link the fighter to the trapeze which would hold the aircraft in the bomb bay during flight, lower it for deployment, and raise it back in after the mission. Due to the size of the fighter, only the cockpit, the fuselage spine, and the tailfin actually fit inside the GRB-36, which considerably increased the drag and reduced the big bomber's range by 5–10%. On a positive note, the fighter pilot was able to leave his aircraft while attached to the carrier, making the 10-hour flights to-and-from the target much more bearable. The initial FICON trials were performed in 1952. First hookup took place on 9 January 1952, with first retrieval into the bomb bay on 23 April, and first flight of the complete system from takeoff to landing on 14 May. In 1953, the GRB-36/F-84E was sent to Eglin Air Force Base where 170 airborne launches and retrievals were subsequently performed. In May 1953, the F-84E was replaced by the faster Republic F-84F Thunderstreak, with the original YRF-84F (briefly called YF-96A) prototype (serial number 49-2430) modified for the role and briefly designated GRF-84F. When the RF-84F Thunderflash tactical reconnaissance fighter began entering service, the FICON role was changed from attack to reconnaissance. As with the F-84, the RF-84 was supposed to utilize its smaller size and superior agility to overfly heavily defended targets and gather intelligence while the bomber loitered outside the range of enemy defenses. The scheme was found to be "tactically sound" and USAF ordered 10 production RB-36D to be converted to GRB-36D carriers with a complement of 25 RF-84K tactical reconnaissance fighters. The RF-84K differed from RF-84F in having retractable hookup equipment and anhedral tailplanes to better fit inside the GRB-36. Since it retained an armament of four 0.50 in. machine guns, it could also act as an escort fighter. The RF-84K could be deployed at altitudes of up to 25,000 ft (7,550 m) and added 1,180 mi (1,900 km) to GRB-36D's 2,800 mi (4,500 km) combat range. FICON in service The FICON system saw limited service with Strategic Air Command in 1955–56. The GRB-36D carriers from 99th Strategic Reconnaissance Wing (Fairchild AFB) operated in conjunction with RF-84K from 91st Strategic Reconnaissance Squadron (Larson AFB). Subsequent test flights demonstrated the FICON concept was indeed "tactically sound", but its operational implementation was difficult. A total of 10 GRB-36Ds and 25 RF-84Ks were built and saw limited service in