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Flying Aircraft Carriers of the USAF:

 

In the early years of the cold war, the United States Air Force was faced with a requirement for an airplane that could photograph targets deep inside the Soviet Union. Many strategic targets were inaccessible to conventional U. S. reconnaissance airplanes. There was no airplane with sufficient range to reach these targets that also possessed the speed and maneuverability to evade Soviet air defenses.

It was envisioned that Fighter Conveyer (FICON) composite aircraft would perform long-range reconnaissance missions into areas equipped with anti-aircraft defenses that existing reconnaissance airplanes could not penetrate. FICON operations would rely on the great range of the Convair RB-36 to carry a jet powered parasite airplane to a location within range of targets inside defended territory. The high speed and maneuverability of the parasite would allow it to dash into enemy territory to take pictures of the targets and then rendezvous with its flying aircraft carrier to be carried back to its home base. Many targets that were out of range of conventional reconnaissance airplanes would be accessible to the FICON parasite airplane.

In the years following World War II, the Air Force modified many heavy bombers to serve as reconnaissance airplanes. Boeing B-29 Superfortresses were converted to serve as photographic reconnaissance platforms. The reconnaissance versions of the Superfortress were given the designation F-13. They had great endurance and could carry large format cameras. These reconnaissance bombers flew long missions along the perimeter of Soviet Bloc countries. They took long-range oblique photographs into the interior of the target countries using extremely long focal-length telephoto lenses. The detailed images were recorded on film that was 18 inches wide. They also used the electronic reconnaissance gear to ferret out sources of radio, radar, and telemetry signals within the target countries.

The giant Convair B-36 was used extensively for reconnaissance in the early post-war period. They were built in two major versions, the standard B-36 bomber variant and the RB-36 version tailored for aerial reconnaissance. The B-36 bomber was equipped with four bomb bays. The RB-36 version had an additional pressurized compartment for camera gear in place of the forward bomb bay of the B-36 bomber.

In the early years of its deployment, the RB-36 was very difficult to intercept. It could cruise at altitudes that jet fighters could not reach. If a fighter did succeed in climbing to the altitude of the RB-36, the lower wing loading of the RB-36 allowed it to turn tighter than the fighter could. The RB-36 could simply turn out of the way of a fighter as it mushed along at a speed only slightly higher than its stall speed.

The maneuvering advantage of the RB-36s did not last long. The Soviet Union was quickly developing more capable interceptors with superior high altitude performance. It was clear that jet fighters with the ability to intercept the RB-36 would be entering service in the Soviet Air Force by the middle of the 1950s. It would become too dangerous to operate the RB-36 on reconnaissance missions near the borders of the Soviet Union.

By June 1954, the Air Force would change the primary mission of the four Strategic Reconnaissance (Heavy) Wings that were equipped with RB-36s from reconnaissance to bombing. The RB-36s would no longer be used for the mission of strategic reconnaissance. They were modified to carry nuclear weapons as strategic bombers.

A new aircraft was needed for the strategic reconnaissance role. The new aircraft needed the long range of the RB-36 and the speed and maneuverability of a jet fighter. Many thought that it would not be possible to accomplish the projected mission with a conventional airplane. It was proposed that strategic reconnaissance missions could be performed by tactical jet fighters that were launched from RB-36s near the borders of the target countries.

In 1950, in anticipation of the eventual retirement of the RB-36 fleet from the reconnaissance role, the Air Force initiated a program to equip RB-36s with a mechanism to carry a smaller reconnaissance airplane. The smaller airplane would have the speed and maneuverability to penetrate enemy air defenses in the place of the RB-36. The RB-36 would transport the parasite to the enemy zone, where it would be released to perform its own reconnaissance mission. After completing its mission, the parasite would rendezvous with the RB-36 to be retrieved and carried back to its home base.

 

The EF-84 Thunderjet 1952

 

Initial tests were conducted with a modified Convair RB-36F and straight-winged Republic F-84E Thunderjet at the Convair factory in Fort Worth, Texas.

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The FICON test team pose with EF-84E 49-2115 Left to right: B. A. Hohman - Wright Field, Project Officer Levine - Convair, B-36 Pilot Coughlan - Wright Field, F-84 Crew Chief T/Sgt. G. I. Davis - Convair, B-36 Pilot Capt. J. S. McCollom - Wright Field, Project Maj. C. E. Anderson - Wright Field, F-84 Pilot Unknown - Convair, B-36 crew member E. D. Mathis - Convair, Project Engineer Roberts - Convair, Flight Test Engineer Capt. R. D. Hodge - Wright Field, Project Major Pinkerton - Wright Field, Photo Pilot Shedorski - Republic Unknown

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The original trapeze mechanism on the GRB-36F at Fort Worth in early 1952. Th probe of the EF-84E fits into the cone shoped receiver on the front end of hte trapeze. Latches on either side of the yoke engage pins on the Thunderjet.

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	The trapeze receiver.

The hook of the McDonnell XF-85 Gobiln had been mounted directly above the center of gravity of the diminutive jet. Movement of the Goblin on the trapeze was restricted by a retractable "horse collar" mechanism that closed around its nose. The FICON probe was mounted well forward of the center of gravity of the parasite. Under tow, the weight of the parasite was supported by its wings until the fuselage pins seated in the aft latches of the trapeze.

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A special dolly was rigged for ground loading the Thunderjet. The YB-60 jet bomber prototype can be seen behind the EF-84E.

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	Major Clarence "Bud" Anderson made the first attempt to hook F-84E, 49-2115 to the GRB-36F, 49-2707 over Texas on January 9, 1952. A B-29 Superfortress is flying chase off their left wing.

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FICON flight tests moved to the Air Proving Ground at Eglin AFB, Florida in the second half of 1952.

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	The trapeze operator's station in the camera compartment of the GRB-36F. A window in the bulkhead provided a view of the Thunderjet on the trapeze in the bomb bay.

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Trapeze Operator's Station illustration from Utility Flight Handbook USAF Series GRB-36D-III/RF-84F Featherweight Configuration III Composite Aircraft; T.O. 1B-36(R)(G)D-1/T.O. 1F-84(R)(G)F-1; July 30, 1954, revised June 17, 1955.

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	The trapeze boom was shortened to reduce its flexibility. A second probe was installed on the nose of the Thunderjet.

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A shock absorbing snubber was installed between the front end of the tapeze and the front of the bomb bay. It prevented the boom from wiggling, but it allwed it to be slowly raised and lowered.

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	After the Thunderjet engaged the receiver (one-point position), a hydraulic cylinder raisesd the front of the trapeze until the pins on the sides of the EF-84E seated in the aft latches (three-point position). The Thunderjet pilot could push on the stick to lift the tail and force the pins into the latches.

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Taking off with the parasite on the trapeze was no problem, but the landing gear could not be retracted until the trapeze was extended to get the wings of the Thunderjet out of the way. Cycling the trapeze and retracting the gear took nearly ten minutes

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	FICON flight tests moved to the Air Proving Ground at Eglin AFB, Florida in the second half of 1952. A cleaner probe was installed farther forward on the nose of the EF-84E, and the trapeze boom was lengthened.

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More pilots were introduced to the system at Eglin. Penetration missions were flown to evaluate the effectiveness of the composite aircraft system against the Air Defense Network. The parasite consistently manged to fly over the target airfields without being intercepted.

 

 

The YRF-84F Thunderstreak, 1953-1954

 

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YRF-84F Thunderstreak,

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	Follow-on FICON tests were conducted with the sweptwing prototype YRF-84F Thunderstreak at the Convair factory in Fort Worth and the Air Proving Ground at Eglin AFB in 1953 and 1954

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	The YRF-84F had served as the prototype of the swept-wing    F-84F Thunderstreak. It was modified from a straight wing   F-84E. The "drooped" horizontal stabilizer was angled downward to clear the sides of the bomb bay. The pin protruding from the side of the fuselage engaged the aft latch of the trapeze.

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A new fork-type "duck-bill" probe was installed on the nose of the  YRF-84F. In conjunction with a v-shaped receiver on the trapeze, it significantly increased the capture area. The name Christine has been crossed out and the name George added, which appears to be a gender modification reference. Straight wing - female, swept wing - male?

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	EF-84E 49-2115 continued to serve Project FICON as a chase plane after the introduction of YRF-84F 49-2430.

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Lt. Colonel Bud Anderson was drafted back into Project FICON when Major John Davis was killed in the Project Tip-Tow crash on April 24, 1953. Anderson performed the initial evaluation of the YRF-84F parasite in May 1953. He then familiarized Major Clyde Good with the methods of FICON and handed off the evaluation to him.

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	Straight Side View

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The trapeze raises the Thunderstreak to the three-point position. Note the v-shaped receiver on the trapeze. Wright Air Development Center badges have been applied to the fuselage of the YRF-84F.

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	Major Good found that he could influence the flight path of the GRB-36F using the controls of YRF-84F while it was attached to the extended trapeze.

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Major Good completed his initial evaluation of the YRF-84F parasite on July 23, 1953.

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The FICON composite aircraft system was demonstrated at the National Air Show at Dayton, Ohio in 1953 and 1954. The FICON system was also demonstrated at airshows at Carswell Air Force Base, Texas and Eglin Air Force Base, Florida. The GRB-36F, piloted by Raymond Fitzgerald, took off from Fort Worth and flew to Dayton, where Major Good took off in the YRF-84F and hooked onto the trapeze for transportation to the show. The Thunderstreak was released from the trapeze at show center.

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Major Clyde Good working his way from the cockpit of the YRF-84F to the camera compartment. The final FICON evaluation flight of the YRF-84F was flown on June 9, 1954.

 

 

The RF-84K Thunderflash, 1955-1956

 

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	RF 84KThunderflash

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The Air Force conducted evaluations of the FICON composite aircraft system at the Air Proving Ground at Eglin AFB, Florida, the Air Force Special Weapons Center at Kirtland AFB, New Mexico, and the Air Force Flight Test Center at Edwards AFB, California in 1955 and 1956. Air Force Photo A-162244AC via National Archive.

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	Convair conducted ground loading and other FICON system evaluations with GRB-36D 49-2696 and pre-production prototype FICON RF-84F Thunderflash 51-1847 starting in December 1954.

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The GRB-36D had clearance doors that streamlined the bomb bay while the parasite was on board and plug doors to fill the hole left by its release.

Load tests of the main jack mechanism of the trapeze revealed that it required strengthening. High speed tests of the modified FICON RF-84F resulted in flutter that damaged its rear fuselage. The project was delayed as the issues were dealt with and project aircraft were reassigned to accomplish the necessary tests.

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	GRB-36D 49-2701 flying over Grand Coulee Dam in Washington. Ten GRB-36Ds were modified. They could be distinguishced by the AN/APX-29 rendezvous beacon antenna radome on top of the fuselage. Active duty GRB-36Ds were assigned to the 348th Bombe Squadron of the 99th Strategic Bomber (Heavy) Wing at Fairchild Air Force Base, Wshington.

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The 91st Strategic Reconnaissance Squadron of the 71st Strategic Reconnaissance (Fighter) Wing at Larson Air Force Base operated the FICON RBF-84F Thunderflashes. The RBF-84F designation indicated that the fighters had been modified for bombing and reconnaissance. From front to rear these are 52-7268, 52-7266, 52-7269, 52-7260, and 52-7262.

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	FICON training operations began in December 1955

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FICON RBF-84F 52-7269 is lowered from the bomb bay of GRB-36D 49-2696 at Fairchild AFB, Washington following an emergency night retrieval on December 12, 1955. The parasite pilot suffered a partial hydraulic system failure but succeeded in hooking onto the trapeze. Post-flight inspection revealed that he had turned off his own hydraulic system due to the distractions of approaching the trapeze.

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FICON training operations were halted after several pilots from the 91st Strategic Reconnaissance Squadron damaged their airplanes trying to hook on to the trapeze during exercises on Friday January 13, 1956. Less than one month later, Thunderflashes from the 91st SRS took on fuel from a Boeing KC-97 Stratotanker in flight for the first time. The Boeing RB-52B reconnaissance Stratofortress, Lockheed U-2, and aerial refueling superseded the composite aircraft system before it reached operational status.

The Air Force conducted evaluations of the FICON composite aircraft system at the Air Proving Ground at Eglin AFB, Florida, the Air Force Special Weapons Center at Kirtland AFB, New Mexico, and the Air Force Flight Test Center at Edwards AFB, California in 1955 and 1956.

The designation of the FICON RF-84F/RBF-84F was changed to RF-84K in early 1956.

Republic RF-84F/K Thunderflash

Wingspan: 34 feet Length: 48 feet Wing Area: 325 square feet Maximum Take-off Weight: 27,000 pounds Armament: 4x 50 caliber machine guns Powerplant: 7,800 pound s.t. J65 turbojet

 

Initial tests of the production version of the FICON GRB-36D/RF-84F composite aircraft were conducted by Convair in Fort Worth in December 1954.

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Twenty-six Republic RF-84F Thunderflashes were converted to the FICON parasite configuration. Ten RB-36Ds were converted to serve as FICON carriers.

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	GRB-36D 49-2694 and RF-84K 52-7258 were assigned to Phase IV Limited Performance Evaluations at Edwards AFB.

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RF-84K 52-7258 at Edwards Air Force Base with a pair of external fuel tanks on its right wing and a T-63 "special weapon" test shape on its left wing. In order to take off with the heavy load, it is equipped with four 1,000-pound thrust solid fuel rockets, mounted between the external fuel tank and the simulated atomic bomb.

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	The RF-84K Phase IV Limited Performance Evaluation was conducted by future X-2 pilot Captain Milburn "Mel" Apt. He hooked on to the trapeze on one occasion on March 23, 1956. The RF-84K carried no external stores during the hook on. It took eleven tries for Apt to hook on.

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GRB-36D 49-2694 made seven flights during the Phase IV Limited Performance Evaluation between November 29, 1955 and April 27, 1956. The RF-84K hooked on during the fifth flight. External stores were mounted on the RF-84K for the last two flights.

 

The FICON Flight Handbook, Illustrated Parts Breakdown, and Maintenance Handbook defined the modifications and operational procedures of the composite aircraft system.
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Trapeze Operator's Station illustration from the Flight Handbook for the GRB-36D/RF-84F Composite Aircraft.	An illustration of the trapeze mechanism from the GRB-36D/RF-84K Limited Phase IV Flight Evaluation document
Cutaway view of the GRB-36D from the Standard Aircraft Characteristics document for the Consolidated GRB-36D and the Republic RF-84F.
The 91st Strategic Reconnaissance Squadron operated FICON RBF-84F Thunderflashes at Larson AFB, Washington. From front to rear these are 52-7268, 52-7266, 52-7269, 52-7260, and 52-7262.	The 348 Bombardment Squadron operated GRB-36D carriers at nearby Fairchild AFB, Washington.	FICON training operations were undertaken in December 1955, but they were concluded in January 1956 after several pilots from the 91st Strategic Reconnaissance Squadron had damaged their airplanes trying to hook on to the trapeze.

 

 

Epilog

 

The complex and dangerous FICON composite aircraft system was overtaken by the development of the Boeing B-52 Stratofortress, the Lockheed U-2, and aerial refueling using the flying boom method. The FICON Thunderflashes were transferred to the Air National Guard. The GRB-36D carriers were scrapped in short order.

Several of the FICON parasite airplanes are preserved in museums.
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Today the YRF-84F, 49-2430 resides in the Air Force Museum.	The pre-production RF-84K, 51-1847 is also at the United States Air Force Museum.	RF-84K, 52-7259 is at the Yankee Air Museum, Ypsilanti, MI. It has been restored since this photograph was taken.
RF-84K, 52-7265 at the Planes of Fame Museum at Chino, CA on March 15, 1997.	RF-84K, 52-7265 at the Planes of Fame Museum	RF-84K, 52-7266 is currently undergoing restoration at the Wings Over the Rockies Museum, Denver, Colorado.