Category: Cold War Canadian Prototypes

Canada (1953)
Amphibious Ball Tank – None Built

In 1953, in British Columbia, Canada, an odd design for an amphibious vehicle was created. The intention was to create a tracked vehicle surpassing other designs in mobility across marginal or swampy ground and which could provide both firepower and protection in a simple and robust design. The shape, from the side, resembled a tracked football and, from the front, it had the outline of an apple. The design was not destined to be a success in any way, but it is perhaps one of the strangest designs to come out of Canada in the post-World War II era: Hurthig’s Amphibious Vehicle.

Behind the Design

Peter Ernfrid Hurthig of Vancouver, British Columbia, Canada, filed the patent claim in the United States on 26th January 1953, assigning half of the value of the design to Ernest David Wesley of Maxwell, Vancouver. The language within the patent is “my” design and signed by Hurtig, meaning that this was Hurtig’s work and likely the value assigned to Maxwell was for assisting in funding the filing of the claim. Hurthig already had a patent to his name at this time in the form of a low profile in-ground animal trap which he filed in May 1946, but which was not granted until May 1950 and this was to be his last filing as well.

Primary Goal and Design

The goal of this patent was the creation of a vehicle that was able to better cross swamps and other marginal ground either for ‘war purposes’, as a tank, or for peacetime purposes, as some kind of transport. When used for military purposes, the vehicle was to minimize the number of gaps, seams, and angles that would provide weaknesses in the structure, making it vulnerable to enemy fire. Meeting both of those goals, therefore, called for a well rounded and well-sealed vehicle with the primary structure forming a cylindrical housing with hemispherical ends and sealed completely watertight below the water line – in other words, the vehicle would not just be able to navigate marginal terrain, but could also float.

Above this water line, each end would be provided with a blister in which a weapon could be mounted. Around the center, running circumferentially around the cylinder, was a track for propulsion. With just a single point of contact with the ground and based around a cylindrical shape, the vehicle would be inherently unstable, so the design called for a system of internal gyroscopic stabilization. Access to the machine was gained via two small rectangular sliding hatches, with one on each side behind the gun in the side blister, with a small ladder fixed to the outside to assist in access.

Armor and Armament

No specific thickness of the armor was mentioned in the design by Hurthig and Wesley, but they do state that the structure should be formed from some “suitable heavy armour material”. Assuming the vehicle was to be at least bulletproof, then not less than 8 mm or so of armor would be required, although this would be far from ‘heavy armor’. Certainly, the heavy curvature of the side blisters when viewed from the front would add substantial protection from enemy fire and the rest of the body would be covered from fire by the circumferential tracks. From the side, however, the tracks offered zero protection, as they would be all but invisible, and the very heavy curvature would be little more than a shallow curve at that angle.

For the non-military use of the vehicle, no armament would be needed or carried, but this was not the case for the military version. Here, the guns, mounted in the sponsons, would be able to fire forwards and backward, covering up to 180 degrees on each side, but with blind spots directly to the front and rear. Hurthig did not specify what type of guns were to be used, merely stating “cannons”.

Track

Propulsion of the vehicle was not by a single track but two. Both ran circumferentially around the central cylindrical section of the vehicle’s body. Each could be driven independently of the other, meaning the vehicle could rotate itself on the spot or steer by driving just a single track and/or counter-driving the adjacent one in the opposite direction.

Made from a series of rectangular plates, each with a series of three parallel ridges with a pair of valleys between them, each track plate was linked to the plate ahead and behind by a single ovaloid bar with a bolt at each end. The tracks were rather unremarkable and somewhat crude in this regard, certainly for 1953, when far more advanced track linkage systems were in use for armored vehicles. Indeed, in the text of the application, Hurthig even suggests tracks “somewhat similar to ordinary tank treads”, which suggests that he really did not know what tank tracks actually looked like in detail or indeed how they would work with his suspension idea.

However, what was innovative on the tracks was the decision to include suspension within the track system itself. Usually, on tracked vehicles, whether they be a digger, a crane or a tank, the track run goes around wheels fixed to sprung suspension units of some kind, so that the track pushes on the wheels which then move against the springing resistance of the bogie or torsion arm to produce the energy absorption needed to cushion the ride of the vehicle. There are some notable exceptions to that principle, such as the Yuba Ball Track from the early years of the 20th century, where the track included balls that rolled around a frame, but these are outliers as designs.

What Hurtig had in the patent was a continuous circular frame with teeth that ran around the outside of the cylinder and was supported by rollers around the circumference. The teeth would mesh with the drive sprocket on the inside. On the outside of this frame were mounted a series of springs.

At least four springs were mounted on the frame per track link and served to allow the outside of the track – the actual trackpad itself, to move inwards against the resistance of the springs during motion. The deflection was limited to the depth of the coil spring itself.

Propulsion

In longitudinal cross-section, the vehicle has the overall shape of an apple. A depression in the top of the machine allowed the tracks to run through it level with the top of the machine, whilst the inside was divided into sections. The lowest of these was below the floor of the machine and housed fuel tanks or other mechanical equipment or stowage. Above this was the primary fighting chamber, rectangular in cross-section and flanked by a pair of curved blisters or sponsons.

A pair of engines running on either petrol or diesel were located on the floor of the machine, either side of a small central auxiliary power unit or battery. Each engine was directly connected by a series of two gears connected by a driving chain with the main drive sprocket for each track, with that sprocket on the same axle as the second drive gear. In fact, per the drawing from Hurthig, despite both engines being connected to their own gears and chains and drive sprocket, the two sprockets shared a common axle near the roof of the machine to drive the frames and, thus, if one engine failed, then both tracks would still be able to be moved.

Crew

On the lowest level, right in the middle, against the floor plate, was the gyroscope used to stabilize the vehicle, with the pair of small petrol or diesel engines above it on the floor of the machine on which a crew would stand. Between those small engines was a supplementary power unit as well, creating an awkward internal space in which a crew would have to work. They would also have to work exposed to the noise and fumes from the motors, as well as the extreme hazard of becoming entangled in the drive chains or sprockets. Each side gun in the blister would require at least one man to operate it and at least another man to drive the vehicle, although Hurthig made no mention of exactly how the vehicle was to be controlled other than the obvious nature of turning the tracks at different rates to induce a steering force on it. The driver, wherever he may have had to be, presumably sat in the front, over the level of the engine, and would have little or no visibility through the front. At best, he was reduced to the narrow hole to see through in whatever gap the distance between the two tracks afforded him. An even worse position would befall a vehicle commander, who presumably would have to go in the back for lack of anywhere else he could go and thus would have no way to see forwards or effectively command the vehicle, meaning he would probably not even be needed anyway. An alternative might be to have a commander in the front and driver at the rear, but this would still leave the commander with little or no situational awareness on which to command the vehicle, with the added difficulty of then communicating the orders for direction and speed to the driver.

Conclusion

Hurthig’s design was, at best, naive. He had simply taken a general level of knowledge about tracked vehicles, such as the problem of crossing very soft ground or water, and solved it by creating even more and larger problems in its place. At worst, the design was little more than a floating metal ball forming a coffin for at least two men, as the design fundamentally failed to provide a clear advantage over something as simple as the dozens of floating or amphibious tanks already in existence by 1953.

Difficult to steer, difficult to control and command, with poor armament coverage and highly exposed tracks, the vehicle would be unlikely to be able to get to a fight and operate efficiently. In non-military use, the situation would not be much different, as the mobility sought for in the design solution just would not provide the benefits to offset the costs and the project was not a success as a result. No examples are known to have been built.

Sources

US Patent US2506834. Animal trap. Filed 28th May 1946, granted 9th May 1950.
US Patent US2756830. Amphibious vehicle and endless propelling belts therefore. Filed 26th January 1953, granted 31st July 1956.

Canada (1950s)
Tracked Carrier – None Built

Every army, at some point, has to get around to tackling the design of a utility vehicle. These are small, mobile vehicles for a variety of roles, from hauling troops and supplies, to towing field guns, and even for combat. The small 4-wheeled utility vehicle known as the Jeep fulfilled many of these lighter roles during World War 2 as did the not-less-famous Universal or ‘Bren Gun’ Carrier. Both saw extensive use and modification to the extent that Universal Carrier and Bren Gun carrier are used as interchangeable terms and ‘Jeep’ became synonymous with an off-road vehicle.
What is less well known is that the Canadians did an extensive amount of work of their own for a tracked utility vehicle during the War. This was known as the ‘Tracked Jeep’; effectively a go-anywhere multipurpose tracked vehicle made with a lot of components from Jeeps. This small vehicle would be able to be borne by gliders for use by airborne troops and fulfill various support, logistic, and scout functions and had entered prototype testing by 1944. Orders placed in 1945 though were delayed in production and by the end of the War, the Tracked Jeep project was effectively dead, although some testing in the very marshy conditions of northern Canada’s Manitoba province provided useful information for later tracked developments. The primary author of this work was Major M.G. Bekker of the Canadian Army who worked for the Canadian Directorate of Vehicle Development.
Major Miecyslaw Gregory Bekker was a Polish emigree who had worked for the Polish Ministry of Defence from 1931 until 1939. In 1940 he was working for the French Ministry of Armaments, but with the Fall of France, that position did not last long, and by 1943, was living in Canada and working for the Canadian Military until 1946. His speciality was off-road traction and all-terrain vehicles and by 1950 was working on secondment for the Canadian military at the Stevens Institute of Technology in Michigan. He would later go on to become head of general mobility with General Motors Corporation, meaning that this highly experienced and well-travelled engineer could even have had a hand in the early stages of what became the US HMMWV program.

Canadian Tracked Jeep Pilot No.1, May 1944. Photo: MilArt blog
The lessons learned from the design were not forgotten though, and in 1950, with the Korean War (June 1950 – July 1953) starting, the US and Canadian authorities worked together on a new series of highly mobile tracked vehicles, and in doing so, looked back on developments including the experience from Canada with the Tracked Jeep. By 1950 though, the Tracked Jeep of WW2 had substantially evolved and was now more of a tank destroyer than a utility tractor.

Front and side views of the Tracked Jeep circa 1950. Source: Army Service Technical Information Agency 1951

Design

The Tracked Jeep name had been kept, but the old suspension of 5 small 12 inch (300mm) diameter wheels had been abandoned in favour of a much simpler big-wheel design. The new design featured four much larger diameter wheels about 24 inches in diameter (600mm) with three of them in contact with the ground via the tracks, and the fourth at the front providing the drive. The rear-most wheel was on a trailing arm and was also provided with a large spring for suspension. The other wheels were sprung individually, horizontally.

Original suspension on the Canadian Tracked Jeep Pilot No.1, May 1944. Photo: MilArt blog

Improved suspension arrangement for Canadian Tracked Jeep showing the three ground contact wheels and rear trailing arm spring. Source: Army Service Technical Information Agency 1951
This tracked Jeep bore little or no resemblance to the older one. The hull one was different too. In place of the clean lines of the 1944 vehicle, this new 1950 vehicle was much more angular and now sported a turret. Not a full turret, but an unusual offset turret mounted on the rear right-hand side of the vehicle with limited 30 degrees traverse to the left and right. One similarity with the original tracked jeep though, was the retention of the original Willys Jeep engine, although as the original design had switched to the more efficient Carmazin radiator, it is likely this 1950 version retained that improvement too.

Crew

This diminutive vehicle was to have a crew of just two. A driver, located in the front left, and the overworked commander/gunner/loader in the rear centre sat facing outwards towards the breech of the rifle with the ammunition for the gun stowed behind him.

Illustration of the ‘Modified Tracked Jeep’ produced by Yuvnashva Sharma, funded by our Patreon Campaign.

Protection

The hull of the Tracked Jeep was just 112” inches long (2.84m) extending to 134” (3.4m) to the end of the gun barrel which overhung the front of the vehicle. The vehicle was light too, just 6,400 lbs gross weight (2.9 tonnes), but this was at the expense of protection. The armor was seriously thin with just 5/16” inch (8mm) at the front and ¼” (6.4mm) on the sides, making the vehicle barely bulletproof to normal small arms and not able to withstand machine-gun fire.
The small size of the vehicle (just 2.84m without the gun and 3.4m with it pointing forwards) was a very important factor. and could be reduced by stowing the gun at an angle across the hull to the front left corner). The vehicle was just 73” inches (1.85m) wide and 64” inches (1.63m) high and under 3 tons, meaning it was small enough and light enough to fit in every transport aircraft and glider in service at the time.

Armament

The advantage of this small vehicle was the armament. This design would provide a highly mobile platform, ideal for airborne troops with firepower to match. This firepower was in the form of a single 105 mm recoilless rifle. Assuming this to be the American M27 rifle, this would be able to fire the T-43 High Explosive Anti-Tank (HEAT-T) round at 1,250fps (381m/s), as well as the T268 High Explosive (HE)(standardised as the M323), T-269 White Phosphorus (WP)(standardised as the M325), T139 High Explosive Plastic (HEP-T)(standardised as the M345B1) and M326 High Explosive Plastic (HEP)(standardised as the M326) rounds. Only eight rounds could be carried in the vehicle though, limiting its usefulness for infantry support. If American practice was followed, this would be increased to 9 as the weapon was expected to be carried loaded into a combat zone.
There were three types of ranging available for the main gun from plain visual ranging, to stadiametric ranging, and finally, a rangefinder. With just a single shot, the estimated accuracy for a first shot hit with this weapon assessing those three types of range-finding was assessed in 1951 as 8%, 18%, and 49% respectively at 1000 yards (914 m). It should be noted too that the High Explosive Anti-Tank (HEAT or HEAT-T) round was capable of defeating 13” (330 mm) of armor plate which meant it was able to defeat any tank then in service.
The small turret in which the main gun was housed is shown in data tables as having 60 degrees of traverse with 30 degrees each side, however, a measurement of the blueprints shows, only 30 degrees to the right and just 21 degrees to the left for a total of 51 degrees. Elevation and depression are not stated but are measured from the blueprints as -10.5 degrees to +30 degrees.

Plans of the Tracked Jeep circa 1950. Source: Army Service Technical Information Agency 1951

Conclusion

The tracked jeep was not a bad concept in 1944 and it was still a viable concept in 1950, but it had very little growth potential. The vehicle was not really much more than a universal carrier with a very lightly protected superstructure and a recoilless rifle. That rifle could and was already easily fittable on a normal wheeled jeep or onto almost any other tracked vehicle. The small size, two-man crew and lack of ammunition with just 8 rounds meant that the tracked jeep of 1950 was not heavily armored enough to withstand enemy counterfire and not well-armed enough to provide sustained fire support in battle. As such the project was discontinued, the merits simply did not outweigh the problems and other solutions were available.

Sources

Army Service Technical Information Agency. (1951). Working Paper ATI 149375: Analysis of a Light Cross Country Combat Vehicle ‘The Cobra’.
Hall. C. (2008). A Biographical Dictionary of People in Engineering. Perdue University
Lucy, R. (2014). Canadian Tracked Jeep (Willy’s). MilArt blog.

Canada (1988-2000)
Firefighting Vehicle – None Built

Canada is a vast nation with enormous forested areas, so it is of no surprise that a variety of designs have cropped up over the years to fight forest fires. For a vehicle firefighting in remote and rugged areas, good levels of mobility are required and so it is also no surprise that tracked vehicles are particularly well suited for the sort of job in question.
Likewise, the use of jet-exhaust for firefighting activities is not a completely new concept, nor is the repurposing of old tanks for civilian usage.
The real question is, has anyone ever combined a surplus tank with jet engines for fighting fires? Surprisingly to many, the answer is yes. There was a T-34 tank hull with jet engines used in the aftermath of the 1991 Gulf War, where the force of the jet exhaust could blow out the oil wells left burning by retreating Iraqi forces. Less known is a daring idea from 1998 in Canada using a similar principle.

The Name

First and foremost, the use of the name ‘Firefly’ has to be addressed. Despite it including the word ‘fire’, neither the Sherman nor Churchill tanks used in this Canadian modification were ‘Firefly’s’ in the tank sense of the word, that is, fitted with the 17 pounder gun, which clarifies some of the confusion over which version of tanks are being described.

The hull selected for this version appears to be that of an M4A3(76)W HVSS Sherman and is described (but not shown) as using the trailer for water and fire retardant. Source: Patent CA2242736.

The Design

The design for the Firefly tank was submitted by Robert Matheson of Edmonton, Canada on July 1988 and covers the use of a ‘Turbine Jet Engine-Army Tank Forest Fire-Fighter’ described as:

“an apparatus which will enable the user to fight forest, brush or grass fires by injecting water or another fire retardant into the high pressure large volume of air being exhausted from a turbine jet engine mounted on the turret of an obsolete army tank which provides the required with, mobility and ability to direct airflow from the jet engine by use of the rotatable turret”

The description is therefore simple and explanatory but requires some elaboration. The tanks to be used are not necessarily Shermans or Churchills, as shown in the patent, but are an indication that any surplus or obsolete tank would be fit for the purpose.
It should also be noted that, although Canada did use Churchill tanks, and Firefly’s and Crocodiles and Shermans at various times, they did not operate the M4A3E8 shown in the drawing domestically, they only operated M4A2E8’s.
The tank itself should be selected because it has the mobility to go off-road for firefighting and because the mass of the vehicle means that the back pressure from the use of the jet turbine would not cause it to lift off the ground. Mounting the turbines onto the turret also adds the ability to turn and direct the blast of air/water in any direction. The only modification other than the addition of the two jet turbines to the turret was the removal of the gun from whichever tank was selected. No additional heat insulation for the vehicle or cooling system was envisaged, relying instead on the vehicle to provide inherently some “substantial protection from the heat of the fire to allow the operator to attack the fire where such action would be most effective”.

Artists impression of the Churchill-based ‘Firefly’, based on existing drawings.

Artists impression of the M4A3E8-based ‘Firefly’, based on existing drawings.

Both of these Illustrations were produced by Alexe Pavel, based on work by David Bocquelet.

Critique

The use of aircraft to fight forest fires is a very expensive endeavor and depends on the weather conditions at the time. Fire trucks struggle to go off-road and further struggle to deliver a sufficient volume of water to stop a fire. With a particular emphasis on the protection of buildings at the margins of the forested areas, these Firefly vehicles would be able to deliver a large quantity of water and fire retardant like AFFF at high pressure injected into the exhaust of the engine blasted at the fire.
The example vehicles on the patent were both drawn or described equipped with a trailer carrying water and fire retardant. However, the quantity of liquid in such a trailer would be just a fraction of what would be needed to make a difference to a forest fire. There was only brief consideration of a direct hook-up to available mains supplies of water or pumps feeding water from a stream or lake described as “a means could be readily provided to have the ability to supply a constant supply of water”. In this regard, the design is a failure, as even if it gets to the fire in the right place, it would not be able to sustain operations long enough to make much of a difference. The reuse of the existing Churchill (A.22F) Crocodile fuel trailers would indicate a volume of water of about 400 Gallons (UK), (1,818 liters) but the drawing also clearly shows the Firefly trailer is at least twice as small as the Crocodile one relative to the tank. Perhaps as much as 1000 Gallons (UK) (4,546 liters) could be carried, although this would not last very long pumped into the exhaust to fight the fire.
Fires are hot. This may seem obvious, but tanks are made of metal and riding in a hot metal box would be an exhausting experience. With the operators of the tank most likely having to be inside the vehicle with the hatches shut, the temperatures may well have become intolerable, and there is no discussion of additional cooling or air-handling systems provided to ensure that the operators did not succumb to the heat and stifling conditions inside.

Churchill Mk. VII (A.22F) version with modified Crocodile trailer. Source: Patent CA2242736
Attaching the turbines to the turret causes additional problems. The weight of these jet turbines would likely overstress the ability of the turret motors to rotate the turret properly, and even if they did not, the pipework connections would prevent a full range of motion. The force from the turbines would also cause a lot of stress on the turret ring as well.

Conclusion

The idea of attaching jet-turbines to tanks is definitely possible and had been done before, as had the idea of using them for fire-fighting purposes. This plan was no doubt well-intentioned and did combine the elements needed for firefighting, but overlooked some key design and operational hurdles, not least of which being that regardless of the technical merits of the design, who was going to pay for the operational costs and maintenance of these obsolete tanks. Presumably, lots of these modifications would be needed in every province due to the slowness of moving them from A to B and the vast landmass of Canada. Hazards to the crew from smoke and heat were inadequately addressed and there was insufficient consideration given to providing a sufficient supply of water for sustained operations. Other matters, like whether it was advisable to blast a fire with air at high velocity possibly adding to the spread of burning embers was not discussed at all. The final note should, of course, be the tanks. Yes, it is true the design is shown using a Sherman and a Churchill tank and, whilst these might be amusingly anachronistic, they are only indicative of how such equipment would look on a surplus tank. Whilst the design has no military value and a questionable value for civilian purposes, these designs are probably more interesting to model makers today.

Source

Canadian Patent CA2242736, filed 7/8/1998, granted 1/8/2000