Christie's SPGs/Tanks/Amphi Cars/Half Track/ Fire truck/Race cars

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Christie SPGs
by Charlie Clelland

Walter Christie was a prolific, idiosyncratic inventor who often produced designs which were very advanced but his abrasive personality meant that he had many problems in his dealings with the Ordnance Dept. His most successful designs prior to the SPGs had been the front-wheel drive engine and transmission modules used by many fire departments before WW1. Christie’s manufacturing company was known as the “Front Drive Motor Company” based at Weehawken, NJ. Christie was an early adopter of the wheel/track concept where a vehicle could be changed from running on wheels to tracks dependent on ground conditions. The available information on the Christie SPG designs is fairly limited and ignored by most authors in favour of the tank and suspension designs.

It is surprising that Christie had any of his designs accepted by the Ordnance Dept never mind actually constructed. The Holt Manufacturing Company and the Rock Island Arsenal had a very close relationship during the period of SPG construction, 1917-23, even to the extent of Pliny S. Holt supervising SPG designs and construction at Rock Island during WW1.

Christie Motor Carriage for 8inch Howitzer

This vehicle was delivered to the Ordnance Dept for testing in 1918. The odd looking single large return wheel was part of an arrangement to adjust track tension in combination with the two roadwheels. The vehicle was designed to run on wheels or tracks with the central roadwheels jacked up so it ran on only the front and rear pairs of wheels. Only the centre roadwheels were sprung which must have made steering the vehicle on wheels very difficult. It was powered by a Christie built 6-cylinder 120 hp engine, the transmission type is unknown but a max. speed of 16 mph was attained. Testing showed that the vehicle had many faults and it was rejected. However, some of the design ideas were interesting and Christie was encouraged to continue development.

Christie Motor Carriage for 3inch Anti-aircraft Gun

It’s not certain when this vehicle was built, best guess is 1918-19. The original identity of the vehicle was a mystery until a patent assigned to Walter Christie was found. The drawings in the patent are a match for the available images of the vehicle. The vehicle was four-wheel drive was powered by a 4-cylinder 60 hp engine with a 3 forward 1 reverse speed transmission giving a max. speed of 15 mph. No comments have been found on the suitability of the vehicle for its role as a mobile AA gun.

Christie Motor Carriage for 155mm GPF Gun

In 1919 Christie delivered a new SPG design for testing at APG (Aberdeen Proving Ground). The SPG was designed, as the 8inch gun carrier was, to run on wheels or tracks. The conversion from tracks to wheels took about 15 minutes and the tracks were strapped onto the mudguards when not in use. The rear driving wheels were rigid but the steering wheels were independently sprung. The centre two roadwheels were sprung and jacked off the ground when running on wheels. All of the wheels had a pair of 36" x 3" solid rubber tires - the drive wheels used the typical Christie sprocketless drive - the track guide plates entered slots in the drive wheel. The engine was the same as 8inch vehicle - the 120 hp Christie engine with a transmission which had 4 forward and 4 reverse speeds. The 155mm SPG could travel almost as fast in reverse (12mph) as forward (15mph) on wheels. The max. forward speed on tracks was about 9 mph, considerably faster than the early Holt SPGs. Testing showed that 155mm SPG was very promising and Christie built two further versions of the SPG delivered in 1920 and 1921. These vehicles looked very similar to the original except that mudguards were replaced with a shallow box structure with rollers at the ends presumably to make it easier to secure the tracks when the SPG was running on wheels. Final testing of the Christie 155mm SPG in 1921-22 was very successful and the Ordnance Department recommended placing the vehicle in production. However, due to the hostility of Field Artillery branch to SPGs and declining defence budgets this never happened.

There are many comments in the modern literature about the unreliability and poor performance of the Christie vehicles - this is clearly not so. In 1919 a report in the Field Artillery Journal notes that:
“In the run from Hoboken, NJ to Washington, DC, a distance of 276 miles, the running time was 51 hours 16 minutes and average speed of 53⁄4 mph.”
“On a 100-mile maximum speed test, an average speed of 13.23 mph was maintained. A speed of 21 mph over a measured mile was attained”
“The mount has negotiated slopes exceeding 100% (i.e. 45°), and very difficult terrain.”

Christie Motor Carriage for 75mm M1920 Gun

There is very little information on this SPG, two vehicles were tested at APG in 1920. It appears to be roughly equivalent to the Holt Mark VII. It was powered by a 90hp Christie engine and a 4 speed transmission which gave a top speed of 20mph on wheels. The vehicle weighed about 7,200 kg and was 3.65m long and 2.28m wide. The gun was the U.S. built version of the French 75mm Mle 1897.

Christie Motor Carriage for 75mm M1920 Gun / 105mm M1920 Howitzer

Very few details about this vehicle are known. It was tested at APG in 1921. The suspension appears to be very similar to the Christie M1919 medium tank. The SPG was, as most Christie vehicles were, designed to run on wheels or tracks, the two small roadwheels could be jacked up out of ground contact. The weight of the vehicle was 8,170 kg.

Unknown - 75mm SPG about 1924

Known only from a single image, no details about this vehicle have been found.

[Kriegerfaust007]

. 1919. . 1921 t4 combat car 1923 . 1922 1921 1928 . American airborne Christie M1936 tank. so many designs so few made question how much of a a****** was Chrsite

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American extended tech tree for World of Tanks proposal by PikPikker and Zinoviy Alexeev 1942 Walter Christie’s Models

Christie Model 1919

J. Walter Christie débuta dans le développement de véhicules blindés, par des canons d’artillerie motorisés. En 1915-1916, Front Drive Motor Co obtena de la part de l’armée des USA un contrat pour un canon de 76 millimètres motorisé. Le véhicule réalisé était très lourd et sous-motorisé. D’ailleurs l’ affût était à peine satisfaisant. En 1917 Christie développera un obusier de 203 millimètres sur affût Mark VI qui fut commandée à 4 exemplaires. Ce modèle était le prototype de tous les réalisations de Christie. L’ engin pouvait se déplacer sur chenilless ou sur ses roues, une idée se récurante ensuite chez Christie, et atteindre les 26 km/h sur route. En Christie 1919 a obtenu la commande d’un char Un prototype fut développé, le Christie M1919. La suspension était trop lourde et trop rigide. Le Moteur de 6 cylindres, qui développait 120 cv n’était pas très puissant pour les 12 tonnes de l’engin et de celui-ci atteingnait avec la difficulté les 13 km/h sur route avec chenilles et 24 km/h sur ses roues.

J. Walter Christie began in the development of armoured vehicles, with artillery motorized guns. In 1915-1916, the Front Drive Motor Co, obtained from US Army a contract for a gun of 76 mm motorized. The vehicle developped was very heavy and under-was motorized. Moreover the mounting was hardly satisfactory. In 1917 Christie will develop an howitzer of 203 mm on mounting Mark VI which was ordered from 4 specimens. This model was the prototype of all the achievements of Christie. The machine could move either on tracks or on wheels, a recurring idea thereafter at Christie, and reach the 26 km/h on road. In 1919 Christie obtained the ordering of a tank. A prototype was developed, Christie M1919. The suspension was too heavy and too rigid. The engine of 6 cylinders, which developed 120 hp was not very powerful for the 12 tons of the machine and this one reached with difficulty the 13 km/h on road with the tracks and 24 km/h on wheels.

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|Christie M1919|
|src: Blindés des origines à 1940, Connaissance de l’ Histoire (Hachette), HS n°3|src: TANKS!|

M1919 Specifications
General
Type: Convertible Combat Car
Crew: 2
Number built: ?
Dimensions
Length: 5.54 m Width: 2.51 m Height: 2.74 m Weight: 18684 kg
Armament
Main: ? Ammo: ? rounds Secondary: ? Ammo: ? rounds
Armor
Maximum: 25.4 mm Minimum: 12.7 mm
Automotive & Suspension
Engine: Christie 6 cylinders Horsepower: 120 hp Power/weight ratio: 39.3 hp/t
Suspension: ?
Performances
Maximum Speed : 21 km/h on wheels, 11 km/h on tracks Range: ? km

Drawings
M1919

Christie réalisé en 1921, un modèle amélioré, sans tourelle. Ce modèle était armé avec un canon de 75 millimètres assemblé dans un casemate sphérique devant le véhicule.

Christie realized in 1921, an improved model, without turret. This model was armed with a gun of 75 mm assembled in a spherical casemate in front of the vehicle.

M1921 Specifications
General
Type: Convertible Combat Car
Crew: 2
Number built: ?
Dimensions
Length: ? m Width: ? m Height: ? m Weight: 11478 kg
Armament
Main: 1 x .30cal MG Ammo: ? rounds Secondary: ? Ammo: ? rounds
Armor
Maximum: 19 mm Minimum: ? mm
Automotive & Suspension
Engine: ? Horsepower: ? hp Power/weight ratio: ? hp/t
Suspension: ?
Performances
Maximum Speed : 24 km/h on wheels, ? km/h on tracks Range: ? km

Christie Model 1928

Cependant, l’armée américaine n’était pas très intéressée par les développements de Christie et celui-ci se consacra ensuite à l’étude des véhicules de débarquement. Cependant en 1928, le gouvernement lui paya le prix de ses brevets et Christie fonda la US Wheel Track Layer Corporation. Le premier modèle produit par cette compagnie fut le M1928. Le M1928 qui était également un char convertible, fut présenté seulement en octobre 1930 à l’armée (deux officiers du Moteurering department of Artillery, un certain Major Patton et d’un certain lieutenant-colonel Chaffee). Ce modèle fut examiné lors de déplacements sur chenilles sur orute et en tout terrain. Les résultats étaient plutôt flateurs. En effet le char pouvait atteindre les 112 km/h sur ses roues et les 67 km/h sur chenilles, ce qui est énorme. Toujours sur chenilles en terrain difficile, il pouvait atteindre les 48 km/h. Impressionnée, la commission promulgua l’adoption immédiate du char et le 25 mars 1931 passa une commande de cinq prototypes.

However, the American army was not very interested by the developments of Christie and this one was devoted thereafter to the study of landing vehicles. However in 1928, the government paid him the price of its patents and Christie founded US Wheel Track Layer Corporation. The first model produced by this company was M1928. M1928 which was also a convertible tank, was presented only in October 1930 at the army (two officers of the Engineering department of Artillery, a certain major Patton and a certain lieutenant-colonel Chaffee). This model was tested with displacements road on on tracks and cross-country. The results were rather flattering. Indeed the tank reached the 112 km/h on wheels and the 67 km/h on tracks on road, which is enormous. Always on tracks, in rough ground, it could reach the 48 km/h. Impressed, the commission promulgated the immediate adoption of the tank and on March 25, 1931 had placed an order of five prototypes.

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|Christie M1928|
|src: Blindés des origines à 1940, Connaissance de l’ Histoire (Hachette), HS n°3|src: TANKS!|

M1928 Specifications
General
Type: Convertible Combat Car
Crew: 3
Number built: ?
Dimensions
Length: 5.18 m Width: 2.13 m Height: 1.83 m Weight: 8600 kg
Armament
Main: 1 x .50 Browning MG (12.7 mm) Ammo: ? rounds Secondary: ? Ammo: ? rounds
Armor
Maximum: 25.4 mm Minimum: 6.35 mm
Automotive & Suspension
Engine: V12 Liberty Horsepower: 338 hp Power/weight ratio: 39.3 hp/t
Suspension: Christie
Performances
Maximum Speed : 112 km/h on wheels, 67 km/h on tracks Range: ? km

Christie M1928
src: TANKS!

Drawings
M1928

Christie Model 1931

La commission cependant demanda à Christie d’ améliorer son modèle de base, et celui-ci proposa le M1931. Cependant le M1931 connaissait beaucoup de difficultés techniques (en particulier le moteur) et les essais furent sans cesse reportés. Christie et l’armée sont entrés d’ailleurs en conflit et le premier retourna à son usine. Cependant il produisit 7 prototypes dont trois furent employés pour le développement du T3 Medium Tank.

The commission however asked Christie to improve its basic model, and this one proposed M1931. Cependant M1931 knew many technical difficulties (in particular the engine) and the tests were unceasingly deferred. Christie and the army entered moreover in dissension and the first was turned over from there in its factory. However 7 prototypes were produced of which three were used for the development of Medium Tank T3.

Des pays étrangers comme la Grande-Bretagne et la Union soviétique étaient en grande partie intéressés par les modèles de Christie. Ceux-ci ont employé le système de la suspension breveté pour réaliser pour les Anglais, les Cruiser Tanks et pour les Russes, les chars du type BT et T-34.

Foreign countries like Great Britain and the Soviet Union were largely interested by the achievements of Christie. Those used the system of suspension patented to realize for the English, the Cruiser tanks and for the Russians, the tanks of the type BT and T-34.

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|Christie M1931|
|src: TANKS!|

Christie M1932
src: Blindés des origines à 1940, Connaissance de l’ Histoire (Hachette), HS n°3

M1931 Specifications
General
Type: Convertible Medium Tank
Crew: 2
Number built: ?
Dimensions
Length: 5.43 m Width: 2.24 m Height: 2.21 m Weight: 10668 kg
Armament
Main: 37 mm Gun Ammo: ? rounds Secondary: 1 x .30 Browning MG (7.62 mm) Ammo: ? rounds
Armor
Maximum: 16 mm Minimum: ? mm
Automotive & Suspension
Engine: V12 Liberty Horsepower: 338 hp Power/weight ratio: 1.68 hp/t
Suspension: Christie
Performances
Maximum Speed : 113 km/h on wheels, 64 km/h on tracks Range: 402 km on wheels, 274 km on tracks

Drawings
M1932

T3 Medium Tank & T1 Combat Car

Le M1931 devenu T3 était un véhicule à traction arrière, équipé d’un moteur puissant et d’un train de roulement composé de trois grands galets (dégagement de 35 centimètres) à suspension indépendante avec balancier et ressort à boudin. Les roues d’avant de direction étaient équipées d’une suspension avec ressorts horizontaux et non-verticaux comme sur les galets. Le but de cette disposition était de permettre la direction du réservoir quand celui-ci se déplaçait sur ses roues et pas sur ses chenilles. Le moteur était un Liberty Ordnance V12 développant la 330 cv à 1400 t/mn qui pouvait être poussé à 387 cv à 2500 t/mn. Ce moteur procurrait au T3 une vélocité de loin supérieure à n’importe quel char existant. Les seules limites étaient l’usure de l’équipement et de l’équipage en tout terrain.

M1931 become T3 meanwhile was a vehicle with rear-wheel drive, equipped with a powerful engine and a train of bearing made up of three large road wheels (clearance of 35 cm) with independent suspension with beam and arises with roll. The steering front wheels were equipped with suspensions with horizontal and non-vertical springs as for the road wheels. The purpose of this provision was to allow the steering of the tank when this one moved on its wheels and not on its tracks. The engine was V12 Liberty Ordnance developing 330 hp to 1400 rpm which could be thorough if need be to 387 hp to 2500 rpm. This engine got for the T3 a swiftness by far higher than any existing tank and on any ground. The only limits was the wear of the equipment and the tiredness of the crew into cross-country.

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|Christie T3 Medium Tank|
|src: Blindés des origines à 1940, Connaissance de l’ Histoire (Hachette), HS n°3|src: WWII Vehicles|

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|Christie T3 Medium Tank|
|src: TANKS!|

Le T3 était équipé des chenilles composées des larges patins (250 millimètres) en acier moulu, reliés par des axes en acier faciles à enlever. Un patin sur deux était équipé de guide central haut de 18 centimètres qui s’intercalait entre les barres barbotins entre les deux bandages de caoutchouc. Cette disposition empêchait à haute de vitesse de perdre les chenilles. Cependant les efforts latéraux sur les articulations causaient une usure significative des axes d’assemblage. Les chenilles de Christie étaient cependant légères et très maniables. Deux hommes pouvaient en trente minutes les démonter et les placer sur les supports situés au dessus du train du roulement. Cette opération finie le char pouvait se déplacer grâce à deux chaînes qui détournaient la puissance fournie aux barbotins arrières vers les dernières galets. Les premières galets assuraient la direction du char. Naturellement, les poulies de tension étaient inutiles dans cette configuration. Le T3 était dirigé par un équipage de trois hommes: le commandant, le conducteur et le canonnier. À l’intérieur du char il n’y avait aucune séparation entre le compartiment du combat et le compartiment moteur qui occupait toute la moitié arrière du char. Le pilote avait accès au char au moyen d’une trappe à deux volets à l’avant du char qui fermée formait un petit casemate blindée. Le pilote dirigeait le char à l’aide d’un volant de direction pour la marche sur les roues ou de deux palonniers agissant sur les chenilles pour la marche en tout terrain. Boîte de vitesses, accélérateur et accessoires étaient de type classique.

The T3 was equipped with tracks made up of broad links (250 mm) in ground steel, connected by steel axes easy to remove. A link on two was provided with a 18 cm height central guide which was introduced in the bars of the sprocket-wheels located between two bindings of rubber. This provision prevented when the speed high to lose tracks. However the lateral forces related to the articulations caused a significant wear of the clevis pins. The Christie tracks were however light and very handy. Two well involved men could in thirty minutes dismount them and place them on the supports located at the top of the train of bearing. This operation finished the tank could move thanks to two chains which made pass the horse-power of the back sprocket-wheels to the last road wheels. The first road wheels ensured the steering of the tank. Of course, the idlers were useless in this configuration. The T3 was operated by a crew of three men: the commander, the driver and the gunner. At the interior of the tank there was no separation between the compartment of combat and the engine compartment which occupied all the back half of the tank. The pilot had access to the tank by means of a trap door with two shutters in front of the tank which closed once formed a small armoured casemate. The pilot directed the tank by means of a steering wheel for the drive on wheels or two swing bars acting on the tracks for tracked drive. The gear box and other accessories were of traditional type.

Quand le T3 roulait sur ses roues, les chenilles étaient rangées sur les côtés. Notez la chaîne qui transmettait la puissance du barbotin arrière à la dernière roue.
When the T3 rolled on its wheels, the tracks were suspended on the sides. Note the chain which transmitted the power of the back sprocket-wheel to the last road wheel.
src: Blindés des origines à 1940, Connaissance de l’ Histoire (Hachette), HS n°3

La tourelle qui vait la forme d’un grand tambour, surmontée d’une coupole de commandant de même forme, était actionnée manuellement sur 360°. Le compartiment moteur était également équipé de grands radiateurs et ventilateurs qui aspiraient l’air par l’intermédiaire de deux fentes visibles sur la plaque arrière. Neuf exemplaires de ce char furent seulement produits dont deux furent livrés avec licences aux Soviétiques qui s’en inspirèrent pour réaliser la famille des chars BT. Les chars livrés à l’US Army furent versés dans la cavalerie sous la désignation T1 Combat Car et dans l’infanterie en tant que T3 Medium Tank. Le T3 était armé d’un canon de 37 millimètres avec une mitrailleuse Browning coaxiale de 7.62 millimètres tandis que le T1 était armé seulement avec une mitrailleuse Browning de 12.7 millimètres.

The turret which had the shape of a large drum, surmounted of a commander cupola of of the same forms, was operated manually with a traverse of 360°. The engine compartment was also provided with large radiators and ventilators which aspired the air via two slits visible on the back plate. Nine specimens of this tank were only manufactured of which two were yielded with licence of construction to the Soviets who realized the BT family from them. The tanks allotted to US Army were versed in the cavalry under designation T1 Combat Car and in the infantry under designation Medium Tank T3. The T3 was armed with a gun of 37 mm with a coaxial Browning machine-gun of 7.62 mm whereas the T1 was armed only with one Browning machine-gun of 12.7 mm.

T1 Combat Car
src: Blindés des origines à 1940, Connaissance de l’ Histoire (Hachette), HS n°3

Data
T3 Medium Tank
T1 Combat Car

Drawings
T3 Medium TanK (1928)
T3 Medium TanK (1931)
T1 Combat Car
Model 1940

En 1932, on commanda à un autre fabricant cinq exemplaires du char de Christie, sous la désignation T3E2. Cette version était propulsée par un Moteur Curtiss TD12, développant 435 cv et était équipée d’une tourelle octogonale mieux formée et pesait dans les 12 tonnes. Une autre version équipée d’une direction à différentiel contrôlé fut fournie par la même société en 1936 sous la désignation T3E3. Tous ces véhicules furent considérés de comme des chars de développement et d’ expérimentation et finirent leur vie comme véhicules de formation.

In 1932, one ordered to another manufacturer five specimens of the tank of Christie, under designation T3E2. This version was propelled by an engine Curtiss TD12, developing 435 hp and was equipped with a better shaped octagonal turret and weighed in the 12 tons. Another version equipped with a controlled differential steering was delivered by the same firm in 1936 under designation T3E3. All these vehicles were regarded as tanks of development and experimentation and finished their life like training vehicles.

Medium Tank T3E2
src: Blindés des origines à 1940, Connaissance de l’ Histoire (Hachette), HS n°3

Medium Tank T3E2
src: TANKS!

Malgré leur designs très avançés et révolutionnaires, les modèles de Christie eurent peu de succès aux Etats-Unis mais ont fortement inspiré d’autres armées étrangères. Les raisons de cet désintérêt américain, étaient que les performances étaient inférieures à celles souhaitées et que l’ on doutait de la valeur pratique du système convertible. En effet les chars traditionnels se déplaçant seulement sur des chenilles possédaient de meilleures qualités tactiques et étaient moins complexes et chers à produire. Ajoutons que Christie était peu apprécié par les techniciens de l’armée US. Celui-ci une fois que son brevet était vendu refusait n’importe quelle collaboration pour améliorer le véhicule, ce qui déplaisait fortement au militaires.

In spite of their revolutionist and very advanced designs, the Christie models hardly had success in the USA but strongly inspired other foreign armies. The reasons of this American scorn, were that the performances were lower than those wished and that one doubted of the practical value of the convertible system. Indeed the traditional tanks moving only on tracks had better tactical qualities and were less complex and expensive to produce. Let us add that Christie was hardly appreciated by the technicians of US Army. This one once its patent sold refused any collaboration to improve the vehicle, which strongly upset the soldiers.

T3E2 Specifications
General
Type: Convertible Combat Car
Crew: 4
Number built: ?
Dimensions
Length: 5.72 m Width: 2.44 m Height: 2.34 m Weight: 11500 kg
Armament
Main: 37 mm Gun Ammo: ? rounds Secondary: 5 x .30 Browning MG (7.62 mm) Ammo: ? rounds
Armor
Maximum: 12.7mm Minimum: 6.35 mm
Automotive & Suspension
Engine: Curtiss TD12 Horsepower: 435 hp Power/weight ratio: 37.8 hp/t
Suspension: Christie
Performances
Maximum Speed : 111 km/h on wheels, 65 km/h on tracks Range: ? km

Drawings
T3E2 Combat Car

T4, T4E1 Medium Tank - T4E1, T4E2 Combat Car

Rock Island Arsenal en employant des brevets achetés à Christie, réalisa le T4 équipé d’une tourelle semblable à celle du Light M1 Combat Car. Le développement utilisa divers types d’Armement avec ou sans tourelle pour l’infanterie et la cavalerie.

Rock Island Arsenal by using patents bought to Christie, built T4 equipped with a turret similar to that of the Light M1 Combat Car. The development was related mainly on various types of armament with or without turret for the infantry and the cavalry.

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|Christie T4 Medium Tank|
|src: TANKS!|

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|Christie T4E1 Medium Tank|Christie T4E2 Combat Car|
|src: TANKS!|

T4 Specifications
General
Type: Convertible Medium Tank
Crew: 4
Number built: ?
Dimensions
Length: 4.90 m Width: 2.31 m Height: 2.01 m Weight: 8727 kg
Armament
Main: ? Ammo: ? rounds Secondary: ? Ammo: ? rounds
Armor
Maximum: ? mm Minimum: ? mm
Automotive & Suspension
Engine: Continental 7cyl 668ci Horsepower: 250 hp Power/weight ratio ratio: 28.6 hp/t
Suspension: Christie
Performances
Maximum Speed : 84 km/h on wheels,43 km/h on tracks Range: ? km

T4E1 Specifications
General
Type: Convertible Medium Tank
Crew: 4
Number built: ?
Dimensions
Length: 4.90 m Width: 2.31 m Height: 2.01 m Weight: 9072kg
Armament
Main: .50 Browning MG (12.7 mm) Ammo: ? rounds Secondary: 5 x .30 Browning MG (7.62 mm) Ammo: ? rounds
Armor
Maximum: ? mm Minimum: ? mm
Automotive & Suspension
Engine: Continental 7cyl 668ci Horsepower: 250 hp Power/weight ratio: 27.5 hp/t
Suspension: Christie
Performances
Maximum Speed : 71 km/h on wheels, 48 km/h on tracks Range: ? km

Drawings
T4
T4E1

Convertible Tank M1

Le char moyen M1 était un véhicule convertible utilisant la célèbre la suspension de J Walter Christie. Il pouvait rouler sur route sur ses roues. Quand il était sur ses roues, deux chaînes reliaient les barbotins arrières aux dernières roues. Trois exemplaires du M1 furent produits sans tourelles, et furent équipés d’une superstructure blindée avec des barbettes. Ce char était armé d’une mitrailleuse de 12.7 millimètres et un mitrailleuse de 7.62 millimètres à l’avant aussi bien que trois autres mitrailleuses de 7.62 millimètres situées de chaque côté et à l’arrière.

The Medium Tank M1 was a convertible vehicle using celebrates suspension of J Walter Christie. It could roll on road on its road wheels. At the time of the drive on wheels, a chain connected the back sprocket-wheels to the last road wheels. Three specimens of M1 were built without turrets, and were equipped with an armoured superstructure with barbettes. This tank was armed with a machine-gun of 12.7 mm and a machine-gun of 7.62 mm in front as well as three other machine-guns of 7.62 mm located on each side and to the back. Walter Christie's Models

[Kriegerfaust007]

In spite of the significance of his contributions, J. Walter Christie probably remains the most obscure and ambiguous figure to be found in the history of the development of tanks.
From the early 1900’s until his death in 1944, Christie devoted himself to the construction of armored fighting vehicles in the USA. Underlying and providing continuity to his work during this period was the attempt to design a chassis possessing superior mobility. While such emphasis is open to conflicting opinions, it should be pointed out that Christie was one of the few who had recognized the full implications of the the concept of mechanized warfare. In aiming for cross-country speeds of 30 to 40mph, and tank transport by air, he sought to create a fighting vehicle which was capable of simply devouring great distances.

M1919	M1921	M1928	M1931	M1932	M1935/A
M1935/B	M1936	M1937	M1938	M1941	M1942

FOR A BRIEF INTRODUCTION TO THE CHRISTIE TANKS, CLICK ON ANY
OF THE ABOVE MODELS.

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M1919

Produced in 1919 by THE FRONT DRIVE MOTOR COMPANY. Total production = 1.

• CREW: 3
• ARMAMENT: One 6pdr (57mm) gun in main turret and one cal. 30 MG in upper turret.
• ARMOR: 0.25" to 1.0".
• MAXIMUM SPEED: Probably 7 mph on tracks, 14 mph on wheels.
• SUSPENSION: Rubber tired wheels, only center wheels sprung.
• TRACKS: Removable, flat steel plates 15" wide, pitch 9.75".
• GENERAL ARRANGEMENT: Driver in front; gunners in center; engine & final drive in rear.
• DIMENSIONS: Length: 18’ 2"; Width: 8’ 6"; Height: 8’ 9".
• WEIGHT: 13.5 tons.
• ENGINE: Christie, 6 cylinder, 120 HP, forced water cooling.
• HORSEPOWER Per Ton: 8.9.
• TRANSMISSION: Sliding gear, 4 speeds forward, 4 reverse.
• FUEL RANGE: 35 miles on tracks, 75 miles on wheels.
• FUEL CAPACITY: 59 gallons.
• SPECIAL FEATURES: Tracks carried above the wheels when driving on wheels. Small pyramidal lugs on inside of plates for driving and guiding tracks. Center bogies raised when running on wheels. About 15 minutes to change from wheels to tracks or vice versa. The M1919 chassis was originally planned for use as either a truck or a tank. Haste in construction resulted in mechanical unreliability, inaccessibility of engine and transmission, and poorly designed tracks. Capable of equal speeds in forward and reverse.

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M1921

Rebuilt from the 1919 tank in 1921 by THE FRONT DRIVE MOTOR COMPANY. Total production = 1.

• CREW: 4
• ARMAMENT: One 6pdr (57mm) gun in front and one cal. 30 MG on each side.
• ARMOR: 0.25" to 0.75".
• MAXIMUM SPEED: 7 mph on tracks, 14 mph on wheels.
• SUSPENSION: Wheels with double rubber tires; front wheels sprung with coil springs, center wheels on pivoted bogies.
• TRACKS: Removable, flat steel plates with grousers and driving lugs; 15" wide, pitch 9.75".
• GENERAL ARRANGEMENT: Gunners in front; commander and driver in center (driver at left); engine & final drive in rear.
• DIMENSIONS: Length: 18’ 2"; Width: 8’ 6"; Height: 7’ 1".
• WEIGHT: 14 tons.
• ENGINE: Christie, 6 cylinder, 120 HP, forced water cooling. Mounted laterally.
• HORSEPOWER Per Ton: 8.6.
• TRANSMISSION: Sliding gear, 4 speeds forward, 4 reverse; a complete transmission on each side.
• OBSTACLE ABILITY: Trench 7.5 feet; slope 40 degrees.
• FUEL RANGE: 60 miles on tracks, 100 miles on wheels.
• FUEL CAPACITY: 67 gallons.
• SPECIAL FEATURES: Drive wheels unsprung; small crew compartment; poor maneuverability; underpowered.

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The CHRISTIE M1921 by Robert J. Icks from the Sept/74 AFV News

WWI on the Western Front, except for the first few and last few weeks, consisted of trench warfare and its influence continued for many years afterward. Because of low track life, medium and heavy tanks had travelled as little as possible outside of combat, while light tanks were carried on trucks. The Westerveldt or Caliber Board, recommended the direction that future weapons development whould take, including a recommendation that only a medium tank be developed.
The US Tank Corps in 1919 urged negotiations with Walter J. Christie, whose self-propelled guns represented a different approach, designed to conserve track life. This was done, and the Christie M1919 tank resulted, but it had been hastily built and assembled. It had poor suspension and the engine and transmission were difficult to get at. Changeover from tracks to wheels required 15 minutes. The center wheels were raised when running on roads.
This tank was armed with a 6pdr(57mm) gun in the main turret and one MG in the cupola. It had 1/4" to 1" armor, steel tracks 15" wide, and 9-3/4" pitch. The road wheels were rubber tired and only the center wheels were sprung. After generally unsatisfactory performance, the tank was returned to Christie, who rebuilt it into the M1921. The appearance was changed by eliminating the turret and placing the 6pdr in the nose, and lowering the height to 7’1". Another MG was added and one was placed on either side of the main weapon. The suspension was similar, but the front wheels in this model were sprung with long recoil springs.
At first this tank performed so well that Army TO&E were rearranged on the premise that eventual rearmament with this type of tank would take place. However, manoeuverability was poor, the crew compartment was cramped, and more and more defects appeared. After testing by Ordnance, it was turned over to the Infantry, who dropped it in 1924.
Christie came back with a new vehicle with a more advanced suspension in 1928 and this evolved into the T3 Convertible. The later T4 finally was also dropped. Christie built 15 vehicles between 1916 and 1924 at a cost to the Ordnance Dept. of $739,240 plus $100,000 for all current and future suspension patent rights. When Congress began cutting funds to the military in 1921, there was little money for experimental designs.
Many of Christie’s designs were ingenious, but they were mechanically unreliable. In addition there were other factors during this period. A surplus of tanks was left over from WWI, and the National Defense Act of 1920 assigned tanks to the infantry but the War Dept. made no policy statement on tanks until 1922. At that time they were classified as light, medium and heavy, to be few in number and possessed of slow speed so as to accompany infantry under conditions of trench warfare. Ordnance designed a Medium A tank in 1921 and rebuilt it into the M1922 the following year. It was turreted, armed as the Christie M1919 and was rugged and dependable, and had a longer track life. Interest swung to it and away from Christie.

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M1928

Produced in 1928 by U.S. WHEEL TRACK LAYER CORPORATION. Total production = 1.

• CREW: Undetermined
• ARMAMENT: One 37mm gun and one cal. 30 MG in upper turret.
• ARMOR: 0.5".
• MAXIMUM SPEED: 42.5 mph on tracks, 70 mph on wheels.
• SUSPENSION: “Christie Suspension” (individually suspended bogie wheels, each mounted on a coil sprung bell crank).
• TRACKS: Forged steel plates with U-shaped driving lugs attached to each alterate plate, 10" wide, pitch 10".
• GENERAL ARRANGEMENT: Crew compartment in front; driver in left rear part of crew compartment; engine & final drive in rear.
• DIMENSIONS: Length: 17 ft.; Width: 7 ft.; Height: 6 ft.
• WEIGHT: 8.6 tons.
• ENGINE: Liberty, 12 cylinder, V-type, 338 HP, forced water cooling.
• HORSEPOWER Per Ton: 39.3.
• TRANSMISSION: Sliding gear, 4 speeds forward, 1 reverse. First equipped with 5 separate gear shift levers; later replaced with standard gear shift. OBSTACLE ABILITY: Trench 7 ft.; stream 5 ft.; slope 37 degrees; vertical wall 28 in.
• FUEL RANGE: 75 miles on tracks, 115 miles on wheels.
• FUEL CAPACITY: 35 gallons; 50 gallons on rebuild.
• SPECIAL FEATURES: This was the forerunner of the 1931 tank and although lighter in weight was similar as a vehicle to the later tank in all essential features. The U.S. Army wished to buy the chassis but Christie refused to sell since he felt it could be improved upon. Rebuilt, tested and then sold for junk. The “Christie Suspension” developed for the M1928 was employed in the M1931 and all subsequent Christie tanks.Apart from the independent suspension, Christie also pioneered two other tank suspension features which were generally applicable: large diameter road wheels and rubber tires. Christie’s introduction of both was rather fortuitous, for it was essentially a by-product of his aim to design tanks so that they could operate without tracks as well as with them.

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M1931

Produced in 1931 by U.S. WHEEL TRACK LAYER CORPORATION Total production = 9.

• CREW: 2
• ARMAMENT: One 37mm) gun in main turret and cal. 30 MG in one mount (T-3 Medium); and one cal. 50 MG and cal. 30 MG in coaxial mounting (T-1 Combat Car).
• ARMOR: 0.25" to 0.625", exclusive of 0.188 inner hull of nickel steel.
• MAXIMUM SPEED: 40 mph on tracks, 70 mph on wheels.
• SUSPENSION: “Christie Suspension”. Four large weight-bearing wheels each side, each with dual runner tires; long vertically placed, adjustable coil springs. The liberal compression amplitude gave each wheel an independent maximum vertical movement of about 14 inches .
• TRACKS: Forged steel plates, each alternate plate having a driving lug integral therewith; 10.25" wide, pitch 10". When on wheels the tracks were carried on shelves at the sides of the tank.
• GENERAL ARRANGEMENT: Driver in front; gunner in center; engine & final drive in rear.
• DIMENSIONS: Length: 17’ 10"; Width: 7’ 4"; Height: 7’ 3". (The height varied slightly with adjustment of suspension springs.)
• WEIGHT: 10.5 tons.
• ENGINE: Liberty, 12 cylinder, V-type, 338 HP, forced water cooling.
• HORSEPOWER Per Ton: 32.2.
• TRANSMISSION: Sliding gear, 4 speeds forward, 1 reverse.
• FUEL RANGE: 170 miles on tracks, 250 miles on wheels.
• FUEL CAPACITY: 89 gallons.
• SPECIAL FEATURES: Five tanks were originally ordered (chain driven) and later two more (gear driven) were acquired after the Polish government, which had contracted for them was turned down by Christie. Starting in September 1931, delivery of these vehicles (minus armor, armament, engine, guns, and radio) was made at a cost of $34,500 per tank. Armor, armament and engine were installed by the Ordnance Department. Two additional chassis of this type were purchased by Russia. Thirty minutes was required to change from tracks to wheels or vice versa.
• COMMENT: There has always been a dispute over exactly which chassis eventually went to England for their Cruiser Tank development, and it appears as though it was a 1930 transitional version of the above. It also appears to be the same chassis that the Polish government tried unsuccessfully to buy, and after being impounded for six years by U.S. Customs during the dispute, it was finally released to the British and purchased by Lord Nuffield for their A13 project. The Poles meanwhile had adopted some of the ideas developed by Christie and started work on their own version, the 10TP cruiser tank.

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M1932

Produced in 1932 by U.S. WHEEL TRACK LAYER CORPORATION Total production = 1.

• CREW: 3
• ARMAMENT: Could carry one cannon and one or more machine guns.
• ARMOR: 0.375" to 0.5". (Thicker armor could be installed).
• MAXIMUM SPEED: 60 mph on tracks, 120 mph on wheels.
• SUSPENSION: Similar to 1931 model but with a maximum vertical movement of 24 inches; wheels of duraluminum with Firestone pneumatic tires. The two rear wheels had a slightly greater diameter than the front pairs.
• TRACKS: Forged steel plates; 11" wide; 7" pitch; track pin 3/8" diameter.
• GENERAL ARRANGEMENT: Cannon in front; crew in front center; engine & final drive in rear.
• DIMENSIONS: Length: about 22 ft.; Width: about 7 ft; Height: about 5’ 8".
• WEIGHT: about 5 tons.
• ENGINE: Hispano-Suize, 12 cylinder, V-type, 750 HP, forced water cooling.
• HORSEPOWER Per Ton: 150.
• TRANSMISSION: Sliding gear, 3 speeds forward, 1 reverse. It had a power take-off for the flying propeller. One modification provided for a transfer gear case to propel a helicopter roter above the vehicle for lift purposes.
• OBSTACLE ABILITY: Could jump across a 20 foot trench from a 45 degree slope.
• FUEL RANGE: unknown.
• FUEL CAPACITY: 89 gallons.
• SPECIAL FEATURES: Of very light construction throughout for airborne role. Chassis consisted of a double hull which enclosed the suspension springs. The inner hull was made of welded duraluminum plates, and the outer hull of welded steel plates. Rear ground wheels were driven through a knee-armed gear box when the tracks were off.

Originally it had been proposed that the chassis be equipped with a disposable biplane and propeller assembly. Using this arrangement the vehicle would become airborne by taxiing along the ground on its tracks to gain momentum and then transferring power to the propeller. Later plans contemplated carrying the tank by a special aircraft and releasing it close to the ground. In this case dual air-speed indicators would enable the tanks driver, before being dropped, to accelerate his tracks to a speed equaling that of the aircraft. Adaptation of these concepts and designs in the form of permanently installed, high speed track-laying airplane undercarriages would permit the operation of large aircraft from unimproved fields. Erratic and undependable, the M1932 was modified twice and then sold to Russia, who had a keen interest in the flying tanks idea.

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M1935/A

Produced in 1935 (?). Total production = 1.

• CREW: 2
• ARMAMENT: Dummy gun only. Intended to house any gun up to 75mm.
• ARMOR: 0.5".
• MAXIMUM SPEED: 60 mph on tracks, 90 mph on wheels.
• SUSPENSION: “Christie Suspension”. Rubber tired wheels.
• TRACKS: (?)
• GENERAL ARRANGEMENT: Cannon in front; crew in center; engine & final drive in rear.
• DIMENSIONS: Length: 15 ft.; Width: 6.5 ft.; Height: 5.5 ft.
• WEIGHT: 4 tons.
• ENGINE: 300 HP, supercharged to 450 HP.
• HORSEPOWER Per Ton: (?)
• TRANSMISSION: (?)
• FUEL RANGE: (?)
• FUEL CAPACITY: (?)
• SPECIAL FEATURES: Airborne convertible wheel-track vehicle; reported to have been gas proof and water tight. Rebuilt Combat Car M1933(?).

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M1935/B

Produced in 1935 (?). Total production = 1.

• CREW: 2 or 3
• ARMAMENT: Dummy 75mm gun.
• ARMOR: (?).
• MAXIMUM SPEED: 65 mph on tracks, 95 mph on wheels.
• SUSPENSION: “Christie Suspension”. Rubber tired wheels.
• TRACKS: (?)
• GENERAL ARRANGEMENT: Cannon in front; crew in center; engine & final drive in rear.
• DIMENSIONS: Length: about 21 ft.; Width: about 7 ft.; Height: about 5.5 ft.
• WEIGHT: Probably 5.5 tons.
• ENGINE: Believed to be Hispano-Suisa, 12 cylinder, 750 HP, forced water cooling.
• HORSEPOWER Per Ton: (?)
• TRANSMISSION: Selective.
• FUEL RANGE: (?)
• FUEL CAPACITY: (?)
• SPECIAL FEATURES: Airborne convertible wheel-track vehicle. Twin cupolas toward the rear of chassis. Rebuilt M1935/A(?).

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M1936

Produced in 1936 by THE CHRISTIE CHASSIS, Inc. Total production = 1.

• CREW: 2
• ARMAMENT: Dummy cannon.
• ARMOR: (?)
• MAXIMUM SPEED: (?)
• SUSPENSION: “Christie Suspension”. Coil springs housed in horizontally placed tubes.
• TRACKS: High grade forged nickel steel having no bolted parts.
• GENERAL ARRANGEMENT: Cannon in front; crew in center; engine & final drive in rear.
• DIMENSIONS: Length: 17.5 ft.; Width: 6.5 ft.; Height: 5.5 ft.
• WEIGHT: 6 tons.
• ENGINE: Curtiss D-12, 300 HP.
• HORSEPOWER Per Ton: (?)
• TRANSMISSION: Christie synchro-mesh with aluminum case.
• OBSTACLE ABILITY: Could jump 15 foot trench.
• FUEL RANGE: (?)
• FUEL CAPACITY: (?)
• SPECIAL FEATURES: An airborne type vehicle capable of being released from moving aircraft. No provision to be driven with tracks removed. Its gear ratio permitted acceleration to 60mph in 100 feet.

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M1937

Produced in 1937 by U.S. CONVERTIBLE SYSTEM, Inc. Total production = 1.

• CREW: 2
• ARMAMENT: None
• ARMOR: Maximum 11/16 in.
• MAXIMUM SPEED: (?)
• SUSPENSION: “Christie Suspension”. As on M1936. Maximum vertical movement of 16".
• TRACKS: (?)
• GENERAL ARRANGEMENT: Crew in center; engine & final drive in rear.
• DIMENSIONS: Length: 17.5 ft.; Width: 6.5 ft.; Height: about 5 ft.
• WEIGHT: 6 tons.
• ENGINE: Curtiss Wright aviation engine, 430 HP.
• HORSEPOWER Per Ton: (?)
• TRANSMISSION: 3 speeds forward, 1 reverse.
• FUEL RANGE: (?)
• FUEL CAPACITY: (?)
• SPECIAL FEATURES: Airborne type vehicle similar to M1936. Christie took this tank with him when he traveled to England in 1937 to assist Morris Company in designing the Cruiser Tank Mk.III. During a demonstration for Gen. Le Q. Martel at the Aldershot Proving Grounds a speed of 64 mph was achieved over moderately rough ground.

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M1938 (T-12)

Produced in 1938 by U.S. CONVERTIBLE SYSTEM, Inc. Total production = 1.

• CREW: 2
• ARMAMENT: None
• ARMOR: Maximum 5/8 in.
• MAXIMUM SPEED: 80 mph.
• SUSPENSION: Similar to M1936
• TRACKS: Forged steel; weight of both tracks and connecting pins only 1600 lbs; pitch 5 in.
• GENERAL ARRANGEMENT: Crew in center; engine & final drive in rear.
• DIMENSIONS: Length: about 17.5 ft.; Width: 7.5 ft.; Height: about 5 ft.
• WEIGHT: 4.5 tons.
• ENGINE: Modified Curtiss Wright aviation engine, 450 HP, liquid cooled.
• HORSEPOWER Per Ton: (?)
• TRANSMISSION: 3 speeds forward, 1 reverse.
• FUEL RANGE: (?)
• FUEL CAPACITY: (?)
• SPECIAL FEATURES: Airborne type vehicle similar to M1936-37 models. It may have been a rebuilt M1937. Extensive use of aluminum (e.g. transmission box, fuel tanks, etc.) and flexible tube hosing (e.g. fuel and oil feed lines, etc.) permitted operation at extremely high speeds over rough terrain. Improved brake and clutch system. Its high speed and low silhouette suited it for the role of tank destroyer.

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M1941 (Bigley GMC)

Produced in 1937 by U.S. CONVERTIBLE SYSTEM, Inc. Total production = 1.

• CREW: 2
• ARMAMENT: None. 90mm recoilless rifle contemplated.
• ARMOR: (?)
• MAXIMUM SPEED: (?)
• SUSPENSION: Similar to M1936.
• TRACKS: (?)
• GENERAL ARRANGEMENT: Crew in center; engine & final drive in rear.
• DIMENSIONS: Length: about 18 ft.; Width: about 7 ft.; Height: about 5 ft.
• WEIGHT: (?)
• ENGINE: (?)
• HORSEPOWER Per Ton: (?)
• TRANSMISSION: (?)
• FUEL RANGE: (?)
• FUEL CAPACITY: (?)
• SPECIAL FEATURES: Rebuilt T-12 (?). Airborne type to be employed as a high speed tank destroyer. Modified and used as a tracked truck for a number of years and then junked. Christie’s AFVs, especially the later airborne models, have been criticised on the following grounds:
  • Calculations based upon the employment of simulated armor in the prototypes produced an overloaded vehicle, and components incapable of standing the additional strain when actual armor and armament were added.
  • Exclusive employment of dummy armament resulted in ignoring problems which would be raised when installing real guns.
  • High horsepower-to-weight ratios made for “flash performances” which could not be expected under conditions of actual combat.
  • A tendency to throw tracks on turns at high speeds and undue wear caused by too great a track pitch.
  • Inadequate fighting compartment.

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M1942

Produced in 1942. Total production = 1.

• CREW: Undetermined.
• ARMAMENT: Dummy: six machine guns, one small calibre cannon.
• ARMOR: (?)
• MAXIMUM SPEED: (?)
• SUSPENSION: Similar to M1936.
• TRACKS: (?)
• GENERAL ARRANGEMENT: Cannon and one MG in front, two MGs on either side; engine & final drive in rear.
• DIMENSIONS: (?)
• WEIGHT: (?)
• ENGINE: (?)
• HORSEPOWER Per Ton: (?)
• TRANSMISSION: (?)
• FUEL RANGE: (?)
• FUEL CAPACITY: (?)
• SPECIAL FEATURES: Mockup on M1941 chassis. A high-speed light tank with no means for release from moving aircraft…https://www.oocities.org/firefly1002000/chrisindex.html

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