Category Archives: Firecontrol

Post # 68 The Chieftain’s Hatch does the M4A1, we review it.

Post # 68 The Chieftain’s Hatch does the M4A1, we review it: A great Hatch!

The video comes in two parts.

The subject of the video is  Black Magic, a small hatch, late production M4A1 if the turret came on it, though the turret or gun mount could be from other tanks. When it comes to restored Sherman tanks, I think being concerned about matching numbers is not a thing that seems to be worried about, and since it was so well designed and built, parts readily interchange. This sherman started life as a canadian Grizzly, basically totally the same as an M4A1 with an extra small hatch in the hull floor.

This tank has almost all the quick fix upgrades, the extra armor over the hull ammo boxes but lacks the cheek armor on the turret, and the turret may, I can’t tell for sure, have the cast in cheek armor, meaning it almost for sure didn’t come on the hull.  It also lacks the armor plates added in front of the driver and co drivers positions, that the Chieftain calls “sheet metal”.  It also has some late Sherman stuff, either added by the restorers, or by a depot rebuild later in the tanks life. The spot light, and ‘gun crutch’, or travel lock as normal people use were not on most small hatch shermans. Also the all around vision cupola would not be found on these tanks during WWII.

The Tom Jentz tangent. 

The Idea that the Sherman was no more reliable than any other tank, well, I don’t buy it. I like Mr Jentz’s work, and to some degree, his books helped inspire this site, since there was so little info on the web with really detailed info on the Sherman other than the Sherman Minutia site. I don’t think he really knows much about the Sherman if he thinks tanks like Panther and Tiger just needed more spare parts to be as reliable as the Sherman, it is a ridiculous idea. I do not think there was a single part on the Sherman that had a 500 kilometer life span, and that’s double the Panthers final drives.

First: The Chieftain himself has done Hatch posts on reports from the British, about how much more reliable, the M4A4 Sherman was than the Cromwell, even when both had full crews working to keep them running. both tanks were run thousands of miles, something late war German tanks could not do.

Second: In one of his own Hatches talks about the French experience with the mighty panther showed they averaged 150 kilometers per final drive set! Much less if the crew was hard on them.  There was no major automotive component including the oil, that had to be changed every 150 kilometers on any model of Sherman.

Third: This will focus on the Panther, since it was a major part of Germany’s late war armored force, and how terrible it was. This tank didn’t have just one flaw that should have disqualified it for production it had at least five. It was generally poorly reliable across all its automotive components, along with the final drive, 2500 kilometers for the motor and 1500 for the tranny were hugely optimistic and most of these tanks broke down and or were destroyed before they had to refuel. You had to take the whole drivers and co drivers compartment apart and the top of the hull off to change a transmission! Don’t get me started on the weak turret drive system that Rube Goldberg would have loved.  The  ‘wonderful’ dual torsion bar suspension and interleaved road wheels would cause any maintenance nazi to find the nearest US Line and surrender instead of working on it!

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Another thing to note, you can see the holes drilled vertically in the suspension bogies, these are the tops of the holes the bolts that hold the suspension caps on go into. They were covered up with body filler by the factory, but on most restored and old Shermans the filler is gone, and they don’t fill the holes.

Note: the odd groove in the center of the rear Hull casting, this wasn’t done on all M4A1 tanks, and may have been unique to General Steel castings.

On the problems with the R975, I have not heard of complaints about the engine being easy to blow, and would be very surprised if the throttle wasn’t governed to prevent it.  On having to crank the engine before starting, I have it on good authority, that the crew could just start the tank and run it for a few minutes every 45 minutes to an hour to avoid having to hand crank the motor.

Many of units removed the sand shields in ETO to prevent problems with mud.

The Commanders vane site is an early version bolted to a late war vane site pad. The tank has the early style gunner’s periscope.  The gunners periscope is missing the linkage going down to the gun.  The radio looks like a 528.  Note the Armored doors on all the ammo boxes and ready rack. The tank is missing a lot of interior storage, it may have been removed in preparation on shipping the tank out to it’s new owners.

I‘m no expert, but I think the Chieftain confused a .30 cal ammo bin for the 75mm ammo bin right next to his shoulder for the location of an SCR-506, I just can’t see a WWII radio fitting in the tiny box! You can see how sparsely filled the interior is, as issued the tank would be stuffed full of items to help fight it, live with it, or keep it running.  The Chieftain shows just how easy even a small hatch Sherman was to get out of,  the the Loader was still going to have some issues though.  I wish he would have tried the belly hatch out, but maybe it’s welded shut or something.

He covers the small floor hatch on the Grizzly tanks, and you get a nice shot of the early escape hatch.  They also show the generator mounted on the rear of the transmission in one of the shots, briefly.  You can also see the full turret basket’s mesh screening that separated the turret crew from the hull crew. Part of the quick fix was to cut this all out.  I suspect most of the inconsistencies in the tanks details are due to the restoration crew using the Sherman parts they could get their hands on.  Very few people would  even notice or know it had the wrong commanders hatch, or even whole turret.

A note on the tank, it belonged to a the Military Vehicle Technology Foundation, a fancy name for the collection of a man named Jacques Littlefield. He had a passion for armored vehicles of all types but really liked tanks. He restored many to full functionality, including working main guns and machine guns on some tanks.  Owning a working tank cannon is easier than you would think, and far easier than getting the paperwork approved to own machine guns in California, and Jacques Littlefield did both.  He employed a restoration crew with world class skills and did some amazing restorations, including a Panther A that was impossibly damaged, but still brought back to life.  That Panther was his crowning achievement, and he was a real mover and shaker in the international military vehicle restoration scene, seeing that tank run was one of the last things he achieved, because cancer claimed him shortly after.

The MVTF was supposed to make sure the collection of vehicles, that were a labor of love his whole life, lived on when he passed. Unfortunately the location of the MVTF, Portola California, on a large chunk of very private property, with very limited parking really presented some problem.  The collection was used often while it was there, by TV productions like Myth Busters, and was a staple for the Wargaming Staff for their productions, and occasionally opened up to groups of vets, or other interested people.  There were other difficulties with the location, and ultimately the collection was donated to the Collings Foundation.  They reportedly decided to keep 40 of the most significant vehicles and auction the rest off.  The money from the auction was going to be used to build a facility in Stowe Massachusetts, but due to zoning issues, the permits were not provided, leaving the vehicles they did keep in limbo.

I‘m sure the Collings Foundation, a really amazing Charity, they keep many rare WWII aircraft, and cars, including race cars running, has a plan for the rest of the tanks. Their website only lists the Panther in their collection, I hope that doesn’t mean they sold the rest when the museum fell through.  That’s not a criticism of the CF, they I’m sure know their business far better than I do, and they really are a top notch group of people. Just browse that site to see the airplanes they’ve gotten flying.  The only real B-24 liberator and a working F-4 Phantom are just two of the notable planes!!  If you know anything about aviation, you know just how complicated and expensive keeping an aircraft like a Phantom flying is, especially if you don’t have the resources of the U.S. Navy or Air Force backing you.

I have to say, this is one of the best Chieftain’s hatches they have done. Granted, I’m a tad biased, since it was on the Sherman, well a Grizzly made into a later model small hatch Sherman anyway, and the Chieftain really has gotten pretty good with the Sherman and its sub variants, and even has a book on US WWII TDs on the way.

 

 

 

#64 Sherman Fire Control: How the Gun Was Aimed, not Putting Out Fires!

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Sherman Fire Control: How the Sherman aimed its Main Gun.

The Sherman tank went through a series of fire control changes each an improvement over the last.  The first tanks lacked telescopic sight mounted on the gun mount. The only site was incorporated into the gunner’s periscope, and it wasn’t magnified. Since the periscopes were all interchangeable, updating the older tanks was easy at least were the periscope was concerned.

The final fire control setup the Sherman gunner had at his disposal was pretty impressive by the standards of the time. He was in a hydroelectrically driven turret that rotated fast; he had very nice periscope setup with 1x and 6x scopes hooked into the gun with strong linkage.  He also had a telescopic sight to work with and the gun was stabilized.  This was a vast improvement over the unmagnified reticle on the first production models.

The Lee used a unique setup; the 75mm gun was aimed with an M1 periscope, with an M21A1 periscope built into it. The 37mm was aimed with an M2 periscope with an M19A1 periscope built in. Both the 37 and 75 mounts were stabilized. The prototype M6 Sherman used its own unique sight built into the sight rotor on the top of the turret, this was only used on a small number of production Shermans tanks.

Let’s look at the various periscopes and telescopes the Sherman used through its long life.  Let’s start with a look at the various versions of the periscope sights the production Sherman and the TDs based on the chassis below.

 

The M3 Periscope Sight

Since I just have a little info on this from TM 9-731B on the early M4A2, don’t have much to put here. Maybe this periscope is the one I’ve read about getting foggy on the inside in cold or humid locales. It was quickly replaced with the M4 detailed below.  This was one of the non-magnified periscopes.

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The M4 Periscope sight

The Periscope M4; it had an M38 telescope with ballistic reticle inside, but no magnification. The M4 was not well liked, and the mount it fit in, was made from sheet metal and was a little flimsy.  The linkage that attacked it to the gun wasn’t very robust, and could be knocked out of alignment annoyingly easily.  On early Shermans this was a big complaint, since they did not have a direct telescope yet. You couldn’t really take advantage of the M3 75mm guns range with this sight setup either since it had no magnification. The later better periscopes like the M4, M4A1 and M8 series would all fit in the old mount though.

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The M4A1 Periscope Sight

Next came an improved version of the M4, the M4A1, and they came with an M38A2 telescope, this one was magnified, but not much at 1.44x, and a 9 degree field of view. Later versions of this periscope had illuminated reticles. The mount was not improved though nor was the linkage.  The M4A1 periscope was changed when the 105mm and 76mm armed Shermans came online, when used with these guns, they had the M47A2 for the 76 tanks, and M77C for the 105 tanks. Hunnicutt doesn’t specify if these were also 1.44X. This periscope was found on M4A1, A2, and A3 76 tanks during WWII.

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The M8/M8A1 Periscope Sight

The M4A1 periscopes were replaced by the M8 and M8A1 periscopes. They were a lager tougher improvement on the M4 series, and had the M39A2 telescopic reticle for use with the 76mm gun, since it had the same reticle as the M47A2 used in the M4A1 periscope.  The M39A2 had 1.8x magnification, and a 6 degree FOV.  Even though at this point this was no longer the primary sight, the Army kept improving it. But the mount and linkage still remained an issue.

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The M10 Periscope Sight

The Army came up with another new periscope sight system called the M10. They started issuing it late in the war around the same time wet tanks start appearing. This was a much improved periscope; it incorporated two telescopes with reticles, one 1.x, with a field of view of 42 degrees, ten minutes for engaging close targets. The second periscope had a 6x telescope with an 11 degree 20 minute field of view. This periscope could be used with the 76, 75, and 105mm guns when the right reticle was fitted. There was also an M16 periscope, pretty much the same as the m10, but with a reticle adjusting system.

M10C was specific to 75mm Shermans.

M10D was used on 76mm tanks, and 105 tanks.
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The Periscope mount

for these periscopes were improved greatly when the 76mm gun and 105 tanks arrived, and the mount was made from a beefy casting, and all the linkage was made much stronger will ball bearing in all the pivot points. These would have shown up on M4A1 75w, M4A3 75w, M4A3 105, M4 105, and M4A3 76w, M4A2 76w and M4A1 76w tanks.

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You can see the old style periscope mount in this shot.

This improved mount was also incorporated into most of the post war rebuild and overhauls. It is very easy to spot, by the heavy cast iron hood over the periscope hole.

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In this shot you can see the improved heavy duty gunners periscope mount, spikes optional.

The Telescopic sights.

The Shermans fire control system was improved further by the incorporation of a direct telescope mount to the M38A1 gun mount. This prompted the creation of the full length gun mantlet to protect the scope. When these were retrofitted into older tanks, sometimes they would weld on armor over the scope, leaving a half armored mantlet.

The later 76mm armed tanks had the M62 mount, and it had a telescopic sight mount from the start.

The direct scopes went through their own evolution, and this information is put together from the various TMs on the tanks and Hunnicutt’s Sherman, and is not complete. I will update this section as I get more info on the topic.

The M55 Telescope: The first! For the 75mm and 105

This telescope had 3x magnifications with 12 degree 19 minute FOV. This sight was also used on the early production 105 tanks and most 75mm Shermans.

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The M51: Also the First, but for the 76 M1A1

The same scope as above, with the same specs, but with the reticle for the 76mm guns, and that’s all. There were complaints about the optical quality on these scopes, since the clarity wasn’t optimal.

M70 Telescopic Sight

The M50 sights were replaced with the M70 Series sights, the same size and magnification. What set them apart was there superior optical quality. The Army went on to develop many different versions of this sight. It was a 3X scope with a 12 degree 19 minute FOV.

M70F Telescopic Sight

This was version used on M4A3 75W Shermans.

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M70G Telescopic Sight

This sight was used on M10 GMC tank destroyers.

M70P Telescopic Sight

This sight was used on some M36 CMCs tank destroyers.

M71D Telescopic Sight

This was a 5x with a 13 degree FOV version of the scope. It had the reticle for the 76mm guns and was used on those tanks. This was the sight commonly found on M4A1 and M4A2 76 tanks.

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M71G Telescopic Sight

This version of the M71 was issued with the Jumbo tanks.

M72D Telescopic Sight

This was used on the 105mm armed Shermans.

M76F/D Telescopic Sight

These telescopes were used on the M36 GMC tank destroyers.

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M76G Telescopic Sight

This scope only had a 3x magnification, with a 21 degree, 30 minutes FOV, and was used in 105 tank applications later in the war.

M83 Veritable Power Telescopic Sight.

This scope had two settings, 4x 7 degrees, 40 minutes and 8x 4 degrees, 15 minutes, and M83D version of this sight worked with the 76mm guns when in an M62 mount. I have not seen this one mentioned anywhere but Hunnicutt’s Sherman book. That doesn’t mean it didn’t get issued as a replacent later in the war, since I’m going off TM’s and spec sheets and those are a small snapshot into a tanks actual combat gear.

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Indirect Fire Control Gear

You would think that would be it for fire control equipment, but it’s not, because all Shermans came equipped with the equipment for their tanks to work as impromptu artillery batteries all Sherman based TDs had this gear as well. The US Army had this extra gear installed all the way up to the M60 tanks. During the war, some tank and TD battalions were very good at being artillery; other units didn’t train for it, and were not good.  This was a good way of keeping tanks useful in Italy, and they filled this role a lot there. I do not think this was something many other nations did with their tanks.

Azimuth Indicator M19

The Azimuth Indicator was mounted near the gunner, right behind the traverse control. This device was used to dial in what direction the gun needed to be pointed in to carry out the fire mission.

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Gunners Quadrant M1

The Gunners quadrant is a portable precision instrument used for measuring the elevation or depression angles of guns and howitzers. It can also be used for checking the adjusting of elevation devices on sighting equipment furnished with a gun or howitzer. This was taken right from the Characteristics in tech manual 9-1527.

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Elevation Quadrant M9

The Elevation Quadrant M9 was used to lay the tanks main gun in elevation for indirect fire. There are detailed instructions for setting it up in TM 9-748.

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A Sherman unit trained in how to act as an artillery battery would probably be told they were on call when not in direct combat but close enough for the 75s to reach. They would have men manning radios in the tanks while other tasks were being done, like maintenance, personal things and eating. When they got the call, the designated battery commander for each platoon would listen to the directions on the arty net or get in direct contact with the spotter. In many cases they would wired into the directly, so they wouldn’t need to worry about radio reception. They would relay the aiming information out the tanks on the radio or phone net and then they would start firing.

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M4 being used as artillery

Once they started firing the hole crew would help feed the gun, and if they were doing it as a common thing they might even have large amounts of ammo unboxed outside the tank, where the driver and co-driver could feed them to the commander who then fed  them to the loader.  The M3 75mm gun worked well in this role, since the barrel had a life in excess of 4000 rounds.

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M4 105 acting as artillery.

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Sources: Sherman by R.P. Hunnicutt, TM9-731b, TM9-731G, TM9-748, TM9-748, TM9-750, TM9-752, TM9-754, TM9-759