DogDodger

Ah, if it was converted from an M32B3 then it's an M74B1.

M74, perhaps?

M26 was rated for 60% (31 degrees) as well.

For the record, the design to which I was referring as poor was the final drives, not the Panther per se. Going over all of its inherent pluses and minuses would take a longer post.

As we discussed previously, the design itself was poor because it was known that the available materials were not up to the task. Spielberger says that a higher-strength steel was intended for the gears, but after this was "unexpectedly" replaced no alterations in the design were made (and depending on when this replacement occurred, alterations may have been impossible). The report was from Hauptmann Noak, commander of s.H.Pz.Jg.Abt.654, and was written on 24 July 1944, before the final drive improvements, to be fair.

Ha, thanks! That's awesome, I didn't even realize until you said something. Unbalanced loads are hard on tracks: e.g., the weight imposed by the Tiger Ausf.B's overlapping Staffellaufwerk was biased to the inboard portion of the tracks, resulting in track pins bent to the point that they couldn't be pulled out of the link.

Definitely unexpected results! Interesting assertion about the reduction gear preventing the Pershing's torque converter from slipping and that the Soviets found it performed well on slopes. In Marine Corps Tank Battles in Korea, Gilbert says, "The M26 was a powerful vehicle, but as the tank crews soon discovered, if it stopped on a steep gradient the transmission would slip, and it was difficult or impossible to get it moving again. Help was needed and Eugene Viveiros, who, with one of the Headquarters Platoon [Sherman] blade tanks, attached himself to the 3rd Platoon, was ready to supply it. He was called upon 'to pat them on the butt end with the blade of the 'dozer tank to shove 'em up and get 'em going again. Once they got traction, then they were all right,' Viveiros explained." Although at least some Army Pershings arrived in Korea in need of repairs or overhaul, these USMC tanks were in decent working order (despite a shipborne flooding mishap en route), so this wasn't a maintenance issue: in a discussion on the state of Korean Pershings over on TankNet Ken Estes said, "...the USMC [Pershings] were drawn from depots, with no miles...all the USMC WWII flame tanks and postwar M26s went from storage through the depot line before being shipped to the units." Any idea what "average technical speed" means? Too bad the off-road test was cancelled; didn't General Fedorenko know that people would be arguing about these things on the Internet 80 years later??

If it doesn't count as spam, there are some pictures of the spaced-out suspension on a hybrid M4 here.

Ha, thanks. Flattery will get you...well pretty far, I suppose. Indeed. The state of German automotive technology was unprepared for mass-production of a 45,000 kg tank. As we've been over, and as Spielberger notes, "Since it was envisaged to produce the Panther in large numbers, production costs of various subassemblies would have to be kept to a minimum...If it had been possible to foresee what difficulties the final reduction gearing was to cause, it would have been a much better solution to have selected a more expensive final drive which provided a greater degree of reliability. In the end, the final drive proved too weak to handle braking with the Klaue disk break [sic] when steering through tight curves. The use of epicyclic gearing for the final drive hinged upon the bottleneck being encountered in the supply of gear cutting machines for producing the hollow gearing. When passing judgement on the double-spur final reduction gear it should be noted that the high-quality steel originally planned for the spur gears in the final drive was not available for mass production and was unexpectedly replaced by VMS 135 (today 37 MnSi5) tempered steel (not as suitable for this purpose)... "The final drive (gear teeth and bearings) was the weakest part of the Panther. It was a risky proposition to use a spur gear system for transferring the drive power - especially considering that the available steel during the war did not have a particularly high stress tolerance. A better solution would have been to use an epicyclic gear system; a prototype final reduction drive using planetary gear reduction had already been tested and had performed flawlessly. However, as mentioned previously, a shortage of gear cutting machinery for the hollow gearing prevented this type of final drive from being mass produced. In order to bridge the gap a final reduction gear system was installed in front of the main gear drive, but due to installation restrictions its mountings were far too weak and could not be strengthened. Because of gear teeth breaking under too great a load and the weak mountings, the gears were pushed out of alignment - virtually guaranteeing mount and tooth breakage. "The general consensus in the industry was that inner-toothed gear wheels could not be produced due to a lack of proper machinery. This meant that a final drive using planetary gear reduction and pre-selector spur gearing - found to be reliable in company testing - could not be installed in production tanks. All attempts to improve the final drive met with failure, despite the offers of a special bonus as an incentive..." To quantify this a bit, Ristuccia and Tooze in "Machine tools and mass production in the armaments boom: Germany and the United States, 1929-44" note that Germany did make strides in increasing the number of gear-cutting machines in service, going from at least 10,407 in 1939 to 28,621 in January 1945. Even with these increases, compared to the US there were only 0.74 gear-cutting machines per German metalworking employee in 1945.

Could be, haven't read about that. Interesting, thanks; what is this from? Ogorkiewicz differentiates between double-differentials and the Panther's steering system, and has a pretty high opinion of it: ... Seeing M48s in person, the gun seemed a bit unimpressive compared to the size of the vehicle to me as well. The original cupola was pretty slick, but couldn't be reloaded from under armor, of course, so the bad M1 cupola was a go. Because he's the assistant driver; the radio was in the turret bustle. Perhaps a better question would be: why was the assistant driver not provided with duplicated controls in all US designs? The TC's cupola has a rotating periscope in the hatch door, as well. As we mentioned earlier, trials at Aberdeen indicated that the T26E1 was better cross-country than the HVSS Sherman. We're lamenting the M26's near-vertical turret armor while comparing it to the Centurion? The M26's performance in Korea can be considered an outlier as far as reliability goes. MacDonald et al in "The Employment of Armor in Korea," vol.I, noted, "The M26 tanks were a later World War II development and were in a generally poor physical condition." And when discussing the cannibalization required due to spare part scarcity: "This situation was aggravated because many of the tanks brought to Korea had seen extensive service elsewhere or had deteriorated while in storage. One battalion with M26 tanks departed the US with all but 10 to 12 tanks in unsatisfactory operating condition. These tanks, in operation since 1946 in troop training, were in serious need of complete overhaul." Scarce indeed. In Korea, the physical width of the tank precluded some routes, and the steep hills were taxing, but what issues were prevalent off-road? The Pershing wasn't really a heavy tank, as noted earlier. It was named a heavy for morale purposes for a couple years, but actual heavy tanks were in development. The T26E5 was tested starting in July 1945 and performed well besides having to take it easy over rough ground to avoid suspension damage. World War II was over, though, so a prototype was all that was going to be produced. Panther's steering design was clever, but in practice the final drive design and material hindered this advantage since using the steering brakes caused the final drives to shear, no?

The 90 mm gun T54 was in response to the PITA of loading the separate projectile/propellant case of the 90 mm gun T15E2 found in the T26E4 Pershing. The 90 mm gun T15E2 was in response to the PITA of loading the unitary ammunition for the 90 mm gun T15E1, which was fitted to the first T26E1 pilot and sent over to Europe during World War II, and whose adventures can be read in Hunnicutt's Pershing and Irwin's Another River, Another Town. The T54 gun went back to a unitary round, but the propellant case was shorter and wider, which eased handling in the confines of the tank but kept the chamber volume and ballistics equal to the gun T15E2. Two M26 pilots were armed with the T54 and designated M26E1; forty-one 90 mm rounds were stowed, with five in the loader's ready rack and the rest in the hull floor bins. Tests were conducted from 1947-1949, and the T54 was deemed the best extant US tank gun. Then nothing else happened with it... MV with AP-T was 3,200 ft/s (4.9" RHA penetration at 1,500 yards and 30 degrees); HVAP 3,750 ft/s (7.7" RHA at 1,500 yards and 30 degrees).

You might be able to get close with extra normally-spaced road wheels, but then you risk getting into TOG- or T-35-sized length, which would itself affect maneuverability. Not suggesting that the Schachtellaufwerk is worth the effort (the caveats at the end of the post hint toward my opinion), but when comparing the Pershing and Panther, just wanted to point out that nominal ground pressure tells far from the whole story. Perhaps Schachtellaufwerk might be thought of as almost a sort of technology demonstrator: outstanding softer-terrain performance though not necessarily cut out for the ease of use desirable for a war machine. Not the lifting capacity per se as I understand it, but as N-L-M said, more of an issue of the products which were presented. Armored Force commander MG Devers said in December 1942, "Due to its tremendous weight and limited tactical use, there is no requirement in the Armored Force for the heavy tank. The increase in the power of the armament of the heavy tank does not compensate for the heavier armor." Hunnicutt opines that the Armored Force would rather have shipped two medium tanks than a single heavy tank. But of course, the heavy tank that Devers was talking about was the M6, so it's no wonder...

You have high standards for ground clearance. The Pershing was designated as a heavy for a short while, but was begat by a medium design; actual heavy designs were ongoing but didn't see service before the war ended. Hunnicutt and Yeide agree that the "heavy" nomenclature was mostly for morale purposes. I'm not sure it was quite as bad off-road as you make it seem, but I do find the T25 a tantalizing what-if. Panther used a geared steering system and not a triple-differential, no? The nominal ground pressures were indeed similar (and even favored the Pershing, depending on the source), but the Panther's mean maximal pressure and other off-road performance characteristics would benefit from its maintenance-unfriendly road wheel setup. Wong has some interesting simulations in Terramechanics and Off-road Vehicle Engineering between a baseline M113-type vehicle with 5 road wheel stations, the same vehicle with 6 road wheel stations, and the same vehicle with 8 overlapping road wheel stations. The simulations are run on snow and clayey soil, and the machine with more road wheels shows better performance in everything from wheel sinkage to drawbar pull to tractive effort to trim angle, etc. Panther weighed 6.9-8.6% more than the M26, but its tracks were 2-3" wider and it had 2 more road wheel stations per track in the same ground contact length and essentially the same track pitch (5.9" for the Kgs 64/660/150 vs. 6" for the M26's tracks). Double torsion bars were probably needlessly complex, the interleaved wheels required inordinate effort and time for maintenance, and the final drive was never adequately strengthened, but credit where due: the thing should perform quite well off-road.

Of course, I took it as a figurative statement. What I was hoping to illustrate, though, was that despite being ~17,000 lb heavier than an HVSS M4A3 and having essentially the same engine, the T26E1 was a large improvement in cross-country mobility with just a single torsion bar supporting each road wheel pair. The Panther's system doubtlessly provided a good and stable ride, but should the improvement over a single-bar system have justified its implementation? Germany was never going to out-produce its enemies, so a strategy of "qualitative" enhancement was logical, but it still seems that discretion is the better part of valor in some areas, especially when your tanks are expected to fire from the short halt. Could you please expand on what you mean by Pershing was not a finished vehicle as a medium? Thanks. Although tank maintenance was a struggle for all US tank types in Korea, especially in the first year of the conflict, the M26 still showed itself to be the least reliable in that theater. To be fair, many of the M26s shipped to Korea were in poor condition and some overdue for overhauls, so the M26's performance there may be an outlier... One was designed, but it seems it was not possible to actually manufacture it in the numbers needed to install on the new medium tank. Spielberger notes an epicyclic final drive had been tested successfully, but "a shortage of gear cutting machinery for the hollow gearing prevented this type this type of final drive from being mass produced." So spur gears with weakish steel were used by necessity.

Thanks The Pershing was labeled a heavy tank from 29 June 1944 to May 1946, mostly for morale purposes. It was begat from a program to replace the M4 medium tank, and there were actual heavy tanks being concurrently developed. The M26, though more heavily armored than its T25 sibling, still weighed over 34,000 lb less than the heavy tank M6. In September 1944, i.e., two months before the 90 mm gun, 92,000 lb T26E3 emerged from the T26E1, the Ordnance Committee recommended the development of the 105 mm gun, 141,000 lb T29 and the 155 mm gun, 142,000 lb T30. These were the US heavy tanks. Production of 1,200 T29s was requested on 1 March 1945, but of course the war ended before this could occur. Also, the passage of the post being replied to was referencing the suspension systems specifically, as I understood it? The M26's relatively low power:weight became an issue in the mountains of Korea, but cross-country its single-torsion bar suspension (and automatic transmission?) could be quite an improvement over even much lighter tanks: A race was held at Aberdeen Proving Grounds' Churchill cross country area involving T26E1, T25E1, HVSS M4A3, and VVSS M4A3. The T25E1, being torsion bar-sprung and having a pretty sprightly weight, came in first with a 23-minute time. The heavier T26E1 was second at 26 minutes. The M4A3s, with the same engines but ~13,150-17,750 lb less weight than the T26E1, crossed the line in 28 minutes 25 seconds for the HVSS machine and 30 minutes 40 seconds for the VVSS machine. So perhaps "immobile" is a bit unfair, and perhaps the double torsion bars were in fact a bit of luxury.

Depends on what military leaders and which doctrinal publications one reads, I suppose. In October 1941 Armored Force commander Major General Jacob Devers was on the record saying the desired defense to have versus enemy tanks was more tanks, which echoed the viewpoint of the previous Armored Force commander, Major General Adna Chaffee. US medium tanks M2 and M3 and light tanks M2A4/M3/M5 were all topped by extant 37 mm antitank guns, and it was intended to arm the M4s (along with the 75 mm gun and 105 mm howitzer thanks to its interchangeable turret front plate) with the 3" antitank gun later found in the GMC M10 and heavy tank M6 (which was armed with both 37 mm and 3" antitank guns). The 3", of course, turned out to be too unwieldy for the medium tank turret, hence the 76 mm gun's genesis. But on the subject of doctrine, Armored Force field manuals consistently listed enemy tanks as potential targets for friendly medium tanks. In March 1942, FM 17-10 Armored Force Field Manual: Tactics and Technique directed, "Medium tanks...protect the light tanks against the attack of hostile tanks. When the enemy is composed of mechanized troops, a large medium tank component, if available, is held in the reserve." Referring to GHQ tank battalions, this manual advised, "[Medium tanks] are used offensively against hostile tanks...During the course of an attack GHQ tank units may be used offensively, in conjunction with other available antitank measures, to attack hostile mechanized forces threatening to break up or disorganize the main effort...GHQ tank units attached to army corps or divisions may be used in large numbers to break up hostile mechanized formations." The September 1942 edition of FM 17-33 Armored Force Field Manual: The Armored Battalion, Light and Medium included the "support by fire [of] the advance of light tanks, other medium tanks, or infantry in tank versus tank action" among the uses of medium tanks. The December 1944 revision of FM 17-33 asserted that medium tanks may be used "[w]hen necessary, against enemy tanks", and indeed one purpose specifically assigned to 76mm gun medium tanks was to "reinforce the antitank defense of a supported infantry unit." Similarly, technical manuals for the Sherman also evinced the intention of taking on enemy armor with both 75mm and 76mm guns. TM 9-731B Medium Tank M4A2 from January 1943 suggested that fully 40% of the 75 mm ammunition loadout should be armor-piercing, and TM 9-759 Tank, Medium M4A3 from September 1944 alleged that both the 75 mm and 76 mm guns were "employed chiefly against enemy tanks and other ground objectives." So while not all FMs said tanks were the primary antitank weapon, taking on enemy armor was a main mission listed in others. Indeed even the Tank Destroyers themselves recognized this: FM 18-5 Tank Destroyer Field Manual Organization and Tactics of Tank Destroyer Units from June 1942 says of TD battalions attached to armored divisions or GHQ tank groups: "Tank destroyer battalions with armored divisions are not the only units fitted for offensive engagement against hostile tanks as is the case with other types of divisions..." The July 1944 edition of FM 18-5 Tactical Employment Tank Destroyer Unit noted in the section describing TD attachment to armored divisions, "Since the armored division can meet strong armored attacks with effective organic weapons, tank destroyers may execute secondary missions on rare occasions, even when a hostile armored attack or counterattack is imminent." During study and the extractions of lessons directly after WW2, the General Board of the European Theater explicitly stated in its postwar studies that "[t]he European campaign demonstrated that tanks fight tanks," and also that the "current thought is that the medium tank is the best anti-tank weapon." The January 1946 report by the War Department Equipment Board agreed with the General Board, saying, "The best antitank weapon is a better tank." Re: the other mechanization proponents listed, there seems to be agreement that tanks are an important, if not primary, antitank weapon. In Tanks in the Great War, Fuller describes his view of future war: "The tank fleets under the cover of dense clouds of smoke, or at nighttime, move forward, not against the body of the enemy's army but against his brains...What is the answer to this type of brain warfare? The answer is the tank; the brains will get into metal skulls or boxes, the bodies will get into the same, and land fleet will maneuver against land fleet...If the enemy will not accept peace terms forthwith, then, wars in the air and on the earth will take place between machines to gain superiority. Tank will meet tank and, commanded from the air, fleets of these machines will maneuvre between the defended ports seeking each other out and exterminating each other in orthodox naval fashion." In Armoured Warfare, he says, "...the art of attacking will largely consist in establishing moveable strong points from which carefully directed fire can be brought to bear on the enemy's machines, whilst other forces of moving machines drive him towards them...In these battle tactics there is one minor point that requires examination, and that is--how wil tank engage tank? I think the eventual answer to this question is likely to be that normally tank will not engage tank, but instead that tank unit will engage tank unit." Indeed, Holden Reid says of Fuller: "Fuller's view of mechanized battles was...[t]he decisive act of battle would be the tank versus tank encounter or, depending on conditions, the tank verus anti-tank gun. Tanks should be armed, then, with small calibre armour piercing guns which could destroy their own kind." In the Christopher Duffy translation of Achtung--Panzer!, Guderian says of tank-versus-tank combat: "Military literature tends to steer clear of this subject, invoking as an excuse our lack of experience. This attitude cannot be sustained over the long term. We will unfailingly be presented with the reality of tank versus tank action in the future, as we have already established, and the outcome of the battle will depend on the issue of that combat, irrespective of whether or not we are cast in the role of attackers or defenders...The tank's most dangerous enemy is another tank. As soon as a tank force identifies enemy machines, and is in a state to do battle with them, that force is duty bound to drop all its other missions and engage in combat. This also happens to be the best service we can render to our own infantry, since they will be in as much danger as our tanks if the enemy manage to break through with an armoured counter-attack...We cannot be content with training for individual combats of tank against tank. We must reckon on the appearance of large forces of tanks, and it is much more useful to work out how to manage combat on this scale." In Constantine Fitzgibbon's translation of Panzer Leader, he says of the equipment being discussed for the German armored forces, "Our opinion then was that for the eventual equipment of the Panzer Divisions we would need two types of tank: a light tank with an armour-piercing gun and two machine-guns, one in the turret and the other in the body; and a medium tank with a large caliber gun, and two machine-guns as before...We had differences of opinion on the subject of gun calibre with the Chief of the Ordnance Office and with the Inspector of Artillery. Both these gentlemen were of the opinion that a 37 mm. gun would suffice for the light tanks, while I was anxious that they be equipped with a 50 mm. weapon since this would give them the advantage over the heavier armour plate which we expected soon to see incorporated in the construction of foreign tanks." Simpkin and Erickson quote Tukhachevsky's New Question of War: "...Decisive success in battle will go to the formation which has more gun tanks capable of destroying enemy tanks. "Thus, for conflict with armies which have mechanised formations, our mechanised formations must be equipped not only with armoured personnel carriers and engineer and other specialist tanks, but with gun tanks--despite the fact that this is an unnecessary luxury for combat with infantry forces." Once they became scared of German tanks they happily did, but this took until the invasion of France to occur. As above, tanks were more than cleared to engage enemy armor per Armored Force doctrine, and this was acknowledged in TD doctrine. In June 1944 it was intended to field 75 mm and 76 mm gun tanks in a two-thirds to one-third ratio, and they weren't employed at all until late July. By the time of the Rhine crossings in March 1945, however, experience had swayed this opinion so that approximately 40% of the Shermans in European Theater stocks were armed with the 76 mm gun. Indeed, production of 75 mm gun tanks totally ceased that quarter. Internecine politics may also have played a role in the 76 not being fielded until Cobra: Baily, for example, asserts that, contrary to the enthusiasm it showed for the idea in 1942, the Ordnance Department may have been opposed to the 76 mm Sherman in 1944 since it had the potential for interfering with the procurement of the T23...

Indeed, during ODS crews found that the engine air filters of the Abrams required cleaning after as little as 6 hours of desert operation, and daily even when the engine was not started. As a result, 2/2 ACR, for example, went to battle with three times the normal stock of engine air filters. While we're on the subject, TM 9-759 for the M4A3 from September 1944 says of dusty conditions: "Even when the above precautions [avoiding other vehicles' dust clouds as much as possible and not exceeding speed specified for whatever gear being used] are taken, it may be necessary to clean the carburetor air cleaners and the air cleaner on the filter pipe as often as every two hours. If the air cleaners are kept clean and their oil level is maintained, little damage to the engine will result. It is possible to wear out the engine in one hour or less if the air cleaners are neglected." TM 9-731B from January 1943 for the M4A2 says, "The frequency of servicing air cleaners depends on the dust and sand conditions encountered. Under extreme dust and sand conditions, service air cleaners every eight hours to prevent premature engine wear." TM 9-754 from January 1943 for the M4A4 also advises, "The air cleaners should be cleaned daily when the vehicle is operated over dusty terrains..." TM 9-731A from December 1943 for the M4 and M4A1 says the air cleaners should be drained, cleaned and refilled "[d]aily, when operating on dirt roads or cross country, or every 250 miles, when operating on paved roads or during wet weather..." And for completeness's sake, TM 9-756 from December 1943 for the M4A6 instructs that air cleaners are serviced "[e]very 5 to 60 hours of operation, depending on dust conditions..." and that they are to be drained, cleaned, and refilled daily. Also, "Every 100 miles, remove air cleaners, wash all parts, and reoil." So for the CIA engineers to complain that the T-34-85's oil bath air cleaners needed to be serviced daily in dusty conditions to provide decent protection seems strange. When the report says of the subject's "wholly inadequate engine intake air cleaners", "Several hundred miles in very dusty operation would probably be accompanied by severe engine power loss" or "The cleaners were of such low efficiency and low dirt capacity that, in dusty operation, they should have been cleaned at least once each day and preferably several times if any appreciable engine protection were to be obtained", one wonders if they had read manuals for their own country's vehicles. The T-34-85's air cleaners may well have been inefficient and of low dirt capacity, but the fact that they needed servicing at least daily in dusty conditions does not per se seem to be good supporting evidence. Some type of quantification would have gone far in supporting that assertion.

I've always leaned towards this as well.

Pasholok's original article linked at the bottom of the English-language version cites Материалы ЦАМО РФ among its sources, presumably for the Soviet tests he went over where the engine performed "flawlessly?" Canadian consideration of the A57 for the Ram sounds interesting. Production of the Ram, of course, was well underway before any A57-engined tanks entered service (fifteen Rams were ready for shipment by January 1942 and 39 more were awaiting accessory installation; 22 Ram IIs were produced by that March), so had it been offered to Canada significant redesigns of the Ram would presumably have been necessary. Such a redesign scheme may have been deemed not worth it as in February 1942 the Director of Mechanisation Colonel MacFarlane recommended that Canada change over to Sherman production ASAP; a tripartite subcommittee recommended the next month that Montreal Locomotive Works and Canadian Pacific Railways' Angus shop change to Sherman production in 1943. The tests referenced in Planning Munitions for War, occurring in February 1942, were likewise performed before the M3A4 was first accepted for service in June 1942. As that book goes on, "Except for the weight problem, none of the reported difficulties proved insurmountable..." and concludes, "...after several improvements the engine ultimately gave a remarkable account of itself." If during the APG tests referenced by Ross the A57s were provided with lavish maintenance, it would follow that the other engines were as well, and the A57s still excelled compared to them. FWIW, I tend to agree with Toxn that the pendulum of online opinion seems to be swinging past the centerpoint of the Sherman bad-Panther good/Panther good-Sherman bad continuum. All I've read, however, indicates the A57 was not the problem child, and the radials, for example, were more of a pain.

Thanks; Samsonov's blog is a valued bookmark, and I have his Sherman book pre-ordered. In a cursory search of his blog, I failed to find the articles complaining of the M4A4 overheating and leaking. Indeed, in this article Pasholok says of the A57, "This monster had its upsides as well. The design worked quite reliably and had sufficient power for a medium tank," "The experimental tank travelled for 6500 km. Trials showed that the experimental engine needed a little more work, but overall it performed well," "The tanks turned out to be quite reliable, but service turned into a nightmare for its crews. Each engine had its own water pump with its own linkages" [this was changed with the 1304th engine produced for the M4A4, where a single water pump served all engines], "The British became active users of the M4A4. Why would they use a tank that the Americans rejected? Short answer: reliability. According to data given to the GBTU by the British, the M4A4 (Sherman V) was the most reliable tank from the M4 family. The mean distance between refurbishments was 3200 km for the M4A2 (Sherman III), but 4000 km for the Sherman V. This explains why the British were not fazed by difficulty of servicing the engine." Pasholok relates that during Soviet trials of the M4A4, "The only advantage of this engine was that it worked flawlessly. The only problems during the trials were with the running gear and oil filter. The oil consumption was much less than the gasoline: only 2 L for 118 hours of work." I mentioned Exercise Dracula in addition to the APG tests, where the M4A4 gave no issues beyond fuel thirst.

The rear hatch for the loader may very well have been his primary egress method, since there was no loader's hatch on the roof... The Sherman indeed had no loader's hatch until October 1943, and a small hatch is better than no hatch. Where can we read of reliability issues of the M4A4? Thanks! G. Macleod Ross, a member of the British Purchasing Commission, says of engine testing when there was discussion of dropping the A57 from production: "...four engines of each type [Ford GAA, R975, GM 6046, Chrysler A57 were] being run in their respective tanks. Only four engines completed 400 hours when the trial was stopped. Of these four, three were Chrsyler A57 engines, while the fourth Chrysler entrant logged 339 hours to failure." Likewise, the M4A4 seemed to give no undue issues during Exercise Dracula.

FWIW...

Definitely the best book I've seen on Czech AFVs of that era. The English version has drawings as well--both apparently from the factories and from HL Doyle--but they are regular pages that aren't removable. Also, a couple hundred pages of Kursk left, and then I'll move this to the front of the line.

Is this what you're talking about? Not 100% legible but I think it's the closest I have. Taken at the Memorial Day event at Ft. Knox on 26 May 2007. Link to original: click

That's exactly right Jeeps. Here's a comparison between this vehicle and an M74 (since I don't have a direct comparison handy of an HVSS tank). Lord_James, the M4A1 was the cast-hull variant, so it wouldn't have the sharp edges on the upper hull.