RF-84 FICON / YF-96A FICON (FIghter CONveyor)
In the years after World War II, when the Cold War with the Soviet Union was just beginning, the Air Force modified heavy bombers to serve as reconnaissance platforms. The nation required an aircraft that could photograph targets deep inside Russia. Modified Boeing B-29s and, later, Convair RB-36s served in that role. The RB-36 version had an additional pressurized compartment for camera equipment in place of the forward bomb bay. It also had electronic gear to capture sources of radar, radio and other signals. When the Air Force first fielded the B-36, the Soviets had a difficult time intercepting the aircraft. The B-36 cruised at altitudes fighters could not reach.
The US Air Force's Global Attack mission really began with the arrival of the jet propelled bomber in the early 1950s. The Strategic Air Command's new B-47s and B-52s could travel long distances without the need for fighter escort. But SAC also depended on its propeller-driven B-36 Peacemakers, especially for the vital reconnaissance mission. These airborne giants would have to fly over the most heavily defended target areas, and were quite vulnerable to an enemy's jet interceptors.
In time, as seen in the rapid advancements in aircraft during the Korean War, the Soviets developed more capable fighter aircraft, so that advantage did not last very long for the bombers. In a quest to keep the massive bomber viable and to provide a means by which a small reconnaissance aircraft could be carried close to Soviet space to conduct reconnaissance missions, the Air Force initiated the Fighter Conveyor, or FICON, Project. In this program, the large B-36 would carry smaller fighter aircraft which would have the speed and maneuverability to execute either a reconnaissance or attack mission. The fighter could be loaded onto the bomber or take off from a separate base and could be picked up enroute to the target area. The RB-36 would then transport the fighter to the edge of enemy airspace and release the fighter to fly its assigned mission, after which the fighter returned to the bomber and was carried home.
The first technical proposal, which was considered by developers and the Air Force, was the possibility of suspension under the wing of the B-36 aircraft two F-84E "Thunderjet" fighter. The flight range of fighter aircraft with additional fuel tanks on the cruise was about 3200 km. It was assumed that the fighter will not be taken back to the bomber, and after a cutaway and aerial combat will fly to the nearest base. The F-84 became a limited flight range fighter which, under the condition of air combat with maximum flow rate of fuel was further reduced.
By the late 1940s, a scheme to have B-36 bombers carry along their own fighter protection had come to nothing. Northrop had developed a tiny parasite fighter, the XF-85 Goblin that fit into a bomb bay and could be released to drive off enemy fighters. But the system had too many development problems, and anyway the XF-85 was too small to offer much in the way of protection. The basic concept still seemed to hold promise, however. Could an RB-36 carry along a full-sized reconnaissance fighter to overfly the critical zone and return to the mother ship for the long trip home?
Air Force Headquarters authorized a fighter-reconnaissance project - dubbed FICON (Fighter Conveyor) - to explore the possibility. A conventional RB-36F was stripped of most of its operational equipment and modified by the addition of a trapeze mechanism in the bomb bay for stowing, releasing, and retrieving the parasite aircraft. The latter was an F-84E with a special "duck-bill" nose probe mechanism installed on top of the forward fuselage for engaging the trapeze boom's forward receiver. Once attached to the boom, the smaller plane could easily be lifted into the bomb bay. Only the canopy area and upper fuselage spine actually fit inside the mother ship; most of the rest rode below, adding significantly to the bomber's drag.
Suppose it was desired to bomb a target in the Donets Basin area with RF-84F's based 2000 miles away in Kellavik, using B-36's based in Limestone. The parasite could be released outside the early warning radar network, 8OO miles from the target, and fly a sea level zone radius of 150 n. mi. This mission would not require a full carrier fuel load. It is interesting to note that the RF-84F could be launched 8OO miles from the target, fly a 460 n. mi. zone at sea level and proceed 500 miles to rendezvous with a second carrier based in Casablanca; or it could be released 600 miles from the target, fly a 200 mile zone at sea level and proceed 500 miles from the target to Tripoli for staging. If the parasite and carrier were based in Casablanca, of course, this target would require only about one half capacity fuel load for the carrier which could release the parasite, loiter and rendezvous outside the defense area, allowing the bomber to fly a 500 mile radius to and from the target, with a 330 mile zone radius.
The composite aircraft consisted of a B-36 aircraft equipped as a carrier, with a parasite airplane suspended bv a trapeze installed in the B-36 bomb bay. The trapeze was designed to support, launch, and retrieve the parasite during flight, and provided parasite support during carrier take-off and landing. It consisted primarily of a trapeze actuating cylinder, drag brace, boom snubber and suspension boot. The susrension boom supported the parasite at three roints - at the nose and on each side of the fuselage. The nose attnchiment was an open fork receiver moving in a horizontal plane which was engaged by the parasite vertical nose latching fork. The aft boom latches were engaged from below by the pins on the parasite fuselage.
In 1951, the Air Force awarded Convair a contract to modify one RB-36 for the FICON mission. The bomber had to be capable of carrying, launching and retrieving a fighter from its bomb bay. The RF-84F's high performance, coupled with its long range and high load carrying ability, made it the best available fighter type aircraft for parasite use. The fact that both are existing aircraft, available in appreciable numbers, makes realization of operational parasite systems possible at an early date at low costs.
Initial testing was conducted at Eglin AFB, Florida. The first trapeze-style retrieval occurred on April 23, 1952, using a modified Republic F-84E Thunderflash as the parasite fighter. Testing proved successful, so the Air Force awarded another contract to Convair to modify an additional 10 RB-36s into carriers. These were designated GRB-36D. At the same time, the Air Force awarded a contract to Republic Aviation to modify 25 F-84s called RF-84K Parasites. The GRB-36Ds carried an H-shaped cradle (a recover-release trapeze) in the bomb bay which was lowered to launch or recover the fighter. While the fighter was stowed in the bomb bay, RF-84s pilots could exit the fighter and relax in the bomber. The fighter could also be refueled between launches. The GRB-36D could also supply electrical power, preheat air and pressurization air while matted. Further testing was conducted at the Conair facility in Fort Worth, Texas. This testing found that the modified GRB-36Ds could carry a fighter as far out as 2,800 miles, where it could launch the fighter for its designated mission.
The initial tests of the FICON Project were conducted at Eglin Air Force Base, Fla., early in 1953. These validated the parasite operation as "tactically sound," and recommended that a production RB-36 and a recon fighter based on the more advanced RF-84F be made available for operational suitability testing at the earliest possible date.
The Composite GRB-36F / F-84E was transferred for further tests Eglin Air Force airbase, where until February 20, 1953 it carried out 170 releases and acceptances in the air F-84E. Then began the test with a high-speed swept fighter F-84F (under the "parasitic" fighter was re-designated prototype YF-84F). Until May 1953, all the tests and mining had been successfully completed.
The ensuing flights revealed that the novel parasite concept was achievable but not practical. Hook-ups with the carrier were difficult enough under ideal flight conditions, and nearly impossible to achieve in turbulent air. In essence, what a trained test pilot could accomplish would likely be unworkable for most operational pilots under combat conditions.
There were other problems as well. Ground clearance with the fighter mounted was very close under the best of circumstances. But the RF-84K, like all the members of its family, was chronically fuel-thirsty and required one or more externally mounted 450-gallon fuel tanks to accomplish most missions. This reduced ground clearance to around 6 inches. The problem of drag was even worse. The stowed fighter reduced the range of the B-36 by 5 to 10 percent.
On Oct. 4, 1955, the AFFTC was directed to conduct operational suitability tests of the mother ship and a modified photo-reconnaissance Thunderflash. The RF-84K was equipped with anhedral (downward-pointing) horizontal stabilizers to clear the bomb bay when in the stowed position. Maj. James O. Rudolph, a Class 1954A graduate of the Test Pilot School, was the project pilot. He flew the modified fighter during the first FICON flight on Nov. 29, 1955.
By October 1955, the GRB-36s had been assigned to the 99th Strategic Reconnaissance Wing at Fairchild AFB. Ironically, because the RB-36s were becoming obsolete, on Oct. 1, the 99th SRW had been re-designated the 99th Bombardment Wing. The 348th Bombardment Squadron was tasked with implementing and conducting operational FICON tests. Meanwhile, the 91st Strategic Reconnaissance Squadron of the 71st Strategic Reconnaissance Wing, at Larson AFB, Moses Lake, Washington, began receiving the first of their Republic RF-84K Thunderflash fighters in preparation for this FICON Phase II of operational testing and training.
The wings made operational history on Dec. 7, 1955, when crews of the 99th SRW and the 71st SRW completed the first operational aerial hook-ups of the lumbering bombers with parasite RF-84K fighters. Capt. Bobby Mitchell took off in his RF-84K parasite from Larson AFB and rendezvoused with Maj. Clyde Perry's crew in the GRB-36D bomber. Despite experiencing radio difficulties, Mitchell maneuvered his Thunderflash into position where Lt. O.C. Rutter, the boom operator, was able to toggle the trapeze and raise the RF-84K into the bomb bay. Mitchell shut off his engines after the hook-up. Once in the stowed position with the bomb bay doors seated against the fighter, Mitchell climbed out of the fighter to greet Rutter. After a cup of coffee in the photographic compartment with the crew, Mitchell climbed back into his fighter, was lowered, restarted his engines and dropped away. A couple of hours later, Lt. Walter Rudd became the second parasite pilot to accomplish a capture and release. Before releasing the second fighter, the GRB-36D made a low pass over Larson AFB to exhibit the wings' handiwork. Maj. Oscar L. Fitzhenry, the 348th BS operations officer, lauded the success of the mission and was quoted in The Spokesman Review stating, "Results proved to be above and beyond our greatest expectations."
The second scheduled FICON training mission took place on Dec. 12. Mitchell made three more hook-ups but did not make the transfer to the other aircraft. Capt. Frank Robison flew in the second element of fighters and this second round provided much excitement. Approaching the bomber, Robinson experienced a failure of his hydraulic system. Robinson managed to fly the fighter into position for the trapeze operator to hook onto him. If the operator did not capture the fighter, Robinson would have lost control of the fighter and would have had to eject. Despite having only eight inches of ground clearance with the fighter still in its bomb bay, the GRB-36 landed safely at Fairchild AFB and taxied to the ground loading pit.
This was the first time a bomber landed with the parasite and it was the first time the new $55,000 ground loading pit was used. The pit, 142 feet long, 50 feet wide and 12 feet deep - was built to facilitate the ground loading of the fighters. Despite the impromptu landing, the only problem encountered was a slight delay due to the lack of suitable jacks for unloading the parasite fighter. The jacks were unavailable because the first scheduled landing of this type was not scheduled until January 1956. The Fairchild Times reported that the "sky hook-up" saved a $500,000 aircraft and, perhaps, the pilot's life.
On Friday, Jan. 13, 1956, the 99th BW and the 71st SRW launched the first large-scale training evaluation of the FICON operations. When the day ended, this date lived up to the proverbial Black Friday. Ten fighter aircraft launched from Larson AFB to train five new pilots in the fine art of aerial hook-ups. The weather was clear but the parasite pilots encountered turbulence.
After 13 successful hook-ups, light turbulence combined with the inexperience of the novice pilots resulted in damage to three fighters and damaged the V-receptacle on the GRB-36D. One fighter returned home with a four-inch hole in its nose. Lt. Col. Curry, the 91st Strategic Reconnaissance Squadron commander, commented on this incident, "Turbulence caused the GRB-36 to yaw, resulting in the trapeze movement causing a near miss and damage to the nose section (of the fighters)." It was found that the lower wing loading of the bomber made it more responsive to wind gusts than the fighter, especially at the low speeds flown during the hook-up.
Because of the events of Black Friday, on Jan. 18, 1956, 15th Air Force suspended FICON operations indefinitely pending the outcome of an investigation into the incidents of that day. Ultimately, on Feb. 15, the Air Force permanently terminated the operational testing of the FICON Project. Rudolph flew the FICON project's final on April 27, 1956. By then, however, the outcome was obvious. The Air Force had dropped the requirement for Phase IV testing a few weeks earlier, and the entire project was canceled shortly thereafter.
In trials the original idea of "parasitic" fighter for the defense of B-36 was gradually transformed into a composite attack system. With this approach, the aircraft carrier survival was achieved by using the second stage of the system - fighter-bomber, armed with tactical nuclear bomb for hitting the target, without the low-speed carrier in the active zone of action of enemy air defenses. For these purposes, the B-36 / F-84E did not require special modifications, as serial F-84E were equipped in version fighter-bomber - the support tactical nuclear bombs. The emergence of more high-speed fighter-bomber F-84F, equipped with swept wings and is a further development of the F-84E, allowed to pass the tests of the composite system GRB-36F / F-84F. For this purpose, it was converted into a "parasitic" aircraft prototype YF-84F, with which the system was successfully tested in May 1953 new aircraft were designated YF-96A.
While seemingly simple in theory, implementation of the FICON system proved to be much more complicated. Testing demonstrated that the hook-ups could be achieved, but, ultimately, they were not practical. Hook-ups were difficult enough under ideal flight conditions but nearly impossible in turbulent air. The fighter was chronically fuel-thirsty and required an externally mounted fuel tank. Finally, the stowed fighter reduced the range of the bomber by nearly 10 percent.
Additionally, the development of alternate methods to accomplish the mission of the FICON Project aircraft virtually rendered the program obsolete before it could be implemented. Technological advancements in reconnaissance platforms such as Lockheed's U-2 and the development of Boeing's B-52 Stratofortress and the KC-135 Stratotanker, which had the flying boom, eliminated the need for the FICON system. The B-52 was a much more advanced aircraft than the B-36 and could fare much better against Soviet Air Defenses. Air refueling gave the nation "reach" in regard to global power.
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