The cannon pictured in my last thread is a copy of another very similar cannon. In the pictured one, the trunnion mounts are welded onto the frame. The other cannon has the same mounts but I have yet to anything with them. In consideration of the rendering height and comments made on the last pictured cannon, I believe that this type of mount would offer me room to install shocks on both sides and have the mounts articulate on the axel . hope that made sense... Ideas?
How do you put shocks on a cannon?
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kBob
Member
The "shocks" on modern cannon you are thinking of actually work in both directions via a set of valves in a piston head. Not likely auto shocks alone would be that good of an idea. You really don't want the gun going back into battery as fast as it went out. Think, You have your spades dug in. Barrel comes screaming back and stops, then snaps forward so fast the gun leaps forward out of position.
Honestly I think your best bet if you insist on firing a projectile from this thing is to scrap that carriage and go with something lower and more traditional and just accept the gun recoiling back with each shot. Just be sure it has someplace to go when it jumps back other than over someone or something.
Personally I would want St. Barbara, in the flesh, wearing body armor, standing between me and any home built cannon firing projectiles.
-kBob
Honestly I think your best bet if you insist on firing a projectile from this thing is to scrap that carriage and go with something lower and more traditional and just accept the gun recoiling back with each shot. Just be sure it has someplace to go when it jumps back other than over someone or something.
Personally I would want St. Barbara, in the flesh, wearing body armor, standing between me and any home built cannon firing projectiles.
-kBob
25cschaefer
Member
I would use a couple of McPherson struts, shocks with coil-over springs. Let me know how it goes, I have a few in the planning stages.
ironworkerwill
Member
Recuperator? Looks like you'd have plenty of room. The more inline with the bore the less binding will occur. Maybe centered on the barrel on both sides rather than under.
Officers'Wife
Member
If you want to have fun with it. Design a tube with a standard piston set up full of water and a return spring on the cannon. That way when the cannon fires it will spray water to the side then the intake will be slowed by resisting the water flow into the piston.
I'm thinking of motorcycle shocks in the back. One on each side and springs in the front. I'm going down to a motocross dealership to learn about how their shocks work. I like the in-line-with -the-barrel approach but not the finished look. Thanks, I keep ya'll posted.
Gordon
Member
Well I know alot about shock absorbers and some about cannons. Normal shocks don't really have any springs and dampen in both directions. An additional outside coil over spring is designed to support the vehicle weight, really not what you are looking for. What you are looking for is a hydraulic cylinder with an accumulator which will return the shock at a metered rate. I think on your cannon a couple old garden tractor sized bucket cylinders with accumulators hosed in with an adjustable bleed back valve would do what you want. The barrel would be dampened to the rear with a one way valve opened to the resevior and when the recoil impulse is over the bleed back filling the cylinder would be at a slower rate.
BCRider
Member
Some of the old time fixed guns used parallel links with shock absorbers. The modern stuff uses gas charged inline sliding shocks.
The pistons are certainly using different valving ports for the compressio stroke to control how much recoil goes into the carraige and a different more restrictive set for the return stroke.
One option is to use mountain bike shock absorbers if you go with a parallel link setup. The amount of travel is lower on these but if positioned correctly in a parallel link setup it'll work well.
Or you can use gas charged automotive shocks. The gas pressure will ensure a return stroke even without an external spring. If you need a spring then look at motorcycle fork springs for a smaller sort of size. And in fact a single motorcycle fork with spring and damping intact might just work perfectly for you. The ones of dirt bikes have about 7 or 8 inches of travel. Spring is already inside and the compression and rebound damping are both adjustable on the better ones.
The pistons are certainly using different valving ports for the compressio stroke to control how much recoil goes into the carraige and a different more restrictive set for the return stroke.
One option is to use mountain bike shock absorbers if you go with a parallel link setup. The amount of travel is lower on these but if positioned correctly in a parallel link setup it'll work well.
Or you can use gas charged automotive shocks. The gas pressure will ensure a return stroke even without an external spring. If you need a spring then look at motorcycle fork springs for a smaller sort of size. And in fact a single motorcycle fork with spring and damping intact might just work perfectly for you. The ones of dirt bikes have about 7 or 8 inches of travel. Spring is already inside and the compression and rebound damping are both adjustable on the better ones.
Gordon
Member
after rethinkingit a good long off road type of gas filled shock just might work well if they have adjustable valving to "soft" to let the cannon recoil pretty quickly . the gas pressure come back to extended pretty slow on these.
Exactly! One on both sides for a couple of reasons. [pun intended] Mostly cuz on in the middle is gonna mess up my elevator design. I'm out of aluminum so I might get this one done prior to the other. Anyone else have a problem with starting something then think of another only to find several unattended projects with another in the works. I call it R.A.D.D. Retirement Attention Deficit Disorder.
BCRider
Member
Off road cars are pretty heavy. I think you'll find that even with the compression damping set to full soft that the truck's idea of what "full soft" is compared to a lightweight motorcycle's or mountain bike's idea of "full soft" is going to be more suitable.
A fork leg from a reasonably upscale mountain bike that has compression and rebound damping might also be more along the line of what you're looking for. The only downside with motorcycle and bicycle forks is that they sort of expect to be right side up for most of the time.
I wonder if the gas struts used on tail hatches of cars might work out? The ones on my car seem to damp well as they extend to control the rise of the hatch. But I don't hear them hissing the same way when I lower the hatch to shut it. And I sure don't feel any resistance when doing that. And these sorts of cylinders are pretty common and come in a variety of sizes, stroke length and overall lengths. And they have a floating piston in them to separate the gas end from the oil and piston end so they don't care which direction you mount them.
A fork leg from a reasonably upscale mountain bike that has compression and rebound damping might also be more along the line of what you're looking for. The only downside with motorcycle and bicycle forks is that they sort of expect to be right side up for most of the time.
I wonder if the gas struts used on tail hatches of cars might work out? The ones on my car seem to damp well as they extend to control the rise of the hatch. But I don't hear them hissing the same way when I lower the hatch to shut it. And I sure don't feel any resistance when doing that. And these sorts of cylinders are pretty common and come in a variety of sizes, stroke length and overall lengths. And they have a floating piston in them to separate the gas end from the oil and piston end so they don't care which direction you mount them.
danez71
Member
What about using bump stop(s)?
The cheapest air one I see at Poly Performance is about $200. - $300 for hydraulics. I think both of those return to their extended state.
Or even a poly or rubber bump stop with a gas pressure shock(s) to return?
The return only takes a few seconds which seems fast enough considering he has to reload (IMO, which isn't much since I don't have cannon experience)
Those return to extended length when in a relaxed state.
kBob
Member
This is all starting to sound like a discussion on the old 1632 board at Baen Books about an up coming article for the Grantville Gazette.........
You guys are scaring me.
-kBob
You guys are scaring me.
-kBob
Gordon
Member
Long travel gas shocks don't really carry any "load" of the suspension , that is what the springs or airbags do. They compress fairly rapidly as when you hit a huge obstacle at speed. I presume the kenetic engery in Joules of the cannon recoil is substantial too so it should work ok. Thew reboud is decent slow from the gas pressure only.
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DD4lifeusmc
Member
Two suggestions pickup truck 4x4 steering damper
Regular car shocks do dampen in both directions, but more so on the compression stroke.
How big a cannon are we talking anyway.
Car type springs and shocks would likely be too big and bulky physically.
Think more along the lines of Motor cycle in size.
Either way won't be very cheap unless you go to a wrecking yard.
Regular car shocks do dampen in both directions, but more so on the compression stroke.
How big a cannon are we talking anyway.
Car type springs and shocks would likely be too big and bulky physically.
Think more along the lines of Motor cycle in size.
Either way won't be very cheap unless you go to a wrecking yard.
CapnMac
Member
Well, have we applied a calculator to any of this?
Is there a fully fixed carriage version that we could put a strain gauge on and fire to judge the amount of forces to be resisted?
If the recoil impulse were, say, 800#, a pair of 200# shocks will meet a messy end in the fist test fire.
Then, there's some design to be considered. As a for instance, naval rifles need a very short recoil strock (to allow for reloading equipment). So, they can have 3, 4 recoil buffers, only one of which might be a recuperator to return to battery.
Now, in the early 1800s, they just used a pi through the wheel rim and a chain back to the trail. In a hasty artillery placement, the gun slid across the ground in recoil. The crew than pulled the wheel pins and slid it back into batery.. In a proper emplacement, slit trenches held the wheels, and a pocket hole the end of the trail. The gun would jump, sometimes getting the wheels up an out, but being back in battery was simpler than manhandling the gun how ever many yards it would slide.
Is there a fully fixed carriage version that we could put a strain gauge on and fire to judge the amount of forces to be resisted?
If the recoil impulse were, say, 800#, a pair of 200# shocks will meet a messy end in the fist test fire.
Then, there's some design to be considered. As a for instance, naval rifles need a very short recoil strock (to allow for reloading equipment). So, they can have 3, 4 recoil buffers, only one of which might be a recuperator to return to battery.
Now, in the early 1800s, they just used a pi through the wheel rim and a chain back to the trail. In a hasty artillery placement, the gun slid across the ground in recoil. The crew than pulled the wheel pins and slid it back into batery.. In a proper emplacement, slit trenches held the wheels, and a pocket hole the end of the trail. The gun would jump, sometimes getting the wheels up an out, but being back in battery was simpler than manhandling the gun how ever many yards it would slide.
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