Medium Mark D

Last updated

Medium Tank Mark D
MediumMarkDModified.jpg
Medium Mark D Modified
Production history
DesignerPhilip Johnson, Tank Design Department
ManufacturerFowler, Vickers, Royal Ordnance
Specifications (D Modified)

Main
armament
3 x Hotchkiss machine guns
Engine Rolls-Royce Eagle V-12 petrol engine
360 hp (270 kW)
SuspensionCable spring

Medium Mark D was a British medium tank developed at the end of the First World War.

Contents

It was envisaged as a vehicle to be used in "Plan 1919" an offensive on the Western Front which would use large numbers of heavy and medium tanks to break through the German defences, destroy lines of communication crippling the German army and thus end the war. The Armistice ended the war in 1918 and it would never be tested in combat but development continued for the post-war needs of the British Army. The unusual suspension proved problematic and the earlier tanks were replaced by a Vickers design - the Medium Mark I - in the 1920s [1]

It should not be confused with export Vickers Medium Mark D tank, built in one unit for Ireland in 1929.

Development

J F C Fuller's plan 1919 (circulated in mid-1918) was for the heavy tanks to engage and pin the German troops allowing faster tanks to penetrate the flanks and encircle the enemy isolating them from the chain of command precipitating a breakdown of morale and fighting capacity. Fuller calculated this fast tank, which he called Medium Mark D in the text, would have to manage 20 mph (32 km/h) - substantially faster than any tank then in service - and that it would be no more than 20 tons in weight. [2]

Major Johnson, working at the Mechanical Warfare Department's grounds at Dollis Hill, identified that a more powerful engine and a sprung suspension would be needed. He had experimentally fitted leaf springs to both a Mark IV heavy tank and a Medium Mark A "Whippet" and also fitted powerful Rolls-Royce Eagle aeroplane engines to a Whippet [3]

Johnson's ideas were tested by conversion of a Mark V tank MarkVSnaketrack.jpg
Johnson's ideas were tested by conversion of a Mark V tank

To give a suspension that could flex without adding the weight of individual springs for each roller, Johnson, based on his pre-war experience with Fowler ploughing engines, used steel cable ropes wound between the rollers and terminated in springs. Wire ropes were also used to connect the track links together, allowing them to flex during turning manoeuvres and for the individual links to pivot on rough ground. [4] This was tested on a converted Mark V, which reached 20 mph (32 km/h)

With the end of the war the immediate need for the Mark D disappeared. Fuller was now at the War Office and continued to champion the tank adding on a requirement for amphibious use. [5]

The wooden mockup shows the forward tilt of the track run MediumDMockup.jpg
The wooden mockup shows the forward tilt of the track run

Before the war a wooden mockup of the Mark D had been built and shown to members of the Tank Corps and an orders for ten prototypes placed (four from Fowler and six from Vickers). [6]

The tank as built was relatively long and narrow with a cylindrical fighting compartment at the front with machine gun ports to the front and sides. As it was so narrow the driving position was displaced to the back of the fighting compartment with the driver under a small cupola. To improve the view forward the roof of the fighting compartment sloped down from the cupola. Because the track runs sloped forward, another feature to improve driver views, in order to cross taller obstacles the driver was expected to take them by reversing. [7] Powered by a Siddeley Puma engine the speed was in excess of Fuller's specification.

Swimming trials were carried out with two modified tanks; the Mark D* which was widened to 8 ft 5 in (2.57 m) and the Mark D** at 9 ft (2.7 m); the latter swimming well in a river test. [8]

Sufficient funds were provided for production of 45 tanks complete with Rolls-Royce engines, later cut to 20 of which only three were built - by the Royal Ordnance Factory - based on the D** and known as the "D Modified" (DM). [9]

Johnson's design department, and any further work on the D was terminated in 1923. [10]

Variants and derivatives

See also

Notes

  1. White p 9
  2. Fletcher, 2001 p180
  3. Fletcher, 2001 p180
  4. Fletcher, 2001 p181
  5. Fletcher, 2001 p181
  6. Fletcher, 2001 p184
  7. Fletcher, 2001 p185
  8. Fletcher, 2001 p185
  9. Fletcher, 2001 p186
  10. David Willey (2 March 2024). Bigger Isn’t Always Better: A1E1 Independent | Tank Chats Reloaded. The Tank Museum. Event occurs at 2:27-2:35. Retrieved 3 March 2024.
  11. Fletcher, 2001 p186
  12. Fletcher, 2001 p186

Related Research Articles

<span class="mw-page-title-main">Matilda II</span> British Army tank of World War II

The Infantry Tank Mark II, better known as the Matilda, is a British infantry tank of the Second World War.

<span class="mw-page-title-main">Valentine tank</span> British infantry tank

The Tank, Infantry, Mk III, Valentine was an infantry tank produced in the United Kingdom during World War II. More than 8,000 of the type were produced in eleven marks, plus various specialised variants, accounting for approximately a quarter of wartime British tank production. The many variants included riveted and welded construction, petrol and diesel engines and a progressive increase in armament. It was supplied in large numbers to the USSR and built under licence in Canada. It was used extensively by the British in the North African campaign. Developed by Vickers, it proved to be both strong and reliable.

<span class="mw-page-title-main">Cromwell tank</span> British WWII cruiser tank

The Cromwell tank, officially Tank, Cruiser, Mk VIII, Cromwell (A27M), was one of the series of cruiser tanks fielded by Britain in the Second World War. Named after the English Civil War-era military leader Oliver Cromwell, the Cromwell was the first tank put into service by the British to combine high speed from a powerful, reliable engine and reasonable armour. The intended dual-purpose high velocity gun could not be fitted in the turret, so a medium velocity dual purpose gun was fitted instead. Further development of the Cromwell combined with a high velocity gun led to the Comet tank.

<span class="mw-page-title-main">Cruiser Mk I</span> British cruiser tank

The Tank, Cruiser, Mk I (A9) was a British cruiser tank of the interwar period. It was the first cruiser tank: a fast tank designed to bypass the main enemy lines and engage the enemy's lines of communication, as well as enemy tanks. The Cruiser Mk II was a more heavily armoured adaptation of the Mark I, developed at much the same time.

<span class="mw-page-title-main">Medium Mark A Whippet</span> Medium Tank

The Medium Mark A Whippet was a tank employed by the British in World War I. Intended for fast mobile assaults, it was intended to complement the slower British heavy tanks by using its relative mobility and speed in exploiting any break in the enemy lines.

<span class="mw-page-title-main">Medium Mark B</span> Medium Tank

The Medium Mark B was a British tank of the First World War developed as a successor to the Whippet, but ultimately unsatisfactory and production was cancelled at the end of the war.

<span class="mw-page-title-main">Medium Mark C</span> Weapon

The Medium Mark C Hornet was a British tank developed during the First World War, but produced too late to see any fighting.

<span class="mw-page-title-main">Valiant tank</span> British assault tank prototype

The Tank, Infantry, Valiant (A38) was a British tank design of the Second World War that only reached the prototype stage. It was intended to meet a specification for a well-armoured, light-medium tank, for use against Japanese forces in the South-East Asia theatre. The prototype demonstrated that the design was a failure and this sole example produced was retained by the School of Tank Technology as a lesson to its students.

<span class="mw-page-title-main">Mk VI light tank</span> British light tank during the Second World War

The Tank, Light, Mk VI was a British light tank, produced by Vickers-Armstrongs in the late 1930s, which saw service during the Second World War.

<span class="mw-page-title-main">Horstmann suspension</span> Type of tracked vehicle suspension

Horstmann suspension, also known as Horstman, Vickers-Horstman and rarely Slow Motion, is a type of tracked suspension devised by British tank designer John Carden and worked into a production design by engineer Sidney Horstmann.

<span class="mw-page-title-main">Tanks of the interwar period</span>

Tanks were initially deployed in World War I, engineered to overcome the deadlock of trench warfare. Between the two world wars, tanks were further developed. Although they had demonstrated their battlefield effectiveness, only a few nations had the industrial resources to design and build them. During and after World War I, Britain and France pioneered tank technology, with their models generally serving as a blueprint for other countries. However, this initial advantage would slowly diminish during the 1930s, shifting in favor of the Soviet Union and, to a lesser degree, Nazi Germany.

<span class="mw-page-title-main">Vickers Medium Mark II</span> British medium tank

The Vickers Medium Mark II was a British tank built by Vickers in the Inter-war period.

<span class="mw-page-title-main">Vickers Medium Mark I</span> British medium tank

The Vickers Medium Mark I was a British tank of the Inter-war period built by Vickers from 1924.

<span class="mw-page-title-main">Little Willie</span> British prototype armoured tank

Little Willie was a prototype in the development of the British Mark I tank. Constructed in the autumn of 1915 at the behest of the Landship Committee, it was the first completed tank prototype in history. Little Willie is the oldest surviving individual tank, and is preserved as one of the most famous pieces in the collection of The Tank Museum, Bovington, England.

<span class="mw-page-title-main">Birch gun</span> Self-propelled gun

The Birch Gun was the first practical British self-propelled artillery gun, built at the Royal Arsenal, Woolwich in 1925.

<span class="mw-page-title-main">Mark V tank</span> British WWI tank

The British Mark V tank was an upgraded version of the Mark IV tank.

<span class="mw-page-title-main">Medium Mark III</span> British medium tank prototype

The Medium Mark III was a medium tank developed in the United Kingdom during the Interwar period.

<span class="mw-page-title-main">Tanks in the British Army</span>

This article on military tanks deals with the history and development of tanks of the British Army from their first use in the First World War, the interwar period, during the Second World War, the Cold War and modern era.

The Vickers Medium Dragon was a fully-tracked British field artillery tractor made by Vickers, produced in various versions from 1922 to 1937. The Medium Dragon towed a wide range of artillery, from 18-pounder field guns to BL 60-pounder heavy field guns. It was developed from the carrier version of a 'Tropical Tank' designed by Lt-Colonel Philip Johnson, using components from the running gear of the Vickers Medium Mark I tank.

<span class="mw-page-title-main">Vickers Light Dragon</span> British field artillery tractor, 1929–1935

The Vickers Light Dragon was a fully-tracked British field artillery tractor made by Vickers-Armstrongs Ltd from 1929 to 1935. Designed to tow small-calibre field guns, it complemented Vickers' Medium Dragon tractor, which pulled medium to heavy artillery.

References