Andreas Posted February 20, 2023 Share Posted February 20, 2023 (edited) On 9/15/2022 at 2:42 PM, Tim the Tank Nut said: those early radials weren't quite up to snuff which is unusual for an American drivetrain. They were aware of it from the Louisiana Manuevers and were working on it. Numerous minor upgrades were implemented. In sum they did help. One report I saw said that the Lee's were getting 100 hours out of an engine. That's simply unacceptable. As far as I know the tanks that actually went to the desert were better but how much? Clearly by Normandy the radial was good enough but sand is a funny thing... It would be interesting to see the sources for this. There were no complaints about engine reliability with the M3 Stuart in British hands when it appeared. Of course, the British tank teams and maintenance at that time (mid-1941) had ample experience of maintaining their own, much more challenged, tanks in the desert, so maybe that helped. It is the belief of the British that American M-3 is the fastest, soundest mechanically and most maneuverable tank in Libya. https://rommelsriposte.com/2014/09/29/an-assessment-of-the-m3-stuart-tank/ The General Stuart proved itself more sound than the Crusader, and required far less maintenance. The air-cooled engine did not overheat, and naturally, gave no anxiety about water leaks. It stood up well to fast work. https://rommelsriposte.com/2011/10/13/the-battle-for-1-army-tank-brigades-repair-shop-2/ All the best Andreas Edited February 20, 2023 by Andreas Link to comment Share on other sites More sharing options...
Tim the Tank Nut Posted February 20, 2023 Author Share Posted February 20, 2023 there was an American liaison officer that wrote about it. I remember a specific report but that's from 20 years ago. I couldn't begin to reference it now. It's probably that the British were happy as they were comparing to British expectations and the Americans weren't happy as they were comparing to American mechanical expectations. Link to comment Share on other sites More sharing options...
RichTO90 Posted February 21, 2023 Share Posted February 21, 2023 I have found no mention of problems with the the Continental Motors Corporation W670. First run in 1934, it was a well-tested engine both in terms of technical testing and service testing. At least nothing that Edward Promack, the Ordnance engine-development historian saw fit to mention in his exhaustive series of histories he wrote during the war. The Wright 9-cylinder Whirlwind, designated the R-975, selected by Ordnance for the new series of medium tanks starting with the R-975-EC2, in the Medium Tank T5, Phase III, in 1939, had some problems. Testing at Aberdeen beginning on 21 March 1941 found the Medium Tank M3 was badly underpowered. Engineers discovered the Wright R-975-C2 engine simply incapable of driving the nearly 30-ton tank with the speed and agility desired by the Armored Force. The experience was repeated later in the year during the maneuvers in Louisiana and the Carolinas. It was found the engine was developing as little as 280 net HP and was also suffering from short operational life, many lasting for fewer than 100 hours before requiring overhaul. Further testing conducted at Aberdeen by engineers from Ordnance and Wright that extended to 8 January 1942 revealed the causes for the lost power. The primary problem was cooling, linked to the design and placement of the air cleaner and muffler, which produced high temperatures in the carburetor air, reducing the weight of vaporized fuel entering the cylinders and so reducing power. The engineers solved the problem by cooling the carburetor intake air, which required relocating the intake tubes and air cleaners, redesigning the engine fan shroud, and redesigning the mufflers. The redesign not only restored the lost engine power, it also improved fuel consumption. However, the Medium Tanks M3 shipped to the British in early 1942 should all have had the improved engine design. Link to comment Share on other sites More sharing options...
Tim the Tank Nut Posted February 23, 2023 Author Share Posted February 23, 2023 definitive answer that is about what I recall. Thank you very mush as always You want a funny engine take a look at the Guiberson radial diesel that they put in some M3 tanks! It actually worked okay. I got to drive one on several separate occasions. Link to comment Share on other sites More sharing options...
Andreas Posted February 26, 2023 Share Posted February 26, 2023 On 2/21/2023 at 12:09 AM, RichTO90 said: Further testing conducted at Aberdeen by engineers from Ordnance and Wright that extended to 8 January 1942 revealed the causes for the lost power. The engineers solved the problem by cooling the carburetor intake air, which required relocating the intake tubes and air cleaners, redesigning the engine fan shroud, and redesigning the mufflers. However, the Medium Tanks M3 shipped to the British in early 1942 should all have had the improved engine design. Thanks for this Rich. Given the timeline, I have my doubts that any vehicles delivered prior to Gazala would have had these fixes? Most if not all regiments had been re-equipped by the end of April and were ready for action. That leaves just about 3.5 months from the discovery of the issue. I suspect any replacements coming after June would have a higher chance of having the fix. Would be interesting to know if this was communicated to the Middle East, and fixes applied locally. All the best Andreas Link to comment Share on other sites More sharing options...
RichTO90 Posted February 26, 2023 Share Posted February 26, 2023 I'll have to dig out Promack's histories again and see if there are some clues in it. I do recall the fixes were iterative and were introduced as they were developed. It might help to discover just when the convoys arrived with the tanks, which would give some idea when they might have left the depot. Link to comment Share on other sites More sharing options...
Andreas Posted February 27, 2023 Share Posted February 27, 2023 It would be interesting to see if these first vehicles were suffering from the defects when they went into battle at Gazala. All the best Andreas Link to comment Share on other sites More sharing options...
RichTO90 Posted February 27, 2023 Share Posted February 27, 2023 10 hours ago, Andreas said: It would be interesting to see if these first vehicles were suffering from the defects when they went into battle at Gazala. All the best Andreas On hand versus operational over time could be an indicator. Link to comment Share on other sites More sharing options...
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