"Air-Burst Question" Topic

I'm curious as to how many rounds a crew needed to fire in order to get Air-Burst shells on target and at effective height. What if your target is moving?
If fuses are delineated in one second increments, would you have to set up your field piece a certain distance from your target? What I mean is, what if the target is, for example, five and a half seconds down range? Was there a way to set the fuse for fractions of a second?
Thank you for time.

While you did not specify the period you're thinking of,
some things will carry from era to era.

If you haven't studied this resource, I think you'll find most of what you need right here: link

If you're more interested in ACW era information, please look here: link

I think either site will give you just the info you need.

Enjoy!

TVAG

Was there a way to set the fuse for fractions of a second?

Sure, you just cut the fuse a little shorter. You are talking about black powder fuses here, precision isn't exactly something that comes to mind

Yes, the photo of the Bormann Time Fuse appears to have it broken down into quarter second intervals.

link

Officers and gunners were trained to estimate distances fairly accurately. In addition, stadia sights were provided which helped to increase the accuracy of the range estimation.

You also wanted the round to burst just slightly ahead of the target. The bursting charge would exand equally in all directions, but it's force to rearward would be countered by the speed of the round and the fragments from there would fall almost straight down.

Fragments from the forward 1/3 to 1/2 of the round would tend to expand out in a cone, and their force was magnified by the speed of the round. The best solution was to have the shell burst just ahead of the target, while it's front face (where the fuze was located) was pointing directly AT the target as it began it's descending arc of it's trajectory.

Also, although shell was carried in the limbers, most bursting rounds were case, sometimes called spherical case due to it being designed for the smoothbore guns. Case rounds were iron shell filled with musket balls or small iron balls with a central bursting charge. This gave a better spread of missiles, as opposed to the random-sized fragments of regular shell.

A good crew could estimate the range to target and closing speed, and cut the fuzes to burst appropriately.

Both the 7-second Sawyer and 5-second Bormann fuzes could be set in quarter-second increments.

Some interesting data on Union tests of ACW fuze serviceability:

Type--------------------Number Tested-----Serviceability
Parrot percussion-------5946--------------85 pct
Parrot time-------------2820--------------75 pct
Schenkl percussion------2141--------------82 pct
Schenkl combination-----161---------------55 pct
Dyer time---------------202---------------71 pct
Absterdam percussion----188---------------53 pct
Tice concussion---------41----------------73 pct
Sawyer combination------88----------------85 pct
Bormann time------------654---------------77 pct

Source –
Notes on Ammunition of the American Civil War 1861-1865
Col Berkely R Lewis
The American Ordnance Association, Washington DC, 1959

B

As an addition, CS manufactured fuzes became more and more problamatic as the war progressed. CS powder for artillery was fine. It was the fuzes that caused issues, starting in early 1863.

Lee had prohibited his own artillery from firing over the heads of his troops because of the increasing accounts of shells exploding prematurely. Part of the problem with the CS artillery bombardment prior to Pickett's Charge was that many of the shells either burst early, or failed to burst at all. It wasn't that the CS artillery was inaccurate in it's fire, but that the rounds passing overhead were actually shells whose fuzes failed and they didn't burst.

In addition, there is a danger zone in front of artillery of about 100yds for all troop types. Even when prone, infantry are susceptible to being wounded or killed by fragments of the wooden sabots which held the round to the powder charge, as well as screws and/or staples used to hold the metal straps which affixed the round to the sabot itself.

Supporting infantry should always be placed either behind, or to one side and slightly back of the battery they are tasked to support.

Wow, lotsa great info there, thank you everyone.
However my 1st question still remains: HOW MANY ROUNDS did it take before the crew got their shells on target at the proper height? That seems pretty complicated for this technology. As dragon6 pointed out.

How good is the gunner? He is probably the guy that calls for the fuse setting after estimating wind, humidity, speed of the target, smoke, where will the target be when the round goes off, and he cannot guess precisely the quality of the powder. In JRIII or ADF, I figure with a high die roll, the gunner got it right, a low roll and he did not. There are times when the fire is directed by the section commander or the battery commander who announces at what range to set the fuse.

Type of round selected is also often based upon the type of formation the target is in. Columns were still attacked with solid shot at long range, with shell and spherical case being used as the target closes, until finally canister is selected.

The idea wasn't just to inflict casualties, but to also force the target to change formation and deploy into line, which would also slow down the advance and potentially disrupt morale, cohesiveness, etc.

For percussion-fuzed direct HE fire by turn of the century 75mm field guns upon targets at an unknown range, I have seen a figure of 5-6 rounds for 800-1000 yards, 7-9 rounds at 2000 yards and 10-11 round at 3000 yards.

B

The lid of the ammunition box had a table showing the flight times at various ranges and tied to the type of gun.

Officers and NCO became very adept at estimating ranges.