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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)
Speed25 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 off 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 multiple salvoes. The T40 was a "limited procurement" weapon that was later classified as "limited standard".[3]

Service historyEdit

This vehicle saw barely any use in 1944–1945.[3] They were originally planned to be used for D-day, but testing was delayed, so the final model came too late to be integrated into the plan for D-day.[4] Testing had also shown that the rockets were potentially dangerous not only to the crew, but to people in the immediate vicinity as well.[5] The Marine Corps examined the T40 for possible use in the Marianas Campaign in 1944, but it was not put into service in the campaign.[6]

Thirty T40s were put into service in December 1944 on the Ardennes Front. The German attack caused the T40s to be moved to a safe place, and be used for the rest of the war in northern Italy.[5] The Army then authorized 1,000 conversion kits to try to make use of the surplus, but only two were converted. Further delays caused the project to be cancelled.[4]

T40 (short version)Edit

The T40 (short version) was an experimental version of the T40, with shorter rocket tubes and with the main gun removed, which was replaced with an elevation mechanism for the rocket launchers. The side access door for the crew was added to the vehicle, which was a M4A2 Sherman.[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