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Airborne Rockets Used By the British During WWII PDF Print E-mail
Written by David Boyd   
Thursday, 01 January 2009 15:46

Airborne Rockets

Before the war and even in the first few months of the war when A.A. rockets were being used successfully, little interest had been shown in the use of rockets as an aircraft weapon. In July 1940 the Air Ministry discussed the possibility of using rockets fired from aircraft to break up large formations of enemy bombers - the idea was soon dropped. It was not until June 1941 that use of rockets was again considered, but for different targets.

Weapons for attacking tanks with aircraft were sought and while armour piercing ammunition was being developed for the 20mm Hispano cannon it did not have the performance to deal with the larger German tanks, bombs, while effective against tanks if dropped near them were not accurate enough to do the job. The Fleet Air Arm and Coastal Command also were looking for a weapon to attack submarines and shipping.

Priority for airborne rockets was first given for use against seaborne targets and greater interest was given when in August 1941 reports that the Russians had been using rockets against German tanks and bomber formations with good effect. Efforts were made to secure sample rockets/drawings but when these were received it was found that little could be learnt from them.
 
As the development of airborne rockets was urgent, it was decided to use the 3 inch rocket motor used for A.A. use and to develop a 25lb shot and 60lb shell rocket head. The 25lb shot was relatively easy to design as it was similar to shot used in gun ammunition, these were first used in action in June 1942. It was also later found that 25dpr AP shot could be modified to be fired from rockets, towards the end of 1944 a new type of shot was introduced, this also weighed 25lbs but had a more tapered shape and thus a straighter underwater trajectory.

The 25lb shot headed rockets were used successfully against seaborne targets, especially submarines. In trials the AP rockets were found to cause serious damage to tanks, especially as after penetration of the armour they introduced burning and unburnt cordite into the tank which virtually guaranteed a fire to take place inside the vehicle. Although very damaging, the rockets were inaccurate and even if several rockets were fired at once a hit was not guaranteed.

The 60lb shell was intended to be used against seaborne targets and was not completed until the end of 1942. It was introduced into service in mid 1943, these shells had a base fuse that allowed them to penetrate the target before exploding.

Trials of the 60lb shell has found them to be ineffective against seaborne targets so it was decided to restrict their use to land targets, for these a non delay fuse was developed. These rockets were found to have an extremely good destructive effect against land targets, they were able to penetrate the top armour of both the Panzer IV/Panther and with a direct hit were able to disable a Tiger tank. Results in France showed that the rockets destroyed tanks even if penetration of the armour had not occurred.

I've seen several websites claim 5% chance to hit with these rockets, this seems a little low considering in a trial 9 hits were obtained with 116 rockets fired (7.76%) and the trail was carried out in extremely poor weather, some of the pilots had never fired the rockets before, most of the attacks were carried out on the front of the tank and the pilots were required to fire their rockets no closer than 400 yards, then again the pilots where not being shot at!

Later developments included attempts to launch a 250lb bomb using several rocket motors and a Hollow Charge 60lb rocket (RDX/TNT 50/50 filling).

60lb and 25lb AP rocket specifications

Rocket 60lb. F. 60lb S.A.P. 25lb A.P. Mk I 25lb A.P. Mk II
Length 22in (55.88cm) 21.8in (55.37cm) 12.4in (31.49cm) 14.7in (37.33cm)
Diameter 4.5in (11.43cm) 6in (15.24cm) 3.44in (8.73cm) 3.8in (9.65cm)
Total Weight 46.9lb (21.31kg) 60lb (27.27kg) 25lb (27.27kg) 24.75lb (11.25kg)
Fuzing No. 899 Mk I No. 865 Mk I - -
Filling TNT or RDX/TNT 60/40 TNT or Amatol 60/40 - -
Filling weight 3lb (1.36kg) 12lb (5.45kg) - -

Rocket performance data

Type Projectile Weight Weight of complete Cartridge Angle Penetration at 400 yards (with 350f/s ac speed) Penetration at 700 yards (with 350f/s ac speed) Penetration at 1000 yards (with 350f/s ac speed) Time of flight

400 yards

(secs)

700 1000
25lb AP Shot 24.75lb 58lb 20 78 88 83 0.5 0.89 1.29
60lb SAP/Shell 60lb   - - - - - - -
60lb  HE/GP (Hollow Charge) 60lb   0 198 198 198 - - -

Production of Rockets

Type 1943 1944 1945
25lb AP 224,000 57,000 -
60lb SAP/Shell 50,300 393,000 263,000
60lb SAP/Shell (modified) - 30,000 29,000

 

 
Comments (2)
3 inch aircraft rockets (R/P)
1 Thursday, 08 January 2009 18:27
Antoon Meijers
I know the following warheads for the 3 inch aircraft rocket motor.

Shot A.P. 25 lb. Mk I
Shot A.P. 25 lb. Mk II
Shot S.A.P. 25 lb. Mk I
Shell H.E. 60 lb. S.A.P. No. 1 Mk I & No. 2 Mk I
Shell H.E. 60 lb. “F” No. 1 Mk I
Head Rocket Flare Mk 1
Phosphorous R/P
Shell 25 lb. Practice (Concrete) Mk I
Shell 60 lb. Practice (Concrete) Mk I

Head Solid A/S a/c 3 in. No. I Mk I
Shell H.E. 60 lb. S.A.P. No. 2 Mk 3 and Mk 4.
Shell H.E. 60 lb. G.P. (Hollow Charge) No. 1 Mk I
Shell H.E. 60 lb. S/H (Squash Head) No. 1 Mk I
Head H.E. 18 lb. G.P. No. 1 Mk I
Head H.E. 12 lb. G.P.
Head Rocket Flare Mk 2N
Head Practice 12 lb. No. 1 Mk 1.

Container Smoke No.1 Mk I & No. 2 Mk I (attached to the Shell Practice 25 and 60 lb.

Only the first nine are WW-2 productions and the other eight are post-war.
From the phosphorous warhead is little information available. As far as I know these were “field made” by attaching the 25 lb. Shell Smoke Mk I from the 5 inch Barrage Rocket “Sea Mattress” to the 3 inch rocket motor. Some UXO’s of these have been found in the Netherlands. Also these “specials” are mentioned in the Daily Log from 2nd TAF and in the ORB’s of 266 sqdn.
There is also not much information about the 12 lb. GP warhead.
The container smoke is also post war.
60 lb. SAP/HE Shell (modified)
2 Friday, 09 January 2009 12:40
Antoon Meijers
David,

What do you mean with 60 lb. SAP/HE Shell (modified)?
Is this the No. 2 Mk I? If so, the only modification is that the fuze is instantaneous and has no delay.

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