The Bomarc was an unmanned surface-to-air missile and was a joint project of the Boeing Airplane Company and the Michigan Aeronautical Research Center, the name *BOMARC* standing for BOeing and the Michigan Aeronautical Research Center. Work on the project began in the late 1940s.
The Bomarc missile resembled a small aircraft, with a pair of shoulder-mounted delta wings. It was launched from a vertical position by a 23,000 lb.st. Aerojet General LR59-AG-13 liquid-fueled rocket motor mounted in the tail. Second-stage thrust was provided by a pair of 10,000 lb.st. Marquardt RJ43-MA-3 ramjet engines attached to the fuselage sides. Maximum speed attained during an intercept was Mach 3.45 (2275 mph) at 105,000 feet. Launch weight was 15,500 pounds. The dimensions were wingspan 18 feet 2 inches, length (excluding the first stage rocket nozzle) 47 feet 4 inches, height 10 feet 3 inches, wing area 65 square feet.
The warhead consisted of 1000 pounds of high explosives. Alternatively, a nuclear warhead could be carried. The warhead was detonated by a proximity fuse activated from the ground control center.
At that time, under a ruling of the newly-formed Defense Department, the US Army was given the responsibility for ground-to-air defensive systems, with the newly-formed US Air Force having the responsibility for fighter and bomber aircraft. When the USAF began work on the Bomarc project, the Army was already at work on the Nike antiaircraft missile, and it was felt that two separate ground-to-air missile projects would be deemed an unacceptable duplication of effort. Consequently, in order to preserve its program, the USAF chose to designate the BOMARC as a ground-to air pilotless aircraft, and gave it a fighter designation of XF-99
The first Bomarc launch took place on September 1, 1952. A short time later, it was decided that it was not a good idea to give fighter designations to unmanned missiles, and the Bomarc was redesignated IM-99A, where IM stood for "Intercept Missile".
The IM-99B version of the Bomarc had a first-stage Thiokol solid-fuel rocket motor in place of the liquid-fueled engine of the A. In addition, the B version differed from the A version in replacing the original vacuum-tube electronics with improved solid-state components.
On September 18, 1962, the IM-99A and B were redesignated CIM-10A and CIM-10B, where the C prefix stood for "Coffin" which described the intercept missile's launch environment, i.e. horizontal storage in a protective encounter.
On Jun 7, 1960, a nuclear-armed Bomarc missile caught fire in a hangar at Fort Dix, New Jersey. This contaminated an area up to a half-mile from the site with radioactive plutonium. It took several decades to clean up the contamination.
The Bomarc served well into the 1960s with the USAF Air Defense Command. The Bomarcs were finally withdrawn from service in 1972. Many of the surplus Bomarcs were expended as target drones.
In the late 1950s, the Canadian government decided to abandon work on the advanced Avro Arrow two-seat interceptor and opted for the unmanned Bomarc. The Bomarc served in Canada for about a decade. At first, the warheads were conventional, since the Canadian government of the day (Progressive Conservative Party) could not decide whether to accept nuclear warheads or not. When the Liberal Party came into power in 1963, the government finally decided to accept nuclear warheads. The nuclear warheads were supplied by the US, and there was a "double key" launching arrangement similar to that used by US missiles in the United Kingdom. The warheads were removed and returned to the USA in April/May of 1972, and the Bomarc missiles were decommissioned at the same time.
A CIM-10A Bomarc (serial number 59-1897) is on display outside the USAF Museum at the Wright-Patterson AFB in Ohio.
Sources:
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Fighters of the United States Air Force, Robert F. Dorr and David
Donald, Temple Press Aerospace, 1990.
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E-mail from Chris Gainor, Victoria, BC.
- Guttman, Robert, The US Air Force's Pilotless Fighter, Aviation History, Sept 2017
