SpudFiles

We're thinking of something similar to Jeepkahn's design. He says it removes a considerable amount of recoil. We're thinking 4" pipe at 8" long ported on the top and sides to reduce muzzle flip and recoil and in actuality giving us a version of a compensator type muzzle break. Here's the question. Jeepkjan's brake is open on the end, while i've seen others where the brake is reduced back to just over the bore size. I'm pretty sure the reduced ended muzzle break will work slightly better than the open ended one, but I don't want to risk our sabots getting lodged inside the brake. Is my paranoia well founded?

McCoytheGreater wrote:We're thinking of something similar to Jeepkahn's design.

Simply poking holes in the barrel would redirect the gasses to the sides and reduce recoil. If you add baffles though to direct the gasses in the direction of the recoil, as they leave the muzzle will actually try to propell the launcher forward, providing an active counter to recoil.

Very nice. I haven't had internet for a while, so I didn't see this.

As far as cleanout caps and DWV goes, DWV is usually fine for a combustion, but the large scale of this cannon could pose a problem (fittings which maintain a relatively constant wall thickness while increasing in size (I believe after 4" pipe all sizes have the same wall thickness for SCH-40, which is 1/4") will generally be weaker). Also, people forget there are two types of cleanout caps common, which are sewer caps and DWV caps. It appears (though I can't be sure) that you have a sewer cleanout cap on the cannon. A DWV cap is thicker, which is what I use on my cannons, and I've never had a cleanout blow out on me.

All in all, good job.

We have DWV caps and pressure rated PVC fittings. I've only had an endcap blow out on me once on a smaller gun. Luckily it only scared the hell out of my instead of injure me. It was during cold weather, though, which is why we're not firing the big gun much. If I knew the cannon wouldn't explode during this cold, I wouldn't have a problem with it. That's a lot of force in there. We calculated that our 187 gram projectile has a force of roughly 3010 Ft.Lbs., so I'm not taking any chances with an end cap on this build.

At the instant of firing the force on a 6" endcap is well above 2,500lbs, it's no wonder that it can fail.

Dang man that's a HUGE canon/howitzer! Wonder how far your ammo would go at 45* angle 8)

I like this thing. Straight up massive! Also, as long as you aren't standing behind the end cap, then it can be replaced if it does fail. Hopefully it doesn't damage the coupling somehow when it blows out though. You can also make a much stronger cap like the way ultimatespudgun makes theirs. You are likely aware of this by now though and I think someone may have already even mentioned it in this thread.

in my experience moonbogg is on the money, as long as you're clear of it you should be fine, but it will make a much more deafening bang compared a normal launch. also, because all of the hot gases are exiting through the end cap in a big hurry, if your chamber fan is near the end that will go with the end cap.

Ok. So I did some more accurate speed calculation for the muzzle velocity because the first calculation was approximate (it was made from just three frames). Here is the final muzzle velocity on the ME 1-05. The 7.2 oz projectile traveled 8 Ft. in 12/1000th of a second. That breaks down to 1.5 Ft in 1/1000th of a second. 1000 / 1.5 = 666.666666667 FPS.
I guess that we were correct in naming this cannon Cerberus .
(edit) that's supposed to be 1.5 frames per foot, sorry. I almost broke the math . The end number is still the same though.

dang! nice! That is almost as fast as the High Speed Rocket Sled was travelling on an MythBusters episode where they smashed a car with 4'x6' 1" thick steel plate. It was going 948 FPS or 646 MPH, and your lil 7.2oz projectile was going 666.667 FPS or 455 MPH.

The launcher of the beast

McCoytheLesser wrote:The 7.2 oz projectile traveled 8 Ft. in 12/1000th of a second. That breaks down to 1.5Ft in 1/1000th of a second. 1000 / 1.5 = 666.666666667 FPS.

That's just over 3,100 ft/lbs of muzzle energy, more than double that of a bullet from an AK-47

Muzzle brake installed. Reduced the recoil by over 75%. Forecast for tomorrow is clear skies at a comfortable 74 degrees which means extensive testing and damage videos. We conducted some preliminary tests tonight and...well...lets just say that a tennis ball plus 3/4" plywood equals broke stuff.

Here is the video of said test. The muzzle velocity for the 94 gram tennis ball was 769 FPS.
[youtube][/youtube]
Tomorrow should prove to be a very destructive day.

Impressive, though I expected more muzzle flash would come out of the brake. Adding elbows to the tee pointing backwards (maybe not directly) will reduce recoil even more.

This is some nasty damage for a tennis ball!! Like JSR I was expecting a big muzzle flash, and i'm astonished by the 75% recoil reduction!
Jack, have you seen my hybrid preview? What recoil should I expect? Would it be adivsed to add a muzzle brake?