Max Hit Probability

[:USERNAME:]

Originally posted by rexford:

Lewis,

Maybe your reading isn't getting it.

Do you have any substantive response to offer regarding the trajectory analysis on Page 7 that shows that 75L24 HE is better at placing rounds near the target point than 75L70 HE?

I presented a mathematical analysis with all the things you continously and non-stop asked for, descent angles, dispersion, flight times, etc., and you didn't say one word about the work. Just switched to another issue to hammer on.

Is this true (I am not just asking this of Rex et all but of anyone that might have followed this thread):

1. You only have data on some german weapons? Specifically it seems the 75mmL48? Perhaps the 88L56?

2. You said:

"German data on HE "beaten zone", area where 50% of HE shots will land if range to a ground target {that?} is perfectly estimated, clearly shows that low velocity HE is more accurate than high velocity HE."

and:

"One additional note. At 800m, German data predicts that 50% of 75mm L48 HE will fall within a 61m long distance when range estimation against a ground target is exact. (50% will be more than 30m away from target ground point). This is at 550 m/s muzzle velocity." {Lewis: Why do you say predicts? Why not say "that measures a"?}

3. You flip-flopping?:

"88L56 HE at 810 m/s has a much larger ground dispersal."

"On another matter, 88L56 HE fired at 810 m/s but vertical dispersion very small, so beaten zone not as large as velocity would imply." {Lewis: which is it? what is the value(s)?}

4. More clarifications:

"If dispersion drives trajectory up by 1m at 800m (German data shows that 50% of 75mm L48 HE shots will have vertical dispersion of at least 1m at 800):"

"1.0m vertical dispersion for 50% of shots is from German ballistic tables, as I mentioned previously. A careful re-reading of the accuracy analysis will verify this. This is figure for 75L48 HE at 550 m/s.

1m vertical dispersion at 800m for 50% of 75L48 HE is doppelte streung dispersion. Actual vertical dispersion at 800m is 0.45m above aim center and 0.45m below, double dispersion used in analysis is 1.0m above or below." {Lewis: So its now less? You are correcting yourself? You are using data from the L48 to prove out the L70 and L24? Thats the way its reading to me}

Response to calculations:

Now as far as your calculations, In your first attempt you seem to have calculated that the descent angles are less than the firing angle. This is really improbable. In reality most descent angles are steeper than the firing angle. I see that this is the case in your second calculations.

Do you need to use the updated 0.45 data or are you going to skip that? You are comfortable with having data from one gun and applying it to two different weapons? Why would the two different guns be able to use the same data anyway?

Did your calculations take into account the height of the gun? Why did you not comment on Ben's calculations? Can you relate the vertical dispersion numbers into angles?

5. Vertcal Dispersion:

Someone correct me if I am wrong but is the way that vertical dispersion as Rex et all takes it?

1. MEASURE the distribution of rounds that fall (actually this is horizontal dispersion).

2. CALCULATE the angles that would place those rounds where they fell so as to get an angle of fire.

3. CALCULATE (why I have no idea) the mean vertical height the trajectory of the calculated anngle would have. This seems to be what Rex is saying in his definitions.

If you had the calculated data from 3. above, then work your way backwards to get the 1. distribution of rounds? Does everybody agree? Disagree? Care to clarify or just repeat themselves? Is there a "Rex et all Hysterisis Gap"?

Maybe only Rex can answer but I think he wont. I am beggining to see a certain character here. He makes errors, changes data, wont answer requests for clarifications, etc.

Lewis

[Jeff Duquette]

ASL_Squadleader:

I would be interested to take a gander at your Soviet Munitions info. It might be interesting to bat about this info.

Regarding the remainder of your post...I concur.

[:USERNAME:]

OH! i just came up with a quiz:

You have 3 guns; A, B, and C.

A has velocity of 1 and a barrel length of 1

B has a velocity of 1.3, barrel length of 2

C has a velocity of 1.7, barrel length of 1.8

All three guns fire the same weight/size/diameter shell.

Q:Which of the three guns has put the highest G forces on its respective shell? Answer in order of most to least..

Neglect rifling for now..

[:USERNAME:]

Originally posted by Paul Lakowski:

As to APDS , one of the big problems is seperation of the sabot pelts or pot sabot after it leaves the barrel. If theres even the slightest contact with the subcalibre projectile it will 'kick in' a large amount of error or dispersion.

I used to think this was true also (It might still be a factor).

I recently sped-read through a book while researching fuzes. It appears that the real cause is wobble developed in the barrel as the shell goes down the rifled barrel. This was proved out because the x-ray photos were all showing that the sabots were leaving perfectly. It seems that the critical technique is in centering the very balanced tungsten penetrator as well as having highly balanced sabots. If there is a weight distribution problem it manifests itself in slight movement of the barrel that throws off the round!

It occurs to me that this would be a factor in any non-homogenous round. In steel AP rounds, this would be minimzed but in others (maybe HE too?) this could be a factor.

Also interesting in this book (written in 1948, I forget the name but will post it later, it is part of a series of books..) , is the US attempt at developing APDS for its weapons. Seems they were very close but the war ended. The author claimed that Tigers would have been KO'd from the front at 1500 meters by 76mm. Which flavor tiger is not clear. When they got the APDS right it also boasted the same accuracy as normal AP.

Lewis

[:USERNAME:]

Originally posted by Jeff Duquette:

ASL_Squadleader:

I would be interested to take a gander at your Soviet Munitions info. It might be interesting to bat about this info.

http://www.geocities.com/Pentagon/Base/1852/57mm.html#29

I have seen similar data showing 85mm AP and HE having the same velocities. But it seems that nothing could be further from the truth when it came to 45mm and 57 mm ATG's (see website).

Check out the toxic mercury tungsten round the soviets used in their weapons. Anyone here like to shot that at me in my car?

Lewis

[:USERNAME:]

I recieved an email from someone adding info to the German 75mm HE issue.

Lewis

You are probably correct that the listed 0.86 Kg weight of HE in the german 75mm KWK (34) shell is a typo. It more than likely is 0.68.

If it were 0.86, then it would have to be quite a thin walled long shell. Even a mortar round of this caliber would not have that much.

The mystery about the "other" HE shell might be some sort of projectile for bunkers and the like. A sort of semi-armor piercing shell with thick walls and reduced HE content.

I have seen many shell "lineups" (where either in museums or books the shells with cartridges for various calibers are put on end next to each other for inspection), and it would appear that the german 75mm projectiles all have about the same size to them.

I believe you are probably right and fear that you will enjoy that too much."

It was nice of him to write but I think hes a jerk. That reminds me, someone here wrote me out of the blue and I schooled his ass on pitch, yaw and roll. He gave me no credit when he immediately started using my stance that first round shots should have reduced hit chance because of this (I agree with BTS on this). He knows who he is and he is really an unsavory character in my opinion.

Lewis

[rexford]

I now have Diehl's original article on 75mm HE, found in my storage shed.

Following rounds have 0.853 kg of 60/40 Amadol bursting charge in HE:

KwK 37

StuK 37

KwK 40

StuK 40

Pak 40

Following round has 0.654 kg of 60/40 Amadol in HE:

Panther KwK 42

So 75L24 HE is not only more accurate than Panther HE against ground point targets, but short 75 contains more bursting charge. Since 75L48 HE is similar to 75L24 in muzzle velocity (an opinion that is seconded by my honorable adversary), it is no wonder that 75L24 and 75L48 HE have the same bursting charge.

Diehl's data supports Will Phelps' PzKpfw IV site, and the possibility of a typo on Mr. Phelps' site regarding 75mm HE has now been resolved in his favor.

My recent posts regarding effect of cant were researched over 15 years ago, and have not benefited from anyone's assistance in the last year, though help was requested in a direct e-mail which appears to have gone unanswered.

[rexford]

Double actual dispersion is normally used on first shot attempts to include errors that occur on the battlefield, as well as weapons that go out of adjustment.

0.45m on testing ground is 0.9m for first shot on battlefield and was rounded to 1.0m for convenience. 75L24 vs 75L70 HE analysis would yield same relative result regardless of the dispersion value that was used.

[rexford]

Lewis,

In both of my trajectory analyse's the descent angle is greater than the firing angle. See bottom of page 7.

Please read both analyse's.

Though the give and take has really been beneficial, and we were forced to dig up info that was out of sight and mind for years, we're moving on. This has gotten too booring, too repetitive and your comments are too often baseless. You can accuse me of whatever but we're (me and you trading posts) finished on the 75L24-versus-75L70 HE thread. You can continue if you wish.

And I never opened a post from you after asking for more info. Your posted comment on pitch, roll and yaw reminded me of previous work we did over 15 years ago, and we went back to it and used OUR PREVIOUS RESEARCH to analyze first shot impacts when gun is firing across an angle.

We have been at this for almost 30 years, and have looked at most things.

[rexford]

Here are my parting words on the 75L24 vs 75L70 controversy:

1. our trajectory analysis resulted in a firing elevation less than the descent angle, since the listed elevation angle was not used in the simplified trajectory equation.

More exact analysis clearly has firing angle less than descent angle.

2. German manual suggests using twice the testing ground dispersion on battlefield to model combat errors and misaligned sights. This was explained many times in past.

3. An e-mail was sent to Lewis asking for more info on pitch, roll and yaw. When a response was not forthcoming we re-examined our research from 15 years ago and started posting on the subject.

4. Earlier statement on 88L56 was a mistake, turns out that HE from that weapon is accurate even at high velocity due to small dispersion. Mistakes happen, especially when things must be explained over and over again, and then again and again, and ....

5. Trajectory analysis shows that 75L24 HE is more accurate than 75L70 given equal dispersion, or even when 75L24 dispersion is twice L70. 75L48 HE dispersion used because it was only 75mm HE data with dispersion, as was explained in earlier post (see previous comment on continuous explanations).

6. We found Diehl's original work on German 75mm HE. 75mm guns except Panther 75mm fired HE with 0.853 kg bursting charge of 60/40 Amadol. Panther 75 HE had 0.654 kg of 60/40 Amadol, so 75L24 HE had 30% more bursting explosive than 75L70, which supports concept that high muzzle velocity is associated with a decrease in weight of explosive.

7. Phelps' web site on PzKpf IV appears to present correct info on 75mm HE shells, comparing info on that site to Diehl article.

8. 75L24 HE trajectory is more accurate than Panther 75 HE against ground point targets, 75L24 HE contains more HE than 75L70 HE and 75L24 also fires cannister. with 960 9mm steel balls in each round.

9. We have German ballistic data on just about every APC, APCBC and HE round used during WW II, in original German and interpreted by a group of people we know.

[:USERNAME:]

[This message has been edited by :USERNAME: (edited 01-26-2001).]

[:USERNAME:]

sorry. I jammed everything with a triple post.

[This message has been edited by :USERNAME: (edited 01-26-2001).]

[:USERNAME:]

Originally posted by rexford:

Lewis,

In both of my trajectory analyse's the descent angle is greater than the firing angle. See bottom of page 7.

Please read both analyse's.

{Lewis: Lets have a look!}

{From page 7}

"75L70 HE took 1.2 seconds to reach 800m with 10 mil gun elevation, or 0.573° gun rise.

This is from German ballistic data that we have.

"75L24 (estimated from 75L48 HE ballistic data starting with 450 m/s at 1075m and going to 390 m/s at 1875m) takes about 1.905 seconds to go 800m.

Using our simplified trajectory equations, descent angles at 800m are 9.49 mils for 75L70 HE and 23.0 mils for 75L24. In terms of degrees this equates to 0.544° for 75L70 and 1.318° for 75L24."

{Lewis: Whats steeper 0.573 or 0.544 degrees? Whats the excuse this time? dentist? dog ate the calculator? I will give you credit. You are are consistant.}

Though the give and take has really been beneficial, and we were forced to dig up info that was out of sight and mind for years, we're moving on. This has gotten too booring, too repetitive and your comments are too often baseless. You can accuse me of whatever but we're (me and you trading posts) finished on the 75L24-versus-75L70 HE thread. You can continue if you wish.

{Lewis: Oh Thank you!!! But I dont need to accuse you of anything. Only point out that this was your last post but then again you posted one after this. I also note you continue to avoid technical questions. Just let me know when you have really quit rehashing bad points.}

We have been at this for almost 30 years, and have looked at most things.

LOL!!!!!!!!!!! Ponderous. I like the way BTS has disappeared from the thread.

Lewis

[Jeff Duquette]

Sorry...Lewis your posts are always so...uhhh...funny. I take it that you intend all your future posts here to be taken as jokes as well.

<embed src="http://www.geocities.com/jwduquette/laugh3.wav" width=145 height=60 autostart=false>

[This message has been edited by Jeff Duquette (edited 01-27-2001).]

[:USERNAME:]

Originally posted by Jeff Duquette:

Sorry...Lewis your posts are always so...uhhh...funny. I take it that you intend all your future posts here to be taken as jokes as well.

Weeeellllll.... since you are sorry.. I guess its OK. I think its funny how many clear errors were made by we-rex. They have alot of 'xplaining to do.

Try to get some sleep laughing boy.

[Jeff Duquette]

Ohhh…I think I have finally gotten all your points Lewis. I took the time to summarize your thoughts in the following wav.

<embed src="http://www.geocities.com/jwduquette/nothing2.wav" width=145 height=60 autostart=false>

[This message has been edited by Jeff Duquette (edited 01-27-2001).]

[:USERNAME:]

Originally posted by Jeff Duquette:

This is actually data for pzgr39 88mL56.

Thats about as clear as this post. Jeff the audio visual bandwidth killer.

Want to let us in on the ground floor Jeff? I like blurry lettering in other languages...

[This message has been edited by :USERNAME: (edited 01-26-2001).]

[This message has been edited by :USERNAME: (edited 01-27-2001).]

[Jeff Duquette]

Import it into a photoshop program. It will come out clear as a bell.

[This message has been edited by Jeff Duquette (edited 02-21-2001).]

[:USERNAME:]

Tried that already Jeffy. Cant make out the german. Is this the uber data that We-Rex is using?

[Jeff Duquette]

Try it now...it should be easier for you to comprehend.

[This message has been edited by Jeff Duquette (edited 01-27-2001).]

[ASL Veteran]

Okay, here is a cross section of Soviet guns as taken from “Russian Tanks and Armored Vehicles 1917 – 1945” by Wolfgang Fleischer.

152mm Tank Howitzer 1938/40

Barrel Length: L/24

Breech: Screw

Ammunition: Separate, with cartridge case

Weight & Velocity: AP 40kg @ 508 m/s; HE 51.07kg @ 432 m/s

Targeting: targeting scope T-5 152mm M.38 and Panoramic scope PT-5

76mm 1940 and 1942 Tank Gun (F-34)

Barrel Length: L/41.5

Breech: Semi-Automatic vertical wedge

Ammunition: Cartridges

Weight & Velocity: AP 6.3kg (BR-350 A) @ 662 m/s; HE 6.2kg (CF-350) 680 m/s

Targeting: targeting scope TOD-7; Panoramic scope PT-7

76mm 1939 Tank Gun (L-11)

Barrel Length: L/30.5

Breech: Semi-automatic vertical wedge

Ammunition: Cartridges

Weight & Velocity: AP 6.3kg @ 612 m/s; HE 6.21kg @ 610-635 m/s

Targeting: targeting scope I O II-6; Panoramic scope F.-6

76mm 1938/39 Tank Gun (L-10)

Barrel Length: L/30/5

Breech: Semi-automatic vertical wedge

Ammunition: cartridges

Weight & Velocity: AP 6.3kg @ 612 m/s; HE 6.2kg @ 555-635 m/s

Targeting: no data

76mm 1927/32 Tank Gun (KT-28)

Barrel Length: L/16.5

Breech: Screw with tension trigger and cartridge sealing

Ammunition: Cartridges

Weight & Velocity: AP 6.5kg @ 370 m/s; HE 6.2kg @ 381-387 m/s

Targeting: targeting scope 1930; Panoramic scope 1932

45mm 1938 Tank Gun

Barrel Length: L/46

Breech: Semi-automatic vertical wedge

Ammunition: Cartridges

Weight & Velocity: AP 1.43kg @ 760 m/s; HE 2.15kg @ 335 m/s

Targeting: TOD 1932 or TOL tank aiming scope with stabilizer; PT-1 panoramic scope

122mm 1943 Tank Gun (D-25 T)

Barrel Length: L/43

Breech: Semi-Automatic vertical wedge

Ammunition: Separate, with cartridge case

Weight & Velocity: AP 24.9kg @ 781 m/s; HE 24.9kg @ 800 m/s; HEAT 13.2kg @ 550 m/s

Targeting: Tsch-17 tank telescope hinged targeting scope.

85mm 1944 Tank Gun (ZIS-S-53)

Barrel Length: L/54.6

Breech: Semi-automatic vertical wedge

Ammunition: Cartridges

Weigth & Velocity: AP 9.02kg @ 792 m/s; HE 9.2kg @ 792 m/s

Targeting: Tsch-16 tank targeting scope (16-degree field of vision, fourfold magnification)

[:USERNAME:]

I see Jeff has alot in common with We-Rex. they both change thier mind about what they post.

You guys are too slippery for me. Jeff seems amused by his clogging up the board.

I stand behind everything I have said here. We-Rex cannot do anything beyond pontificate. HE cant discuss anything because HE wont address other peoples questioning concerning "HIS" 30 years of doing this.

The funny part is that he had a point but really mauled the data. He flip flops and crabs around in an indefite convoluted style. He makes sweeping statements like the following: "We can't argue with these figures, and would welcome analysis that shows them to be incorrect." Again, We-Rex changed his mind and lost interest.

The fact is the germans FIRED their HE from their tank guns at a lower velocity. The fact is that weapons like the L48 had a lower HE velocity than a sherman 75 HE shell (which people refer to as "low velocity"). I believe the 75mm M48 HE shell (this is an old design and was fired by all kinds of 75mm US weapons) was 2000 fps? If this is true (please correct me if I am wrong), then We-Rex's theory would state that the US weapon was inferior to the german 75 l24 and L48. It seems that the data on HE content also supports that the germans had an edge here.

I asked him to compare the L24, L48 and the L70... He never includes the L48 AND THATS THE WEAPON HE HAD DATA ON!!!! The reason I asked him to do that was because the L24 and L48 fought together in the german tanks. So did the the L48 and L70.

I really believe he wasnt clear on the vertical dispersion and I believe other people here would agree that he never clarified it. If the data was truly the "mean vertical height" of the trajectory (cmon, what does that even give you?), then:

1. It would have to be fired so that the weapon had the end of its barrel at ground level.

2. The fact that higher velocity weapons follow a projectile path that is initially flat that quickly drops off must be accounted for. Use the wrong math and then your "vertical dispersion" is introducing errors. Use the wrong math again to back out the horizontal dispersion and you are compounding this error. I would much rather have the actual horizontal dispersion data then to futz around with some calculated half understood parameters. I really frown upon people taking data from one weapon and applying it to where ever it suits them.

Finally, the Panther luckily had a coaxial MG that had a muzzle velocity very close to the main guns HE velocity. It could use the high rate of fire of the MG and the tracer effect to get the approximate range (and pin down the infantry) subtract some distance from the arnge and skip fire HE. Thats what I would do. His point is really moot in that guaging the range with infantry targets is very difficult.

I will take we-rex's post with a pound of salt in the future.

Lewis

[PzKpfw 1]

Originally posted by :USERNAME::

I will take we-rex's post with a pound of salt in the future.

Lewis

Speaking of that Lewis; I am still waiting for you to post your detailed theories on this topic & why Rex was wrong etc, when will we see it?.

Bcause if you cannot elaborate further yourself, despite being asked to, then why should we take anything you say in the future 'with a grain of salt' either, it cuts both ways Lewis.

Regards, John Waters

------------------

"We've got the finest tanks in the world. We just love to see the

German Royal Tiger come up on the field".

Lt.Gen. George S. Patton, Jr. February 1945.

[:USERNAME:]

Originally posted by PzKpfw 1:

Speaking of that Lewis; I am still waiting for you to post your detailed theories on this topic & why Rex was wrong etc, when will we see it?.

Regards, John Waters

I take it you read my last post?

I never said he was wrong (in theory) but that his data, that he never posts, is being misapplied and applied linearly to OTHER weapon systems! He has shown a pretty good record throughout this thread of waffling, mis-posting, making errors, not addressing questions I post so that he can clarify what he is talking about! He never describes his method of applying the data and expects everyone to accept it or he will become bored!

He tries to blow smoke. He makes statements like the L24 had more HE than the other 75mm german weapons and this further supports his "theories". This turns out to be untrue. He starts claiming velocities of 385 m/s for the HE for this L24, again, untrue.

He disregards the basic target size and the effect that has on the argument! It is absolutely relevant and is part of the basic theory he is making!

That is, "flat" trajectory guns have a variance in the vertical component of their trajectorys. When they are shooting at something like a tank or a house or any target with height, this variance does not play a big part. But if the target is characterized by not height but rather length and width (area target) then the variance can play a BIG part. I HOPE other people here actually understand this and somewhat agree! But the fact is that the targets length and width have also VARIED!!! Its a multivariable situation and very much part of this discussion. It is not something I am just throwing in but a BIG part of what he is saying. If he (or them, I cant figure the we-rex part out) cant see that, then theres no point in even discussing anything with him.

As other people here have asked of me, I have a problem with the way he applying the data and trying to jam it down the throat of reason.

I think alot of good came out of this discussion and I HOPE that BTS takes notice of some of the data here.

Most important:

1. Is the sherman with its antiquated M48 HE shell from the turn of the century NOT the uber gun that everyone claims it to be?

2. Is it susceptible to this velocity effect that rex-et all is putting forth? Is its velocity actually higher than the L24 and L48 german guns?

3. Why do people think that just because a weapon is of a lower velocity that it actually isnt putting more stress on a shell? Thats my point in the quiz. Maybe thats hard for people to get their minds around. I am willing to discuss and post acceleration data. Maybe its pitfall thinking I dunno. Clearly BTS was thinking this way.

Alot of this goes back to my initial discussions with Steve of BTS about the superiority of the StuGs over shermans as close support weapons. He claimed the german gun L24 was so much better than the L48 and the sherman uber-75mm was better than both. I noticed his ears perked up when there was a claim that the 75mmL24 was jam packed full of HE goodness but we havent heard from him since.

I think in light of Jeffs fascination with posting board-clogging A/V aids that there is a need for a moderating prescence here and I will wait for some sort of BTS response/interdiction.

Lewis

PS I am openly challenging Rex and his posse to show, in detail, how they are mathematically using the data and posting this data in a clear manner. The challenge is to clearly explain the mathematics behind your numbers. If you solve for something, then show your work! Dont just list the answer! You claim to be a physicist or something, no?

Since you have data on the 75mmL48 and the 75mmL24 fires the same HE shell, then work the problem that way. Use a similar "variance" (and show how this variance is used to calculate your answers) for the 75mmL24 and use double variance. I cant believe the shorter barreled weapon would have less of this effect. Take into account a MKIVH and a any panzer or assault gun you like with a 75mmL24. Use the vehicle height and assume a flat plain and targets at 800 meters and 400 meters. List your superelevations and descent angles. Show the horizontal shell distribution at the ranges.

I cant believe someone that claims to investigate plasma effects could not do what I am asking.

[This message has been edited by :USERNAME: (edited 01-27-2001).]

[:USERNAME:]

http://library.atlantic.edu/amatol/p-061%20The%20Plant.html

Found this while researching Amotal. Seems its town in Joisey. Go figger, huh.

Theres a whole book, online, about a town in joisey, which exit?

Lewis