The 1960s trend toward turbine-powered military aircraft inevitably led to discussions for a larger turbine-powered derivative of the Caribou. U.S. Army leaders speculated that the heavy demand for Caribous in Vietnam would prove the need for an advanced version and subsequently pave the way for Army participation in the follow on program. In the Spring of 1962 DeHavilland won a U.S. Army competition for a STOL aircraft capable of carrying the same tactical loads as the Boeing Vertol CH-47 Chinook helicopter (which was just entering production). Originally called the Caribou lI, DeHavilland renamed the aircraft the DHC-5 Buffalo and the Army gave the aircraft the designation AC-2 (which became CV-7A in 1962).
Prototype development was undertaken as a cost sharing agreement between the company and the U.S. and Canadian governments. The first stage in the development program consisted of outfitting the first prototype Caribou airframe with two 2,850 hp GE YT-64-GE-4 turboprop engines as a flying test bed. This aircraft made its first flight on 22 September 1961 and was flown for some 300 hours. In March of 1963, the U.S. Army awarded DeHavilland a contract for four prototypes; however, further Buffalo development was not without its setbacks. Since the Canadian design had won out over entries from U.S. companies, pressure from these companies forced changes in U.S. military procurement policies designed to protect U.S. industry. This change in policy limited sales to the U.S. Army to the four CV-7A evaluation aircraft (63-13686 to 689), which were delivered in the Spring of 1965.
Development of the DHC-5 slowed while other customers were sought. The first customer was the RCAF which ordered fifteen Buffalos under the designation CC-115.Otherearly orders came from Brazil and Peru while later customers included: India, Zaire, Zambia and Ecuador. During late 1965 the U.S. Army proposed the procurement of 120 Buffalos, a proposal that the U.S. Air Force viewed as an expensive duplication of the Fairchild C123 Provider. Secretary of Defense McNamara settled the dispute by ruling out any further procurement of the Buffalo in December of 1965.
The Buffalo was a more sophisticated version of the Caribou with increased overall dimensions, having a maximum payload of 41,000 pounds. Except for its distinctive "T" tail which cleared the airflow behind the high-lift flaps and turboprop engines, the Buffalo retained the basic Caribou profile. This reduced the need for new tooling and cut development costs. The wing span was 96 feet, length was 77 feet 3 inches, and the height was 28 feet 7 inches. The DHC-5 made its first flight in April of 1964, and, like its "little brother," proved its STOL capability by landing within 1,050 feet and taking off within 1,225 feet (at gross weight over a 50 foot obstacle). The Buffalo could lift forty-one troops or up to twenty-five litter patients. It had an empty weight of 22,486 pounds, a top speed of 267 mph at sea level, a cruising speed (at 5,000 feet) of 277 mph and a range of 530 miles.
The Army-Air Force controversy over the Caribou mission and ownership carried over to the Buffalo program prompting the Department of Defense to transfer the four CV-7As Buffalos to the Air Force as part of the Caribou transfer. In the interim, two Buffalos were sent to Vietnam for a three month evaluation beginning in November of 1965. These were assigned to the 92nd Aviation Company at Nha Trang and used primarily to support the 5th Special Forces Group. Since these aircraft were still in the research and development stage at the time of their transfer to the USAF, they were assigned to the Air Force Systems Command for tests on 1 July 1966 under the designation C-8A. During the 1970s all four examples were passed on to other U.S. Government agencies.
In post-war discussions concerning USAF commitments to Army airlift Support, the Air Force sought additional Caribous, or as a possible alternative, the Buffalo. Other aircraft considered included a turboprop variant of the C-123 and a C-130 variant modified for short-field work. The DHC-5 production program was shelved temporarily during early 1972 after fifty-nine aircraft had been delivered to foreign customers. Increased engine power from the T-641ed to an improved DHC-5D model and Buffalo production resumed in 1974. The original DHC-5 had been designed to fill the STOL tactical role, while the DHC-5D was intended to carry larger payloads on conventional missions operating from hard surfaced runways.
Climb tests with a standard production Buffalo led to six new time-to-height world records being set on 23 February 1976. Buffalos were also employed for a number of experimental programs. One had an original Canadian CC-1 15 redesignated as the XC8A and modified to test the Bell Air Cushion Landing System (ACLS) during 1972. Another C-8A was modified for the Augmentor Wing Jet STOL project which was being developed jointly through NASA and the Canadian government. The project involved augmenting normal wing lift by ducting turbofan engine air to a trailing edge slot.
Production of the Buffalo ended in December of 1986 after some 126 aircraft had been delivered.
Thanks to Wayne Mutza
for this article, from his book on the C 7 Caribou.
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