Holman Projector
Encyclopedia
The Holman Projector was an anti-aircraft
weapon used by the Royal Navy
during World War II
, primarily between early 1940 and late 1941. The weapon was proposed and designed by Holmans
, a machine tool
manufacturer based at Camborne, Cornwall. A number of models were produced during the war years, but all worked on the principle of a pneumatic mortar
, using compressed air
or high pressure steam
to fire an explosive projectile at enemy aircraft.
Holmans specialised in producing gas compressor
s and pneumatic equipment and its owner, Treve Holman, conceived a way that his firm could aid in the war effort beyond the production of tools. Recalling the World War I
-era Stokes Mortar
and its successor, the Ordnance ML 3 inch Mortar
, Holman believed that it would be possible to produce a version powered by compressed air. Preliminary tests showed that the idea was feasible, with an early prototype throwing an eighteen-pound steel weight nearly 100 yards (91.4 m).
I featured a 4½ foot unrifled
steel barrel. Rounds were dropped down the barrel and the pneumatic system triggered instantly upon the round striking the base. The rounds themselves were made from an open-topped metal container, holding a Mills bomb
fitted with a 3.5 second fuse
. High-pressure air bottles were able to supply enough power to fire fifty rounds each, with a maximum height during trials of around 600 feet (182.9 m). The rate of fire could reach thirty rounds per minute in the hands of an experienced crew. More appealing yet to the armed forces was the fact that the weapon could be produced using only cast iron
and mild steel, both of which were in fairly ready supply at this stage of the war.
An official trial of the Mk I Projector took place in February, 1940 with resounding success. An order was placed by the Royal Navy for 1000 of the Mk I models, and the weapons proved just as successful in action; the first confirmed kill reported only three weeks after the initial batch were sent out. While direct hits were rare, the bombs fired by the projector displayed an unexpected property — the explosion would leave a large puff of black smoke, absent from ground-based explosions from similar grenades. Firing a large number in quick succession gave the impression to incoming Luftwaffe
pilots that the target vessel was armed with something far more deadly than the Holman Projector.
in place of compressed air, since the steam trawlers (both fishing and minesweeping
) had the former in plentiful supply. The Stokes design of the Mk I needed to be abandoned for this, since the harsh weather experienced by the trawlers invariably rusted the valve
s of the pneumatics. When steam was used in such a system, the water would condense in the pipes and prevent firing of the weapon. To solve this, a firing trigger was added, in place of the Stokes design in which the round would be fired automatically.
This new version was fitted to a wide variety of ships, from destroyer
s to minesweepers and motor gun boats
. To demonstrate the weapon's versatility, a trial was arranged in Aldershot, Hampshire
in front of the Prime Minister
, Winston Churchill
. No Mills rounds were brought, as it was assumed that some form of ammunition would be provided by the British Army
, who were overseeing the trials. As it turned out, this was overlooked and the trial was delayed until one officer thought to bring out the bottles of beer
that had been brought to serve at lunch. The smooth bore of the Projector allowed even these irregular projectiles to be fired successfully, with all striking the target with an explosion of glass and foam. The Prime Minister commented on the weapon afterwards, describing it as "A very good idea, this weapon of yours. It will save our cordite
".
Regardless of the successful trials, The Mk II was still highly inaccurate when fired at distant moving targets. Only a dozen or so aircraft were confirmed to have been downed by the weapon in its first year of service. It did, however, succeed in convincing many more aircraft that the target vessel was more heavily equipped than it actually was, and a large number of reports were made about Luftwaffe aircraft turning away from an attack after salvoes from the ship's Holman Projector were launched. Within the Admiralty
, the perception was that the Projector was a useful stop-gap
weapon in the early years of the war, when other more effective anti aircraft weaponry, such as the Oerlikon 20 mm cannon
, were in short supply.
of the weapon had proven useful. Plans were drawn up for a Mk IV version of the Projector to fill this niche more readily, with a shorter barrel and swivel base. However, by the time the plans were ready to be put into action the war had progressed, and more advanced weaponry was now available that made the Projector obsolete. A number of the earlier model Projectors still played a part in the conflict though, discouraging attacks in the Mediterranean by some smaller submarine
s, and a small number were adapted to fire grapnels for commando
cliff assaults. In total around 4,500 Holman Projectors were put into active service during World War II, and several can still be found in museum
s in the United Kingdom
.
Anti-aircraft warfare
NATO defines air defence as "all measures designed to nullify or reduce the effectiveness of hostile air action." They include ground and air based weapon systems, associated sensor systems, command and control arrangements and passive measures. It may be to protect naval, ground and air forces...
weapon used by the Royal Navy
Royal Navy
The Royal Navy is the naval warfare service branch of the British Armed Forces. Founded in the 16th century, it is the oldest service branch and is known as the Senior Service...
during World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
, primarily between early 1940 and late 1941. The weapon was proposed and designed by Holmans
Holman Bros Ltd
Holman Brothers Ltd. was a mining equipment manufacturer founded in 1801 based in Camborne, Cornwall, UK.Holman was Camborne's, and indeed Cornwall's largest manufacturer of industrial equipment. Holman played a part in World War II making the Polish designed 20mm Polsten gun, similar to the...
, a machine tool
Machine tool
A machine tool is a machine, typically powered other than by human muscle , used to make manufactured parts in various ways that include cutting or certain other kinds of deformation...
manufacturer based at Camborne, Cornwall. A number of models were produced during the war years, but all worked on the principle of a pneumatic mortar
Pneumatic weapon
A pneumatic weapon is a weapon that fires a projectile bymeans of air pressure, similar in principle to the operation of pneumatic tube delivery systems...
, using compressed air
Compressed air
Compressed air is air which is kept under a certain pressure, usually greater than that of the atmosphere. In Europe, 10 percent of all electricity used by industry is used to produce compressed air, amounting to 80 terawatt hours consumption per year....
or high pressure steam
Steam
Steam is the technical term for water vapor, the gaseous phase of water, which is formed when water boils. In common language it is often used to refer to the visible mist of water droplets formed as this water vapor condenses in the presence of cooler air...
to fire an explosive projectile at enemy aircraft.
Holmans specialised in producing gas compressor
Gas compressor
A gas compressor is a mechanical device that increases the pressure of a gas by reducing its volume.Compressors are similar to pumps: both increase the pressure on a fluid and both can transport the fluid through a pipe. As gases are compressible, the compressor also reduces the volume of a gas...
s and pneumatic equipment and its owner, Treve Holman, conceived a way that his firm could aid in the war effort beyond the production of tools. Recalling the World War I
World War I
World War I , which was predominantly called the World War or the Great War from its occurrence until 1939, and the First World War or World War I thereafter, was a major war centred in Europe that began on 28 July 1914 and lasted until 11 November 1918...
-era Stokes Mortar
Stokes Mortar
The Stokes mortar was a British trench mortar invented by Sir Wilfred Stokes KBE which was issued to the British Army and the Commonwealth armies during the latter half of the First World War.-History:...
and its successor, the Ordnance ML 3 inch Mortar
Ordnance ML 3 inch Mortar
The Ordnance ML 3-inch mortar was the United Kingdom's standard mortar used by the British Army from the late 1920s to the late 1960s, superseding the Stokes Mortar.-History:...
, Holman believed that it would be possible to produce a version powered by compressed air. Preliminary tests showed that the idea was feasible, with an early prototype throwing an eighteen-pound steel weight nearly 100 yards (91.4 m).
Mk I
The design eventually settled on for the MkMark (designation)
The word Mark, followed by number, is a method of specifically designating a standardized, integrated, assumed to be functional and unique version of a mechanical and/or electrical hardware product that has completed the design process and has been approved to be put into final production, as well...
I featured a 4½ foot unrifled
Rifling
Rifling is the process of making helical grooves in the barrel of a gun or firearm, which imparts a spin to a projectile around its long axis...
steel barrel. Rounds were dropped down the barrel and the pneumatic system triggered instantly upon the round striking the base. The rounds themselves were made from an open-topped metal container, holding a Mills bomb
Mills bomb
Mills bomb is the popular name for a series of prominent British hand grenades. They were the first modern fragmentation grenades in the world.-Overview:...
fitted with a 3.5 second fuse
Fuse (explosives)
In an explosive, pyrotechnic device or military munition, a fuse is the part of the device that initiates function. In common usage, the word fuse is used indiscriminately...
. High-pressure air bottles were able to supply enough power to fire fifty rounds each, with a maximum height during trials of around 600 feet (182.9 m). The rate of fire could reach thirty rounds per minute in the hands of an experienced crew. More appealing yet to the armed forces was the fact that the weapon could be produced using only cast iron
Cast iron
Cast iron is derived from pig iron, and while it usually refers to gray iron, it also identifies a large group of ferrous alloys which solidify with a eutectic. The color of a fractured surface can be used to identify an alloy. White cast iron is named after its white surface when fractured, due...
and mild steel, both of which were in fairly ready supply at this stage of the war.
An official trial of the Mk I Projector took place in February, 1940 with resounding success. An order was placed by the Royal Navy for 1000 of the Mk I models, and the weapons proved just as successful in action; the first confirmed kill reported only three weeks after the initial batch were sent out. While direct hits were rare, the bombs fired by the projector displayed an unexpected property — the explosion would leave a large puff of black smoke, absent from ground-based explosions from similar grenades. Firing a large number in quick succession gave the impression to incoming Luftwaffe
Luftwaffe
Luftwaffe is a generic German term for an air force. It is also the official name for two of the four historic German air forces, the Wehrmacht air arm founded in 1935 and disbanded in 1946; and the current Bundeswehr air arm founded in 1956....
pilots that the target vessel was armed with something far more deadly than the Holman Projector.
Mk II
The Mk II Projector was developed after a request from the Royal Navy for a version that could be fired using steamSteam
Steam is the technical term for water vapor, the gaseous phase of water, which is formed when water boils. In common language it is often used to refer to the visible mist of water droplets formed as this water vapor condenses in the presence of cooler air...
in place of compressed air, since the steam trawlers (both fishing and minesweeping
Naval trawler
A naval trawler is a vessel built along the lines of a fishing trawler but fitted out for naval purposes. Naval trawlers were widely used during the First and Second world wars. Fishing trawlers were particularly suited for many naval requirements because they were robust boats designed to work...
) had the former in plentiful supply. The Stokes design of the Mk I needed to be abandoned for this, since the harsh weather experienced by the trawlers invariably rusted the valve
Valve
A valve is a device that regulates, directs or controls the flow of a fluid by opening, closing, or partially obstructing various passageways. Valves are technically pipe fittings, but are usually discussed as a separate category...
s of the pneumatics. When steam was used in such a system, the water would condense in the pipes and prevent firing of the weapon. To solve this, a firing trigger was added, in place of the Stokes design in which the round would be fired automatically.
This new version was fitted to a wide variety of ships, from destroyer
Destroyer
In naval terminology, a destroyer is a fast and maneuverable yet long-endurance warship intended to escort larger vessels in a fleet, convoy or battle group and defend them against smaller, powerful, short-range attackers. Destroyers, originally called torpedo-boat destroyers in 1892, evolved from...
s to minesweepers and motor gun boats
Motor Gun Boat
Motor Gun Boat was a Royal Navy term for a small military vessel of the Second World War. They were physically similar to the Motor Torpedo Boats but equipped with a mix of guns instead of torpedoes. Their small size and high speed made them difficult targets for E-boats or torpedo bombers, but...
. To demonstrate the weapon's versatility, a trial was arranged in Aldershot, Hampshire
Aldershot
Aldershot is a town in the English county of Hampshire, located on heathland about southwest of London. The town is administered by Rushmoor Borough Council...
in front of the Prime Minister
Prime Minister of the United Kingdom
The Prime Minister of the United Kingdom of Great Britain and Northern Ireland is the Head of Her Majesty's Government in the United Kingdom. The Prime Minister and Cabinet are collectively accountable for their policies and actions to the Sovereign, to Parliament, to their political party and...
, Winston Churchill
Winston Churchill
Sir Winston Leonard Spencer-Churchill, was a predominantly Conservative British politician and statesman known for his leadership of the United Kingdom during the Second World War. He is widely regarded as one of the greatest wartime leaders of the century and served as Prime Minister twice...
. No Mills rounds were brought, as it was assumed that some form of ammunition would be provided by the British Army
British Army
The British Army is the land warfare branch of Her Majesty's Armed Forces in the United Kingdom. It came into being with the unification of the Kingdom of England and Scotland into the Kingdom of Great Britain in 1707. The new British Army incorporated Regiments that had already existed in England...
, who were overseeing the trials. As it turned out, this was overlooked and the trial was delayed until one officer thought to bring out the bottles of beer
Beer bottle
A beer bottle is a bottle made to contain beer, usually made of glass.Bottled beer has been in use since as early as the 16th century. Beer bottles come in various sizes, shapes and colours....
that had been brought to serve at lunch. The smooth bore of the Projector allowed even these irregular projectiles to be fired successfully, with all striking the target with an explosion of glass and foam. The Prime Minister commented on the weapon afterwards, describing it as "A very good idea, this weapon of yours. It will save our cordite
Cordite
Cordite is a family of smokeless propellants developed and produced in the United Kingdom from 1889 to replace gunpowder as a military propellant. Like gunpowder, cordite is classified as a low explosive because of its slow burning rates and consequently low brisance...
".
Regardless of the successful trials, The Mk II was still highly inaccurate when fired at distant moving targets. Only a dozen or so aircraft were confirmed to have been downed by the weapon in its first year of service. It did, however, succeed in convincing many more aircraft that the target vessel was more heavily equipped than it actually was, and a large number of reports were made about Luftwaffe aircraft turning away from an attack after salvoes from the ship's Holman Projector were launched. Within the Admiralty
Admiralty
The Admiralty was formerly the authority in the Kingdom of England, and later in the United Kingdom, responsible for the command of the Royal Navy...
, the perception was that the Projector was a useful stop-gap
Improvised weapons
An Improvised weapon is a device that was not designed to be used as a weapon but can be put to that use. They are generally used for self-defence or where the person is otherwise unarmed...
weapon in the early years of the war, when other more effective anti aircraft weaponry, such as the Oerlikon 20 mm cannon
Oerlikon 20 mm cannon
The Oerlikon 20 mm cannon is a series of autocannons, based on an original design by Reinhold Becker of Germany, very early in World War I, and widely produced by Oerlikon Contraves and others...
, were in short supply.
Mk III
In 1941, production of the Mk III Holman Projector began. This version was semi-automatic, and capable of firing multiple projectiles in a single salvo to a height of around 1000 feet (304.8 m). The Admiralty placed an order for a further one thousand units, to be fitted to coastal gunboats and other light craft, where the light recoilRecoil
Recoil is the backward momentum of a gun when it is discharged. In technical terms, the recoil caused by the gun exactly balances the forward momentum of the projectile and exhaust gasses, according to Newton's third law...
of the weapon had proven useful. Plans were drawn up for a Mk IV version of the Projector to fill this niche more readily, with a shorter barrel and swivel base. However, by the time the plans were ready to be put into action the war had progressed, and more advanced weaponry was now available that made the Projector obsolete. A number of the earlier model Projectors still played a part in the conflict though, discouraging attacks in the Mediterranean by some smaller submarine
Submarine
A submarine is a watercraft capable of independent operation below the surface of the water. It differs from a submersible, which has more limited underwater capability...
s, and a small number were adapted to fire grapnels for commando
Commando
In English, the term commando means a specific kind of individual soldier or military unit. In contemporary usage, commando usually means elite light infantry and/or special operations forces units, specializing in amphibious landings, parachuting, rappelling and similar techniques, to conduct and...
cliff assaults. In total around 4,500 Holman Projectors were put into active service during World War II, and several can still be found in museum
Museum
A museum is an institution that cares for a collection of artifacts and other objects of scientific, artistic, cultural, or historical importance and makes them available for public viewing through exhibits that may be permanent or temporary. Most large museums are located in major cities...
s in the United Kingdom
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...
.
See also
- Northover projectorNorthover projectorThe Projector, 2.5 inch—more commonly known as the Northover Projector—was an ad hoc anti-tank weapon used by the British Army and Home Guard during the Second World War...
, another WWII grenade throwing device - AA Mine DischargerAA Mine DischargerThe AA Mine Discharger was a Japanese anti-aircraft weapon of the Second World War. The device was a simple tube like an infantry mortar of 70 mm or 81 mm caliber. Instead of a standard mortar bomb, the projectile was a tube containing seven individual mines, each approximately 11/16ths...
, a Japanese anti-aircraft mortar. - Unrotated ProjectileUnrotated ProjectileThe Unrotated Projectile, or UP, was a short range rocket-firing anti-aircraft weapon developed for the Royal Navy to supplement the 2 pounder Pom-Pom gun due to a critical lack of close-range anti-aircraft weapons. It was used extensively by British ships during the early days of World War II...
, another Royal Navy anti-aircraft weapon. - Steam cannonSteam cannonA steam cannon is a cannon that launches a projectile using only heat and water. The first steam cannon was designed by Archimedes during the Siege of Syracuse. Leonardo da Vinci was also known to have designed one ....
, other steam-powered missile launchers
General references
- Pawle, G. The Secret War, White Lion, 1972. ISBN 0-85617-120-4
- Central Office of InformationCentral Office of InformationThe Central Office of Information is the UK government's marketing and communications agency. Its Chief Executive, currently Mark Lund, reports to the Minister for the Cabinet Office...
, British Coaster, 1939-1945, HMSO, 1947. - Ministry of InformationMinister of InformationThe Ministry of Information , headed by the Minister of Information, was a United Kingdom government department created briefly at the end of World War I and again during World War II...
, Merchantmen at war: the official story of the Merchant Navy, 1939-1944, HMSO, 1944.