe less I blew the bottom out of it. I was puitting like a 1/2 cup of powder in that I think.... dont really remember its been a few years. I appreciate any help.

Brad

Cat Whisperer · « **Reply #3 on:** January 12, 2007, 04:45:26 PM »

More noise than an 1-1/2" eh?

More noise requires more pressure and/or shorter barrel.

There IS something special about big bore! The mortar on the left is 4.55" bore shooting 4" PVC pipe (4.50" OD) weighing 7-1/2 pounds. It has a deep loud voice. Smaller bores have a sharper crack. Blanks in big bore require substanial resources in the powder deprartment.

Louder is ok, but after a certain loudness your eardrums meet in the middle - what point is there in getting louder than that?

Rickk · « **Reply #4 on:** January 12, 2007, 04:49:20 PM »

A one inch bore in a 4 inch barrel sounds almost indestructable (no one take me up on that please).

My 1 inch bore Dictator (much shorter than 14 inches) sounds like a 12 g shotgun and I don't really think I'm pushing the barrel strength at all.

For blanks, you can stay with 2F powder (easier that 1F to find locally no doubt)

firebuckeye · « **Reply #5 on:** January 12, 2007, 05:00:10 PM »

If you all think steel would be stronger I could gothat rout, probably cheaper. I want one that creates wind when it goes off. someone had a post about that and I am not sure on the bore were talking, but thats kind of what I am going for. 1 shot and thats probably it for the night. Who know maybe I will wish it was smaller but I really want to go big for now. Please everyone keep chimeing in.

Brad

Double D · « **Reply #6 on:** January 12, 2007, 05:26:15 PM »

Yes Brad welcome to the board, glad to have you.

I would go withthe brass and build a nice cannon. Later if you want to you can build a larger gun.

Even if you get the brass at a discount you are still going to have some money tied up in. You want make that money well spent. So don't get in a hurry. Do your research and them decide what you are going to make. Fireman don't make big money so unless you have a shop full of equipment or access to a shop full of equipment you are going to have farm some of the work out. It might take a while to build but it will be worth while if done right. Some thing like this can become a family heirloom.

If you need a cannon builder look at the top of the board for the Cannon Resource list an the first post is our Sponsors. Contact them and see what they can do for you.

Do not decieve yourself, if you build or have built a nice cannon out of this piece of brass, sooner or later you will want to fire a projectile. Or later when it passes on, someone down the road will want to fire a projectile. So build it for the heaviest possible use. The safety Rules of N-SSA and AA dictate a mimumum wall thickeness equal to the caliber of the gun. The maximum bore probably should be 1.25 after machining.

Without doing the math the guns that come to mind that you could build are a Danial King howitzer, carronade or a Mountain howitzer.

This piece of metal is also a prime candidate for a golf ball or billiard ball mortar.

Any of the cannons will give you a loud report, loud enough to serve the purpose. The mortar will be more muffled but a bunch more fun to especially with light reasonable loads. all these guns will have muzzle blast when fired. Build a proper foil wrapped cartridge and they will make all the noise you need. Bigger gun, bigger noise, bigger cost to make, bigger powder bill.

We have a whole crop of new guys coming on the board and we are glad to have you all. So I guess it's time to pitch Matt Switliks book.

Shooting cannons is not like shooting a big over sized muzzleloader. There is a completely different set of internal ballistics involved. Read up on cannon shooting before you acquire a cannon. Suggested reading is THE MORE COMPLETE CANNONEER By M.C. Switlik with selected excerpts from other artillery manuals
The book can be ordered from these two suppliers by clicking on these hotlinks:

GGaskill · « **Reply #7 on:** January 12, 2007, 06:15:36 PM »

14" long is a couple of inches too short for a half scale mountain howitzer even if you make the cascable separate and screw or weld it on. 3/8 scale is appropriate for the length but then you would be wasting an inch and a quarter of diameter of expensive material. I suppose you could make a two inch short version of a mountain howitzer if you aren't that concerned about prototypical accuracy. It would still look like a mountain howitzer, more or less. The top drawing is the shortened one, the bottom a normal one to the same scale. Sorry about the color used.

Rickk · « **Reply #8 on:** January 13, 2007, 12:10:29 PM »

GG... do original Mountain Howitzers have a sub-chamber?

firebuckeye · « **Reply #9 on:** January 13, 2007, 06:04:12 PM »

IVE decided on a mortar. So can some one please help with some plans. Also how is it you can get by with thinner barrels with a mortar.

GGaskill · « **Reply #10 on:** January 13, 2007, 07:07:54 PM »

do original Mountain Howitzers have a sub-chamber?

Yes. In full scale, 3.34" dia and 2.75" deep according to my drawing. Followed by another 2.75" long tapered section that goes to full bore diameter (4.62"). The sabot rides in the tapered section.

Also how is it you can get by with thinner barrels with a mortar.

The part that has to resist the high pressure is the chamber (loosely defined as the section of the bore containing the unfired powder charge.) As the projectile moves up the bore, the volume of the expanding powder gas increases which lowers both the temperature and the pressure of the gas. In a chambered piece (mortars and howitzers, typically), the gas expands into an area of much greater cross section which causes the pressure to drop much faster than in a straight bored gun. Since the pressure is lower, the walls can be thinner.

firebuckeye · « **Reply #11 on:** January 14, 2007, 03:11:46 AM »

And since the pressure drops quicker does it make it less loud? Can you fire blanks with good success or is something else besides a mortar more suitable for blanks? Thanks so far for everyones help.

Double D · « **Reply #12 on:** January 14, 2007, 05:22:09 AM »

The Mortar will sound more muffled. But don't be decieved. From where you are standing your cannon or mortar may not sound very loud but get in front of it...I use to work for a company that made muzzle brakes, you learn real quick working with muzzle breaks that loudness is partially determined by the direction of the muzzle blast and your position in relationship to the blast path.

The sound is a product of the velocity of the expanding gas as it escapes confinement.

Shooting blanks just for noise is no where near as fun as shooting projectiles at targets. But if you must, load the powder in a foil cartridge for cannons and follow Norms advice for mortars and put one cardboard wad over the powde chamber.

What kind of mortar do you want. Since you have a piece of Brass I owuld go for a Coehorn. Use any o the Cohorn plans up in the safe loads and Cannon Plans post and scale them to your piece of metal.

firebuckeye · « **Reply #13 on:** January 14, 2007, 05:40:39 AM »

I do want the coehorn. I want one just like CU CANNON or RICKK has in his avatar. I do not have any machining skills at all. Is there peopleout there thtat would machine this piece for me, even build the box? I also am thinking of going with a steel one for no so I can build it bigger, dont know yet? You mentioned projectiles are more fun, is there a safe projectile? I would be afraid of where it landed, even if shooting it out in the sticks.

GGaskill · « **Reply #14 on:** January 14, 2007, 06:15:43 AM »

And since the pressure drops quicker does it make it less loud?

Yes. You might not get more than a whoosh if you use a typical shot powder charge without a shot.

Can you fire blanks with good success or is something else besides a mortar more suitable for blanks?

The howitzer mentioned above would be better for blanks without using excessive quantities of powder but see below.

I would be afraid of where it landed, even if shooting it out in the sticks.

Why should you be more afraid of where the shot lands than when shooting a high power rifle? The issue is to know where it is going to land and making sure there is nothing there (except maybe a varmint or two) that can be injured by the falling shot.

If you truly want to make noise only and want a mortar, don't bore the barrel to full size. You can do a half scale Coehorn with a 1" bore that will be 6" deep which should be OK for noise making and can always be bored out for beer cans if you change your mind.

firebuckeye · « **Reply #15 on:** January 14, 2007, 06:19:20 AM »

I like that idea and thought I would do that. I want it to look big and massive but not all that big of a bore. Also I sent you a pm

jeeper1 · « **Reply #16 on:** January 14, 2007, 06:20:45 AM »

Quote

is there a safe projectile?

No.
Is there a less dangerous projectile?
Yes. Golf balls once they have lost most of their forward momentum and are falling.
Film canisters filled with sand are another.
I am waiting on a friend to get me a piece of 3 inch round steel to make a mortar to shoot the translucent white film canisters (1.375 bore) I have several hundred of. It will be a very short range affair, 100 yds max.

GGaskill · « **Reply #17 on:** January 14, 2007, 06:30:21 AM »

is there a safe projectile?--No.

To paraphrase Honest Bill Clinton, this depends on your definition of safe. In a properly constructed piece using an appropriate powder charge, any legal projectile would be safe from the perspective of not causing harm to the shooter.

There is the same exposure to the rest of the world with artillery shot as there is with any firearm; you have to be sure of your backstop and the path the projectile will take getting there. Even a blank load is dangerous if someone stands right next to the gun. If not punctured by a wad, then burned by the hot gasses.

As with any firearm (and many other things), some intelligence is required for safe use.

[I replied to your PM].

firebuckeye · « **Reply #18 on:** January 14, 2007, 06:34:23 AM »

I did not get your reply? Can you check or resend?

GGaskill · « **Reply #19 on:** January 14, 2007, 06:40:23 AM »

Check again.

firebuckeye · « **Reply #20 on:** January 14, 2007, 06:42:15 AM »

Thank You

Cannonmaker · « **Reply #21 on:** January 14, 2007, 04:04:02 PM »

When shooting the 1/2 scale 24 pd Corehorn Mortars with a blank I can get a real good report. I just pack the grass in good and tight. Soda Pop can goes up to 320 yds. at this range do check for low flying airplanes. I our area I have seen airforce planes lower than the hight of the projectial.

Rick

firebuckeye · « **Reply #22 on:** January 14, 2007, 04:26:14 PM »

Thats hillarious, couldyou imagine? I would tell thim it was a bird if they ever asked. Deny, deny, deny

Double D · « **Reply #23 on:** January 14, 2007, 04:53:12 PM »

Quote from: Cannonmaker on January 14, 2007, 04:04:02 PM

When shooting the 1/2 scale 24 pd Corehorn Mortars with a blank I can get a real good report. I just pack the grass in good and tight. Soda Pop can goes up to 320 yds. at this range do check for low flying airplanes. I our area I have seen airforce planes lower than the hight of the projectial.

Rick

Let me point out here that in town I would not recommend grass wads, they become projectiles. Where Rick lives--I was by there on the freeway last February running 7-8 hours behind schedule--Rick can get a way with it. His neighbors hear a faint rumble, look out the window to see if there are any clouds. If they see clouds , they know it's a thunder storm, no clouds it's Rick. They can't see his plkace, but they can hear his place.

Rick you really need to make a Round ball mould for that gun.

Santa Dave · « **Reply #24 on:** January 15, 2007, 10:37:21 AM »

Quote from: Cannonmaker on January 14, 2007, 04:04:02 PM

When shooting the 1/2 scale 24 pd Corehorn Mortars with a blank I can get a real good report. I just pack the grass in good and tight. Soda Pop can goes up to 320 yds. at this range do check for low flying airplanes. I our area I have seen airforce planes lower than the hight of the projectial.

Rick

This brings about an interesting mental picture: On post-flight they find a beer-can stuck in the airframe some where!
Dave

GGaskill · « **Reply #25 on:** January 26, 2007, 08:08:08 PM »

If you are really interested in noise only, you could consider a thunder mug.

Double D · « **Reply #26 on:** January 26, 2007, 08:35:14 PM »

Good idea George, then those of you insist on rattling the neighbors windows and setting off car alarms, might avoid arrest when the local cop drives by and only see you and your beer mug.

Cat Whisperer · « **Reply #27 on:** January 27, 2007, 04:40:17 PM »

Quote from: GGaskill on January 26, 2007, 08:08:08 PM

If you are really interested in noise only, you could consider a thunder mug.

That explains why my Dad always refered to the chamber pot as a thunder mug!

firebuckeye · « **Reply #28 on:** January 27, 2007, 05:30:29 PM »

Cat do you sell them? Or who does? What size bore are they?

Rickk · « **Reply #29 on:** January 28, 2007, 02:43:27 AM »

there are two brass original thundermugs for sale on e-bay at this very moment... owner wants $300 minimum each for them... a little steep maybe... no bidders yet and the auction ends today.