RP-3
Encyclopedia
The RP-3 was a British
rocket
used in the Second World War. Though primarily an air-to-ground weapon, it saw limited use in other roles. Its 60 lb (27 kg) warhead gave rise to the alternative name of the "60 lb rocket"; the 25 lb (11.3 kg) solid-shot armour piercing variant was referred to as the "25 lb rocket". They were generally used by British fighter-bomber
aircraft against targets such as tanks, trains, motor transport and buildings, and by Coastal Command and Royal Navy
aircraft against U-Boat
s and shipping.
. The "Unrotated Projectiles" were Le Prieur rocket
s which were mounted on the interplane strut
s of Nieuport
fighters. These were used to attack observation balloon
s and were reasonably successful. Sopwith Baby
and Pup
and Home Defence B.E.2 fighters also carried rockets.
With the end of the war the Royal Air Force
, intent on retrenching, forgot about the potential uses for rockets fired from aircraft. The British Army
, however, did see a use for rockets against low flying aircraft; from late 1940 parts of Britain were defended by increasing numbers of "Z-Batteries
" 2 inch (51 mm) rockets supplementing the conventional anti-aircraft guns.
When German forces under the command of Rommel
intervened in the Western Desert
from early 1941 it became clear that the Desert Air Force
did not have the weapons capable of damaging or destroying the large numbers of armoured fighting vehicle
s, particularly the heavier Panzer III
and Panzer IV
tanks possessed by the Germans. Something needed to be done and in April 1941 Henry Tizard
, the Chief Scientist, called together a panel to study "Methods of Attacking Armoured Vehicles."
The types of weapons investigated included the 40 mm Vickers S
gun and related weapons manufactured by the Coventry Ordnance Works
, as well as the 40mm Bofors and the US 37 mm T9
cannon fitted to the Bell P-39 Airacobra: however, it was already recognised that these weapons were only capable of dealing with light tank
s and motor transport and using larger weapons on fighter-bombers was ruled out because of weight and difficulties handling recoil. The chairman of the panel, Mr. Ivor Bowen (Assistant Director of Armament Research) turned to the idea of using rocket projectiles as a means of delivering a large warhead capable of destroying or disabling heavy tanks. Information was sought from the Russians who had just started using unguided RS-82 rocket
s against German ground forces in the opening phases of Operation Barbarossa
. The possibility of the Russians sending a team of engineers to help set up production of these weapons was a possibility in August 1941. However, the Russian offer was withdrawn, in spite of British efforts at supplying a Wing of Hawker Hurricane
s and training Russian aircrew in their use.
By September 1941 it was decided that two models of UP (Unrotated Projectiles) would be developed:
When it was realised that the 2 inch version would be less effective than the Vickers S cannon it was decided to concentrate on development of the 3 in version which could be developed from the 2 inch rocket used in the Z-Batteries.
The rocket body was a steel tube 3 inches (76.2 mm) in diameter, hence the name. The tube was filled with 11 pounds (5 kg) of cordite
which was the propellant; this was fired electrically. A warhead was screwed into the forward end, initially a solid 25 pounds (11.3 kg), 3.44 inches (8.7 cm) armour piercing shell which was quickly supplemented by a 6 inches (15.2 cm) diameter, 60 pounds (27.2 kg) high explosive head. Another type of head was a 25 lb (11 kg) mild steel (later concrete) practice head. Once the rocket had been mounted on the rails, an electrical lead (nicknamed "pigtail") was plugged into the exhaust of the rocket.
Four small tailfins were fitted which gave enough spin to stabilize the rocket, though it was unguided and targeting was a matter of judgment and experience. For a start the approach to the target needed to be precise, with no sideslip or yaw which could throw the RP off line. Aircraft speed also had to be precise at the moment of launch, and because the launch rails were a fixture, the angle of attack also required precision. Trajectory
drop was also a problem, especially at longer ranges.In tests carried out by the A&AEE, dispersion (when aimed at a 20 ft square (1.858 sq m) target) was 13 ft 6 in (4.1 m) at 1,000 ft (305 m) range - equal to 3-4 degrees aiming error..
On the plus side the rocket was less complicated and more reliable than a gun firing a shell and there was no recoil on firing. It was found to be a demoralising form of attack against ground troops, and the 60 lb warhead could be devastating. The rocket installations were light enough to be carried by single seat fighters, giving them the punch of a cruiser
. Against slow-moving large targets like shipping and U-boat
s the rocket was a formidable weapon.
Unfortunately the weight and drag of the all-steel rails as initially fitted to British aircraft had a detrimental effect on the aircraft's performance. Some aircraft such as the Fairey Swordfish
had steel "anti-blast" panels fitted under the rails to protect the wing, which further increased weight and drag. Aluminium
Mark III rails, introduced from late 1944, reduced the effect. American experience with their own rockets (the USAAF's 3.5-Inch Forward Firing Aircraft Rocket
(FFAR) and the USN's 5-inch FFAR & HVAR) showed that the long rails and anti-blast panels were unnecessary. British aircraft only started being fitted with "Zero-Point" mounting pylons in the post-war years.
The 3-inch rocket motors (less warhead) were used in the bunker buster Disney bomb
; 19 of them propelling the 4500 pounds (2,041.2 kg) bomb to 990 miles per hour (442.6 m/s) at impact with the target.
, a Swordfish
, a Boston II and a Sea Hurricane.
At the same time the Aeroplane and Armament Experimental Establishment
(A&AEE) had to develop tactics for all the individual aircraft types which were to be armed with the RPs.
Aiming was through a standard GM.II reflector gunsight
. A later modification enabled the reflector to be tilted with the aid of a graduated scale, depressing the line of sight, the GM.IIL.
The first operational use of the RP was in the Western Desert
as a "tank-busting" weapon on Hawker Hurricane
Mk. IIEs and IVs. The 25 lb armour-piercing heads were found to be ineffective against the Tiger I
tanks coming into German service. With the example of the success of Royal Artillery
gunners using high-explosive shells from the 25 pdr gun-howitzer
, it was decided to design a new 60 pound semi-armour-piercing (SAP) head. These were capable of knocking turrets off tanks.
Soon after some encouraging results from the initial deployment, trials of the weapon were conducted against targets representing U-Boat
s. It was discovered that if the rockets were fired at a shallow angle, near misses resulted in the rockets curving upwards in seawater and piercing the targets below the waterline. Soon Coastal Command and the Royal Navy's Fleet Air Arm
aircraft were using the rockets extensively. The first U-Boat destroyed with the assistance of a rocket attack was U-752
(Kapitän-Leutnant Schroeter), on May 23, 1943 by a Swordfish
of 819 NAS
. The rockets used on this occasion had solid, cast-iron heads and were known as Rocket Spears. One of these punched right through the submarine's pressure hull, rendered it incapable of diving; the U–boat was scuttled by its crew. On May 28, 1943 a 608 Squadron
Hudson destroyed a U-Boat in the Mediterranean, the first destroyed solely by rocket.
From then until the end of the Second World War in Europe, Coastal Command and the Fleet Air Arm
used the rockets as one of their primary weapons (alongside torpedo
es, which, to a certain extent they replaced) against shipping and surfaced U-Boats.
A typical RP-3 installation was 4 projectiles on launching rails under each wing. A selector switch was fitted to allow the pilot to fire them singly (later omitted), in pairs, or as a full salvo. Towards the end of the war some RAF Second Tactical Air Force
Hawker Typhoon
s had their installation adapted to carry an additional four rockets doubled up under the eight already fitted.
Possibly the best known action involving RP-3s was that of the Falaise pocket
of mid-August 1944. During the battle German forces, retreating to avoid being trapped in a pincer movement
by Allied ground forces, came under air attack. Amongst the waves of light, medium and fighter bombers attacking the German columns the Typhoons of 2 TAF attacked with their rockets, claiming hundreds of tanks and "Mechanised Enemy Transport"also known as "Motorized Enemy Transport", as opposed to HDT - "Horse Drawn Transport". However, after the battle Army and 2nd TAF Operational Research Sections studying the battleground came to the conclusion that far fewer vehicles (17 in total) had been destroyed by rocket strike alone. What was clear was that in the heat of battle it was far harder for pilots to launch the weapons while meeting the conditions needed for accuracy. Smoke, dust and debris in the target areas made accurate assessment of the actual damage caused almost impossible.
However, it was also clear that the rocket attacks were devastating to the morale of the enemy troops: many vehicles were abandoned intact or with superficial damage and interrogation of captured prisoners showed that even the prospect of rocket attack was extremely unnerving.
s were fitted with two rails, one either side of the turret, to carry two 60 lb (27 kg) headed rockets. These were used at the Rhine Crossing by tanks of the 1st Coldstream Guards
. The tanks were called "Sherman Tulips". The tanks fitted included both conventional Shermans and the more heavily armed Sherman Fireflies
.
The rockets were highly inaccurate when fired from a tank as they were being fired from a stationary point and had little slipstream over the fins. Despite this, the RP-3 was valued by tank crews for the destructive effect of its 60 pound warhead .
to denote that it was a modified Landing Craft Tank
. These were used for shore bombardment during amphibious landings.
LCT(R)s carried 1,000 launchers and 5,000 rockets. The firepower was claimed to be equivalent to 80 light cruiser
s or 200 destroyers.
The method of operation was to anchor off the target beach, broadside to the shore. The range to the shore was then measured by radar and the elevation of the launchers set accordingly. The crew then went below, with the exception of the commanding officer who retreated to a special cubby hole to control the firing. The launch could comprise the either the entire set or individual ranks of rockets.
A full reload was a very labour-intensive operation, and at least one LCT(R) went alongside a cruiser and got a working party from the larger ship to assist in the process.
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...
rocket
Rocket (weapon)
A rocket is a self propelled, unguided weapon system powered by a rocket motor.- Categorisation :In military parlance, powered munitions are broadly categorised as follows:* A powered, unguided munition is known as a rocket....
used in the Second World War. Though primarily an air-to-ground weapon, it saw limited use in other roles. Its 60 lb (27 kg) warhead gave rise to the alternative name of the "60 lb rocket"; the 25 lb (11.3 kg) solid-shot armour piercing variant was referred to as the "25 lb rocket". They were generally used by British fighter-bomber
Fighter-bomber
A fighter-bomber is a fixed-wing aircraft with an intended primary role of light tactical bombing and also incorporating certain performance characteristics of a fighter aircraft. This term, although still used, has less significance since the introduction of rockets and guided missiles into aerial...
aircraft against targets such as tanks, trains, motor transport and buildings, and by Coastal Command and 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...
aircraft against U-Boat
U-boat
U-boat is the anglicized version of the German word U-Boot , itself an abbreviation of Unterseeboot , and refers to military submarines operated by Germany, particularly in World War I and World War II...
s and shipping.
History
The first use of rockets fired from aircraft was during World War IWorld 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...
. The "Unrotated Projectiles" were Le Prieur rocket
Le Prieur rocket
Le Prieur rockets were a type of incendiary air-to-air rockets used in World War I against observation balloons and airships. They were invented by the French Lieutenant Yves Le Prieur and were first used in the Battle of Verdun on 1916...
s which were mounted on the interplane strut
Interplane strut
An interplane strut is an aircraft airframe component designed to transmit lift and landing loads between wing panels on biplanes and other aircraft with multi-wing designs. They also maintain the correct angle of incidence for the connected wing panels and are often braced with wires...
s of Nieuport
Nieuport
Nieuport, later Nieuport-Delage, was a French aeroplane company that primarily built racing aircraft before World War I and fighter aircraft during World War I and between the wars.-Beginnings:...
fighters. These were used to attack observation balloon
Observation balloon
Observation balloons are balloons that are employed as aerial platforms for intelligence gathering and artillery spotting. Their use began during the French Revolutionary Wars, reaching their zenith during World War I, and they continue in limited use today....
s and were reasonably successful. Sopwith Baby
Sopwith Baby
-See also:...
and Pup
Sopwith Pup
The Sopwith Pup was a British single seater biplane fighter aircraft built by the Sopwith Aviation Company. It entered service with the Royal Flying Corps and the Royal Naval Air Service in the autumn of 1916. With pleasant flying characteristics and good maneuverability, the aircraft proved very...
and Home Defence B.E.2 fighters also carried rockets.
With the end of the war the Royal Air Force
Royal Air Force
The Royal Air Force is the aerial warfare service branch of the British Armed Forces. Formed on 1 April 1918, it is the oldest independent air force in the world...
, intent on retrenching, forgot about the potential uses for rockets fired from aircraft. 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...
, however, did see a use for rockets against low flying aircraft; from late 1940 parts of Britain were defended by increasing numbers of "Z-Batteries
Z Battery
The Z Battery, was a short range rocket-firing anti-aircraft weapon which fired 3-inch diameter rockets, used in ground-based single and multiple launchers for the air defence of the United Kingdom in World War II.- See also :...
" 2 inch (51 mm) rockets supplementing the conventional anti-aircraft guns.
When German forces under the command of Rommel
Erwin Rommel
Erwin Johannes Eugen Rommel , popularly known as the Desert Fox , was a German Field Marshal of World War II. He won the respect of both his own troops and the enemies he fought....
intervened in the Western Desert
Libyan Desert
The Libyan Desert covers an area of approximately 1,100,000 km2, it extends approximately 1100 km from east to west, and 1,000 km from north to south, in about the shape of a rectangle...
from early 1941 it became clear that the Desert Air Force
Desert Air Force
The Desert Air Force , also known chronologically as Air Headquarters Western Desert, Air Headquarters Libya, AHQ Western Desert, the Western Desert Air Force, Desert Air Force, and the First Tactical Air Force , was an Allied tactical air force initially created from No...
did not have the weapons capable of damaging or destroying the large numbers of armoured fighting vehicle
Armoured fighting vehicle
An armoured fighting vehicle is a combat vehicle, protected by strong armour and armed with weapons. AFVs can be wheeled or tracked....
s, particularly the heavier Panzer III
Panzer III
Panzer III was the common name of a medium tank that was developed in the 1930s by Germany and was used extensively in World War II. The official German designation was Panzerkampfwagen III translating as "armoured battle vehicle". It was intended to fight other armoured fighting vehicles and...
and Panzer IV
Panzer IV
The Panzerkampfwagen IV , commonly known as the Panzer IV, was a medium tank developed in Nazi Germany in the late 1930s and used extensively during the Second World War. Its ordnance inventory designation was Sd.Kfz...
tanks possessed by the Germans. Something needed to be done and in April 1941 Henry Tizard
Henry Tizard
Sir Henry Thomas Tizard FRS was an English chemist and inventor and past Rector of Imperial College....
, the Chief Scientist, called together a panel to study "Methods of Attacking Armoured Vehicles."
The types of weapons investigated included the 40 mm Vickers S
Vickers S
The Vickers Class "S" was a 40 mm cannon used to arm British aircraft for attacking ground targets in the Second World War.-History:...
gun and related weapons manufactured by the Coventry Ordnance Works
Coventry Ordnance Works
Coventry Ordnance Works was a British manufacturer of heavy guns, particularly naval artillery. The firm was based in the English city of Coventry.-History:...
, as well as the 40mm Bofors and the US 37 mm T9
M4 cannon
The 37 mm Automatic Gun, M4, known as the T9 during development, was a 37 mm autocannon designed by John Browning and used in the Bell P-39 Airacobra and P-63 Kingcobra fighters, as well as experimentally on other designs. It provided interceptors with a weapon that could shoot down any...
cannon fitted to the Bell P-39 Airacobra: however, it was already recognised that these weapons were only capable of dealing with light tank
Light tank
A light tank is a tank variant initially designed for rapid movement, and now primarily employed in low-intensity conflict. Early light tanks were generally armed and armored similar to an armored car, but used tracks in order to provide better cross-country mobility.The light tank was a major...
s and motor transport and using larger weapons on fighter-bombers was ruled out because of weight and difficulties handling recoil. The chairman of the panel, Mr. Ivor Bowen (Assistant Director of Armament Research) turned to the idea of using rocket projectiles as a means of delivering a large warhead capable of destroying or disabling heavy tanks. Information was sought from the Russians who had just started using unguided RS-82 rocket
RS-82 rocket
RS-82 and RS-132 were unguided rockets used by Soviet military aircraft in World War II.-Development:...
s against German ground forces in the opening phases of Operation Barbarossa
Operation Barbarossa
Operation Barbarossa was the code name for Germany's invasion of the Soviet Union during World War II that began on 22 June 1941. Over 4.5 million troops of the Axis powers invaded the USSR along a front., the largest invasion in the history of warfare...
. The possibility of the Russians sending a team of engineers to help set up production of these weapons was a possibility in August 1941. However, the Russian offer was withdrawn, in spite of British efforts at supplying a Wing of Hawker Hurricane
Hawker Hurricane
The Hawker Hurricane is a British single-seat fighter aircraft that was designed and predominantly built by Hawker Aircraft Ltd for the Royal Air Force...
s and training Russian aircrew in their use.
By September 1941 it was decided that two models of UP (Unrotated Projectiles) would be developed:
- A 23 lb plastic explosivePlastic explosivePlastic explosive is a specialised form of explosive material. It is a soft and hand moldable solid material. Plastic explosives are properly known as putty explosives within the field of explosives engineering....
on a standard 2 inch (51 mm) UP. - A 20 lb solid armour piercing head on a 3 inch (76 mm) UP.
When it was realised that the 2 inch version would be less effective than the Vickers S cannon it was decided to concentrate on development of the 3 in version which could be developed from the 2 inch rocket used in the Z-Batteries.
Design
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...
which was the propellant; this was fired electrically. A warhead was screwed into the forward end, initially a solid 25 pounds (11.3 kg), 3.44 inches (8.7 cm) armour piercing shell which was quickly supplemented by a 6 inches (15.2 cm) diameter, 60 pounds (27.2 kg) high explosive head. Another type of head was a 25 lb (11 kg) mild steel (later concrete) practice head. Once the rocket had been mounted on the rails, an electrical lead (nicknamed "pigtail") was plugged into the exhaust of the rocket.
Four small tailfins were fitted which gave enough spin to stabilize the rocket, though it was unguided and targeting was a matter of judgment and experience. For a start the approach to the target needed to be precise, with no sideslip or yaw which could throw the RP off line. Aircraft speed also had to be precise at the moment of launch, and because the launch rails were a fixture, the angle of attack also required precision. Trajectory
Trajectory
A trajectory is the path that a moving object follows through space as a function of time. The object might be a projectile or a satellite, for example. It thus includes the meaning of orbit—the path of a planet, an asteroid or a comet as it travels around a central mass...
drop was also a problem, especially at longer ranges.In tests carried out by the A&AEE, dispersion (when aimed at a 20 ft square (1.858 sq m) target) was 13 ft 6 in (4.1 m) at 1,000 ft (305 m) range - equal to 3-4 degrees aiming error..
On the plus side the rocket was less complicated and more reliable than a gun firing a shell and there was no recoil on firing. It was found to be a demoralising form of attack against ground troops, and the 60 lb warhead could be devastating. The rocket installations were light enough to be carried by single seat fighters, giving them the punch of a cruiser
Cruiser
A cruiser is a type of warship. The term has been in use for several hundreds of years, and has had different meanings throughout this period...
. Against slow-moving large targets like shipping and U-boat
U-boat
U-boat is the anglicized version of the German word U-Boot , itself an abbreviation of Unterseeboot , and refers to military submarines operated by Germany, particularly in World War I and World War II...
s the rocket was a formidable weapon.
Unfortunately the weight and drag of the all-steel rails as initially fitted to British aircraft had a detrimental effect on the aircraft's performance. Some aircraft such as the Fairey Swordfish
Fairey Swordfish
The Fairey Swordfish was a torpedo bomber built by the Fairey Aviation Company and used by the Fleet Air Arm of the Royal Navy during the Second World War...
had steel "anti-blast" panels fitted under the rails to protect the wing, which further increased weight and drag. Aluminium
Aluminium
Aluminium or aluminum is a silvery white member of the boron group of chemical elements. It has the symbol Al, and its atomic number is 13. It is not soluble in water under normal circumstances....
Mark III rails, introduced from late 1944, reduced the effect. American experience with their own rockets (the USAAF's 3.5-Inch Forward Firing Aircraft Rocket
3.5-Inch Forward Firing Aircraft Rocket
The 3.5-Inch Forward Firing Aircraft Rocket, or 3.5-Inch FFAR, was an American rocket developed during World War II to allow aircraft to attack enemy submarines at range...
(FFAR) and the USN's 5-inch FFAR & HVAR) showed that the long rails and anti-blast panels were unnecessary. British aircraft only started being fitted with "Zero-Point" mounting pylons in the post-war years.
The 3-inch rocket motors (less warhead) were used in the bunker buster Disney bomb
Disney bomb
The Disney Bomb, also known as the Disney Swish, was a rocket-assisted bunker buster bomb developed during the Second World War by the British Royal Navy to penetrate hardened concrete targets, such as submarine pens, that could resist conventional free-fall bombs...
; 19 of them propelling the 4500 pounds (2,041.2 kg) bomb to 990 miles per hour (442.6 m/s) at impact with the target.
Air to ground use
Before the new weapon was released for service extensive tests were carried out by the Instrument, Armament and Defence Flight (I.A.D.F) at Farnborough. Hurricanes were fitted with rockets and rails and flown during June and July 1942. Further tests were undertaken from 28 September to 30 November to develop rocket firing tactics. Other aircraft used were a HudsonLockheed Hudson
The Lockheed Hudson was an American-built light bomber and coastal reconnaissance aircraft built initially for the Royal Air Force shortly before the outbreak of the Second World War and primarily operated by the RAF thereafter...
, a Swordfish
Fairey Swordfish
The Fairey Swordfish was a torpedo bomber built by the Fairey Aviation Company and used by the Fleet Air Arm of the Royal Navy during the Second World War...
, a Boston II and a Sea Hurricane.
At the same time the Aeroplane and Armament Experimental Establishment
Aeroplane and Armament Experimental Establishment
The Aeroplane and Armament Experimental Establishment was a research facility for British military aviation from 1918 to 1992.-History:...
(A&AEE) had to develop tactics for all the individual aircraft types which were to be armed with the RPs.
Aiming was through a standard GM.II reflector gunsight
Reflector sight
A reflector or reflex sight is a generally non-magnifying optical device that allows the user to look through a partially reflecting glass element and see an illuminated projection of an aiming point or some other image superimposed on the field of view...
. A later modification enabled the reflector to be tilted with the aid of a graduated scale, depressing the line of sight, the GM.IIL.
The first operational use of the RP was in the Western Desert
Western Desert Campaign
The Western Desert Campaign, also known as the Desert War, was the initial stage of the North African Campaign during the Second World War. The campaign was heavily influenced by the availability of supplies and transport. The ability of the Allied forces, operating from besieged Malta, to...
as a "tank-busting" weapon on Hawker Hurricane
Hawker Hurricane
The Hawker Hurricane is a British single-seat fighter aircraft that was designed and predominantly built by Hawker Aircraft Ltd for the Royal Air Force...
Mk. IIEs and IVs. The 25 lb armour-piercing heads were found to be ineffective against the Tiger I
Tiger I
Tiger I is the common name of a German heavy tank developed in 1942 and used in World War II. The final official German designation was Panzerkampfwagen Tiger Ausf. E, often shortened to Tiger. It was an answer to the unexpectedly formidable Soviet armour encountered in the initial months of...
tanks coming into German service. With the example of the success of Royal Artillery
Royal Artillery
The Royal Regiment of Artillery, commonly referred to as the Royal Artillery , is the artillery arm of the British Army. Despite its name, it comprises a number of regiments.-History:...
gunners using high-explosive shells from the 25 pdr gun-howitzer
Ordnance QF 25 pounder
The Ordnance QF 25 pounder, or more simply, 25-pounder or 25-pdr, was introduced into service just before World War II, during which it served as the major British field gun/howitzer. It was considered by many to be the best field artillery piece of the war, combining high rates of fire with a...
, it was decided to design a new 60 pound semi-armour-piercing (SAP) head. These were capable of knocking turrets off tanks.
Soon after some encouraging results from the initial deployment, trials of the weapon were conducted against targets representing U-Boat
U-boat
U-boat is the anglicized version of the German word U-Boot , itself an abbreviation of Unterseeboot , and refers to military submarines operated by Germany, particularly in World War I and World War II...
s. It was discovered that if the rockets were fired at a shallow angle, near misses resulted in the rockets curving upwards in seawater and piercing the targets below the waterline. Soon Coastal Command and the Royal Navy's Fleet Air Arm
Fleet Air Arm
The Fleet Air Arm is the branch of the British Royal Navy responsible for the operation of naval aircraft. The Fleet Air Arm currently operates the AgustaWestland Merlin, Westland Sea King and Westland Lynx helicopters...
aircraft were using the rockets extensively. The first U-Boat destroyed with the assistance of a rocket attack was U-752
German submarine U-752
German submarine U-752 was a Type VIIC U-boat built for the German Kriegsmarine for service during World War II. She served with 3rd U-boat Flotilla from 24 May 1941 to 23 May 1943 under the command of Karl-Ernst Schroeter....
(Kapitän-Leutnant Schroeter), on May 23, 1943 by a Swordfish
Fairey Swordfish
The Fairey Swordfish was a torpedo bomber built by the Fairey Aviation Company and used by the Fleet Air Arm of the Royal Navy during the Second World War...
of 819 NAS
819 Naval Air Squadron
819 Naval Air Squadron was a Royal Navy aircraft squadron before and during World War II. Along with No. 815 Squadron, it performed the successful night attack on the Italian fleet at Taranto on 11 November 1940...
. The rockets used on this occasion had solid, cast-iron heads and were known as Rocket Spears. One of these punched right through the submarine's pressure hull, rendered it incapable of diving; the U–boat was scuttled by its crew. On May 28, 1943 a 608 Squadron
No. 608 Squadron RAF
No. 608 Squadron was an Auxiliary Air Force squadron of the Royal Air Force during World War II. It flew during its existence as a bomber, fighter and reconnaissance unit and was the only RAF squadron to be equipped with the unsuccessful Blackburn Botha torpedo bomber.-Formation and early years:...
Hudson destroyed a U-Boat in the Mediterranean, the first destroyed solely by rocket.
From then until the end of the Second World War in Europe, Coastal Command and the Fleet Air Arm
Fleet Air Arm
The Fleet Air Arm is the branch of the British Royal Navy responsible for the operation of naval aircraft. The Fleet Air Arm currently operates the AgustaWestland Merlin, Westland Sea King and Westland Lynx helicopters...
used the rockets as one of their primary weapons (alongside torpedo
Torpedo
The modern torpedo is a self-propelled missile weapon with an explosive warhead, launched above or below the water surface, propelled underwater towards a target, and designed to detonate either on contact with it or in proximity to it.The term torpedo was originally employed for...
es, which, to a certain extent they replaced) against shipping and surfaced U-Boats.
A typical RP-3 installation was 4 projectiles on launching rails under each wing. A selector switch was fitted to allow the pilot to fire them singly (later omitted), in pairs, or as a full salvo. Towards the end of the war some RAF Second Tactical Air Force
RAF Second Tactical Air Force
The former RAF Second Tactical Air Force was one of three tactical air forces within the Royal Air Force during and after the Second World War...
Hawker Typhoon
Hawker Typhoon
The Hawker Typhoon was a British single-seat fighter-bomber, produced by Hawker Aircraft. While the Typhoon was designed to be a medium-high altitude interceptor, and a direct replacement for the Hawker Hurricane, several design problems were encountered, and the Typhoon never completely satisfied...
s had their installation adapted to carry an additional four rockets doubled up under the eight already fitted.
Possibly the best known action involving RP-3s was that of the Falaise pocket
Falaise pocket
The battle of the Falaise Pocket, fought during the Second World War from 12 to 21 August 1944, was the decisive engagement of the Battle of Normandy...
of mid-August 1944. During the battle German forces, retreating to avoid being trapped in a pincer movement
Pincer movement
The pincer movement or double envelopment is a military maneuver. The flanks of the opponent are attacked simultaneously in a pinching motion after the opponent has advanced towards the center of an army which is responding by moving its outside forces to the enemy's flanks, in order to surround it...
by Allied ground forces, came under air attack. Amongst the waves of light, medium and fighter bombers attacking the German columns the Typhoons of 2 TAF attacked with their rockets, claiming hundreds of tanks and "Mechanised Enemy Transport"also known as "Motorized Enemy Transport", as opposed to HDT - "Horse Drawn Transport". However, after the battle Army and 2nd TAF Operational Research Sections studying the battleground came to the conclusion that far fewer vehicles (17 in total) had been destroyed by rocket strike alone. What was clear was that in the heat of battle it was far harder for pilots to launch the weapons while meeting the conditions needed for accuracy. Smoke, dust and debris in the target areas made accurate assessment of the actual damage caused almost impossible.
However, it was also clear that the rocket attacks were devastating to the morale of the enemy troops: many vehicles were abandoned intact or with superficial damage and interrogation of captured prisoners showed that even the prospect of rocket attack was extremely unnerving.
Tank use
In 1945, some British ShermanM4 Sherman
The M4 Sherman, formally Medium Tank, M4, was the primary tank used by the United States during World War II. Thousands were also distributed to the Allies, including the British Commonwealth and Soviet armies, via lend-lease...
s were fitted with two rails, one either side of the turret, to carry two 60 lb (27 kg) headed rockets. These were used at the Rhine Crossing by tanks of the 1st Coldstream Guards
Coldstream Guards
Her Majesty's Coldstream Regiment of Foot Guards, also known officially as the Coldstream Guards , is a regiment of the British Army, part of the Guards Division or Household Division....
. The tanks were called "Sherman Tulips". The tanks fitted included both conventional Shermans and the more heavily armed Sherman Fireflies
Sherman Firefly
The Sherman Firefly was a World War II British variant of the American Sherman tank, fitted with the powerful British 17 pounder anti-tank gun as its main weapon...
.
The rockets were highly inaccurate when fired from a tank as they were being fired from a stationary point and had little slipstream over the fins. Despite this, the RP-3 was valued by tank crews for the destructive effect of its 60 pound warhead .
Shore bombardment
RP-3s were used to arm the Landing Craft Rocket, also referred to as the Landing Craft Tank (Rocket)Landing craft tank (rocket)
The Landing Craft Tank or LCT was developed from the British Mk.2 and Mk.3 Landing Craft Tank during the Second World War. It was designed to saturate beaches with up to 1,066 RP-3 60 lb rockets prior to the landing of troops. Used by both British and U.S...
to denote that it was a modified Landing Craft Tank
Landing craft tank
The Landing Craft, Tank was an amphibious assault ship for landing tanks on beachheads. They were initially developed by the British Royal Navy and later by the United States Navy during World War II in a series of versions. Initially known as the "Tank Landing Craft" by the British, they later...
. These were used for shore bombardment during amphibious landings.
LCT(R)s carried 1,000 launchers and 5,000 rockets. The firepower was claimed to be equivalent to 80 light cruiser
Light cruiser
A light cruiser is a type of small- or medium-sized warship. The term is a shortening of the phrase "light armored cruiser", describing a small ship that carried armor in the same way as an armored cruiser: a protective belt and deck...
s or 200 destroyers.
The method of operation was to anchor off the target beach, broadside to the shore. The range to the shore was then measured by radar and the elevation of the launchers set accordingly. The crew then went below, with the exception of the commanding officer who retreated to a special cubby hole to control the firing. The launch could comprise the either the entire set or individual ranks of rockets.
A full reload was a very labour-intensive operation, and at least one LCT(R) went alongside a cruiser and got a working party from the larger ship to assist in the process.
Specification
- Length: 55 in (1.4 metres)
- Propelling charge: 11 lb (5 kg) cordite, electrically ignited.
- Max speed 1,200 mph (480 m/s)
- Range: 1 mile (1,600 m)
- Weight: 47 lb (21 kg) with 25 lb (11 kg) AP head
- Warhead
- 60 lb Shell, HE/SAP (Semi-armour piercing)(27 kg)
- 60 lb Shell, HE/GP, Hollow ChargeHeatIn physics and thermodynamics, heat is energy transferred from one body, region, or thermodynamic system to another due to thermal contact or thermal radiation when the systems are at different temperatures. It is often described as one of the fundamental processes of energy transfer between...
- 18 lb Shell, HE (8 kg)
- 25 lb Shot, AP (11 kg)
- 25 lb Head, Solid, A/S (anti-submarine) (11 kg)
- 60 lb Shell, Practice (training only) (27 kg)
- 12 lb Head, Practice (training only)(5 kg)
Aircraft using the RP-3 in the Second World War
These are aircraft that used the RP-3 operationally, a number of aircraft types were fitted with RP-3s on an experimental basis.RAF and Commonwealth Air Forces
- Boeing Fortress Mk. II and IIA: (Coastal Command)
- Bristol Beaufighter Mk. VI, VIC, X and 20Bristol BeaufighterThe Bristol Type 156 Beaufighter, often referred to as simply the Beau, was a British long-range heavy fighter modification of the Bristol Aeroplane Company's earlier Beaufort torpedo bomber design...
: (Coastal Command, South East Asia CommandSouth East Asia CommandSouth East Asia Command was the body set up to be in overall charge of Allied operations in the South-East Asian Theatre during World War II.-Background:...
and Royal Australian Air ForceRoyal Australian Air ForceThe Royal Australian Air Force is the air force branch of the Australian Defence Force. The RAAF was formed in March 1921. It continues the traditions of the Australian Flying Corps , which was formed on 22 October 1912. The RAAF has taken part in many of the 20th century's major conflicts...
, Pacific Theatre.) - Consolidated Liberator B. Mk. III, VI: (Coastal Command.)
- de Havilland Mosquito F.B. Mk. VIDe Havilland MosquitoThe de Havilland DH.98 Mosquito was a British multi-role combat aircraft that served during the Second World War and the postwar era. It was known affectionately as the "Mossie" to its crews and was also nicknamed "The Wooden Wonder"...
: (Coastal Command, SEAC and RAAF, Pacific Theatre.) - Hawker Hurricane Mk. IIE & IVHawker HurricaneThe Hawker Hurricane is a British single-seat fighter aircraft that was designed and predominantly built by Hawker Aircraft Ltd for the Royal Air Force...
: (DAFDesert Air ForceThe Desert Air Force , also known chronologically as Air Headquarters Western Desert, Air Headquarters Libya, AHQ Western Desert, the Western Desert Air Force, Desert Air Force, and the First Tactical Air Force , was an Allied tactical air force initially created from No...
, 2 TAFRAF Second Tactical Air ForceThe former RAF Second Tactical Air Force was one of three tactical air forces within the Royal Air Force during and after the Second World War...
, SEAC.) - Hawker Typhoon Mk. IbHawker TyphoonThe Hawker Typhoon was a British single-seat fighter-bomber, produced by Hawker Aircraft. While the Typhoon was designed to be a medium-high altitude interceptor, and a direct replacement for the Hawker Hurricane, several design problems were encountered, and the Typhoon never completely satisfied...
: (2 TAF.) - Republic Thunderbolt
- Vickers Wellington GR Mk. XIVVickers WellingtonThe Vickers Wellington was a British twin-engine, long range medium bomber designed in the mid-1930s at Brooklands in Weybridge, Surrey, by Vickers-Armstrongs' Chief Designer, R. K. Pierson. It was widely used as a night bomber in the early years of the Second World War, before being displaced as a...
: (Coastal Command)
Royal Navy Fleet Air Arm
- Fairey Firefly Mk. IFairey FireflyThe Fairey Firefly was a British Second World War-era carrier-borne fighter aircraft and anti-submarine aircraft of the Fleet Air Arm ....
- Fairey Swordfish Mk. II, IIIFairey SwordfishThe Fairey Swordfish was a torpedo bomber built by the Fairey Aviation Company and used by the Fleet Air Arm of the Royal Navy during the Second World War...
- Grumman Tarpon/Avenger Mk. I, II, IIITBF AvengerThe Grumman TBF Avenger was a torpedo bomber developed initially for the United States Navy and Marine Corps, and eventually used by several air or naval arms around the world....