Author Topic: Recoil (Read 1320 times)

Farmer Dean · « **on:** March 11, 2007, 02:37:18 PM »

I'm new to this forum and this sport. I'm just slightly into the thinking stage. I have not started building anything yet, however I have ordered a Full Scale Six Pounder from Hern. I am going to put it into a yet to be build Navel Carriage. I have a farm shop and plan on building the carriage myself. I want to try and control the recoil in my cannon placement in my front yard. I have seen pictures in this forum using ropes and block and tackle to control recoil. My question: Am I trying to minimize the recoil or is it possible to eliminate it through massive restraints? Am I asking for trouble trying to keep this carriage still? I understand that I will be putting tremendous forces on the carriage, but if constructed properly can it hold? I see pictures of both carriage and barrel restrained by ropes, maybe this is how you do it. My intent is to fire mostly blanks, but I'm sure at some point projectiles will come into the picture. Is it my understanding that the recoil forces would be less with blanks than with a projectile? Thanks, Dean.

GGaskill · « **Reply #1 on:** March 11, 2007, 03:03:35 PM »

Am I asking for trouble trying to keep this carriage still?

Yes. Everything you do that reduces the distance moved in recoil increases the forces. This effects almost everything--trunnions, trunnion irons, cheeks, axles. You could make the carriage from metal which would likely make it strong enough (and the extra weight will asorb additional recoil) but that will increase the force on the trunnions.

Even blanks have recoil as something must be expelled from the bore to provide enough resistance to get a boom versus a whoosh. While the recoil is less than with a shot, it is still there.

What's the problem with recoil anyway? You can lessen its distance by making the firing surface graded uphill. That should be enough to dispense with the tackle.

Rickk · « **Reply #2 on:** March 11, 2007, 03:57:57 PM »

A couple inches thick layer of sand in the recoil area will help bit. Remember that they successfully fired these things on smooth planked ships. A more resistive surface (like sand) will not stop the initial recoil (which is good), but will dissapate the force and reduce distance.

GGaskills idea about an uphill grade sounds doubly good... it will slow it down and also make it easier to move back in place.

Tropico is the naval cannon expert... he was traveling... not sure when he will be back.

I'm planning on a naval style gun with one of Hern's Carronade barrels myself this spring. Havn't ordered the barrel quite yet, but I did put in an order already for enough white oak to build both the naval carrage and another Coehorn.

If you don't have wood yet, and are planning on getting it right from a mill, get it asap to get some drying time on it. To do it right you will need a couple years at least. I know I won't be able to wait that long myself. I have a 14 foot box cube van with a translucent top that doesn't get used much this time of the year. The oak will go in there for a while. The transparent top keeps it pretty warm in there... sort of like a solar heater.

Will Bison · « **Reply #3 on:** March 11, 2007, 05:16:46 PM »

Most of the recoil (the hard recoil) takes place before the shot leaves the tube. Probably measured in miliseconds The rest is just inertia. As soon as the projectile leaves the bore, recoil stops. Inertia makes the gun move after the shot. The initial inertia is generally not measurable except with high speed video.

The "After Travel" can be slowed down with ropes, chains, sand and ramps.

Double D · « **Reply #4 on:** March 11, 2007, 05:49:40 PM »

In the olden days before I discovered Switliks book I used the N-SSA quideline of 2 ounces per inch as the load for my one inch cannon shooting a cylinderical slug that weighed about 7 ounces. I would drive stakes in the ground and attach a block and tackle to the stake and the truck to control recoil. If I didn't my 65 lb or so cannon became a secondary projectile. When fired I had the triple block pulled up tight. The recoil pulled the block open and the pully system acted as a recoil dampening system. The gun wasn't tied down solid. The gun could recoil. But it also wasn't flying over backwards tearing the gun up as it tumbled over the ground.

I got the idea after reading some where that even though everyone thought that the block system was used shipboard to pull the gun back in battery, it was also there to keep the gun from recoiling across the deck and out through the opposite bulkhead or bulwark when fired. They were not fired loose on a deck. They had to be control from recoil and they had to be control from the roll of the ship. I fired a couple hundred rounds over 20 years using that heavy load and this block and tackle system, with no breack downs.

The pictures above were taken the last time I used the heavy loads. The bottom picture taken in full recoil. All pictures were taken pre digital camera

I now use the load data from Switliks book 185 grs. Fg and 1/4 oz. round ball. And, I still set up the the block and tackle system. The gun still recoils, but no where near as much.

Farmer Dean · « **Reply #5 on:** March 11, 2007, 06:27:26 PM »

Now it makes perfect sence to me that life will be better if the carriage is allowed to recoil a bit. Everything will have less stress. The sand and incline are both good ideas. Back in the olden days, like in this picture, what do you think was going on? Were these cannons held tight to the bulkhead, or were the ropes somewhat slacked to let the cannons recoil? Those wooden wheels on a wooden deck couldn't have created much friction, so when carriage came to the end of a couple of feet of slackened rope, it must have stopped with jolt. The forces must have been extreme. Any comments?

Farmer Dean · « **Reply #6 on:** March 11, 2007, 06:38:37 PM »

Double D; I know what a block and tackle is, but honestly have never had the need to use one. When you say the recoil 'pulled the block open', what do you mean? There's no drag involved other than the rope paying it's way through the block system? You relied just on the friction created by the excess rope moving through the block? Thanks for helping me understand this principle.

moose53 · « **Reply #7 on:** March 12, 2007, 05:31:29 AM »

One thing you may not have thought of is the effect of the shock wave on the house .Both me and my friend have been baned from shooting close to our homes again.I broke all my moms bud vases and my friend knocked all his wifes Hummel figurines of the wall. And we only had 1/2 size guns.

Double D · « **Reply #8 on:** March 12, 2007, 05:50:49 AM »

If you look closely at my pictures you will see the blocks pulled up fairly close to each other. In the bottom picture you see the gun in full recoil and the blocks pulled apart or open from each other.

Pulley physics was long enough ago for me not to be able explain it but it has to do with ratios of the length rope, total distance travel, number of blocks and weeight distribution. http://www.howstuffworks.com/pulley.htm . The best way to see how it works its get a multiple gang block and tack, pull it closed, then grab each block and try and rip them apart as fast as you can. It's difficult.

In the case of the carronade in the other picture they have great heavy ropes to restrain these heavy smashers at the apex of the recoil. The guns need all the help they can get. The block and tackle an are still there. You can see one end hooked to the ring bolt on the bulkhead and the other hocked in the side of the truck just above the rear wheel. The block and tackles main purpose is to pull the gun back in battery, but also serves to restrain the gun in rough seas and it dampens recoil.

Farmer Dean · « **Reply #9 on:** March 12, 2007, 06:34:46 AM »

O.K. Double D, I see now. At first inspection I did not notice the second block and tackle at the stake. I understand the principle.

Now about shockwave. My installation is only 15 feet from my house. The barrel will be exactly perpendicular to the house (obviously, muzzel away). Do you think I will have any potential damage to windows, etc. in the house? I have no experience with firing, so therefore know nothing about shockwaves. I know out in front is a danger zone, but don't know any rules of thumb for behind the barrel as far as possible damage.

Rickk · « **Reply #10 on:** March 12, 2007, 07:07:17 AM »

You may want to have a place further from the house to actually shoot it.

I saw a 6 pounder at a civil war re-enactment vibrate a car enough to set off it's car alarm several hundred feet away.

seacoastartillery · « **Reply #11 on:** March 12, 2007, 07:12:00 AM »

In addition to the friction of the ropes going through the block and tackle as described by Double D, you also might consider the more refined Marsilly Carriage. It is restrained during the recoil impulse just like the 4-Truck Naval Carriage, but it also gets some of its recoil retardation through friction with the deck by action of the large wood "foot" at the rear of the carriage upon the deck. Increased pressure on the foot is provided by the "preponderance" of the tube and a slight shift to the rear of the trunnion placement in the carriage. If it can control a 100 Pdr. Parrott Rifle as pictured, it must have been fairly efficient. Just one more option.
Regards,
Mike and Tracy

[img width= height= alt=image hosting by https://www.gboreloaded.com/mhp/]https://www.gboreloaded.com/mhp/images/jurnan54/cwp48a.jpg[/img]

Photo courtesy Library of Congress, American Memory Collection

moose53 · « **Reply #12 on:** March 12, 2007, 09:29:45 AM »

The shock wave can be very powerful . But you can try it if you remove any breakables from the walls and start with very light charges . I was using blanks for a new years demonstration in a 1.65 cal naval gun pointed away from the house. It won't take long for you to realize how far away from the house you need to be.

Farmer Dean · « **Reply #13 on:** March 12, 2007, 04:49:24 PM »

Hey Seacoast, thanks for the picture, I like that idea of the giant foot.

Moose: I think I will hold off building that 'installatuion' right near my house until I test fire a few rounds a little further away. Thanks for the heads up.

Tropico · « **Reply #14 on:** March 12, 2007, 05:49:35 PM »

I Am Back

Not too much I can add to this other than I like recoil....., I live for it ! ! !
I cant live with-out it

Actually it does soften the stress to the carriage., Double D definitely has it covered with the rope and tackle system ., George as well.

Double D · « **Reply #15 on:** March 12, 2007, 07:30:51 PM »

Even with the Marsilly Carriage the block and tackle is there and you will get a dampening effect when this is opened under recoil. My gues that withthe big shoe at the back block and tackle with abe used for training the gun also.

Who was it, Dom who was looking for a design for a pivoting elevator...there it is on the Marsilly Carriage. Bottom of the elevator screw is a pivot point.

rusty barrels · « **Reply #16 on:** March 16, 2007, 05:33:49 AM »

I don't think you would have to worry much about recoil on a heavy navy carriage in grass or sand and a 850lbs barrel, it's the blast that might a problem for your windows. I've witnessed guns on sailing ships being fired on a smooth deck and they didn't seem to recoil much with a blank load and they were not tied very tight at all, and they were not as big as yours is going to be.

GGaskill · « **Reply #17 on:** March 16, 2007, 10:02:37 AM »

One other thing to consider if you are planning a naval truck carriage is that the small wheels will dig into a dirt setting and cause the gun to tumble wheels up. The wheels need to be able to roll to prevent this; use a hard deck (plywood, concrete, etc.) of some kind.

Farmer Dean · « **Reply #18 on:** March 16, 2007, 11:02:59 AM »

RB: You think there might be enough of a shockwave behind the implement to shatter a window? I have no idea; I've never been behind or near a cannon going off.

GG: Here's what I'm thinking about doing: Building a Marsilly like Carriage with a rear foot, placing it on a concrete pad with a slight incline and installing a dual block and tackle assembly from the front of the carriage to heavy wall steel pipe in the ground in front. My thought would be that the block and tackle would provide resistance and help keep the carriage from flipping over. Comments?

GGaskill · « **Reply #19 on:** March 16, 2007, 11:20:15 AM »

That ought to work fine as long as the concrete is as smooth as possible.

Artilleryman · « **Reply #20 on:** March 16, 2007, 11:42:30 AM »

Another idea (I think some of this is in a previous post) would be to build a wood deck on a slight incline. This should control the recoil, and make it easier to put it back into battery. Then if you need to move your shooting site it should be a relatively easy task to move the platform (some disassembly may be required). Full service loads with 6pdr field pieces usually only recoil 5-8 feet on dirt.

The best bet is to get a sheet of 3/4 plywood for a platform, take the gun and plywood to a safe place, and fire a few test shots. With that information you should be able to plan accordingly.

Double D · « **Reply #21 on:** March 16, 2007, 06:09:14 PM »

Quote from: GGaskill on March 16, 2007, 10:02:37 AM

The wheels need to be able to roll to prevent this with a hard deck (plywood, concrete, etc.) of some kind.

It will still tumble on smooth hard surfaces...ask me how I know

Farmer Dean · « **Reply #22 on:** March 16, 2007, 06:20:06 PM »

I'll bite DD, I bet you have a story that I know I haven't heard. I'm on the edge of my seat.

Double D · « **Reply #23 on:** March 16, 2007, 07:50:49 PM »

No edge of your seat stuff at all. Just put down a sheet of plywood and fire. Of course this was in the pre Switlik days and I was using the formula found in the muzzleloading Artilleryman of 2 oz per inch of bore. Must of missed the part about this was for bores larger than 2 inch.

Now lets see... 7000 grs in a lb divided by 16 is 437.5 grs time 2 is 875 grs....yes I use to have some recoil issues and until the tackle was added it was tumble and roll time. What is really interesting is my carriage withstood the abuse. Switlik says max load for a 1 inch bore is 185 grs.

You gotta love 4140 for barrel steel.

Cannonmaker · « **Reply #24 on:** March 16, 2007, 08:34:17 PM »

DD wrote:
Now lets see... 7000 grs in a lb divided by 16 is 437.5 grs time 2 is 875 grs....yes I use to have some recoil issues and until the tackle was added it was tumble and roll time. What is really interesting is my carriage withstood the abuse.

Been there, done that. The intention was to check the integrity of the carriage.

Allways glad to see another sunrise.

Rick