U.K. Ground/Air Launched Rockets

(Updated 29 March 2014)

General Notes on US/UK Rocketry Research in WWII:

German R&D work first began with spin stabilized rockets, while US/British research concentrated first on Fin-Stabilized Rockets. US Spin-Stabilized work began in 1943 with the team of CIT/Army Ordnance working on it. The first US SSR developed was a 3.5” rocket intended to substitute for the 75mm Pack Howitzer used by the USMC.

The big difference in Fin vs Spin Stabilization is accuracy – when launched at zero or low airspeed (from ground or from a surface craft), fin stabilized rockets have poor accuracy. However, in air launched applications, the aircraft’s air-speed ensues good stabilization at the moment of launching; as shown in the following list below:

Average Cannon/Gun: 1 mil or less dispersion
Fin Stabilized Air Launched:
6 to 8 mil dispersion
Spin Stabilized 4.5" Ground Launched: 20~ mil dispersion
Fin Stabilized 4.5" Ground Launched:
20 to 40 mil dispersion

References:
U.S. Rocket Ordnance, development and use in World War II, US GPO, 1946.
Eugene Slover’s Ordnance Pages

Land Mattress

Dispersion (30-32 Rocket Salvo): 50% of all rockets within a 215m by 219m area

References:
The Encyclopedia of Weapons of World War II edited by Chris Bishop

Land Mattress (Cut Down)

A smaller, lightweight version with just 16 launchers, designed to be towed behind a jeep or similar light vehicle.

References:
The Encyclopedia of Weapons of World War II edited by Chris Bishop

“LILO” Rocket

39.25 lb Rocket
   Length: 48.75 inches
   Diameter: 3.25 inches
   Warhead Mass: 21 lbs

78.25 lb Rocket
   Length: 52 inches
   Diameter: 6 inches
   Warhead Mass: 60 lbs

Notes: Designed to be manhandled forward and set up in series to destroy heavy Japanese fortifications – it was estimated that five LILO rockets would have to be fired to ensure a 95% hit on a point target 45 to 50 meters’ distance.

References:
The Encyclopedia of Weapons of World War II edited by Chris Bishop