Aircraft Economics the forgotten consideration

[RCAFson]

There is a long discussion about 17pdr accuracy with APDS and the potential reasons for it at the link below. The matter then got complicated as there seems to have been 3 different APDS Marks issued as the war drew to a conclusion.

17 pounder APDS - & 17 pdr in general.

Extracts from a US report: U.S. Army Firing Test No.3 U.S. Army Firing Tests conducted August 1944 by 12th U.S. Army Group at Isigny, France....

ww2talk.com

And then there is the question about what was the average engagement range in NWE in 1944/45. The US Army research suggested about 800 yards. (It is in one of the links in the above thread).

6 pdr APDS was quite accurate and consistent.

I wonder if 17pdr and 77mm (Comet) APDS differed?

 

[Shortround6]

I wonder if 17pdr and 77mm (Comet) APDS differed?

Most accounts say they were the same and the 77mm didn't appear to have problems or at least none that were so bad they required comment unlike the 17pdr.

However you had different barrels, different velocities and different powder charges at the least. Canadians seemed to have gotten at least adequate accuracy from the 17pdr using their APDS round. I believe the British later (several years?) adopted the Canadian design.

 

[Shortround6]

Probably half of that, at least when looking here.
It will take the advent of APFSDS to much improve that figure.

I didn't specify at what angle.

Most WW II ratings were done at 30 degrees or vertical or both.
By the 1960s a lot of ratings were done at 60 degrees as they were interested (in the west) at taking out T-54/55 and T-62 tanks with the 60 degree front plates.
However;

This is a generic curve. Individual projectiles exhibit different characteristics as to ricochet or skidding.
This "effective" curve is for kinetic energy projectiles.
Shaped charges are close the actual distance.
There are a crap load of graphs and charts that show difference in geometry on the web however what is overlooked is that geometry alone offers no advantage to sloped armor from a design stand point.

If we design a 3ft high nose plate 8in think that is vertical it will weigh 960lbs per foot of width.
If we design a 3ft high nose plate 4in think that is sloped 60 degrees it will weigh 960lbs per foot of width because we need an 6ft plate to cover the 3ft of vertical difference
Without that tendency to ricochet or skid the protection is the same.

We can argue about the weight of the top and bottom plates but that kind of misses the point.

There was some confusion in the past as to if armor was measured at degrees from vertical or degrees from horizontal which can obviously make a huge difference.

 

[tomo pauk]

I didn't specify at what angle.

You have specified the following:

Now what made the "universal" tank a workable preposition in the late 50s and 60s was the British/NATO 105mm gun firing APDS that could take out 50-65ton tanks at several thousand meters range.

That was not the case for the tanks that were of same generation as the British L7 gun.

 

[Shortround6]

You have specified the following:


That was not the case for the tanks that were of same generation as the British L7 gun.

The Conqueror tank and the big US T-29/34 series were intended to be heavies needed to tank on the Soviet JS-3 and later versions that western nations thought their Centurions and M-26/46/47 could not do.

This period does cover quite a number of years, like from the end of WW II to around 1960 so there is quite a bit of overlap. Since there was not a lot of information coming out of the Soviet Union (took until 1954-55 for the T-54 to become known the western press) tank development often tended to worst possible scenario. How much was known about the follow ups to the JS-3 in the 40s and early 50s?

The US and Britain didn't get their heavies into service until 1957 and 1955 respectively and by that time the British were well on their way to the L7 gun.
The Germans started the Leopard project in 1956 and I don't believe they had a heavy tank project (?) so the Leopard became the "standard" or universal tank for the Germans and a number of other NATO allies. It just took until 1965 for it to actually show up so there was a lot of time to change names, argue about force structures and all of that stuff.

The US never fielded either an APDS or APCR round for the M-103 120mm gun, It was full bore AP or HEAT for anti-tank work.
The Gun in the Conqueror used APDS and HESH so there was no interchangeability at this point. The L1 gun was also rated at '
"The APDS round had a muzzle velocity of approximately 4,700 fps (1,433 m/s) and could penetrate up to 15.3 inches (390 mm) of flat steel armor – or 120 mm (4.7 in) of 55-degree angled steel armor – at 1,000 yards (914 meters)." It also used a large, heavy brass cartridge case.

Now in the absence of good information of Soviet tanks, western design teams are going to use their own heavy tank designs as to what the Soviets could do as a "best guess estimate" and since it seemed to be taking 8-10 years to design and get an tank into service waiting for the latest Moscow parade to begin to design something new was not a giid idea.

Note that the L7 gun with APDS was very near to the performance of the L1 and the gun in the M103 tank (4.9in/124mm at 914meters at 60 degrees) so using L7 armed tanks and getting rid of (or stopping) that generation of heavy tanks in favor of a "universal" tank made a lot of sense.

 

[tomo pauk]

Thank you.

The Gun in the Conqueror used APDS and HESH so there was no interchangeability at this point. The L1 gun was also rated at '
"The APDS round had a muzzle velocity of approximately 4,700 fps (1,433 m/s) and could penetrate up to 15.3 inches (390 mm) of flat steel armor – or 120 mm (4.7 in) of 55-degree angled steel armor – at 1,000 yards (914 meters)." It also used a large, heavy brass cartridge case.

I think that we can agree on two things:
- 105 mm was not 120mm
- 1000 yds was not 'several kilometers'

 

[Shortround6]

Thank you.



I think that we can agree on two things:
- 105 mm was not 120mm
- 1000 yds was not 'several kilometers'

The 105 could equal or better the two 120mm guns of the 1950s, making the universal tank possible.
With APDS penetration difference was small with increasing range. The difference in velocity between 1000 meters and 2000 meters was about 6.3% So maybe 12% in penetration?
Perhaps the 105 could not guarantee penetration but since it was doing as well or better than pre-Chieftain's 120s the need for over 50 ton MBTs was greatly diminished.

There was also quite a difference of opinion in the late 50s and early 60s as some people thought that HEAT rounds and anti tank missiles made heavy armor (anything more than 20-50mm) obsolete as seen by the AMX 30 and the Leopard (not quite as extreme) and the French leapt in the HEAT bandwagon and it took until 1979 (?) for them to issue a kinetic energy AP round.

And then we can argue about differences between HEAT rounds and HESH (1962 ?) rounds so just about all of the L7 armed tanks had two different anti armor rounds in the tank.
Max effective range of either one of those was ????

edit, most people agree that in order to get a "kill" the HEAT rounds need a certain amount of over penetration.
Just like countries disagree on the actual KE penetration standards (what percentage of shots fired have to actually penetrate or what percentage of a projectile has to penetrate to count) there are different standards or criteria for shaped charge success, a hole in the armor only 2-3mm across may not count?

 

[ThomasP]

All NATO standard targets impact angles for armour penetration purposes are listed as degrees of strike from perpendicular. So if the penetration is being measured at perpendicular it would be listed as 0°. The following diagram is for the original M60A1 with the upper glacis plate marked to show the standard designation for the angle of impact vs a projectile traveling in the horizontal plane. For NATO purposes, a projectile penetration requirement might be descried as 120mm RHA at 64° at 2000m. Since the penetration of any given projectile is measured in testing against one or more of the NATO standard targets, it can be predicted (either through measured or calculated tables) at what ~range the projectile will penetrate a specific target such as the upper glacis of the M60A1.

In the Wiki tables tomo pauk linked to in his post#139 the UK/US 105mm L36A1/M392 APDS is listed as having a penetration of 120mm at 60° at 914m. These values indicate that the M60A1 upper glacis would probably not be penetrated at 914m.

Make sense?

 

[marathag]

From the Heer's point of view, probably the only shortcoming was that it came too late?

View is a good thing to bring up.

Hetzer had terrible crew ergonomics, and even worse view looking outside of the vehicle

Gunner has single periscope, TC has the stereo Periscope in the forward arc and additional rear facing periscope, and loader has that remote sight for the MG
Nothing with a great field of view.

You can't hit what you don't see

 

[Admiral Beez]

Not with that attitude
A handful Hurricanes were outfitted with radar for night fighting job, while Spitfire might've possibly mimic the Fiat G.55S and carry a torpedo.
Granted, we'd want two-engined A/C to be a night fighter and/or to be a torpedo bomber.

I don't think a single-engined Merlin equipped aircraft ever carried a torpedo.

Edit: Goodness me, I forgot about the Barracuda!

 

[Shortround6]

I suspect what was standing in the way of a 'universal' tank, or MBT at the outset of the war was doctrine as well as available guns.

But gun-wise, that's trickier. Most combatants started WWII with AT guns in the 40mm range (British 2-pounder, German 37mm, etc.). And for the thin-skinned tanks of the day that was enough. But for softer targets you wanted something shooting a bigger shell with more space for HE. So in a sense the separation between between the small caliber high velocity AT guns and low velocity large capacity guns for shooting HE made sense. Some efforts were made to combine both of these gun types in a single vehicle were made, like the M3 Grant, or the Churchill Mk I.

There are a few things that made it hard to make a Universal/MBT in 1938-41.

Gun armament is a problem as you have stated. Oddly enough it was the French who were closest followed by the Soviets.
The French were using a 47mm gun during the 30s and that an the Soviet 45mm were about as good as it got for gun that could fire HE and punch holes through armor.
The 45-47 made a much better 'pop' than the 37-40mm guns (HE content tends to go up with cube of the caliber) but was a far cry from 75mm weapons that went bang. 75mm being about the minimum that was considered sufficient for dealing with 'field fortifications' (things that regular infantry/artillerymen could construct using shovels and axes, etc. NO cement).
The smaller guns were useful for helping keep the defenders down and/or causing casualties but they took an awful lot of shells to destroy 5-6ft deep trenches/weapons pits.

The French promptly screwed up whatever advantage the 47mm guns gave them by using a 1 man turret. The Somua S35 was 19.5 tons (?) or just about the same weight as 1940 MK III & IV tanks. Using only a 190hp engine didn't help either, the 'book' speeds are pretty good but the power to weight ratio means you are not going to make 'book' speed in poor going.
good armor though
The Char B had the short 75mm SA35 L/17.1 gun (not howitzer, just because the barrel is short does not make it a howitzer) which might have worked IF they could have put it in a rotating turret with at least 2 men. They didn't, end of discussion for this post.

Soviet 76.2mm L26 & L 30 guns. These seem to be the best bets, They had both the HE power and at adequate penetration compared to the 45mm gun. Please note that the short L 16.5 gun gun was bit below the German 7.5cm L24 in performance (don't go by barrel length alone.)

Now we do run into a few physics problems, Even a moderate velocity 75mm gun has a fair amount of recoil and needs a certain size/quality of turret ring size to keep from cracking the ring after hundreds of rounds. You also need room in the turret to load the gun at most angles of elevation (Soviets tried doing away with that in the T-54 (?) and later tanks. Bit them in the butt with rate of fire. ) You also have to trade length of recoil (field 75mm guns could have 4 ft of barrel movement) for greater recoil loads on the turret ring and on the crew. The US tried to ignore this several times in US vehicle design history (or we are the only ones who confessed?)

OK, extreme example but 75mm guns (not short ones) in light tanks tend to have problems. However on the flip side note the longer recoil movement than a tank would have. A 90mm M-26/M-48 is going to have a much shorter recoil distance and a much greater recoil load/impulse.
You need a certain weight tank to handle the recoil load a 75mm gun in a tank (or you need a bigger turret) for successful, fast repeat shots.

75mm was also about the smallest you could go with smoke shells and get a worthwhile chemical payload. Perhaps this is not quite as important if you have fast, accurate and good artillery support (which nobody had in early WW II)

The Valentine XI got a 75mm gun but it weighed about 20.5 short tons, turret crew went back to 2 men, lost about 1/2 of it's machinegun ammo and had around 53 (?) rounds of 75mm ammo.

Hitting some really strange stuff on the internet. Like from WiKi on the New Zealand Valentines
"Trials in New Zealand had found that the locally developed 2 pounder HE shell lacked power, especially compared to the 18-pounder shell of the 3-inch howitzer, so 18 Valentine Mk III were converted to Valentine Mk IIICS standard by having their main armament replaced by the QF 3-inch howitzer taken from Matilda Mk IVCS tanks"

Misprint for 14lb shell?
Nobody fired 18lb HE shells out of any 75-76-3in gun. (British 17lb AT guns fired 15.4lb HE shells)
British 18-pounder guns were 83.4 mm bore, good luck firing that out of 76mm barrel.

 

[GrauGeist]

View is a good thing to bring up.

Hetzer had terrible crew ergonomics, and even worse view looking outside of the vehicle
View attachment 752698

View attachment 752699
View attachment 752696
Gunner has single periscope, TC has the stereo Periscope in the forward arc and additional rear facing periscope, and loader has that remote sight for the MG
Nothing with a great field of view.

You can't hit what you don't see

However, the Jagdpanzer 38 typically operated from ambush and was highly effective in that role.

 

[WARSPITER]

Parts manufactured in batches meant that some models of German tanks were not easy to differentiate.

A lot of early Panther G models were still sent out with Panther A turrets without the chin guard.

Some Tiger I photos show one side with the old type side skirt on one side and the new type on the other.
Components were taken from a batch and used up with the next batch having a modification. There are a lot
of arguments as to the exact production type shown in a photo because of this.

The Panther turret was originally a rejected design for the Tiger I which was supposed to get the Kwk 42 gun. The
turret was rejected as it had too many angles on the sides for flat shots to come in. The Tiger ended up with the
taller one piece horseshoe turret and the L56 88mm instead.

The Sherman firefly needed the gun turned 90 degrees so loading was from the left rather than the top. 17lbers had
to be specifically manufactured for the Firefly as the barrel and other parts had to be changed as well.

The Hetzer gun was the standard L48 which created a problem for the loader. To allow the driver and gunner room
to operate the gun was fitted to the right side of the vehicle. The loader the had to fit in behind the gunner on the
left. This meant the loader had to load rounds over the top of the gun as it was accessed from the right side and
the loader was on the left. Sometimes there isn't a way around these things so the saying that there are no
solutions - only trade offs comes to mind.

Most of the main German tanks/assault gun/TD types had poor situational awareness at closer ranges. The gunners
in Panzer IV, Stug, Panther and Tiger I only had the telescopic sight - no panoramic view or periscope. The only
person in the Panther with a view to flanks and rear was the commander. The driver and hull gunner had a periscope
system but neither rotated. Both looked forward and to the side (one to ten o'clock and the other to one o'clock).

I assume there were trade offs in aircraft models as well. I suppose the juggling act must have been to make sure
that the advantage of a modification wasn't outweighed by and disadvantages it could cause.

 

[Denniss]

There is not Panther G turret, it used the same turret as Panther A. The chin mod was a late 44 thing but was only slowly coming up into the Panther G production.
There was no Hetzer, there was a PzJ 38t and later JPz 38, the gun was not the standard L/48 tank gun but a modified one for use in Stugs.
I believe the cupola had 360 degree vision
I never heard of the Panther turret being designed for the Tiger I, the gun was an option but I have never seen drawings with a turret looking similar to Panther.

 

[GrauGeist]

There is not Panther G turret, it used the same turret as Panther A. The chin mod was a late 44 thing but was only slowly coming up into the Panther G production.
There was no Hetzer, there was a PzJ 38t and later JPz 38, the gun was not the standard L/48 tank gun but a modified one for use in Stugs.
I believe the cupola had 360 degree vision
I never heard of the Panther turret being designed for the Tiger I, the gun was an option but I have never seen drawings with a turret looking similar to Panther.

Both the Porsche and Henschel turrets for the Tiger were identical.

Wasn't the turret used on the Panther originally designed by Rheinmetall-Borsig for a tank destroyer?

 

[WARSPITER]

There is not Panther G turret, it used the same turret as Panther A. The chin mod was a late 44 thing but was only slowly coming up into the Panther G production.
There was no Hetzer, there was a PzJ 38t and later JPz 38, the gun was not the standard L/48 tank gun but a modified one for use in Stugs.
I believe the cupola had 360 degree vision
I never heard of the Panther turret being designed for the Tiger I, the gun was an option but I have never seen drawings with a turret looking similar to Panther.

Yes the Panther G used the A turret but the chins weren't on the mantlets from day one as production had to continue so they went with what they had.

You and I know the Hetzer wasn't officially a Hetzer but most other people don't so using the name is usually better to avoid confusion.
The Hetzer used the Pak39 but the Stug used the Kwk40 gun as in Panzer IV. No doubt there would have been some differences in all three.

The Rheinmetall-Borsig turret was designed to take the newer 75mm gun and was originally to have been used on the first series run of the Tiger I.
This would have been the first 200 vehicles. The other reasons it wasn't were that the gun itself wasn't sorted and the 88 received upgraded AP
shells. Interesting that the Tiger I was meant to be an interim vehicle while the actual "new" heavy tank was sorted and yet it became one of the
most famous tanks ever made.

Both the Porsche and Henschel turrets for the Tiger were identical.

Wasn't the turret used on the Panther originally designed by Rheinmetall-Borsig for a tank destroyer?

Porsche and Henschel turrets are certainly a misnomer considering they were both designed and built originally by Krupp.
The "Porsche" turret was from a design first drawn up in 1941 when Krupp worked with Porsche on a heavy tank which
was eventually cancelled due to a lot of envisaged problems - complexity and reliability being foremost (Elefant comes to mind).

A lot of the first turret type were ordered and made apparently for testing purposes. This was the turret with the rounded front
and bulging left side for the cupola.

The "Henschel" type was a different design, again by Krupp mainly to make production easier.

When the first Tiger II's were being manufactured there were all these older turrets already made so the first fifty tanks were
produced with the earlier "Porsche" type turret. There is a story that Porsche was so confident he was going to get the
go ahead for his heavy tank that he ordered the turrets himself but I haven't seen anything that backs that up. Maybe,
maybe not.

 

[GrauGeist]

Porsche was supposedly going to land the contract for the Tiger (I) and built a hundred or so VK45.01 chassis (which later became the Ferdinand), but the turret was much different.

Using the "Porsche" versus "Henschel" turret nomenclature is easier than saying "the first fifty turrets manufactured by Krupp with the rounded front, ordered for the Porsche VK45.02(P) which never entered production and ended up being installed on the Henschel VK45.03".

 

[WARSPITER]

Exactly.

 

[Engineman]

Parts manufactured in batches meant that some models of German tanks were not easy to differentiate.


I assume there were trade offs in aircraft models as well. I suppose the juggling act must have been to make sure
that the advantage of a modification wasn't outweighed by and disadvantages it could cause.

Yes. And really, this is true of many things. What is interesting is sometimes how fine the line can be between an advantage that makes an item a clear winner and the difficulty in defining that advantage before actual use of the item. Horses for Courses, is another deciding factor, where changing the operating circumstances improves or worsens the advantages of a particular thing. Certainly, Military equipment has often been reassigned to different environments or threats to maintain a level of success where the weakness that an item has is less of a problem.
Goes back to the dawn of time. Was it better for a fighting man to have a shield and a sword, rather than two swords, in his hands? Generally, one of each was a standard for hand to hand fighting, so along came the bow and arrow.. etc,etc.

Eng

 

[gruad]

Although the ground war isn't my field, I think calling the Tiger "absolute rubbish" is pretty indefensible as a statement. The Allies went to very considerable effort to ship working captured Tigers home for study, so clearly they didn't think it was "absolute rubbish" at the time. Indeed if you look, you`ll find many people saying the Sherman was absolute rubbish for brewing up at the drop of a hat an incinerating the crews. So you can make the arguments both ways.

Fair point! In context it was meant to say that the Tiger was rubbish economically in that while it met a need economically early on, by the time of the Tiger 2 There was no real need for a breakthrough tank that gobbled gas and transmissions.

The Allies didn't have to destroy these things. They just had to wait for them to run out of gas or breakdown.

Hitler wasted his money on vanity projects. The allied planners were very precise in allocating resources to where they were needed.

An example of that was the Ronson Sherman problem that got resolved very quickly as it was a real problem.