Centrifugal Machine Guns

Today, we’re going to take a look at a little known type of weapon which rose to prominence in around the time of the First World War with a number of examples being developed and some even tested. As you can see from this footage it’s something pretty unconventional, seen here mounted on the back of a truck – is a centrifugal machine gun.

I found this short footage while doing some digging through the online catalogue of the US National Archives. The centrifugal machine gun was not a new concept by the time this footage was filmed in the early 1920s, sadly the footage notes done give an exact date.

Centrifugal Machine Gun   111-h-1246-r1_HD_2Mbps_Trim_Moment - Copy.jpg
A still from footage of the demonstration (US National Archives)

While the technology had risen to a new prominence what was the allure of centrifugal machine guns? The principle of centrifugal force – an inertial force which appears to act on objects moving in a circular path, directs them away from the axis of rotation. As a result a centrifugal machine gun required no propellant powder to propel the projectile, or a case to contain it, nor a conventional rifled barrel to stabilise the projectile. Once released from the axis of rotation the projectile travels on a linear trajectory until it expends its energy. It works along the same principle as a primitive sling. The primary issue is providing power to exert the centrifugal force and a means of accurately firing the projectiles.

Some of the earliest work on centrifugal guns was done in the late 1850s in the US. The hand-crank or steam powered guns patented by William Joslin (US #24,031), C.B. Thayer patent for a ‘machine gun’ in August 1858 (US #21,109) and Charles S. Dickinson (US# 24,997) in 1859. Dickinson went on to secure financial backing from a wealthy Maryland industrialist Ross Winans and developed a steam powered version of his gun. Despite gaining much press attention Dickinson’s centrifugal gun saw no action during the US Civil War. In 1862 G.C. Eaton and S.W. Turner also patented a ‘machine gun’ (US #37,159).

Frank_Leslie's_Illustrated_Newspaper_-_1861-05-18_-_p1_-_Winans_Steam_Gun
An illustration of the Winans Steam Gun, Frank Leslie’s Illustrated Newspaper, May 1861

It wasn’t until World War One that the concept began to be considered again. In June 1918, Major Edward T. Moore and Saul Singer filed a patent for a centrifugal machine gun powered by an electrical motor (US #1,332,992). The motor spooled up the centrifugal barrel assembly to rotate extremely quickly and impart centrifugal force on projectiles. According to Julian Hatcher the gun could fire steel ball bearing projectiles at approximately 1,200 feet per second. Fire was controlled by a stop pin in the ammunition feed tube. Moore claimed the weapon could fire a projectile 1.5 miles with enough force to kill a man. He also suggested the weapon’s rate of fire approached 2,000 rounds per minute. It appears that Moore’s gun may have been tested in 1918 but Hatcher described its accuracy as ‘extremely poor’.

Moore Centrifugal Machine Gun from hatcher's
Photograph of Moore’s gun during testing (Hatcher)

Another centrifugal design developed during World War One was E.L. Rice’s half-inch centrifugal gun, sadly I’ve been unable to find any photographs or drawings of Rice’s design but the weapon was submitted to the US National Research Council in 1917. The NRC’s 1919 report states that the gun had been further developed by the NRC’s Physics Division in Pittsburgh but work had been slowed by “a common defect which has been difficult to eliminate”. Despite what the report described as ‘considerable headway’ the weapon was subsequently abandoned amid some controversy about credit for the design.

There seems to have been something of a centrifugal machine gun craze with several more patents filed between 1917 and 1926. A Scientific American article from March 1918, even noted that “every so often the daily press becomes enthused over a new centrifugal gun.”

US1223069-drawings-page-1
Porter’s Centrifugal Gun patent drawing (US Patent Office)

One of the earliest patents granted appear to have been for a design by E.E. Porter, granted in January 1917. This was followed in July 1919 by inventor, Herbert A. Bullard being granted a patent (US #1,311,492) on a design which fired a disc rather than a ball. At the same time T.A. Gannoe was granted a patent (US #1,309,129) for a large, complex looking gun shown mounted on a pedestal.

In 1920, F.R. Barnes (US #1,327,518) and W.W. Case (US #1,357,028) were also granted patents which had been filed in 1917. In late 1921, Levi Lombard was granted a patent he had filed in March 1918, his gun even appeared in Scientific American. It appears to be notably smaller than Moore’s gun and has a spade grip for aiming.  This was followed in 1923, by an interesting patent from Joseph T. McNaier for a centrifugal gun that could be powered by an electric or petrol engine, some of the patent diagrams show how the gun might be placed in an armoured car or aeroplane (US #1,472,080). Intriguingly, McNaier and Moore appear to have known each other quite well and were partners in a law firm together.

Here’s a gallery of some of the various patents mentioned above, not all are as detailed or as advanced as others:

 

 

 

The question is which of these guns is featured in the footage. The most likely bets are the Moore or the Czegka. Sadly, with only a side view and just 18 seconds of footage we don’t have much to go on. The accompanying reel notes, describing what is seen in each section of the film, describes the gun as being in the “experimental stages only” and that the prototype seen here “is intended for use as aircraft armament, for tanks and for landing parties of the Front line trenches.”

Sadly, we don’t get to see how the gun works but we can see the operator feeding the ball bearing projectiles into the hopper which has a powered feed system – he empties two cylindrical containers of balls into it one after another. It is unclear how many rounds might be in the containers, perhaps 50 each. The gun and its motor are mounted on a truck bed with a soldier in uniform, possibly aiming the weapon via a tiller.

 

Another of the later designs dating from the period came from Victor Czegka, a US Marine Corps Technical Sergeant, who is perhaps best known as the supply officer of Admiral Richard Byrd’s first two expeditions to the Antarctic. Czegka was granted a patent for a centrifugal machine gun in January 1922 (US #1,404,378).

US1404378-drawings-page-1
Czegka’s 1922 patent (US Patent Office)

 

With some further digging I managed to find several articles referring to the gun in the US Army Ordnance Journal. Interestingly, a photo from the same demonstration is printed in one article, from late October 1920, with the caption confirming the man loading the weapon is the inventor, however, he isn’t named. The footage was filmed during the Second Annual Meeting of the US Army Ordnance Association. Another article dating from May 1921, also notes that the tests took place at Aberdeen Proving Ground, with the gun firing at 16,000 revolutions per minute which required 98 horsepower from the engine powering it. The gun apparently needed a “very rapid increase in power required for operation” when the speed of its revolutions was increased incrementally from 12,000 to 16,000 rpm. The article concluded that “a horsepower above 100 would have no material effect in increasing the speed” suggesting that a much more powerful, and therefore larger, engine would be needed to increase the revolution rate.

 

 

Unnamed Centrifugal Gun from 1922 Popular Mech
While researching I came across this set of images from a March 1922 edition of Popular Mechanics showing an unnamed centrifugal gun set up on a truck, powered by an engine on the truck bed. From the images it appears to be a gun similar to Moore’s with a single rotating ‘barrel’. The captions also note that the photographs were taken in New Jersey and Moore was a Major with the New Jersey National Guard, which may also indicate the gun is Moore’s.

 

Despite various designs seeing some US military testing none were ever adopted and relatively little information on them is available. It seems that they were relatively cumbersome weapons with extremely varying accuracy but this footage at least proves the concept. A short report in a may 1921 edition of Scientific American may shed some light, stating an unnamed gun was rejected “because of its great weight and its inability to obtain high initial velocity” concluding that “no centrifugal gun can have military value”. It appears that the range of the centrifugal guns was limited to the speed of their revolution, which in turn was limited by the power of the engine and motor that powered them. The larger the motor, the more cumbersome the weapon system was.

 

 

There are very few photos of centrifugal machine guns so stumbling across actual footage of one guns actually operating is very exciting. They are a fascinating tangent to the history of the machine gun – one that occasionally still garners interest.


If you enjoyed the video and this article please consider supporting our work here. We have some great perks available for Patreon Supporters.


Bibliography:

Demonstration of Ordnance Materiel at Aberdeen Proving Grounds, Maryland, 1920-26, US National Archives, (source)

Scientific American v.124, Jan-Jun 1921, (source)

Scientific American v.118, Jan-Jun 1918, (source)

Hatcher’s Notebook, J. Hatcher (1962)

Army Ordnance: The Journal of the Army Ordnance, v.1-2 (1920-1922) (source)

United States Congressional House Documents Vol.119, 1921 (source)

WW1 2-Inch Trench Mortar

The British Army entered the First World War with very few mortars, and certainly none at the battalion level. As the stalemate of trench warfare set in and the effectiveness of enemy mortars became clear it was decided that trench mortars of various sizes would be needed.

Nicknamed ‘plum pudding’ or ‘toffee apple’ mortars after their projectile’s characteristic shape, the 2 inch Medium Mortar or 2 inch Trench Howitzer, was one of Britain’s first effective light trench mortars to be introduced.

tilt_h13_2_inch_mortar
Right-side view of the 2in Trench Mortar (Matthew Moss)

Trench mortars were the army’s most forward artillery, right up on the front line. These short range weapons were able to throw large, high explosive projectiles, short distances across No Man’s Land at the enemy trench system opposite. The 2 inch mortar was considered accurate out to 350 yards with a maximum effective range out to just under 600 yards.

Introduced in 1915, the 2 inch mortar was originally crewed by men taken from the battalion it was stationed with, along with some specialists from the Royal Artillery. However, with the introduction of the 3 inch Stokes mortar which was operated by the infantry themselves the 2 inch mortars became the sole responsibility of the Royal Field Artillery.

Mesopatamia 4
A young gunner loads a 2in spigot mortar bomb into his mortar (Imperial War Museum)

Mortar positions were often in secondary trenches just behind the infantry’s frontline. This was to help protect the infantry from potential counter-battery fire. The trench mortars were often deployed to sectors to provide counter battery fire against German minenwerfers or in the run up to an offensive or local action. A British Army report on artillery use, drawn up in February 1917, noted that “Owing to their liability to be destroyed by hostile artillery fire it may often be advisable to defer opening fire with these mortars till the last day of bombardment.” The mortars were also tasked with keeping gaps made in the wire clear and with supporting any feint attacks made by infantry during gaps in the bombardment running up to a larger offensive.

Llewelyn Wyn Griffith, a captain with the 15th Royal Welch Fusiliers and later a novelist, recalled in his war memoir:

“At night a trench mortar officer set his guns in a derelict trench about twenty yards behind the line and carried up his ammunition, heavy globes of iron with a little cylindrical projection like a broken handle. In the morning I moved the men from the bays between the trench mortars and their target, to lighten the risk of loss from retaliatory fire.”

Sometimes the width of No Man’s Land required saps to be cut extending out from the frontline so the mortar rounds didn’t fall short. The 50 lb lollipop-like projectile had a maximum effective range of 570 yards (depending on the size of cordite charge used), and could create a crater 5 feet deep and 14 feet wide. The ideal mortar position was a 6 feet wide by 9 feet deep sandbagged pit with the weapon’s heavy wooden bed at the bottom and room for the crew to load the mortar.

Mesopatamia 1
A British 2in Mortar position in Mesopotamia, note the ignitor’s breech is open (Imperial War Museum)

Crews could manage to fire approximately once every two minutes. Much slower than the lighter 3 inch Stokes Mortar and but faster than the heavy 9.45 inch Heavy Mortar. The mortar comprising of just its tube, bed, stand and ignition system weighed 320 lbs (145kg), not including the accompanying tools and the Temple silencer system which could be fitted (which weighed 47 lbs or 21 kg alone).

Typically manned by a 5 man mortar crew comprising of an NCO, gunners, and ammunition bearers. To operate the 2 inch mortar a cordite charge was first placed down the tube, the projectile’s shaft was then inserted on top of the charge, the projectile’s fuse was set and checked and a new blank cartridge chambered in the ignition system. The crew then got clear of the weapon and pulled the lanyard to fire the mortar. To reload the crew ran a clearing stick down the tube and then repeated the loading process.

DSC_0790.jpg
The business end, a view down the length of the mortar (Matthew Moss)

Interestingly, the 2 inch Medium Mortar, like the larger 9.45 inch Heavy Mortar used a cut-down rifle, which screwed into the ‘breech’ end of the mortar tube. This particular mortar has an 1894-dated cut down Lee-Enfield MkI as its ignition system, the cutdown rifle has a wooden insert in its magazine well but it still has its rear volley sight attached. This reusable system replaced the T-tube Friction ignitor, which was in high demand by Britain’s bigger guns. The Lee-Enfield-based system enabled the cordite propellant charges to be ignited by a blank .303 round instead. The rifle’s trigger was pulled with a lanyard from nearby cover. These cutdown ignitor rifle are sometimes confused for Obrez-style Lee-Enfields.

DSC_0787
A close up look at the 2in Mortar’s SMLE ignitor (Matthew Moss)

The weight of the cordite charge used dictated the range while a variety of different fuses were used with the projectiles, these screwed into the nose of the bomb. The sphere was about 9.3 inches in diameter with a 2 inch thread for the fuse at its head and a cup for the 22 inch long, 2 inch thick solid cast iron stick or spigot at its base. The sphere was filled with high explosive (Amatol or Ammonal). The high explosive bombs were painted white with a green or pink stripe around their middle.

They were often deployed in batteries of four with three Royal Field Artillery medium mortar batteries attached to each division. The mortars were predominantly tasked with cutting enemy barbed wire and destroying enemy trenches and forward positions, such a machine gun nests.

Royal Army Ordnance Corps playing cards 1916
Men of the Royal Army Ordnance Corps playing cards on a dump of trench mortar ammunition during Battle of the Somme (Imperial War Museum)

Captain Griffith described a battery of 2 inch mortars opening fire on enemy lines:

“A pop, and then a black ball went soaring up, spinning round as it went through the air slowly; more pops and more queer birds against the sky. A stutter of terrific detonations seems to shake the air and the ground, sandbags and bits of timber sailed up slowly and then fell in a calm deliberate way. In the silence that followed the explosions, an angry voice called out in English across No Man’s Land, ‘YOU BLOODY WELSH MURDERERS.’

The 2 inch medium mortar entered service in spring 1915 and remained in use into 1917 with British and Empire troops. It was used on the Western Front and in Mesopotamia. Over 800 were ordered initially with 675,000 bombs, many of the mortars were made in railway and agricultural machinery workshops, allowing larger factories to focus on more complex weapons. The 2 inch mortar was superseded by the larger bore Newton 6 inch mortar later in the war. Some of the remaining 2 inch projectiles were re-purposed as makeshift anti-tank mines, buried in no man’s land in anticipation of possible German tank attacks.

If you enjoyed the video and this article please consider supporting our work here.


Specifications:

Barrel Length: 3 feet (90cm)
Overall Weight: ~340lbs (154kg)
Projectile Types: High explosive & smoke
Projectile Weight: 51lbs (23kg)
Effective Range: 100-570 yards (90-520m)


Bibliography:

Primary Sources:

Field Artillery Notes No.7, US Army War College, (1917) (source)

‘Artillery in Offensive Operations’ GHQ Artillery Notes No. 4 January/February 1917 (source)

‘History of the Ministry of Munitions’, Volume XI, Part I Trench Warfare Supplies (1922)

Up to Mametz, L.W. Griffith,  (1931)

Newsreels:

The Battle of the Somme, 1916, Imperial War Museum (source)

With the Forces in Mesopotamia, 1917, Imperial War Museum (source)

Secondary Sources:

British Artillery 1914-1919. Field Army Artillery, D. Clarke, (2004)

Tommy, R. Holmes, (2004)