TOT arty fires

[jtcm]

Reading another thread ( the "flogging a dead horse" one), I noticed JasonC mentioning a TOT called down on the jump-off point of a German attack, winter 44.

From various bits of reading, i remember that a "time on target" strike coordinates fires from several batteries for the shells to land at the same time (Paul Fussell in his memoirs describes this as a "showy technique").

Some random thoughts:

do you need a computer to calculate and coordinate this sort of tactic ?

Did only the Americans do this ? I remember mentions of this in Pacific, and on EOT. But did Germans use their artillery this way ? Did the Soviets ?

[LCJr]

Don't need a computer to this just know the time of flight from each battery and have your watches sync'd. Especially since WW2 predates the portable computer:)

My grandfather was an artilleryman(105mm) in the 1st Infantry Division and he's specifically mentioned firing TOT missions when in North Africa. He seem to think it worked.

Far as I know only the Americans used it.

[jtcm]

I thought there were rudimentary computers for e.g. AA work (calculating deflection, etc).

[JonS]

The RA used a TOT-equivalent, but by and large thought it a waste of time. Not in the sense of having all the rounds land at the same time is a waste of time. Literally, a waste of time. Using the Mike, Uncle, Victor, etc targeting procedure they could get the same results faster. The problems seems to have stemmed from the FOO having to designate a 'time' for the TOT to occur at. Invariably the FOOs went conservative, and time was wasted while the btys and regts sat around ready to firing, waiting for the right time to roll around.

The Mike, etc, procedure saved time by having all the guns fire, together, as soon as the last one was ready. Same TOT effect, faster response.

Mechanical or electrical calculators aren't needed to fire a TOT. Firing tables are fairly largish books that have all the necessary information tabulated for quick reference.

Creating the Firing Tables, OTOH, did make use of mechanical or electrical calculators when they became available, since otherwise it was a balls-achingly (actually, vagina-achingly) slow process.

The term 'calculators' comes from the people who used to work these kinds of calculations out, by hand. They were called 'calculators' (like a person who does accounts is an accountant), and were typically women. They generally have better attention to detail, are faster and more accurate, and could be paid less. When mechanical and electrical devices became available to do this kind of work, it made sense to call them calculators too. And the name stuck.

[ April 08, 2005, 11:53 AM: Message edited by: JonS ]

[tar]

The main benefit for using TOT procedures is that research (and unfortunately, I don't have a reference) showed that it was the initial set of shells landing in an artillery barrage that caused the largest casualties.

That was because after the first shells fell, everyone got themselves into the best available cover, which greatly reduced the chance of being hit by the blast and fragmentation effects.

It was one of the particular benefits of the massed rocket artillery that the barrage occurred mostly in one single set of impacts. This was certainly the consideration that (eventually) led the United States to develop the MLRS (multiple-launch rocket system) in the 1980s. (The Soviet Union kept their multiple rocket launchers from WWII in production, upgrading them over time).

So, since the initial strike was the most effective, having several batteries all time their inital shells to land at the same time gave you greater weight of fire in the crucial first few seconds of the barrage, when you were most likely to catch soldiers in exposed positions.

Trivia: There was some work on the US Army's (since abandoned?) new artillery system to allow for multiple round TOT shots from a single artillery tube. The idea was to select different trajectories with the same end point that would take different amounts of time to complete. The longest one is fired first, with successively shorter time of fligth trajectories fired later, with the result that all of the shells hit at about the same time. This required electronic computers to devise....

[John D Salt]

Originally posted by tar:

[snips]

Trivia: There was some work on the US Army's (since abandoned?) new artillery system to allow for multiple round TOT shots from a single artillery tube. The idea was to select different trajectories with the same end point that would take different amounts of time to complete. The longest one is fired first, with successively shorter time of fligth trajectories fired later, with the result that all of the shells hit at about the same time. This required electronic computers to devise....

The current Royal Artillery SP 155mm gun, AS-90 (please don't call it by the stupid name "Braveheart") can do this with three rounds on different trajectories.

Back in the good old days of steam gunnery, I saw the trick done with two rounds at a Larkhill Artillery Day using an M110 203mm SP on a target at about a thouisand metres -- fire one at a very high elevation, then drop the barrel and reload like mad for a flat-trajectory shot before the first one comes whizzing down out of the clouds.

Tactically a bit pointless, but great fun nevertheless.

All the best,

John.

[flamingknives]

The silly name only refers to the varient with the 52 calibre gun, AFAIK. The one with the 39 calibre gun can do the same trick, and doesn't have a silly name, unless you count a contraction of (I presume) "Artillery, Self-propelled, for the 1990's" as being silly.

Following the ecclesiastical tradition, I would have though that the 'Vicar' would have been an amusing play on words, given the guns provenance.

[John D Salt]

Originally posted by flamingknives:

The silly name only refers to the varient with the 52 calibre gun, AFAIK. The one with the 39 calibre gun can do the same trick, and doesn't have a silly name, unless you count a contraction of (I presume) "Artillery, Self-propelled, for the 1990's" as being silly.

Following the ecclesiastical tradition, I would have though that the 'Vicar' would have been an amusing play on words, given the guns provenance.

The great question everyone wanted to know the answer to when SP-70 and later AS-90 were on the drawing board was whether the naming convention was going to continue the ecclesiastical tradition or stick to having names beginning with "A". The Abbott had been an elegant combination of the two.

To my mind it was absolutely clear that the next SP for the Royal Artillery should have been called "Archimandrite". The failure to adopt this wonderful name in preference to a completely irrelevant name from a fifth-rate film about some long-dead frisp was a clear indication of the fundamental rotteness of the British defence acquisition process.

Also, I wish someone had thought up some NATO reporting names for tanks, like the spiffing nomenclature devised for missiles and aircraft. Obviously, these names would begin with the letter T. Instead of a boring procession of T-55s, T-72s and BMPs, we might have had glorious names like Teapot, Tusker and Terrapin.

All the best,

John.

[Wartgamer]

TOT arty fire other benefits besides catching people in the open.

The actual concussions will be so close together that the overpressure would be magnified. In the case of large shells combined with many smaller shells, the victems can be tossed off the ground and vulnerable to fragmentation saturation. Slow firing guns like 8 in or 240mm were therefore magnified by this synergistic approach.

TOT's would be spaced evenly (not just one strike but actually 'back-to-back' strikes). This would force defenders to run back to cover, wait while nothing happens, reoccuppy positions, and then get another dose. One report suggests 10 minute intervals. This actually saves shells.

TOTs were certainly destructive fire missions. They were dangerous to friendlies also. The US radio/communications ability, combined with very good FM radios, enhanced the ability of the US artillery system.

[jtcm]

Paul Fussell in his memoirs describes seeing a German squad, men all dead, still in firing positions-- and guesses that they were done for by overpressure from a TOT-- just to confirm Wartgamer's point about the overpressure being increased by the shells all falling together.

[John D Salt]

Originally posted by jtcm:

Paul Fussell in his memoirs describes seeing a German squad, men all dead, still in firing positions-- and guesses that they were done for by overpressure from a TOT-- just to confirm Wartgamer's point about the overpressure being increased by the shells all falling together.

This sounds physically improbable to me. Contrary to popular belief, human beings are highly resistant to blast. Blast as a wounding mechanism is negligible in field artillery calibres when compared with fragmentation effects. Fast-moving metal is hugely more damaging than fast-moving air.

While it is possible to throw bodies around by blast waves from large explosions (and this would be much more likely from aerial bombs than field artillery shells), this is not going to leave people still in their firing positions. Still less will it leave people "without a mark on them", as one often hears in war-stories about people supposedly "killed just by blast". Lethal amounts of overpressure will tear off clothes, snap bones, or tear a body to pieces. It will not leave them neatly in their firing positions.

It seems to me vastly more likely that the people killed in this sort of case have been killed by very small fragments. A few grams of fast-moving metal is enough in the right place, and the wound may easily be so small as not to be noticed.

As for TOTs producing significantly more severe blast effects than ordinary shoots, I call bull****. I would be surprised if Wartgamer can produce any trustworthy source for such a belief.

All the best,

John.

[Wartgamer]

13.4.1.1 Another aspect of overpressure occuring in air bursts is the phenomenon of Mach reflections, called the "Mach Effect." Figure 13-5 portrays an air burst at some unspecified distance above a reflecting surface, at five successive time intervals after detonation.

When a bomb is detonated at some distance above the ground, the reflected wave catches up to and combines with the original shock wave, called the incident wave, to form a third wave that has a nearly vertical front at ground level. This third wave is called a "Mach Wave" or "Mach Stem," and the point at which the three waves intersect is called the "Triple Point." The Mach Stem grows in height as it spreads laterally, and as the Mach Stem grows, the triple point rises, describing a curve through the air. In the Mach Stem the incident wave is reinforced by the reflected wave, and both the peak pressure and impulse are at a maximum that is considerably higher than the peak pressure and impulse of the original shock wave at the same distance from the point of explosion.

Using the phenomenon of Mach reflections, it is possible to increase considerably the radius of effectiveness of a bomb. By detonating a warhead at the proper height above the ground, the maximum radius at which a given pressure or impulse is exerted can be increased, in some cases by almost 50%, over that for the same bomb detonated at ground level. The area of effectiveness, or damage volume, may thereby be increased by as much as 100%. Currently only one conventional pure-blast warhead is in use, the Fuel Air Explosive (FAE). Of course, all nuclear warheads are blast warheads, and on most targets they would be detonated at altitude to make use of the Mach Stem effect.

[Wartgamer]

The US would use combinations of fuses for the different firing batterys. Some Airburst, some PD and some delay. The total effect is being surrounded by shells exploding all about. The resulting interaction of the shock waves can be additive.

While fragmentation is a greater slayer of troops in the open, blast is really needed to get to troops under cover also. And blast will bounce people out of thier holes.

I can recall one account where a German 75mm tank uses HE directly at a single soldier in a small foxhole. It repeatdly gets near misses and he is flung out each time and has to roll back in before the tank reloads.

[ April 08, 2005, 12:13 PM: Message edited by: Wartgamer ]

[JonS]

Hey look everybody, it's Roger Irrelevant.

[ April 08, 2005, 01:54 PM: Message edited by: JonS ]

[jtcm]

John D Salt:

I'd never paused to reflect that the "not the scratch upon them" stories might be wistful tall tales rather than real anecdotes. Paul Fussell writes that he did see a German squad dead in their positions; that they might have been killed by a TOT is his speculation.

I thought pressure waves from HE blasts killed by rupturing internal organs; but freely, and thankfully, admit that I know little on the subject.

[Wartgamer]

I agree that many large bombs and even certain mortar bombs can produce a very fine fragmentation spray. This is typically when there is very thin walls in the HE container.

But to get a 'mass' kill like the german's in firing positions described above, you would still need a 'bracketing' by many bombs. These small fragments quickly scrub off thier velocity over distance. So a TOT could have been the device that created the kills.

And for those that may have thought the Mach effect irrelevant; just as bombs can attain greater shock waves due to reflections, they can be additive with each other. I suppose that I thought that was obvious.

Weapon planners, especially in small nations, may consider such an analysis a clever originality. It is not. Any person with access to the Internet, a hand calculator, or moderate knowledge can easily arrive at such conclusions. Weapon planners in large nations who contemplate simultaneous bursts of larger weapons pose even greater risk.

Simultaneously detonating nuclear weapons would produce greater and more complex forces than indicated by the individual circles in the above diagram. With 7 weapons in a circle, at the midpoint between zero point distance [half of 4.3 miles], two 20 Kt blast waves would collide at the 1.6 psi overpressure points. On interior points of the circle, the blast waves, depending upon the angles at which they met, would be reflected or merge. The key feature of encirclement in terms of blast forces is that the energy on the interior of the circle would be concentrated in a comparatively small area instead of dissipating from the zero point at a 128° angle over an ever larger area [the angle formed at an intersections of a 7 sided polygon]. The result is greater blast destruction on the interior of the circle than is commonly suggested when contemplating single weapon effects.

The interaction of forces when shock waves collide is suggested in an excerpt from Paul Cooper's text Explosives Engineering (1996) [p. 216]:

"In this example, two shock waves of unequal amplitude approach each other head-on. When they meet they produce a much higher pressure shock that is reflected back in each direction. You will see, as we solve this problem, that the final shock pressure produced is greater than the sum of the pressures of the initial two shocks."

So Mr. Salt should get access to the Internet, a hand calculator, or moderate knowledge before calling 'Bull****'.

[ April 09, 2005, 09:03 AM: Message edited by: Wartgamer ]

[John D Salt]

Originally posted by Wartgamer:

And for those that may have thought the Mach effect irrelevant; just as bombs can attain greater shock waves due to reflections, they can be additive with each other. I suppose that I thought that was obvious.

Obvious it certainly is, and you should not run away with the bizarre idea that people challenging your crackpot assertions are ignorant of such a trivial piece of physics.

However, the fact that it is obvious does not make it relevant -- the words "obvious" and "relevant" have different meanings, you see.

The references you have posted on mach stems and the interaction of blasts from 20Kt weapons are, it is obvious to even the most slapdash and gullible observer, talking about nuclear weapons.

So Mr. Salt should get access to the Internet, a hand calculator, or moderate knowledge before calling 'Bull****'.

Perhaps you should get a clue about the difference between blast effects from nuclear weapons and blast effects from field-artillery calibres.

Neither your ability to use Google nor your possession of a hand calculator seem to be sufficient to stop you spouting bull****. Maybe you ought to go for the option of acquiring moderate knowledge.

John.

[Wartgamer]

How feeble.

Physics is Physics. I am not comparing radiological effects. Its clearly blast effects. And, again, you are wrong. One of the sources was actually discussing HE and fuel-air explosives as well as blast effects from nuclear weapons.

They are not my crackpot assertions. They are actual fact based realities shared by people that know what they are talking about.

You have a foul mouth.

[ April 09, 2005, 01:12 PM: Message edited by: Wartgamer ]

[JonS]

Roger, you moron, in a strict sense your bleating about blast is correct, but you are - as always - also irrelevant. Get your pocket calculator out and figure why that is.

[flamingknives]

Originally posted by Wartgamer:

How feeble.

Physics is Physics. I am not comparing radiological effects. Its clearly blast effects. And, again, you are wrong. One of the sources was actually discussing HE and fuel-air explosives as well as blast effects from nuclear weapons.

They are not my crackpot assertions. They are actual fact based realities shared by people that know what they are talking about.

You have a foul mouth.

*Steps up to the parapet*

Who suggested that anyone was talking about radiological effects? The primary damage-causing effects of atomic weapons are the flash and blast.

I suspect that the objection is to the size of the effect. Field artillery shells of WWII held 2lb of HE? Compare that to an atomic weapon (20kT is pretty small) and that's at least 7 orders of magnitude difference.

Is it really going to make a significant difference?

[Wartgamer]

Its absolutely relevant. Read your own posts above. You mention that the CW's thought TOT wasn't worth it. I am directly rebutting that statement. Do you know what relevance means?

The CW needed to weigh the value to get the worth. Or, more than likely, they did not know the value.

But this thread, like so many, is just going to get ruined by more CW grafitti.

Anyone with any real technical education and experience knows that I am correct. Salt is probably just a buff. He jumped up and took a stand and now he (I hope for his sake) knows it. Nice try trying to help his loss of face JonS. Continue with your grafitti now.

Edit: Again, I repeat, again; the effects are not limited to nuclear weapons. The source I cut'n'pasted above is about conventional weapons. Just to be sure, should I repeat myself again?

[Wartgamer]

In the case of using simultaneous nuclear detonations they are widely seperated. The main benefit is that one '8' cluster of 20kton weapons can handle a city better than one megatonner.

So just as the yield is bigger than a conventional weapon, the wide dispersion of the nukes is offset (by an inverse cube for those that can calculate).

In a TOT, where multiple battalions are targetting the same registration point, the density of many small 3+ pound HE (US 105mm and greater) in very close proximity must be taken into account. Certainly structures like buildings, human skulls and bones and brains, optics, etc will feel the shared reflected blast waves.

Imagine yourself fighting three people at once. If they are very slow/uncoordinated and you can get only one punch at a time from them, you may last awhile. But if all three hit you at once, you are going to be going down quickly.

[JonS]

Bull****. Virtually every statement in your last two posts is wrong. Furthermore you have, again, demonstrated your pathological inability to read and understand what others are saying - or even who said it.

[ April 09, 2005, 03:35 PM: Message edited by: JonS ]

[JonS]

Riddle me this Roger: how close in time and space do two field artillery rounds have to explode before their combined blast is greater than that from a single blast? (show your working)

What is the likelihood of that happening? (show your working)

[ April 09, 2005, 03:37 PM: Message edited by: JonS ]

[flamingknives]

Ok, so let's see if a bit of linear scaling isn't worth a shot (I would go and get my notes for shockwave modelling, but can't be bothered right now)

A reasonably large city is 20km from centre to edge, so that's 20,000m with 20,000,000kg of TNT each. If we scale back to field artillery sizes (let's be generous and say 2 kg) the distance goes down to 2 mm. Of course, it might not be simple and linear but it gives an idea of the problems of applying a principal (even if it is correct) to a problem on a radically different scale.

The effects of large aerial bombs are liable to be significantly different to that of artillery shells and these are still conventional weapons, and more likely to carry a FAE warhead than artillery shells to boot.

Going back onto topic:

The greatest weapon of Time On Target is the element of surprise... and psychological effect

The two greatest weapons of TOT is the element of surprise and psychological effect... and a faint hope that the blasts will reinforce one another.

Among the greatest weapons.... I'll come in again.

Counting against it, it takes longer to deliver, due to plotting time and reserve factors and the CW used larger batteries (8 guns) anyway. The ability to land a Corps' worth of artillery on a target inside of 5 minutes must have been seen as a superior tactic for rush fire missions, such as those used to break up counterattacks.

I guess that the CW preferred response time over a slight increase in destructive effect. But, seeing as 'they probably didn't know the value' of TOT, perhaps you'd like to quantify it for us.

Wartgamer, do be a good chap and stop trying to wrap up everything each time you post. It makes you look desperate.

p.s. What is a 'Real Technical education'? Does it cover accuracy and significance?