YMC-130H Credible Sport II
XFC-130H Credible Sport
In April 1980, the United States launched an abortive attempt to rescue Americans taken hostage during the Iranian Revolution in 1979. The operation experienced numerous difficulties during planning and execution. The entire operation was aborted after a number of RH-53D helicopters experienced issues and aborted. At a forward refueling point, designated Desert 1, an accident occurred involving an RH-53D and an EC-130E aircraft. The 2 aircraft were destroyed, eight members of the rescue operation were killed, and another five were wounded.
Mission planners felt after the debacle that the H-53 type helicopters had been the weakest link in the overall operation. The rescue plan had required their participation because of their ability to use smaller open areas near the American Embassy in Tehran rather than a full runway, allowing the rescuers to quickly onload themselves and rescued hostages and depart.
Across the street from the Embassy was the Amjadien soccer stadium, with a regulation soccer field surrounded by bleachers. This site had been the original landing zone for the helicopter force. The USAF determined that if a fixed wing aircraft could land and take off inside the same area, the rescue might be possible. A revised rescue plan would later be developed involving a highly modified C-130 aircraft that would fly non-stop from the United States to Tehran (with the help of 5 in flight refuels), land in the stadium, deploy the rescue team, retrieve the rescue team and hostages, take off from within the Stadium, and finish the mission by landing on an American aircraft carrier, likely in the Persian Gulf.
The ultra-short field requirement was proposed for the C-130 and included a requirement that the aircraft be able to take off in a distance of approximately 100 yards. The USAF, at the direction of the Office of the Secretary of Defense, contracted Lockheed in July 1980 to conduct a feasibility study and develop a technical concept. The contract authorized the conversion of 2 aircraft. The program became known as Project Credible Sport. Lockheed Air Systems, which had been part of the development of the C-123B modifications used for unconventional warfare in Vietnam, and the development of the subsequent MC-130E Combat Talon aircraft, partnered up with rocket propulsion experts from the US Navy to develop the new aircraft. Combat Talon crews, one each from the 1st, 7th, and 8th Special Operations Squadrons, were brought in to do the flight testing
The test aircraft were designated XFC-130H and were also referred to as Super STOL (Short Take Off and Landing). Three aircraft were used in testing, with the third being purely a test bed for modifications to be integrated in the 2 contract aircraft. Thirty rocket motors in five sets were used to create the capability. These rocket motors included those used in the RUR-5 Anti-Submarine Rocket (ASROC) and Mk 78 series motors used in the AGM-45 Shrike anti-radiation missile. Mk 56 series rocket motors were also used. For landing, the rockets pointed forward to slow the aircraft and downward to slow its descent rate. For take off, the rockets were positioned at the rear, angled downward, similar to a standard RATO (Rocket Assisted Take Off) arrangement for the C-130. The arrangement had far more power than a standard RATO setup, however, and additional stabilizing rockets were mounted in the wing pylons and on pylons in the rear fuselage area in front of the beavertail. The rockets were controlled by a computer, but could also be controlled manually in case the system failed.
Other external modifications included installation of dorsal fins forward of the horizontal stabilizer and a dorsal fin running from near the base of the vertical stabilizer forward on the upper spine of the aircraft. The flaps were modified into a double-slotted configuration, and the ailerons were extended to improve their effectiveness during low-speed flight. As the aircraft was expected to land on an aircraft carrier after its mission was complete, a modified tail hook was installed forward of the ramp hinge on the underbelly of the aircraft.
The aircraft featured the nose radome found on DC-130 drone controller aircraft. This corrected an issue found with the placement of the FLIR and the nose landing gear in close proximity on the MC-130E Combat Talon. The FLIR turret was placed well forward of the nose gear assembly on the new nose. The FLIR's laser range-finding system was integrated into the onboard computer and provided inputs to fire the forward facing ASROC engines when the aircraft was 20 feet above the ground during the landing phase.
To provide in-flight refueling capability, an externally mounted refueling system was installed on the top of the fuselage, similar to the system found on the C-141B aircraft. A Texas Instruments TF/TA radar was installed to enable the aircraft to fly low level, and a Canadian Marconi Doppler, along with a Global Positioning System (GPS), was tied into the aircraft's dual inertial navigation system to improve overall system accuracy. To protect the aircraft from electronic threats, a basic ECM suite was installed on the aircraft.
The first test flight of a Credible Sport aircraft came on 18 September 1980. The initial flights were conducted to test individual airframe and system modifications. A specially built simulator was also built to help understand the handling of the aircraft. On 17 October 1980, the first fully modified Credible Sport aircraft was delivered. In a 29 October 1980 test flight, which involved landings and take offs using the rocket systems, the aircraft achieved nose gear off the ground after a take off roll of a mere 10 feet, and full take off after only 150 feet. Problems occurred during the land, and the pilot, blinded by the forward firing rockets, fired the remaining downward rockets. The resulting loss in altitude caused the right wing to snap between the 3 and 4 engines. The aircraft eventually came to a stop and the resulting fire was extinguished. No one was injured in the crash, but he aircraft had been effectively destroyed.
The destruction of one of the 2 test aircraft was followed by the announcement on 31 October 1980 that Iran had agreed in principle to an Algerian-brokered plan to release the hostages. The pending release of the hostages changed the nature of work being done to prepare for a second hostage rescue attempt. Work, however, did continue on further development of the concept, in parallel with development of the improved MC-130H Combat Talon II. The vehicle tested in the Credible Sport II program, designated YMC-130H, was configured as the end configuration item from the Credible Sport I project. The primary concern of the Credible Sport II test program was to conduct prototype testing of selected avionics and aerodynamic features on an experimental test vehicle in order to reduce the major technological and cost risks associated with the proposed short term procurement of replacement aircraft for the Combat Talon special operations force.
The first phase of Credible Sport II testing, to be conducted between September and October 1981, was to utilize the existing aircraft configuration to determine safe flight envelopes and shake down avionics in preparation for the second round of testing. The second round of testing, to be conducted between February and May 1982, would be directed toward achievement of enhanced mission capability, improved flight crew/systems interaction, and closer alignment of the experimental vehicle configuration with the Combat Talon II requirements.
The problem with the planned test program was mostly that the hostage crisis in Iran had ended in January 1981. There was no longer an immediate requirement for the STOL capability. There was not even a validated statement of need for the Combat Talon II aircraft. The final Combat Talon II STOL requirements were defined as the capability to operate from landing zones of 1,500 feet or less (over a 50 foot obstacle), at 140,000 pounds gross weight. While this was to be an improvement over the MC-130E Combat Talon, it was a far cry from the requirements outlined in the Credible Sport and Credible Sport II programs. In the end, the remaining Credible Sport test aircraft, too costly to demodify and return to service as either a standard C-130H or as an MC-130H Combat Talon II, was placed in the collection of the Museum Of Aviation at Robins Air Force Base, Georgia.
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