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1 - Frandee in 1949. Often on the Frandee, track cleats, as not seen here, were in hard wood., an interesting site.


2 - On some Frandee, steering was assisted by a single ski suspended from a long boom on the external front of the vehicle. It could be folded on top of the machine in a rest position. The skiing was led by a steering wheel in the cabin. Here is model D, S/N 37, Snoshu.


3 - The Sea Wolf Frandee, 1957, the ground surface of the tracks seems somewhat reduced. http://www.amphibious, an excellent site.


4 - Snow-Machine Model 4VL of Thiokol Trackmaster, 1959, had two shafts, one for each track, no differential but a power splitter. Track grousers were made of metal and wood.


5 - A Snow-Machine Model 4VL of Thiokol Trackmaster, 1959, sold on the site ebay in 2007 $ 5,500, that is to say half of its value, which shows the distrust of buyers of a single model, because of the spare parts and the lack of information.


6 - Restored Thiokol Model 4T10 before 600 series with power divider like 4V series.


7 - Thiokoll Model 1101 had a Ford Falcon engine 101 hp, a controlled planetary differential and speed of 56 km / h.


8 - Model 105 of 1 t payload with Ford engine V6 101 hp and controlled planetary differential. He participated in 1962 at the Swamp Fox II Exercise in Panama and extricated itself better than all other from wet vegetation.

 Picture from book of Fred Crismon ‘US Military Tracked Vehicles’, Motorbook International Publishers & Wholesalers, 1992.



9 - Thiokol Trackmaster 601 of the U.S. Air Force, 1963, blue color.


10 - Model 1401 Imp participated in the exercise RAVE II in 1963. He behaved well in dry or marshy land. 18 hp engine, mass only 540 kg. Picture from the review 'Popular Science', Nov 1963.


11 - Each pair of wheels of the Imp hooked at the end of leaf springs. Picture from the review 'Popular Science', Nov 1963.


12 - Model 1401 took part in Exercise RAVE II in 1963 and was tried by the U.S. Army in Alaska in 1964 to pull skiers at 20 km / h. Wisconsin Engine 30 hp with a total mass of 1360 kg.

 Picture from book of Fred Crismon ‘US Military Tracked Vehicles’, Motorbook International Publishers & Wholesalers, 1992.



13 - Model 1402 Imp in 1964 with Wisconsin motor of 30 hp, 635 kg payload, 15 cm ground clearance, planetary differential in oil bath, rubber sprockets, 80% maximum slope in snow.


14 - 1404 Thiokol Imp, 1976.



15 - Super Imp, 1979, Ford Motor 104 hp 6 cyl, maximum speed 48 km / h, direction by band brakes.


16 - The Swamp Spryte, 1964, also known as the Model 603, with no cabin.


17 - Swamp Spryte of 1964 with cab, model 609.


18 - Swamp Spryte amphibious model 604 from 1964, available only without cab. Pict from a brochure of Ratrac, J M M archives.


19 - The same seen from above. Pict from a brochure of Ratrac.


20 - Swamp Spryte Series 1300, 1965, mass 1400 kg, Ford 6 cyl engine 101 hp, speed 55 km / h, in water 7.5 km / h.




21 - Snow Spryte Modèle1200 Series, 850 kg payload, suspension by trailing arms and torsion springs, polyurethane sprockets, two passengers for 1201 and 6 passengers for 1202, Ford 6-cylinder engine 101 hp. This model could receive the new roll and the snow plow hydraulically controlled from the cab. Pict from a brochure.


22 - Spryte Thiokol 1200 B model in 1967 with its wide tracks to move in any snow.


23 - Thiokol Spryte 1200 C model in 1974.


24 - Juggernaut 4T with auger, total mass 13.5 t, 5.4 t payload, maximum speed 34 km / h, Ford 6.4 liter V8 engine.


25 - Juggernaut 4T or 6T extricating itself from a ditch.


26 - Another Juggernaut 6T in 1966. Picture from a brochure.


27 - Super Tracked Carrier Juggernaut 6T of 1972, mass 16 t, 7 t payload.


28 - This Juggernaut 6T, single model, is equipped with a Dodge Ram cab. Front view.


29 - 30 T, payload 30 tons, and even beyond, GM 8V 71 engine, maximum speed 21 km / h, length 14 m. Wading depth of 1.5 m. The picture is a drawing from a brochure.


30 - 30T Thiokol : Foremost had built in the mid-60 the RN 200, a tractor semi-trailer and four tracks and in 1969, the Husky 8 with a rigid frame for 36 t payload. The Husky 8 was also marketed under the trade name Thiokol Juggernaut 30T (photo) but probably made in Calgary, Alberta, not at Logan. Pict from SAE Paper 'Heavy Duty Over-Snow Off-Highway Vehicles' by Ross V. Eskelson N° 690573, 1969.


31 - Packmaster 1969 was equipped with a bar of compaction, which could be used as a rear blade or scarifier and a hydraulic lift. In the 70s, the Packmaster dominated the market in the Eastern USA with its hydraulic lift as did Tucker before.


32 - Hydromaster, in addition to the civilian market, equipped U.S. Air Force around 1981. The hydraulic front blade could follow closely the road or escarpments. Very wide tracks, 1.4 m wide.


33 - ST Ratrac in 1969, Thiokol Packmaster imported into Europe by Ratrac, Zurich.


Thiokol Chemical Company, Birgham City, Utah, founded in 1929 is known since 2007 under the name of ATK Launch Systems Group. Originally, two chemists, J. C. Patrick and N. Mnookin invented a synthetic rubber they called 'Thiokol' (from Greek). This polymer proved to be an excellent fuel for rocket propulsion. The company specialized later in propellants for American solid rocket launchers and missiles.

Meanwhile, since 1948, Utah Scientific Research Foundation in association with Utah State University (USU) of Agriculture and Applied Science, Logan, Utah, conducted research, like many scientists of that time as Tucker, Bombardier, Nodwell and many others, on the travel on areas without roads. Thus, several tracked vehicles were created at USU : the first Frandee 1948 (3 axis), the Frandee Snoshu 1949 (with 4 axes) (photo 1), the Cab-over Frandee Snoshu 1949 (photo 2), the Trackmaster from 1956. The designers were Edward Roy France (still alive in 2009 in Smithfield, Utah), Emmet Devine, the combination of two names giving the name of the vehicle 'Frandee' and Ross Eskelson, the latter having previously developed with USU the 'Eskalsled', a one tracked and one steering skied snow-cat. Thiokol used the vehicles 'Frandee' not far away in the salt marshes for its rocket tests. Some prototypes were sent to Alaska.

Note that a tracked vehicle Frandee served as a model in the 50's to Popular Mechanics magazine which published the construction plans.

Patent No. 2,878,883, asked in 1956 by USRF, Utah Scientific Research Foundation, and granted in 1959, involved a rigid 4-track version made in 1957, the Frandee the Sea Wolf (photo 3). Hydraulic steering system was based on the Tucker Sno-Cat, but the four tracks could rotate (wagon steer).

USU produced the Trackmaster 4VS around 1958 and the most successful, the 4VL.


2.1 - Trackmaster

Meanwhile, Thiokol, like all of the 60’s aviation companies, sought to diversify into off-road vehicles. They bought the rights to the Trackmaster to the State University of Utah in 1959, kept the site of Logan, Utah, and proposed to U.S. Air Force its tracked vehicles. USU had probably already contacted Army about 1958.

In 1959 the Thiokol Trackmaster 4VL Snow Machine (photo 4), still studied by USU and planned for eight passengers, had a 6-cylinder Ford engine 3.7 l. All mechanical components were available on the market. The Thiokol 4VL is rare nowadays (photo 5) and also this 4T10 (photo 6).

The Thiokoll Model 1101 (photo 7) and Model 105 (photo 8) produced in small series led to the Trackmaster 601 marketed from 1962 and built for U.S. Forces, particularly the Air Force (photo 9) as a general purpose and recovery vehicle on the airfields of Alaska during the construction of the Dew Line.

2.2 - Imp

Prototype of Thiokol 1401, 1963 (photo10 to 12), designed by Ross Eskelson, and known as the Imp was an early design of Thiokol. It could carry two passengers and 450 kg for a total mass of 700 kg on any terrain for hunters, fishermen, ranchers and explorers of the week-end for a small fee of $ 3,500 at the time. The fashion of small recreational vehicle ATV (All-Terrain Vehicle) in North America was only beginning in 1963 and will last until the first oil crisis in 1973. A multitude of models were sold.

The Imp 1402, 1964 (photo 13) used for off-road transport at maximum speed of 40 km / h, was available with an amphibious closed hull at extra cost.

The Imp 1404 (photo 14) was produced from 1969 and launched a new concept of damage with very large tracks of 1.2 and 1.8 m wide.

The Super Imp 1450 (photo 15) from 1979, a little longer with a raised rear sprocket for a payload of 1080 kg, will be sold under the name DMC 1450 from 1980.

2.3 - Spryte

The Swamp Spryte (photo 16 to 19), larger, powered by a 101 hp Ford Falcon was amphibious without preparation.

The Series 1300 Amphibious Swamp Sprype All-Terrain Vehicle (photo 20), scheduled to travel in wetlands was launched in 1966.

The Model 1200 Series Spryte or Snow-Spryte (photo 21) designed for surveillance of power lines, the fight against mosquitoes and especially the ski slopes grooming proved to the world at the Olympic Games of Innsbruck in 1964.

The Thiokol Spryte 1200 B, 1967 (photo 22) and Spryte 1200 C, 1974 (photo 23) were expected to carry 10 people.

2.4 - The Juggernaut

 In 1966 the range of Thiokol Juggernaut was introduced , impressive rigid chassis and four-track steering (wagon-steer) vehicles designed to carry heavy loads on soft ground for construction, pipelines and oil industry. The Juggernaut 4T (photo 24 and 25) had four lines carrying wheels, the Juggernaut 6T (photo 26 to 28) and had five rows of bearing rollers. Finally, the Model 30T Juggernaut (photo 29 and 30), a real mammoth, had eight axles carrying wheels (+ 2 axes for the sprockets). All the 'Juggernaut' were studied by Foremost Developments Ltd., Calgary, Alberta, but it seems that the 4T and 6T have been built to Logan, since these two models were only sold under the brand name Thiokol. The T 30, also sold by Foremost, is still in catalog of this later, though modified, under the name Husky 8

2.5 - The Packmaster and Hydromaster

Thiokol introduced the Packmaster 2100 (photo 31) very wide tracked (1.5 m) in 1969 resulting in a ground pressure of 0,035 kg / cm ², a powerful Ford engine to choose from 107 to 165 hp, grooming accessories, a blade and a snow compactor. Thiokol proclaimed that its price was the same as the Spryte.

 In 1970 Thiokol 2500 Hydromaster was commercialized, 3700 Hydromaster in 1976 (photo 32) with Allis Chalmers 200 hp engine, a two-speed hydrostatic transmission, 6 tons force at the helm, forward or rear moving at high speed, pressure on the ground 0039 kg / cm ², mass 4.5 t, 7.5 m² surface of the track, tilt cabin for one person, slope reached 100% on firm ground, on soft snow, 75% max side slope.

Ratrac, Zurich, importer for Europe of Thiokol sold in the years 60 to 90 the Thiokol range whose this model ST (photo 33), in fact a Packmaster.


The great period of diversification of 60-70 years business ended with the first oil crisis in 1973 and forced companies to tighten the purse strings. They separated themselves little by little from their subsidiaries of all-terrain vehicles to focus on their primitive products.

In 1978, Thiokol was already seeking to sell its subsidiary of Snow-Cats. John DeLorean won the case that he renamed DeLorean Manufacturing Company, DMC. Quickly in 1982, it became Logan Manufacturing Company, LMC, to avoid the association with the name John DeLorean.

Indeed, DeLorean, former director of General Motors, had already launched the sports cars of that company and then took its independence. It launched in Ireland in 1979 DMCL DeLorean Motor Cars Ltd with the help of public funds, in order to create jobs, and manufactured a completely new sports car with gull wing doors, the DMC-12 which appeared even in films. 8500 cars were built between 1981 and 1983 for DMC, but reliability was not at the top. Sales lowered and it was soon charged by public opinion to squander public funds.

Meanwhile, LMC maintained its production of transport and grooming Snow-cats, that was the old range handed to the style of the day and modernized, except for the Juggernaut, abandoned : Hydromaster for example, became the DMC 3700. But in 1988 J. DeLorean was trained in a case of drug traffic, trap set by the FBI which he was later cleared. Short of money, he tried to sell his business to his employees but in 1996 an investor, NYC, resumed all. The business was already declining in the 90s, due to lack of investment, competition from Bombardier, Tucker and Pisten Bully of Kässbohrer. Unfortunately, the factory closed in 2000 as before other competitors like Snow-Trac or Kristi.