rexford Posted September 21, 2003 Share Posted September 21, 2003 Pages 84 and 85 in our book, WW II BALLISTICS: Armor and Gunnery, give gun sight magnification and field of sight figures for a variety of tanks and guns. Of interest are: M2 gun on early Grants and Lee (75mm L31) ========================================= 1.00x magnification, 11 degree field of view and uses roof top periscope that is vulnerable to linkage misalignment Not especially good on long shots due to no magnification, very limited field of view 37mm gun on early Grants and Lee uses periscope alongside gun with same characteristics as 75mm sight M3 gun on Early Lee and Shermans (75mm L40) =========================================== 1.44x magnification, 9 degree field of view is VERY limited, uses roof top periscope that is vulnerable to linkage mis-alignment. 37mm uses same sight type as M3 gun 2 pdr ===== 1.9x magnification, 21 degree field of view range marks limited to under 2000 yards (read where an Australian aimed at a fleeing armored car at over 2200 yards by guessing where the range mark would have been, and hit the car on the first try). 50mm Pak ========= 3.0x magnification with 8 degree field of view, it is said that when 50mm Pak reached the desert combat ranges suddenly increased by a significant amound. PzKpfw III and IV ================== 2.5x magnification amd 25 degree field of view 50mm L42 may have lower velocity than 2 pdr but gun sight magnification is almost one third higher. 88mm Flak ========= 5.0x magnification with 8 degree field of view 0 Quote Link to comment Share on other sites More sharing options...
Michael Emrys Posted September 21, 2003 Share Posted September 21, 2003 Originally posted by rexford: 2 pdr ===== 1.9x magnification, 21 degree field of view range marks limited to under 2000 yardsLorrin, I take it this is for the AT gun. Are the sights for the 2pdr gun on the tanks all the same? Michael 0 Quote Link to comment Share on other sites More sharing options...
rexford Posted September 22, 2003 Author Share Posted September 22, 2003 I don't know if the tank and anti-tank gun sights were different with 2 pdr, I've always assumed they were similar since the muzzle velocities are the same. Somewhere I read that the 6 pdr elevation in Valentine tanks was controlled by a harness that fit over the gunner's shoulders, which would not exactly make for the most accurate fine tuning of gun range settings. Hopefully the guy would not have the hiccups. I would appreciate it if someone could check our figures for the early Grant 75mm gun sight, 1.0x magnification seems awfully low. We have ARMORED FORCE FIELD MANUAL on Tank Gunnery, dated April 22, 1943, and the following magnification factors are given for Sherman and Stuart tanks: Sherman M3 75mm gun =================== Telescope M38 with periscope M4 1.5x magnification "The linkage arm connecting the periscopic sight to the elevating mechanism may get out of adjustment. the linkage is adjusted only by ordnance maintenanc e personnel." Telescope M32 with Persicope M3 1.0x magnification "This sight is used with the 75mm gun M3 in Medium tanks of the M4 series. The periscope M3 is substitute standard and will be used only until the periscope M4 is available." German sights also have exceptional light gathering characteristics so would be able to pick up targets at sunrise, sunset, in the rain or through dust and fog better than Allied sights. There is a story somewhere about a Tiger that blew apart a T34 formation in a fog, where the Tiger could see the T34's but the Russian tanks could not pick up the origin of the deadly accurate fire. The Americans in Europe noted that German sights worked better in low light conditions and during overcasts. [ September 21, 2003, 09:03 PM: Message edited by: rexford ] 0 Quote Link to comment Share on other sites More sharing options...
Moon Posted September 22, 2003 Share Posted September 22, 2003 Rexford, the 1x, 11 FOV figures correspond with what one could expect from early war AT Gun sights as far as I know. The Germans had a ZF 1x11 (used in the 3.7cm PaK I think) for example. So I guess it's entirely plausible to find something like this in an early war tank. Light gathering - yes, the Germans clearly had the edge here, both in design (the right combination of lenses) and technology (glass manufacturing, coating and purging). Not surprising I guess, considering that at the beginning of the 20th century something like 95% of the world's optical glass production was coming from Germany Martin 0 Quote Link to comment Share on other sites More sharing options...
rexford Posted September 22, 2003 Author Share Posted September 22, 2003 Paul Lakowski on the Tankers site posted the following: "Yes my father is an optics expert and was in the german army during the war. He remembered that the zeiss lenses had some gas suspended in the glass that increased clarity and allowed for better field of vision at higher magnifications [when compared to other armies optics]...I think the gas was argon?" 0 Quote Link to comment Share on other sites More sharing options...
Michael Emrys Posted September 22, 2003 Share Posted September 22, 2003 Originally posted by rexford: "I think the gas was argon?" Perhaps. I really don't know anything about German practice, but today I think nearly everybody uses nitrogen that has been carefully dehumidified. Added after rereading your post: If he is talking about the argon being injected into the molten glass during casting, that really is something I don't know anything about. What I had in mind with my statement about nitrogen was that it is introduced into the barrel of the lens during final assembly to assure that there will be no internal fogging in cold weather. Michael [ September 22, 2003, 07:10 AM: Message edited by: Michael Emrys ] 0 Quote Link to comment Share on other sites More sharing options...
rexford Posted September 24, 2003 Author Share Posted September 24, 2003 Tom Rodwell posted the following on Yahoo! Tankers site in response to a comment by Vasiliy Fofanov regarding German sight advantages: "The english for "breaking" translation is "articulated" or "hinged" (the latter is more literal) - the advantage is that the gunner can keep his head steady rather than have to move it up and down with the elevation of the gun. The disadvantage is that the sight is much heavier and more complicated to manufacture, requiring more lenses. Only the Germans really had the technological know how to do this at this period of the war without incurring a dramtic loss of either field of vision or magnification. Their sights also had better light gathering properties due to the lens coating and had a wider field of view relative to the magnification than the allied & soviet equivalents. " 0 Quote Link to comment Share on other sites More sharing options...
rexford Posted September 25, 2003 Author Share Posted September 25, 2003 The following info was compiled from posts on the Yahoo Tankers site which were contributed by Vasiliy Fofanov, CG Erickson and Bob MacKenzie: 1. German sights such as in PzKpfw III had sight remain stationary while gun elevated, as opposed to Allied and Russian sights. This reduced gunner workload and allowed faster target aim, although German sights were heavier and more complex. German sights were clearer, had higher magnification and a wider field of view for a given magnification. 50mm L42 sight would be much better and more efficient than 2 pdr telescope due to sophistication advantages. Vasiliy Fofanov submitted the following quote which would apply to differences between the simple articulated 2 pdr sight and PzKpfw III: "In order for the light to pass through the elbow of articulated sight, you need several extra lenses there, and of course every new lens reduces the brightness and sharpness of the picture. That Germans managed to produce the "articulated" sights that outperformed "non-articulated" sights of any nation that opposed them is really a fascinating feat of optics engineering." 2. British 2 pdr tanks used shoulder harness on gunner for weapon elevation, which was attached to a friction plate. This was supposed to help when firing on the move (gunner could counter up and down terrain by leaning in opposite direction). I have read where 2 pdr ATG sights were limited to a range under 2500 yards. My opinion is that shoulder harness would not allow fine tuning of gun elevation like a wheel. 2 pdr ATG seemed to have used elevation wheel. 3. Folks will check to see if 6 pdr tanks used shoulder hardness for elevation. 4. I would suspect that German tanks and anti-tank guns would be more accurate than Allied tanks beyond close range due to all the advantages. 5. The 1.0x magnification which we assumed for Grant 75mm based on prior research may have been in error, 1.44x may be more like it. We are looking for our notes from decades ago. U.S. did use 1.0x magnification scopes in Sherman and Stuart until better sights were available (states this in Sherman and Stuart gunnery manual), which may have been basis of our assumption for early Grants and Shermans. 0 Quote Link to comment Share on other sites More sharing options...
Michael Emrys Posted September 25, 2003 Share Posted September 25, 2003 Originally posted by rexford: 2. British 2 pdr tanks used shoulder harness on gunner for weapon elevation, which was attached to a friction plate. This was supposed to help when firing on the move (gunner could counter up and down terrain by leaning in opposite direction).Something about this does not compute. Assuming that the gunner is sitting upright, he could not possibly effect elevation by leaning unless there were some strangely complicated mechanical linkage between him and the gun, and I am sceptical that that was the case. He could effect it by hunching down or stretching his thorax up. That sounds so ridiculously awkward, I am surprised that such a thing was ever contemplated, but I guess it must have worked somewhat. I have read where 2 pdr ATG sights were limited to a range under 2500 yards.How far out was the round an effective penetrator against its anticipated targets? Not a lot of call for a sight that sees farther than the gun shoots. Michael [ September 25, 2003, 08:46 AM: Message edited by: Michael Emrys ] 0 Quote Link to comment Share on other sites More sharing options...
Joachim Posted September 25, 2003 Share Posted September 25, 2003 Originally posted by Moon: Light gathering - yes, the Germans clearly had the edge here, both in design (the right combination of lenses) and technology (glass manufacturing, coating and purging). Not surprising I guess, considering that at the beginning of the 20th century something like 95% of the world's optical glass production was coming from Germany Martin And not surprising that the Americans captured the town of Jena (50 miles in the Soviet sector, yes - that Jena for the Napoleonics here)) while the Soviets were busy heading for Berlin, took the specialists of the Carl Zeiss works in Jena and re-located many of them to their sector. Just imagine a T34/75L70 with Carl Zeiss optics and a Rheinmetall gun. My what-if post-WW2 favourite. Gruß Joachim 0 Quote Link to comment Share on other sites More sharing options...
Moon Posted September 25, 2003 Share Posted September 25, 2003 Michael Emrys, good point about the 2pdr. In fact 2500 yards is quite a lot. As a comparison, the German 2cm gun sight only had markings out to 1200 meters I believe. Martin 0 Quote Link to comment Share on other sites More sharing options...
Andreas Posted September 25, 2003 Share Posted September 25, 2003 Originally posted by Moon: Michael Emrys, good point about the 2pdr. In fact 2500 yards is quite a lot. As a comparison, the German 2cm gun sight only had markings out to 1200 meters I believe. Martin If the WW2 2cm worked on the same principle as the post-war Rheinmetall 2cm gun, its rounds would automatically detonate (Selbstzerleger) at 1,200m. 0 Quote Link to comment Share on other sites More sharing options...
rexford Posted September 25, 2003 Author Share Posted September 25, 2003 Robert Livingston provided the following information when I asked him about the Grant gun sight magnification: "I located the source for the 1x note I had written into Hunnicutt. It came from a list we got many years ago from the Bovington Tank Museum, a list of "Most secret" guns/ammo/sights for Brit and US tanks. It clearly says the 75mm gun M2 in the Lee/Grant used an M1 periscope enclosing a M21 telescope with a power of 1x." 0 Quote Link to comment Share on other sites More sharing options...
rexford Posted September 25, 2003 Author Share Posted September 25, 2003 2 pdr gunner with shoulder harness would probably have to raise or lower his shoulders to make it work. CG Erickson sat in a Matilda and I'll ask him about the exact workings. 0 Quote Link to comment Share on other sites More sharing options...
rexford Posted September 26, 2003 Author Share Posted September 26, 2003 The following site has some interesting drawings and photo's of the Matilda II turret interior, including the gunners shoulder harness for main weapon elevation: http://afvinteriors.hobbyvista.com/matilda/matilda2.html The gun sights were marked to 1800 yards, according to the article. 0 Quote Link to comment Share on other sites More sharing options...
rexford Posted September 26, 2003 Author Share Posted September 26, 2003 Following two sites have some interesting info on Valentine and Crusader. http://afvinteriors.hobbyvista.com/crusader/crus3.html http://afvinteriors.hobbyvista.com/val/val3.html Early Valentine with two man turret and difficult to load 2 pdr gun (see great photo of tight turret confines for two men). 6 pdr guns in both Crusader and Valentine reduced turret crew to two men (expanded Valentine turret allowed three in 2 pdr armed tanks), and 6 pdr elevated by shoulder brace or crutch. Commander was generally the loader in two man turrets, which probably would be much less efficient than the three man crews in PzKpfw III. 0 Quote Link to comment Share on other sites More sharing options...
rexford Posted September 26, 2003 Author Share Posted September 26, 2003 Info on Churchill gun elevation for 6 pdr: http://afvinteriors.hobbyvista.com/church/church2.html Some had shoulder brace elevation for 6 pdr gun, others had elevation wheel, according to article. 0 Quote Link to comment Share on other sites More sharing options...
flamingknives Posted September 27, 2003 Share Posted September 27, 2003 Interestingly, the shoulder harness elevation design reduces the size of gun you can fit in the tank as it needs to be balanced. It all fits with the British idea that cruiser tanks were to be used like cavalry, and hence should be able to fire on the move. Before the advent of stabilisers, the free elevation is the only way to do this. The 6pdr guns on the WWI tanks were free in both elevation and traverse to enable the gunners to fire effectively. Training involved firing the gun from the deck of a destroyer to simulate the pitch and roll. Some account relate that the standard of gunnery on the move displayed by the RAC was second to none pre-war. Unfortunately, it was still inferior to firing from a fixed position. 0 Quote Link to comment Share on other sites More sharing options...
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