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delft

Brigadier
Thats pretty normal, the energy of a shell can only be eroded after it leaves the barrel (as nothing is propelling it). The path of the shell follows the Brachistochrone curve... which going back to my university years in advanced dynamic... is the path determined cyclic integration between potential energy and kinetic energy.

in simple terms, potential energy does transform into kinetic energy perfectly depending on the path which the projectile takes.

More.. descriptively in this case, since aerodynamic drag is is basically proportional to the velocity of the shell, and for simplicity sake, potential energy is directly proportional of the height the shell is reached above the point of fire.

The shell loses kinetic energy when it gains height; there is a sweet point (angle) where the shell losses velocity so quickly when gaining height (which is quasi regenerated on descend), that it losses less energy to aerodynamically drag (which is not regenerate-able and therefore lost for good). Therefore, the shell losses velocity quickly, but it regains it when it descends.

So this might seem odd, but the flight times should be higher than the lower angle shells (disproportionately so) as the "cruising velocity" is lower.
Just a correction: for subsonic flight the drag is proportional to the square of the speed, at supersonic speed the drag is even higher. so the effect is stronger than you describe. Another point is that the air density decreases with height. This further decreases the energy loss due to air drag substantially.
 

chuck731

Banned Idiot
Keep in mind that US Navy didn't have a clue what Yamato was carrying aboard. Before Samar and photos they got there they thought it was 16in guns as indicated in reports from the battle off Samar. No to even mention they surely didn't had a clue about the protection of those ships. Any kind of of miscalculation could cost a lot of lives.


Not entirely true. The USN already had pretty good idea how big the Yamatos really were from direct overhead reconnaissance photos taken in 1943, where Yamato's size could have been accurately measured from other ships of known dimension that was in company. USN strongly suspected Yamato's extraordinary size was to facilitate 18" guns because it was consistent with USN's own internal studies of what a 18" battleship must be like. It is true this suspicion needed verification. But it is not true that USN had no clue.

Also, even before 1943, the USN thought it was logical for the Japanese to develop 18" battleships, but was awaiting indications that they really were.
 

chuck731

Banned Idiot
Jeff why don't you tell us what you think would have been the tactics of the American battleships ... I'm eager to hear this too ... please :)

The most significant assumption effecting outcome of the encounter is the visibility. Also, if the encounter occurs near dawn and in good visibility, then the direction of encounter matters a a lot. If Japanese squadron is to the east, and US squadron to the west, then the US squadron would be illuminated by the rising sun and give the Japanese optical fire control excellent conditions for accurate ranging and aiming. Conversely if the US squadron is to the east and the Japanese squadron is to the west, the US Squadron would be lost in the glare of the rising sun, and Japanese optical fire control would be severely degraded.

The sea state also matter. Yamato class ships are exceptionally good seaboats even for their size, and very stable with shallow and long rolls even in heavy weather. US battleships of WWII era were all mediocre sea boats for their sizes, rolling more severely in heavy seas even for their sizes. So heavy sea will favor the Japanese battleships over American battleships, although it would hamper the gunnery of Japanese CA's even more than the American battleships. Also, very severe sea states would limit the ability of Japanese CA to keep up with the battleships. This would have tactical implications on overall maneuver the Japanese side can make.
 
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Jeff Head

General
Registered Member
The most significant assumption effecting outcome of the encounter is the visibility. Also, if the encounter occurs near dawn and in good visibility, then the direction of encounter matters a a lot. If Japanese squadron is to the east, and US squadron to the west, then the US squadron would be illuminated by the rising sun and give the Japanese optical fire control excellent conditions for accurate ranging and aiming. Conversely if the US squadron is to the east and the Japanese squadron is to the west, the US Squadron would be lost in the glare of the rising sun, and Japanese optical fire control would be severely degraded.

The sea state also matter. Yamato class ships are exceptionally good seaboats even for their size, and very stable with shallow and long rolls even in heavy weather. US battleships of WWII era were all mediocre sea boats for their sizes, rolling more severely in heavy seas even for their sizes. So heavy sea will favor the Japanese battleships over American battleships, although it would hamper the gunnery of Japanese CA's even more than the American battleships. Also, very severe sea states would limit the ability of Japanese CA to keep up with the battleships. This would have tactical implications on overall maneuver the Japanese side can make.
Well, we know what the conditions were that morning off of Samar.

The Japanese were in fact coming from the North and at 06:30 were about to bear down on the Taffy 3 carriers, and would soon be turning to the West. It is here that I would place the engagement, the American Task Force coming from the West to engage the Japanese with the Island of Samar behind them. The American carriers and destroyer escorts still some distance to the south. In fact it would be another 18 minutes before the Japanese opened fire on the American carrier group at 06:48. So I would have the surface engagement with the American battleships occurring at about 06:30.

We know that there were numerous showers in the area that morning, in fact throughout the morning and on several occasions in the actual time line the American carriers and destroyers sought to try and make use of (particularly the carriers) these showers to mask themselves from the faster moving Japanese surface combatants. So in our conceptual time line, these showers would also be present and would have to be factored in, along with a significant amount of broken cloud cover, which would also mitigate a significant amount of glare.

Also factor in the piecemeal attacks of the aircraft from at least 3-5 escort carriers in support of the four American battleships, and just as spirited an attack by the destroyers and destroyer escorts of the Taffy 3 group as what actually occurred.

I expect the American battleships would charge directly in towards the Japanese formation, and try tom bring maximum firepower of their big guns to bear in an attempt to break up the Japanese formation as it bore down on the American carrier group, and particularly the American anchorage that lay just beyond it.

In this case however, the Yamato would also have the Musashi with her. If the Japanese Admiral Kurita kept his battle sense about him and did not order an attack at will, in essence, an every ship "attack for itself" in an uncoordinated fashion (as he did that morning against Taffy 3), but instead used his battleships effectively to focus the two of them on each US battleship in turn while he used the heavy cruisers to distract the other battleships and/or provide a buffer against the American destroyers, he might be able to either mission kill or severely damage a couple of American battleships and give himself a fighting chance to win the engagement.

On the other hand, if the American aircraft could do some damage, and if the American battleships could, in turn, focus their very significant combined firepower on first one and then the other Japanese battleships, then they could do the same.

My own expectation would be, given what actually happened against U.S. Admiral Sprague's Taffy 3 alone, if in addition to the spirited and effective attack the Central force faced with Taffy 3, Kurita now also faced TF 59.7, I believe the Japanese Admiral may have turned away even sooner. I do not know this...but given the fact that he actually did turn away when facing Taffy 3 alone, it seems a good bet.

Anyhow, two Yamato class BBs against those four US BBs if they were both handled properly, would have been an interesting contest, with a potential for some horrendous firepower and damage on both sides.
 

Lezt

Junior Member
Lezt your explanations inspired this simple question of mine: What was the maximum height of, say, a 15" shell shot at 30 degrees of elevation with the muzzle velocity of 785 m/s? I mean the true value, not obtained neglecting atmospheric drag etc.! as
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just gave me 7852 m :) (but the time of flight was not completely off: 80 s instead of about 69 s I guessed from Campbell's table) A moment ago I quit a google search so ... thanks!

I don't really know. but i trust the admiralty tables. The ballistic calculator you have linked, specifically neglected aerodynamic drag; hence more energy will be retained for height and range; and therefore show a longer flight time. Also, the earth is flat in that calculator

You can try curve fitting the US 16" AA shell to see what the max ceiling might be it. but there is only 3 pt of data so it would be a bit off. I got ~5km height at around 28 sec for a 30deg shell.
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Just a correction: for subsonic flight the drag is proportional to the square of the speed, at supersonic speed the drag is even higher. so the effect is stronger than you describe. Another point is that the air density decreases with height. This further decreases the energy loss due to air drag substantially.

That is true, I was trying to make it very simple.
 

Lezt

Junior Member
Well, we know what the conditions were that morning off of Samar.

The Japanese were in fact coming from the North and at 06:30 were about to bear down on the Taffy 3 carriers, and would soon be turning to the West. It is here that I would place the engagement, the American Task Force coming from the West to engage the Japanese with the Island of Samar behind them. The American carriers and destroyer escorts still some distance to the south. In fact it would be another 18 minutes before the Japanese opened fire on the American carrier group at 06:48. So I would have the surface engagement with the American battleships occurring at about 06:30.

We know that there were numerous showers in the area that morning, in fact throughout the morning and on several occasions in the actual time line the American carriers and destroyers sought to try and make use of (particularly the carriers) these showers to mask themselves from the faster moving Japanese surface combatants. So in our conceptual time line, these showers would also be present and would have to be factored in, along with a significant amount of broken cloud cover, which would also mitigate a significant amount of glare.

Also factor in the piecemeal attacks of the aircraft from at least 3-5 escort carriers in support of the four American battleships, and just as spirited an attack by the destroyers and destroyer escorts of the Taffy 3 group as what actually occurred.

I expect the American battleships would charge directly in towards the Japanese formation, and try tom bring maximum firepower of their big guns to bear in an attempt to break up the Japanese formation as it bore down on the American carrier group, and particularly the American anchorage that lay just beyond it.

In this case however, the Yamato would also have the Musashi with her. If the Japanese Admiral Kurita kept his battle sense about him and did not order an attack at will, in essence, an every ship "attack for itself" in an uncoordinated fashion (as he did that morning against Taffy 3), but instead used his battleships effectively to focus the two of them on each US battleship in turn while he used the heavy cruisers to distract the other battleships and/or provide a buffer against the American destroyers, he might be able to either mission kill or severely damage a couple of American battleships and give himself a fighting chance to win the engagement.

On the other hand, if the American aircraft could do some damage, and if the American battleships could, in turn, focus their very significant combined firepower on first one and then the other Japanese battleships, then they could do the same.

My own expectation would be, given what actually happened against U.S. Admiral Sprague's Taffy 3 alone, if in addition to the spirited and effective attack the Central force faced with Taffy 3, Kurita now also faced TF 59.7, I believe the Japanese Admiral may have turned away even sooner. I do not know this...but given the fact that he actually did turn away when facing Taffy 3 alone, it seems a good bet.

Anyhow, two Yamato class BBs against those four US BBs if they were both handled properly, would have been an interesting contest, with a potential for some horrendous firepower and damage on both sides.

*if* the japanese can identify the american ships and their intel is good (actually misidentification on both sides are likely; so both would choose to engage) I believe the Japanese will turn away at an oblique angle (and yamato and mushashi sailing parallel) so that all her guns can fire on the approaching american ships and to keep the range between 36 - 40 km and keep the SD out of range; 3 Iowa vs 2 Yamato would be better odds. so the Iowas will catch up, but that would maximize 18 barrels of 18" guns shooting at the lead chase ship - and hopefully sink one before the other 2 ships come within range.

If the americans don't give chase, the Japanese task force would sail back to base....

Many more factors to be considered. but I think this gives the Japanese the best chance.

For the US, it would be safer to. shadow the japanese fleet and call in carrier aircraft to cripple them before moving in for the kill. ala bismark.
 
I don't really know. but i trust the admiralty tables. ...

It's good for you :) I just found them using google:
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You can try curve fitting the US 16" AA shell to see what the max ceiling might be it. but there is only 3 pt of data so it would be a bit off. I got ~5km height at around 28 sec for a 30deg shell. ...

I don't know what exactly you did but here are hard data from those Tables (converted to SI units :) and plotted by me quickly):
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and your 5 km estimate is qualitatively correct.

Now I add the path in terms of max. range ("so that the trajectory doesn't look like of a 16-inch antiaircraft gun" heheh):
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Jeff Head

General
Registered Member
*if* the japanese can identify the american ships I believe the Japanese will turn away and keep the range between 36 - 40 km and the Iowas will catch up, but that would maximize 18 barrels of 18" guns shooting at the lead chase ship.

If the americans don't give chase, the Japanese task force would sail back to base....

For the US, it would be safer to. shadow the japanese fleet and call in carrier aircraft to cripple them before moving in for the kill. ala bismark.
In the actual battle, Kurita turned away because he thought he was facing a much larger force than he was. The intensity of the attacks he did face convinced him that there were heavier combatants behind the screen he did have to fight, and that there were fleet carriers in the area...so he turned away.

If he were convinced that he faced those heavier units, then I believe he would have jumped to the same conclusion about the carriers when facing real battleships, particularly if he were already being harassed by significant numbers of carrier aircraft from the Jeep carriers...and turned away.

If he did that, some of his vessels would certainly have not made it back to base.

If he pressed his attack without the fleet carriers being there, but with four American battleships being there (three of them Iowas) I do not think he would have been able to fight through them and the Taffy 3 carriers and their screen. But, if he had been able to knock out two of those BBs before taking any significant damage he may have been able to do so... (and that's a pretty big IF given what we know of how Kurita actually reacted in battle) he then could have probably pressed his attack home into the anchorage.

Interesting scenario for sure, but it is also a big what if.

As it was, Kurita was given the absolute greatest opportunity he could ever hope for in the real battle...and he still did not press it home with victory laying there at his feet. Had he pressed his advantage he would have decimated the American anchorage. Had he done so, it is also likely that none of his vessels would have gotten home...but the whole point was to destroy the massive supplies and troop ships in that anchorage and delay and forestall the American victory in the Philippines.
 

Lezt

Junior Member
It's good for you :) I just found them using google:
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I don't know what exactly you did but here are hard data from those Tables (converted to SI units :) and plotted by me quickly):
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and your 5 km estimate is qualitatively correct.

Now I add the path in terms of max. range ("so that the trajectory doesn't look like of a 16-inch antiaircraft gun" heheh):
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Great find!

As an engineer I learnt to simplify things. the link I have provided have 3 data points for 30 deg AA shell.. out to 10 seconds.

Given that we know that of the energy that a shell losses, most of it would be lost early on and that height gained in height is potential energy; we know that a parabolic curve passing though the first 3 points will give a good estimate of the height reached but it will be incorrect for range. hence I only needed to do a 2nd order parabolic curve fit to get the height.
 

Lezt

Junior Member
In the actual battle, Kurita turned away because he thought he was facing a much larger force than he was. The intensity of the attacks he did face convinced him that there were heavier combatants behind the screen he did have to fight, and that there were fleet carriers in the area...so he turned away.

If he were convinced that he faced those heavier units, then I believe he would have jumped to the same conclusion about the carriers when facing real battleships, particularly if he were already being harassed by significant numbers of carrier aircraft from the Jeep carriers...and turned away.

If he did that, some of his vessels would certainly have not made it back to base.

If he pressed his attack without the fleet carriers being there, but with four American battleships being there (three of them Iowas) I do not think he would have been able to fight through them and the Taffy 3 carriers and their screen. But, if he had been able to knock out two of those BBs before taking any significant damage he may have been able to do so... (and that's a pretty big IF given what we know of how Kurita actually reacted in battle) he then could have probably pressed his attack home into the anchorage.

Interesting scenario for sure, but it is also a big what if.

As it was, Kurita was given the absolute greatest opportunity he could ever hope for in the real battle...and he still did not press it home with victory laying there at his feet. Had he pressed his advantage he would have decimated the American anchorage. Had he done so, it is also likely that none of his vessels would have gotten home...but the whole point was to destroy the massive supplies and troop ships in that anchorage and delay and forestall the American victory in the Philippines.

I don't think we should focus too much on Kurita... lets say we have a more competent admiral like... Tanaka

But of course the Japanese were not in a good position at all.
 
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