T40 Whizbang

The Rocket Launcher T40/M17 (Whizbang) (sometimes spelled WhizBang) was a tank-mounted multiple rocket launcher used by the United States Army during World War II. The launcher was placed atop the Medium Tank M4, and fired a barrage of 7.2 in (180 mm) T37 HE or T21 Chemical rockets from 20 launch tubes. It was developed and used in the late stages of World War II; it saw limited combat in 1944–45. An experimental short variant of the T40 was also developed.

Sherman Whizbang
7.2-inch Multiple Rocket Launcher M17 Mounted on Medium Tank.png
T40/M17 mounted on M4 Sherman
TypeTank-mounted rocket launcher (Rocket-Artillery Tank)
Place of originUnited States
Service history
In service1944–1945
Used byUnited States
WarsWorld War II
Specifications ([2])
Mass84,000 lb (38,100 kg)
Length19.2 ft (5.84 m)
Width8.6 ft (2.62 m)

ShellT37 HE Demolition Rocket
T21 Chemical Warfare Rocket
Shell weightT37: 61 lb (28 kg)
T21: 51.8 lb (23.5 kg)
Caliber7.2 in (180 mm)
Elevation-5° to 25°
Muzzle velocityT37: 160 feet per second (49 m/s)
T21: 680 feet per second (210 m/s)
Maximum firing rangeT37: 230 yards (210 m)
T21: 3,430 yards (3,140 m)

Armor25–74 mm
1× T40/M17 rocket launcher, firing 7.2-Inch Demolition Rockets
75 mm M3 L/40 gun
90 rounds
EngineContinental R975, radial, C1 9-cylinder
400 hp (300 kW)
TransmissionSpicer manual, synchromesh, 4 forward (plus 1 overdrive) and 1 reverse gear[1]
SuspensionVertical Volute Spring Suspension (VVSS)
Fuel capacity75 US gal (280 l)
120 mi (190 km)
Maximum speed 25 to 30 mph (40 to 48 km/h)


The rocket launcher on the T40/M17 WhizBang could hold twenty 7.2-inch rockets in a box-like frame, which could be elevated hydraulically with the controls for the 75 mm gun. The whole-mount could be jettisoned, if needed. If jettisoned, the 75 mm gun could be used as normal. The rockets in the mount could be fired one-at-a-time or in salvoes. The T40 was a "limited procurement" weapon that was later classified as "limited standard".[3]

Service historyEdit

T40s saw limited use in the European Theater in 1944–1945.[3] They were originally intended to be used on D-day, but delays in testing meant that final approval of the design occurred too late for use in the Normandy Invasion.[4] Testing also showed that the rockets were potentially dangerous to both the launcher crew and to anyone else in the vicinity.[5] The Marine Corps examined the T40 for possible use in the Marianas Campaign in 1944, but ultimately it was not used in the Pacific.[6]

In December 1944 thirty T40s were put into service on the Ardennes Front. A large German counter-attack in that sector caused the T40s to be redeployed to safer positions. After the battle, the T40s were redeployed to northern Italy where they remained for the remainder of the war.[5]

The Army authorized the manufacture of 1,000 kits to convert standard M4 Medium Tanks to T40s, but only two conversions actually occurred. Ultimately continuing delays in the project led to its cancelation.[4]

T40 (short version)Edit

The T40 (short version) was an experimental version of the T40 that featured shorter rocket tubes and removed the main gun. In place of the main gun, an elevation mechanism for the rocket launchers was installed. This version also featured a side access door for the crew.[3]

See alsoEdit


  1. ^ Berndt (1993), p. 195.
  2. ^ War Department (1945)
  3. ^ a b c Chamberlain & Ellis (1969), p. 125.
  4. ^ a b Anderson (2010), p. 245.
  5. ^ a b Green (2014), pp. 312–313
  6. ^ Zaloga (2012), p. 16.
  • Anderson, Richard C. (2010) Cracking Hitler's Atlantic Wall: The 1st Assault Brigade Royal Engineers on D-Day. Mechanicsburg, PA: Stackpole Books. ISBN 0-81170-589-7
  • Berndt, Thomas. (1993). Standard Catalog of U.S. Military Vehicles. Iola, WI: Krause Publications. ISBN 0-87341-223-0.
  • Chamberlain, Peter; Ellis, Chris (1969) British and American Tanks of World War II New York, NY: Arco Publishing Company. ISBN 0-668-01867-4
  • Green, Michael (2014) American Tanks & AFVs of World War II. Oxford, UK: Osprey Publishing. ISBN 1-78200-931-0
  • United States War Department (1945) 7.2-inch Multiple Rocket Launcher M17 Technical Manual. Washington, D.C.: War Department.
  • Zaloga, Steven (2012) U.S. Marine Corps Tanks of World War II. Oxford, UK: Osprey Publishing. ISBN 1-78096-032-8