Inhuldiging Tankmonument ter herdenking 60 jaar bevrijding Zutendaal

* US M41 Light Tank "Walker Bulldog" *

14 September 2004

Plechtige inhuldiging oude tank ter herdenking van de bevrijding Zutendaal

US M41 Light Tank "Walker Bulldog".

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Picture 1 :

The waning years of World War Two found the US tank design and manufacturing industry in full bloom, having learned much in the preceding five years of rapid expansion. American AFV designers had taken a quantum leap forward from their positions in 1939, and they were anxious to develop their plans for the next generation of armored vehicles. For the Americans, anything was possible, and there was increased interest in improving the entire line up of light, medium and heavy US tanks even though research and development money had dried up with post-war cuts in the budget.

In spite of the lack of funds, the once expansive design of the experimental Light Tank T37 of 1949 began to take shape as the pared down T41. The T41 was designed together with two others tanks as a new "family" of US vehicles, including a "medium" tank plan called the T42, and a "heavy" tank, the T43. The T42 would continue in development to eventually become the M47 Medium Tank, and the T43 would become the M103 Heavy Tank. With more work, the T41 would evolve into the T41E1 Little Bulldog and eventually the M41 Walker Bulldog, named for General W. W. Walker who died in a jeep accident in Korea in 1951.

One of the driving forces behind these new tank designs was the desire to include common components for all three AFVs to ease their manufacture and spare parts inventories- an honorable idea that almost did come to pass. The other strategy behind co-designing the three new vehicles simultaneously was to simplify as much as possible their mechanical components and operation (soldier proof) while including similar state of the art ranging and sighting equipment.

A new vision of tank design was evolving in the US and the Walker Bulldog was one of the best illustrations of that post-war evolution. For instance, the M41 was the first US tank designed around a power plant, the engine finally being recognized as one of the most important components of an AFV. Previously, a tank's general dimensions were drawn up first and an engine then found to fit the available space and power requirements. The Bulldog was also the first US tank with a bore evacuator to clear the gun tube after firing (seen on the end of the gun tube in this US Army photo). It also had an integrated fire control system to coordinate gun laying between the commander/gunner and an automatic loader to hasten the rate of fire and reduce the turret crew to two men. Unfortunately, due to problems with the development of the autoloader (lack of funding), it was dropped before production of the vehicle began. This US Army photo shows a fine example of a M41A1, except for the blast deflector on the end of the gun tube, which needs some attention from the crew. Notice the M75 APC behind.

Picture 2 :

This is the Part 1 of a two-part series on the post-war M41 Light Tank. This first part will cover the basic hull components, while Part 2 will examine the turret interior. This first image is a cross sectional drawing of the M41 from the technical manual (TM9-2350-201-12), illustrating the basic layout and components. As with most tanks of the time, the vehicle is divided into three general areas- the driver's section at the bow, the fighting compartment and turret in the center (with a gunner on the right, commander behind him, and loader to the left), and the engine compartment at the rear, which now includes both the engine and transmission. This was the first mass-produced US light tank with no hull machine gun or gunner in the bow. Instead, the space to the right of the driver was taken by a large ammo rack containing main gun rounds (recall the preceding US Light Tank, the M24 Chaffee, had an assistant driver/hull machine gunner to the right of the driver).

The turret and basket rotate directly behind the driver's seat and in this drawing you can see the ready round rack on the basket floor, but further ammo storage up in the turret has been deleted for clarity. The gun in the Bulldog is the 76mm M32 and it is layed with different equipment by the gunner in the M41 and M41A1, as we will see later. Notice the large turret bustle, housing the radio gear and a large exhaust fan- the entire mass used to balance the weight of the gun. The engine in the rear of the M41 and M41A1 versions of the tank is a boxer-type Continental AOS 895-3 and it is seen here coupled to the CD 500-3 Cross Drive transmission. The Bulldog was designed as a reconnaissance vehicle, its job to slip through enemy lines, engage and estimate the enemy's strength, and then radio back the news. It was lightly armored, fast, and carried a significant weapon to both cause damage to the enemy and protect itself.

Picture 3 :

There were over 3700 M41 Light Tanks eventually constructed and as the tank matured in use with the troops, changes were made to improve the vehicle. This is the general arrangement of the driver's area in the left bow of the M41 and this equipment remained relatively unchanged until late in production. The main problem up here revolved around the unique T bar steering crossbar; it was too weak and would occasionally break near the right grip when yanked hard by rough handed drivers. As you can see, the control bar rotates from mounts at the top and bottom, and the attachment for the control rod that eventually leads back to the steering mechanism at the stern is all the way over at the far left of the bar, attached to the hull wall. By pushing on the right side of the steering bar the driver turned the tank left and pushing on the other side of the bar turned the tank the opposite direction. But, because the torque on the bar was greatest furthest from the control connection at the far left, the right side of the bar could deform or break near the horn button. The problem was recognized and partially fixed by strengthening the bar from vehicle 603, and by vehicle 2453 there was a new stronger steering bar in use that we will see in a few minutes.

A simple pull knob hand throttle is visible under the control bar's connection at the far left, and both brake and accelerator pedals can be seen directly under the steering mechanism. The seat is adjustable forward/back as well as up/down using the control levers just to the left of the seat bottom (the back has been removed). The accelerator pedal is large so the driver can still use it when he is elevated in his seat while driving head out. A tachometer and speedometer are located in their own small panel under the hand throttle and retaining brackets for the driver's periscopes are at the top of the image. The driver's view outside the tank when buttoned up is excellent, using three M17 periscopes that are angled slightly left, directly forward, and slightly to the right, and a fourth periscope at the far left that was angled back to the left rear.

Initial vehicles had a plan pivoting driver's hatch and movement of the inside hatch control handle would first raise the hatch an inch or so and then pivot it over to the right. When infrared driving equipment was added to the M41, a mount in the hatch was included for an infrared M19 night viewing periscope to be used with additional infrared driving lights added to the bow. The M19 had to be removed before the hatch could be opened. The operating handle for the hatch is seen at the upper right in the drawing, the gearshift gate is at the bottom right, and the main instrument panel is to the far right. Regardless of the hatch type, drivers lived in mortal fear when driving with their heads out because if the turret rotated while they were exposed they could have their necks broken by the bottom of the mantlet. The predominate paint used inside the M41 is typical US gloss white and most of the darker areas seen in these images are black, including the seat padding, instrument dials and the gear shift gate instructions at the right.

Picture 4 :

This is the image from the M41 tech. manual illustrating the driver's seat controls and associated equipment. There is an escape hatch under his seat, and the seat bottom has to be dumped by pulling on the release control at the back of the spring box in order to access the belly hatch. The seat bottom is spring loaded for height adjustment, the spring mounted in the box you see surrounded by seat controls. Simply by lifting yourself off the seat and pulling the vertical seat control lever, the seat bottom would rise to meet you and then lock into position when you released the handle.

US designers gladly borrowed a number of design innovations/developments from captured WWII German AFVs, and the neat, well protected torsion bar suspension system was an American favorite. In the case of the M41, the escape hatch is located between the first and second torsion bars on the floor. While torsion bars do provide a number of suspension benefits, they also introduce problems of vehicle layout and servicing. Heavy German tank designs required many torsion bars crossing the hull, which did not allow spacing for belly escape hatches in most of their tanks.

Other problems inside the vehicle arising from the use of torsion bar suspensions is the additional height required of the hull for the equipment and the more difficult servicing of broken components. The cable looping down at the upper right of the picture is from the hand throttle, while the connecting rods below the throttle cable are from the accelerator pedal and gearshift (range selector). This fire extinguisher is a red 5lb CO2 type and it is portable. The engine compartment is protected by two 10lb fixed cylinders and an automatic fire suppression system.

Picture 5 :

Another image from the M41 manual illustrates some of the equipment immediately to the right of the driver. The gearshift gate allows automatic shifting from two forward ranges (low and high) as well as one reverse range. The single stage hydraulic torque converter allows very smooth gear changes, although there is a bit of slippage at low speeds. We also begin to see further interest in crew comfort in this US M41 design with the inclusion of a built-in crew heater; the heater duct and controls are at the bottom and far left of the illustration. The periscopes are not installed, but you can see the holding clamps for the right periscope at the top left of the picture. The early hatch release control handle is also visible up there, to the right.

In the center of the instrument panel are a number of indicator lights, and the instruments underneath include left and right fuel level gages and the engine oil pressure gage. The large black electrical switches include the main driving lights (left bank of switches) and the main engine power switches. The M47 Medium Tank and M103 Heavy Tank use almost identical primary instrument panels. An auxiliary generator gasoline engine is located in the rear engine compartment and allows power for recharging the batteries as well as lights and other electrical requirements when the main engine is switched off; the controls for the aux. generator are at the far left on the panel. The auxiliary power outlet receptacle (above) allows power connections between vehicles to assist start them when they have dead batteries or other electrical problems. Although we do not see it in this image, the area of the bow to the right of these panels is filled with horizontal storage tubes on a multi-tiered rack for 76mm main gun ammo.

Picture 6 :

This image of a late M41A1 comes from the same tech. manual (it covers both vehicle types) and illustrates the improved steering T bar and the installation of the infrared periscope M19. Most of the other equipment is identical with what we saw before, but notice that the M17 periscopes are now installed and the retaining clips are locked closed. The introduction of infrared lights and viewers on the Walker Bulldog was a big step forward for the US Army. Although research into infrared viewing devices had been occurring in the US during the last years of the war, the capture of German equipment and information provided by German scientists accelerated the program greatly.

Initial post-war US tanks used infrared as a driving aid only because the lights were dim and the beams did not carry far. Tanks were fitted with these smaller infrared driving lights at the bow of the vehicle, next to the traditional service headlights and blackout lights. It was only later that powerful infrared searchlights were mounted up on the turret mantlet, which allowed direct targeting at night. Infrared lights produce a very short wavelength light that, in its pure form, is not visible to the human eye. The simplest infrared viewers, like the M19 here, collect the reflected IR rays and use an image converter tube to change them back to visible images that are seen through the eyepieces.

The periscope consists of two main components- a quickly replaceable head assembly that contains the prism to direct the reflected infrared rays down to the periscope body, and the body that contains the objective lens and image converter for the reflected rays. The viewer requires electricity and you will usually find a power plug for the periscope in the vicinity of the viewer, in this case off to the right. Magnification through the M19 viewer is only 1x, which relegates the periscope to the driver's position in most AFVs. By the way, this same M19 periscope, in one form or another, is still used today by the US Army and a number of other countries, typically in the improved M19A1 form.

Picture 7 :

When the access plates are removed, the hatches fully opened, and the hatch support bracing is removed, the engine compartment looks like this. The Continental engine is an air-cooled, 6-cylinder, opposed, and supercharged gasoline engine. Air cooling does away with liquid coolant systems and their propensity to leak or rupture, but it requires very large fans and many cooling ducts and vents. The black fan and shroud is located at the forward end of the central compartment, and just about covers the entire engine. Off to both sides of the engine you can see the insulated exhaust pipes leading to the mufflers on both side fenders- these are not "cooling" vents as indicated in the legend but the exhaust pipes are covered with protective cooling jackets.

To the upper right of the bay (right/forward) is the top of the auxiliary engine/generator. Also on the right, but further back toward us, are the batteries (24V DC system). The white painted transmission case occupies most of this end of the compartment and is covered here with shifting linkages and other controls. Cross Drive transmissions, like this Allison CD-500-3, combine the transmission and steering unit into one box, providing a very compact package for armored vehicles. This same power shift transmission design is also used in other vehicles that share the same general chassis components of the M41, such as the M44 and M52 SPG and the M42 SPAAG (Duster). This transmission's big brother, the CD-850, has been used in a number of larger vehicles, including the US M48 and M60 tanks as well as the first Israeli Merkavas.

The engine/transmission in the M41 is loud... VERY loud, and anyone standing near it when one of these monsters opens up in first gear will not soon forget it. Each gear has its own characteristic sound, from the load scream of first gear to the whining of the others. The exposed mufflers on the fenders become so hot they glow in the dark and extreme care is required when working around these areas to keep from burning yourself.

Picture 8 :

This is the training manual image of the Continental engine when attached to the Allison transmission- the left picture is the left side of the engine. This was one of the last gasoline power plants to go into a US armored vehicle, as diesel power would shortly become recognized by AFV designers to be necessary to increase the range available for a given amount of fuel. The AOS-895 displaced 895.9 cubic inches and delivered 500 gross horse power at 2400rpm. With the approximately 140 gallons of gas in its tanks, the M41 has a cruising range on roads of only around 100 miles, and roughly 2/3 of that on cross country conditions. However, on those same roads, the maximum speed was over 45mph, so although the range was limited, this was one fast little tank for its time. In order to improve the vehicle's range, the carburetors were replaced with fuel injectors, and the M41s powered with the new engine were renamed M41A2 and M41A3, respectively.

Picture 9 :

Because the M41 was designed to be robust and simple to maintain, it proved popular with a number of country's Armed Services. So when the vehicle was withdrawn from US active inventory with the introduction of the replacement M551 Sheridan, surplus Bulldogs were given/loaned/sold to many countries allied with the USA. This is another US Army photo, in this case showing Thai troops learning transmission servicing from their American instructors in 1962. Although the lower rear transmission cover is still closed, the upper one is hinged open and a number of the smaller side access doors are also opened. Notice the engine oil filler neck and its corresponding port in the upper transmission access cover. If you look closely, you can see both the range selector control rod and the gear changing rod traversing across to the top of the transmission from the left hull wall. The batteries are barely visible on the far right as well as their retaining bracket. Although the interior of the engine compartment was painted the same gloss white as the fighting compartment, the inside of the engine hatches are the primary exterior color, in this case some shade of olive drab green.

Picture 10 :

The primary difference between the M41 and M41A1 is the gun laying equipment inside the turret. The controls to elevate/depress the gun and rotate the turret were changed during early production in order to comply with a new Army Field Force directive in 1951 (after the tank had been in production). The directive required that only 5 seconds would be necessary to fire the gun after the decision to engage a target had been made. For that day, 5 seconds to select ammo type on the ballistic computer and traverse, elevate or depress the gun onto target was very quick indeed, and the initial pulsing relay control gun laying system was not equal to the new requirements.

In order to comply with this new directive, the primary manufacturer, Cadillac Motors of GM, designed a modified turret and new gun control system, and these were introduced into production line on vehicle 1419. The new Cadillac system turned out to be quicker, less complex and occupied less space than the original pulse relay system, and after experimental usage in a number of different vehicles, the Cadillac system and new turret became standard issue from tank number 1803 on. Prior M41 tanks were also supposed to be converted to the Cadillac system, but improvements to the original pulsing relay control allowed it to conform to the 5 second order, and those earlier vehicles were modified with the improved pulsing relay system instead. The tanks with the original turret type and improved pulsing relay were left with the original M41 designation, while those later vehicles with the modified turret and Cadillac system were named M41A1. You will find both vehicle types in photos of the US Army, as well as a number of other armed forces around the world, sometimes side by side in the same unit.

The left image here is the M41 early turret type and the one on the right is the M41A1 later type. When you examine the turret sides of the different vehicles in these US Army photos you will see that the M41 turret (left) uses more cast armor, including a band along the lower area of the turret side. The M41A1 type has cast armor only on the front of the turret and there is no visible weld seam along the lower area of the turret side extending to the rear bustle. Of course there were also changes to the gun mount and interior of the turret, but we will explore these and other internal components in Part 2 of the M41 Walker Bulldog story.

Picture 11 :

The original pulse relay gun laying system in the M41 allowed both manual and power controls for the gunner as well as override control for the commander in both elevation and traverse. It was a remarkable system, but unfortunately, as we discussed in Part 1, it could not meet the requirements of a new 5 second "locate target and shoot" directive, so an "improved" pulsed relay system was developed and installed in all M41 type vehicles. In a nutshell, the improved pulsed relay system provided only manual hydraulic elevation for the gunner as well as power and manual traverse of the turret. While the tank commander could operate the power traverse with his override control, he could not elevate the gun. This improved system did meet the 5 second rule, but limited the ability of the commander to fully operate gun laying and confined the gunner to manual elevation.

This is the technical manual illustration of the improved pulsed relay gun laying system at the gunner's position in the M41. To elevate and depress the gun tube the gunner hand cranked a hydraulic pump at his left, which would pressurize a hydraulic cylinder attached to the gun cradle. Rotating the pump handle in one direction raised the gun and rotating it in the other would lower it. Although it was called a "manual" system, the hand crank was still hydraulic assisted, and was therefore actually a hydraulic powered system, in contrast to an electric power system. The word "powered" when used to describe AFV gun laying is confusing, as some sources and manuals regard powered as having any type of boost assist, while others refer to only electric motors as "powered". The general consensus has been that when a control has to be hand cranked it is "manual" and when it only has to be moved in one direction or another it is "powered", as something else is actually doing most of the work. It is helpful when referring to powered systems to indicate the type of assist, whether it is oil hydraulic, electric, or a combination of the two. Strictly speeding, manual systems should refer only to mechanical manual, where there are only gears and hand wheels to move the gun and turret, but the definitions have become blurred over the years and now manual means any control which requires pumping or turning (work) to activate. Recall when studying this picture that the commander could not control gun elevation.

The gunner's elevation ("manual") hand crank is difficult to see in this image, but it is at the left side of the picture, under the telescopic sight, near the label "F". To traverse the turret the gunner had the option of using either a manual hydraulic crank pump, in this case seen as "C" in the picture, or he could use an electric hydraulic system via the black hand grip you see as "K". This system uses electric contact switches to activate a motor under the turret basket, which then rotates the turret.

For years US tank designers had shied away from electric motors for turret traverse and gun elevation for a couple of reasons. The first was its reliance on power generation and electricity. Dead batteries were a way of life for tankers during WWII and if your electric power went out you were then dead. Therefore, electric motors for gun laying were considered too unreliable in AFVs until late in the 1950's/early 1960's. But, perhaps more importantly, hydraulic motors had served American tanks (as well as US industry) very well in the past, and a hydraulic motor was far more powerful than an electric one of the same weight and size at that time. Of course, hydraulic power still required an electric motor, or small internal combustion engine, or even a hand pump, to compress the hydraulic fluid so it could do its work. But tank design officials believed that pound for pound, hydraulic motors provided more power and were more reliable than heavy electric motors for moving guns and turrets. This belief still reigns today in the US where most turret movement controls are still hydraulic powered, or have a hydraulic back up system to the electric motors.

There are many other important pieces of equipment visible in this illustration. The gunner's primary sight is the over-head M20 periscope. It is both a wide angle periscope and a gun sight with lighted reticle, and it is linked to both the gun cradle and the TC's identical M20 in his cupola, so both tankers have the same sight view. The periscopes and gun are linked at a small box called the Ballistic Drive M4. Here it is seen on the ceiling of the turret to the far left ("A"), and shows a series of range scales that have to be calibrated for each type of ammo round. You can think of the ballistic drive as an early computer for figuring the correct trajectory for ammo type and target range from the tank. The telescopic sight M97 at the left was strictly a backup sight, as the field of view was considered too restricted for normal operations and you could hunt for days just looking for your target. On the other hand, Americans are very fond of their back up sights, as they hate to be in a killing machine the size of a tank and not be able to fight due to the primary sight being temporarily out of action. The white box at the upper right is the gun firing control box (an electric switch panel for energizing parts of the gun laying system) and the traditional black azimuth indicator is located below on the turret ring with its cylindrical light battery mounted to the turret wall above it. The 76mm gun is just out of view to our left.

Picture 12 :

This is the arrangement for the revised Cadillac gun laying system found in M1A1 vehicles. Much of the equipment is the same or similar as the pulsing relay in the M41, but now the odd hand wheel in the center of the picture controls the power turret traverse (an oil gear power traverse). Rotating the wheel clockwise traversed the turret to the right while counter clock wise traversed the turret to the left. The manual traversing hand crank is to the right, between the powered traverse control and the azimuth indicator. To the left of this equipment is the gunner's manual elevation hand wheel. The commander's traversing hand control is visible at the upper right in the photo. Recall that he could also elevate the gun using an electric slewing motor and his controls overrode the gunner's in an emergency.

Both crew members have the same M20 periscopes for viewing and targeting that we saw before and both are visible in this photo, showing the sighting eyepiece to the lower right of the periscope as well as the 1x unity window at the bottom. The 76mm gun is better viewed in this photo than in the previous, with its vertical semi-automatic breech now clearly visible. The weapon was fired electrically by the gunner via a thumb button on the elevation wheel. Notice the gunner's seat and the protective screening at the front of the turret basket to keep him from banging toes as the turret traversed. The screening was installed only around part of the basket as some of the main gun ammo was stored in the space to the right of the driver and had to be retrievable.

Picture 13 :

A closer view of the upper area of the Cadillac gun laying system shows a few more details. The ballistic drive on the ceiling is similar to the one used in the M41 and you can see the control knob for setting ammo type and range. A small power switch is on the right side of the case. The close proximity of the M20 periscope and the M97 telescope is also clear in this image, and the power traverse hand wheel dominates the bottom of the image. Notice the rubber padding around the viewers of both sights to protect the gunner's eye and face. There was no stabilisation for the gun and the vehicle had to come to a halt to fire accurately. Half of the hand elevating wheel is at the lower left and the electrical control box for the gun laying system is at the upper right.

The thin connecting rod rising from behind the traversing hand wheel to the upper right, and then connecting to a cross rod running towards us, eventually ends at the commander's hand control (just out of view over our heads) for traversing the turret. Notice that the gunner's mechanical hand traverse control is visible at the lower right corner. One of the worst problems with the ballistic drive and the periscope sights in early set ups was that their connecting actuators were attached to brackets on the ceiling of the turret. When the roof heated up and expanded in the sun, it threw off the alignment of the sights and gun, so later M41 and M41A1 vehicles were provided with an improvement kit that attached to the devices without support from the ceiling.

Picture 14:

The first M41 tanks used a .50cal Browning machine gun for a coaxial weapon on the left of the main weapon, but most vehicles later used a .30cal instead, and the early tanks were modified to the .30cal standard as time went by. The .50cal was originally included to provide improved firepower against soft skin vehicle targets in order to save main gun rounds. But when the actual use of the MG was evaluated, and the increased amount of ammo that could be carried for the smaller .30cal was considered, the .50cal coaxial was replaced with the smaller MG.

This image shows some of the detail to the left of the 76mm gun that is the loader's cramped corner of the turret. Ready round racks for vertically stored 76mm ammo are seen on the floor and wall and an ammo box for coaxial .30cal rounds is clear at the front of the turret. The 76mm ready rounds sat on rubber rings inside cups that held the face of the shell casing and the rack clips you see have quick release latches, opened by a toggle on the bottom of each latch. The loader's safety switch (ready button) is located in the white box to the upper left in the picture, and the black breech of the main gun is to the bottom right. The gun has a concentric spring hydraulic recoil system that surrounds the gun tube just forward of the breech block; the cylinder seen on the gun recoil case at the left houses a spring to assist opening/closing the semi-automatic breech. Semi-automatic breeches open automatically after the gun is fired and eject the spent shell, allowing the loader to just shove home the next round without having to open the breech himself. A small part of the loader's recoil shield is also seen just to the left of the breech.

Picture 15 :

This is the floor of the early M41 turret with horizontal ammo storage tubes and the vertical storage pads for the ready rounds at the bottom of the picture. This is the loader's floor area, with the main gun pointing to the left of the picture and the loader's seat in the up and stowed position to the right. The M41 could only house 13 rounds in this horizontal rack, due to space taken by the pulsing relay box and other gear on the floor. Nine of the rounds were protected in individual sheet metal boxes and four others were laid on top and retained by clips at this end of the shelves. A large bin for stowing MG ready round belts is at the far left. The spent cartridge bin was a sheet metal collapsible unit at the back of the turret floor, and when opened like it is in this picture, was held open with a latch on the floor you see here. The gunner sits up fairly high in the turret and his metal footrest plate is at the left, above the horizontal ammo rack. Although not seen here, a shell deflector plate was attached to the back of the turret basket (at the turret ring) to deflect ejected cartridges down into the bin.

Along with the 13 stowed rounds in the horizontal rack, the M41 also carried 11 rounds in the vertical ready round racks closest to us and another 33 in the hull rack to the right of the driver. The front rack was not accessible during normal operations and the turret had to be rotated in order for the loader to retrieve new shells to refill the horizontal and ready racks. The pulsing relay box is seen at the center of the floor and the electrical turret master control box is just behind it, mounted on the side of the hydraulic compressor housing. With the use of the Cadillac gun laying system in the M41A1, the hydraulic equipment was reduced in size, and additional floor space was provided to allow additional horizontal racks on the floor, for a total of 21 rounds instead of the 13 in this M41.

Picture 16 :

Another view of the collapsible 76mm spent cartridge floor bin also gives some indication of the equipment at the back of the turret basket. The M41 style bin is again in the open and locked position and the turret electrical control box is now immediately to the bin's left. The spent cartridge deflecting shield is now visible above the bin and behind the gun breech, and one of the two 10lb CO2 fire extinguishers for the engine compartment is visible at the far right. The engine compartment fire suppression system relied on heat sensors and extinguisher chemical nozzles placed at strategic points to douse fires when the system was activated. There were manual pull controls also, one located up by the driver and one on the exterior hull of the vehicle for use when outside. As of this time, there was no automatic system for the crew compartment, the portable 5lb extinguisher we saw earlier was all that was available for interior crew fires.

The two cylindrical air cleaner cans for the engine were also mounted here on the firewall, but to the outside of the fire extinguishers and out of view. Ducts took the cleaned air back to either side of the engine and to the carbs. The loader's stowed seat is at the upper right and the commander's is across the turret from us, at the upper left. It has a simple plywood seat bottom padded with foam rubber, covered with black imitation leather, and adjustable in height. Under the commander's seat is the domed case of the turret power pack (electric motor) and the height adjustment lever for the commander's seat is just visible above the power pack.

Picture 17 :

The spent cartridge bin mounted on the floor of the M41A1 was different and more substantial than the folding one in the M41. This image of the M41A1 floor shows the black bin open and locked and you can make out the hinges at the far right and the locks to keep it open on this side of the bin wall. When closed, the back pivoted over and down, making just a two inch high platform on the floor. Across the turret is the gunner's seat with its special height adjusting mechanism underneath. The top of the larger horizontal 76mm ammo rack is now at the left in the image. In this new arrangement there are individual shell boxes stacked on the floor as before, but now there are 14 and shelves above for another 7, all in a similar style rack as we saw before. Combined with the same sized ready round and forward hull racks as the M41, the M41A1 could carry a total of 65 rounds, compared with the M41's 57.

The 76mm gun fired a number of different rounds over the years, the most common in US service were the AP-T M339, HVAP-T M319, the HVAP-DS-T M331A2, the HE M352 and the canister round, M363. I believe these are all bras cased rounds, with the exception of the M331A2, which was steel. The M339 is a APBC-T shot, the M319 is a APCR-T, the M331A2 is a APDS-T and the HE M352 is a high explosive shell. In addition to these rounds, the Walker Bulldog carried around 5000 rounds of .30cal (for the later coax MG) and up to 600 rounds of .50cal for the AA MG carried up on the turret roof. In the turret were also carried a .45cal Grease Gun with ammo and usually a .30cal carbine for the driver.

Picture 18 :

This is the right side view of the M32 76mm high velocity gun used in the M41 and M41A2, but installed in the M76A1 mount used in the M41A2. There were only a few differences between the mounts. The elevating mechanism and hand wheel are the most obvious as the earlier M41 used the pulsing relay system with the elevation hand crank located on the motors directly in front of the gunner, not on the gun mount as we see here. Notice that the elevating gear that is attached to the roof of the turret is protected by a rubber boot. Just a bit of the concentric recoil is seen surrounding the gun tube, this type of recoil mechanism had become very popular when tight interior conditions were expected and there was no room for bulky recoil cylinders on the sides of the mount. The recoil shield on this side is very large to protect the gunner and the TC from having their left leg or arm broken from the recoil of the breech.

The M32 gun could hurl a 15 pound AP shot down range at 3200fps, or even faster with hypervelocity armor piercing ammo (HVAP). Maximum rate of fire was said to be around 12 rounds per minute and maximum range was greatest for this type of round, nearly 23,000yds. Effective range was limited to less than 2,000 for anti-tank hunting due to the gun accuracy, but this was more than sufficient for killing T-34/85s that were expected to be the main target for this tank. When the Soviets produced the T-55 with its increased armor and bigger gun, the Bulldog's gun was outclassed, and something bigger had to be called upon to deal with the new Soviet "threat".

Picture 19 :

From the top of the M41A1 we can see the arrangement of hatches and other equipment. The commander's cupola on the right side of the turret roof is non rotating and contains five vision blocks as well as his M20 sight. The inside of his hatch has no padding and only a simple latch handle to keep it closed. The .50cal Browning is pintle mounted to the left and slightly forward of his hatch, and it is in an awkward position for rear facing anti-aircraft work, but well placed for forward fire support. The loader's hatch is angled on the left side of the turret roof, and hinges open forward to provide some protection from the front when partially open. It is padded on the inside surface and also has a simple hand latch inside to secure it when closed. The loader is provided with a stationary M13 or M13A1 periscope just forward of his hatch.

At the back of the turret bustle is the exhaust fan dome and the traditional crew storage box is affixed to the back of that, extending the rear of the turret almost to the back of the tank. Some of the driver's hatch and periscopes are also visible, including the rotating M19 infrared periscope mount in his hatch and the one M17 periscope that faces left and slightly to the rear. On these later turrets the three antenna bases wee all on the left side, and they can be seen just forward and to the left of the loader's hatch, behind it some distance, and back by the exhaust fan. Armor on the Bulldog was very thin, ranging from 1.25in (32mm) on the front hull and mantlet, to 1in (25mm) on the hull and turret sides, to .05in (13mm) on some of the rear armor. It was designed to be proof against .light MG rounds and shell splinters, but not much else.

Picture 20:

The large turret bustle of the Walker Bulldog was designed especially for extensive radio equipment, as the recon vehicles were expected to patrol behind enemy lines far from other ground units and still communicate effectively. Most American M41/M41A1 tanks of the early Cold War period used one of a number of AN/GRC-3 through AN/GRC-8 radio sets. During this time, the -3 and -4 were usually armor unit radios (20.0-27.9 MHz), the -5 and -6 were artillery (27.0-38.9 MHz), and the -7 and -8 were infantry (38.0-54.9 MHz). Because there was overlap in the frequencies used by each unit type, it was possible to contact support units with your own radio on most occasions. Notice that infantry could call for artillery support and armor could call in artillery, but armor could not call infantry and vice versa using this set up.

The interphone included inside had provisions for hookups for all four crew members as well as an extension kit for a rear plate mounted phone for conversation with support infantry, just outside the vehicle. In this set up, the interphone radio box is an AM-65/GRC type and is located to the far right. Notice the connecting cords at the bottom of the unit that would lead to each crew member's radio connect box at their station. The "A" set above is probably an RT-70, which is a receiver/transmitter with continual tuning or two presets and operates on FM in the 47-58MHz range. To the left of the RT is a PP-112/GR power supply, taking power from the battery hookup at the lower right and amplifying it for the "B" set you see to its left. The "B" set could be any of three different units, depending on the frequencies needed and the units the tank was assigned to, but usually it was an RT-66 or 67 or 68. She was packed with 27 tubes and was also an FM radio. At the far left is the partially hidden receiver, again one of three types depending on mission. Under the mounting shelf is the main control box for the radio set.

This was a time when radios became increasingly complicated as their capabilities were stretched to new limits and tank crews became as much experts on radio communication gear as they were with their mechanical horses and guns. This was not a situation particularly welcomed by tankers, and it would take years before radio design would again emphasis simplicity and ease of use. But first, technology would have to catch up.

As you've seen, the M41 Walker Bulldog was a remarkable little tank for a number of reasons, not the least of which were its basic design improvements. The Americans did not get the chance to use the light tank in any large-scale actions, as it appeared too late for Korea and too early for Vietnam. But it has had the opportunity to show its worth in other country's inventories, fighting in India-Pakistan, Vietnam with the South Vietnamese, and countless other battles and skirmishes. But by the late 50's, something new was on the drawing boards for light armor in the US Army, and that something new would cause some of the worst controversies within and outside the military that had ever been seen. As the role of light armor was debated and changed, it was lost entirely as US planners searched for one vehicle that could do it all.

Met dank aan Marc Geurts.