(spoilers) what is the termnal V of a Long 12 cannon barrel?

I am only at page 50 of the latest book but I did read the reference of a Zep. this got me to thinking because I had just reviewed info about bunker busters in the pre 2010. the core was a used cannon barrel.

now take a captured long 12 smooth bore.
just use the barrel. the combustion area is the heaviest and thickest. make a nose cone to cover that end.

use the limited production of "new" TNT and fill the barrel to the muzzle.

at the muzzle fit some kind of fuse. add fins to your liking at the muzzle end.

you could make these "bombs" close to the battle areas, that is where you will capture the smooth bores in the first place. take weapon to 10k and release.

now to the q. what is the terminal V of the weapon and how deep will it go before you composition D does it job?

Er...

They haven't got zeppelins (yet). Only tethered baloons, admittedly of rather advanced "kite" design.

The problem with your concept is, that the penetration bombs must have very durable outer shell to survive impact on supersonic speed undamaged. The gun barrels, which were used for GBU-28 were from old M110 howitzers - post-war guns made from VERY GOOD STEEL.

I really doubt that even Charis is currently capable of producing such high-quality steel in sufficient quantites. Definitedly not the Church.

Also, the problem is aerodynamic. The gun barrrel is not very stable in flight. For GBU-28 it doesn't matter, because it's a guided bomb. But problem is, guided bombs are completely impossible without electricity.

If electricity were avaliable, they could design and build more or less effective guided bomb even with XIX-century tech. After all, Lay torpedo (the first actual guided weapon) was designed in 1870s. But - no electricity - no guided bomb.

Which means that supposed bunker-buster must have near-perfect aerodynamical shape, to be able to hit with the precision greater than "well, we DEFINITELY would miss no more than a few miles!") And calculation of such shape...

Dilandu wrote:Also, the problem is aerodynamic. The gun barrrel is not very stable in flight. For GBU-28 it doesn't matter, because it's a guided bomb. But problem is, guided bombs are completely impossible without electricity.

I think "guidance" could be managed with gyroscopes and hydraulic or pneumatic controls. It would be more stabilization than guidance, but stability in flight for a dumb-bomb bunker-buster is a solvable problem without electricity.

Weird Harold wrote:
I think "guidance" could be managed with gyroscopes and hydraulic or pneumatic controls. It would be more stabilization than guidance, but stability in flight for a dumb-bomb bunker-buster is a solvable problem without electricity.

Yes, as long as your bunker is several kilometers big)

Problem is, that for non-nuclear bunker buster to be effective, it must be dropped from relatively high altitude and achieve supersonic speed. The pure mechanical stabilization of supersonic bomb would be... problematic at best. Actually, it would probably do worse; the delays in pneumatic system would cause the bomb to zig-zag more and more.

They should better try large shaped-charge bomb. Or even tandem, with shaped charge in front and durable penetrator behind.

Stabilisation is a solvable problem. In fact, Barnes-Wallis solved it by hand when he designed the Tallboy & Grand Slam bombs in 1940. Which are _not_ weapons you're going to be emulating with captured smooth-bore gun barrels even if they're Fultyn Guns. A major reason that the Brits never made many of them is the machining required to smooth the body enough to be aerodynamic. The half-dozen machine shops that could handle 10,000lb castings had to-do lists from hell. Nonetheless, keeping them stable in the trans-sonic regime is a matter of getting the right spin on them. And that in turn is a matter of getting the tail assembly design just right. A non-trivial problem for anybody except OWL.

However, as it turns out, that's not a problem from 10,000'. Terminal velocity will be well under 245m/s - how much under depends on just how good your aerodynamicist is - or Mach0.8. Stability isn't going to be a huge problem at that speed, but it would still surprise me if the 'bomb' didn't break up on impact. Cast iron is brittle, and most Safehold steels are still not that much better, which is what forces them to use wire-wound barrels for their best guns. Tallboys dropped from 18,000' did go supersonic, and are known to have penetrated 60' of earth and rock or 16' of reinforced concrete, so I'm guessing that cawest's design, assuming it didn't just break up, would make it through 10-12' of packed dirt.

Of course, that also assumes you could build suitable fuses for them, too.

Dilandu wrote:

Weird Harold wrote:
I think "guidance" could be managed with gyroscopes and hydraulic or pneumatic controls. It would be more stabilization than guidance, but stability in flight for a dumb-bomb bunker-buster is a solvable problem without electricity.

Yes, as long as your bunker is several kilometers big)

Problem is, that for non-nuclear bunker buster to be effective, it must be dropped from relatively high altitude and achieve supersonic speed. The pure mechanical stabilization of supersonic bomb would be... problematic at best. Actually, it would probably do worse; the delays in pneumatic system would cause the bomb to zig-zag more and more.

They should better try large shaped-charge bomb. Or even tandem, with shaped charge in front and durable penetrator behind.

cawest wrote:I am only at page 50 of the latest book but I did read the reference of a Zep. this got me to thinking because I had just reviewed info about bunker busters in the pre 2010. the core was a used cannon barrel.

now take a captured long 12 smooth bore.
just use the barrel. the combustion area is the heaviest and thickest. make a nose cone to cover that end.

use the limited production of "new" TNT and fill the barrel to the muzzle.

at the muzzle fit some kind of fuse. add fins to your liking at the muzzle end.

you could make these "bombs" close to the battle areas, that is where you will capture the smooth bores in the first place. take weapon to 10k and release.

now to the q. what is the terminal V of the weapon and how deep will it go before you composition D does it job?

Not sure your idea would work, due to the lifting capacity of the balloon. Here's my calculations:
- Howsym said in an earlier book that a cubic inch of steel would weigh 1/4 pound.
- TNT has a density of 0.953761 ounces/cubic inch.
- Assume a 12-inch internal bore on the barrel.
- Assume an average wall thickness of 4 inches (less at the muzzle, more at the breech end).
- Assume the barrel is 20 feet (240 inches) long.

The volume of steel in the barrel is about 48254 cubic inches (neglecting the amount of steel to close off the breech end), for a mass of 12,063 pounds.

The volume of explosive (yes, I know it's NOT TNT, but that's a decent enough figure for now) is 27,143 cubic inches, for a mass of 1,618 pounds.

The total mass of the barrel + the explosive would be about 13,681 pounds, just over 6.75 TONS. Given the size of the balloons, I just don't think they have the lifting capacity...

(I'm not proud, check my math here... I ran the numbers very quickly).

Also don't forget pinpoint navigation and bomb sights. Both of these also tend to use the evil electricity and often Radar, even in WW2 bombers accurate (as in find the right city at night) navigation was highly dependent on radio transmissions.

All bunker busting missions with Tallboys and Grand Slams bombs were daylight missions for a reason which was to maximize accuracy and even then you needed the best of the best (617 dambusters squadron) to carry out these missions

While you are quite right on a number things, you misunderstood the proposal: a 'long 12' is a 12-pounder, not 12". The standard RW long 12 was ~3000lbs, 8' long with a bore of 4.75".

Giving a bursting charge of a whopping 84.5lbs, BTW. Definitely a kaboom, but hardly an earth-shattering kaboom.

WeberFan wrote:Not sure your idea would work, due to the lifting capacity of the balloon. Here's my calculations:
- Howsym said in an earlier book that a cubic inch of steel would weigh 1/4 pound.
- TNT has a density of 0.953761 ounces/cubic inch.
- Assume a 12-inch internal bore on the barrel.
- Assume an average wall thickness of 4 inches (less at the muzzle, more at the breech end).
- Assume the barrel is 20 feet (240 inches) long.

The volume of steel in the barrel is about 48254 cubic inches (neglecting the amount of steel to close off the breech end), for a mass of 12,063 pounds.

The volume of explosive (yes, I know it's NOT TNT, but that's a decent enough figure for now) is 27,143 cubic inches, for a mass of 1,618 pounds.

The total mass of the barrel + the explosive would be about 13,681 pounds, just over 6.75 TONS. Given the size of the balloons, I just don't think they have the lifting capacity...

(I'm not proud, check my math here... I ran the numbers very quickly).

WeberFan wrote:
The total mass of the barrel + the explosive would be about 13,681 pounds, just over 6.75 TONS. Given the size of the balloons, I just don't think they have the lifting capacity...

(I'm not proud, check my math here... I ran the numbers very quickly).

Well, the really large zeppelin (shutte-lanz, actually, because there is no aluminium avaliable for quite a lot of time on Safehold) could manage with such cargo. Not sure, thought, that such drop wouldn't damage the frames...

But the only real way of hitting something with supersonic bomb in Safehold conditions is to put pilot on the weapon. And shout "BANZAI!!!" really hard.

Louis R wrote:While you are quite right on a number things, you misunderstood the proposal: a 'long 12' is a 12-pounder, not 12". The standard RW long 12 was ~3000lbs, 8' long with a bore of 4.75".

Giving a bursting charge of a whopping 84.5lbs, BTW. Definitely a kaboom, but hardly an earth-shattering kaboom.

WeberFan wrote:Not sure your idea would work, due to the lifting capacity of the balloon. Here's my calculations:
- Howsym said in an earlier book that a cubic inch of steel would weigh 1/4 pound.
- TNT has a density of 0.953761 ounces/cubic inch.
- Assume a 12-inch internal bore on the barrel.
- Assume an average wall thickness of 4 inches (less at the muzzle, more at the breech end).
- Assume the barrel is 20 feet (240 inches) long.

The volume of steel in the barrel is about 48254 cubic inches (neglecting the amount of steel to close off the breech end), for a mass of 12,063 pounds.

The volume of explosive (yes, I know it's NOT TNT, but that's a decent enough figure for now) is 27,143 cubic inches, for a mass of 1,618 pounds.

The total mass of the barrel + the explosive would be about 13,681 pounds, just over 6.75 TONS. Given the size of the balloons, I just don't think they have the lifting capacity...

(I'm not proud, check my math here... I ran the numbers very quickly).

Thought he was talking about one of the new 12" Fultyn Rifles...