JB-4

American air-to-surface missile prototype

Maximum speed 445 mph (716 km/h)

The JB-4, also known as MX-607, was an early American air-to-surface missile developed by the United States Army Air Forces during World War II. Using television/radio-command guidance, the JB-4 reached the flight-testing stage before being cancelled at the end of the war.

Design and development

Developed under the project code MX-607 at Wright Field in Ohio,^[1]^[2] the JB-4 was a modification of the GB-4 glide bomb,^[1]^[3] which had entered service with the U.S. Army Air Forces in 1944.^[4] Powered by a Ford PJ31 pulsejet engine, the JB-4 was intended to give an improved standoff range as opposed to its unpowered predecessor.^[1] In addition, the addition of an engine made the missile capable of being ground-launched as well.^[1] However the requirement to carry fuel for the engine meant that the size of the JB-4's warhead was limited to 750 pounds (340 kg),^[5] compared to the 2,000 pounds (910 kg) bomb that formed the core of the GB-4.^[6]

Utilising primarily plywood construction,^[5] the JB-4 utilised television/radio-command guidance, with an AN/AXT-2 transmitter broadcasting a television signal from a camera in the missile's nose to a remote operator. The operator, viewing the transmitted picture, would then transmit commands to the missile via radio, correcting the missile's course to ensure striking the target.^[1]

Operational history

The JB-4 entered the flight testing stage in January 1945.^[1]^[7] The missile demonstrated the ability to cruise at over 400 miles per hour (640 km/h);^[8] however, the television-guidance concept suffered from the limitations of the technology of the time, the pictures being difficult to make out in anything except completely clear weather.^[4] The missile also suffered from reliability issues; these, combined with the end of World War II in August 1945, resulted in the termination of the project,^[1] with none of the JB-4s built seeing operational service.^[3]

References

Notes

^ ^a ^b ^c ^d ^e ^f ^g Parsch 2024.
^ Ross 1951, p.115.
^ ^a ^b Ordway and Wakeford 1960, p.186.
^ ^a ^b Parsch 2003.
^ ^a ^b Hanle 2007, p.268.
^ Hanle 2007, p.114.
^ Air Force Magazine, Volume 31. 1948. p.25.
^ Gunston 1979, p.33.

Bibliography

Gunston, Bill (1979). The Illustrated Encyclopedia of the World's Rockets & Missiles. London: Salamander Books. ASIN B002K4M822.
Hanle, Donald J. (2007). Near Miss: The Army Air Forces' Guided Bomb Program in World War II. Lanham, MD: Scarecrow Press. ISBN 978-0-8108-5776-6.
Ordway, Frederick Ira; Ronald C. Wakeford (1960). International Missile and Spacecraft Guide. New York: McGraw-Hill. ASIN B000MAEGVC.
Parsch, Andreas (2003). "GB Series". Directory of U.S. Military Rockets and Missiles Appendix 1: Early Missiles and Drones. designation-systems.net. Retrieved 2011-02-02.
Parsch, Andreas (2024). "JB Series". Directory of U.S. Military Rockets and Missiles Appendix 1: Early Missiles and Drones. designation-systems.net. Retrieved 2011-02-04.
Ross, Frank (1951). Guided Missiles: Rockets & Torpedoes. New York: Lothrop, Lee & Shepard. ASIN B001LGSGX0.