The JB-4, also known as MX-607, was an early American
air-to-surface missile developed by the
United States Army Air Forces
The United States Army Air Forces (USAAF or AAF) was the major land-based aerial warfare service component of the United States Army and ''de facto'' aerial warfare service branch of the United States during and immediately after World War II ...
during
World War II
World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposing ...
. 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
Wilbur Wright Field was a military installation and an airfield used as a World War I pilot, mechanic, and armorer training facility and, under different designations, conducted United States Army Air Corps and Air Forces flight testing. Lo ...
in Ohio,
the JB-4 was a modification of the
GB-4
GB-4 (Glide Bomb No.4) was a precision guided munition developed by the United States during World War II. GB-4s used a television guidance system with the weapon being steered by a TV bombardier operating a joystick in the launch aircraft.
The ...
glide bomb,
[Parsch 2005.] which had entered service with the U.S. Army Air Forces in 1944.
[Parsch 2003.] Powered by a
Ford PJ31
The Argus As 014 (designated 109-014 by the RLM) was a pulsejet engine used on the German V-1 flying bomb of World War II, and the first model of pulsejet engine placed in mass production. License manufacture of the As 014 was carried out in J ...
pulsejet
300px, Diagram of a pulsejet
A pulsejet engine (or pulse jet) is a type of jet engine in which combustion occurs in pulses. A pulsejet engine can be made with few or no moving parts, and is capable of running statically (i.e. it does not need t ...
engine, the JB-4 was intended to give an improved standoff range as opposed to its unpowered predecessor.
In addition, the addition of an engine made the missile capable of being ground-launched as well.
However the requirement to carry fuel for the engine meant that the size of the JB-4's warhead was limited to ,
compared to the bomb that formed the core of the GB-4.
Utilising primarily
plywood construction,
[Hanle 2007, p.268.] the JB-4 utilised
television
Television, sometimes shortened to TV, is a telecommunication medium for transmitting moving images and sound. The term can refer to a television set, or the medium of television transmission. Television is a mass medium for advertisin ...
/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.
Operational history
The JB-4 entered the flight testing stage in January 1945.
The missile demonstrated the ability to cruise at over ;
[Gunston 1979, p.33.] 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.
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,
with none of the JB-4s built seeing operational service.
[Ordway and Wakeford 1960, p.186.]
References
;Notes
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External links
B - Bombs/Bomb Units
{{US WWII guided bombs
Abandoned military rocket and missile projects of the United States
JB-004
Pulsejet-powered aircraft
World War II guided missiles of the United States