C-7 / CV-2 Caribou
The Caribou was first flown in 1958 as the DHC-4A, and the US Army acquired the CV-2 Caribou the following year. Starting with the U-6A Beaver -- which was designed as a "bush pilot's dream," and progressing to the reliable, but somewhat clumsy Otter -- the Caribou seemed a natural to those Army planners who saw a significant gap between the Army's organic capability and the C-130 Air Force transport. Initially procuring 173 in 1959, the De Havilland Caribou was the largest Army fixed-wing aircraft. Initially designated AC-1, the aircraft was redesignated CV-2 in 1962 and retained that designation for the remainder of its Army career. When responsibility for all fixed-wing tactical transports was transferred to the U.S. Air Force, the Caribou received the designation C-7.
Two piston engines are mounted in the wings' leading edges, and the engine nacelles extend beyond leading edges. Powered by two Pratt & Whitney engines of 1,450 hp each, it cruised at 149 knots with a service ceiling of 27,500 ft. It is designed to take off and clear a 50-foot obstacle in a distance of 1040 feet with zero wind. With a 20-mile headwind, the takeoff distance over a 50-foot obstacle is just 460 feet. Its landing distance is just over 590 feet while clearing a 50-foot obstacle. These characteristics enabled the Caribou to operate out of tiny jungle landing strips, from beachheads, or from improvised military landing strips as short as 850 feet. The wings are high-mounted with straight leading edge and forward-tapered trailing edge from engines to the blunt tips. The fuselage is slab-sided with a solid, rounded nose and stepped cockpit. The tail flats are mid- to low-mounted on the tail fin and tapered with blunt tips. The large fin is tapered with blunt tip.
The Caribou was the second exception by the Secretary of Defense to his memorandum on the weight limitations for Army fixed-wing aircraft. In 1951 an Army-Air Force memorandum of understanding (MOU) allowed 2 exceptions on weight limitations: OV-1 [AO-1] Mohawk Medium Observation Aircraft and AC-1 [CV-2] CV-2 Caribou Medium Tactical Transport (MTT). In the early 1960's the Caribou and the Mohawk were the two major symbols of Army-Air Force disagreement. The CV-2 was to bridge the gap between the US Air Force (USAF) C-130 and Army capabilities. Its very size threw down a gantlet to the Air Force strategists. It could carry as much as the venerable C-47 and land and take off of remarkably short unimproved airstrips. It had a rear end loading door which facilitated rapid cargo handling and was relatively easy to maintain and operate. The Air Force saw this 32 passenger aircraft as a second invasion of its domain and the projected rise of the Army's inventory at a time that the Air Force aircraft inventory was declining was bound to cause more heat than light.
The Caribou proved to be an extremely useful addition to the United States aircraft inventory and did yeoman service in Vietnam. A not-well-known fact is that the Caribou airplane predated the major helicopter commitment to Vietnam by five months. On 21 August 1961, an experimental "Y model" Caribou landed at Saigon under the auspices of the Advanced Research Project Agency. The Advanced Research Project Agency had its own charter to test almost any device, technique, or prototype that it felt might have application in our counter-insurgency efforts. Consequently, the Agency was able to cut through the red tape of Service disagreements and expedite those tests it deemed appropriate.
The Army ferried the CV-2s to Vietnam in 1962 where their excellent short-field performance and 3-ton payload served as a tactical transport airplane. The Caribou flew up and down the length of Vietnam going into airstrips normally limited to much smaller aircraft such as the O-1 or U-6 Beaver. Initially it specialized in resupply of Special Forces outposts that were in accessible by road and that normally were supplied by either air drop or an occasional helicopter. The Army Caribou pilots took justifiable pride in their proficiency at bringing this big twin-engine airplane into the shortest possible strip. Even the old Southeast Asia hands of "Air America" were impressed when this lumbering bird made its unbelievably slow, steep approach into some of the primitive airstrips.
The Caribou filled a serious gap in the United States inventory. Its short field characteristics, pay load, and light "footprint" made it an ideal aircraft in the counter-insurgency environment. The next plane in size was the C-123B which had a gross weight of 55,700 pounds compared to the Caribou's 28,500 pounds, and the single wheel load of the C-123 was almost double that of the Caribou. Consequently, the Caribou could operate repeatedly and routinely into airfields that were denied to the C-123 and later the C-130.
The very existence of the Caribou in the Army inventory changed one Air Force program-the Fairchild C-123 "Provider." This latter aircraft was scheduled to be phased out of the active Air Force inventory in 1961, with a few programmed to the reserves and the remainder to be declared surplus. When Secretary of Defense Robert S. McNamara suggested that the Air Force turn over the C-123's to the Army (to train on this type aircraft prior to the receipt of the Caribou) , the Air Force suddenly discovered new and pressing Air Force requirements for the C-123. Thus the Army Caribou protagonists not only pushed the Caribou into being, but-incidentally-saved the C-123 for much-needed duty in Vietnam.
The Caribou aircraft performed so well in Vietnam that the Air Force demanded that the Army turn them over to the Air Force, because they were performing missions that the Air Force considered its own better than the aircraft the Air Force had at the time. The Army released the CV-2s to the Air Force in 1966 under an Army-Air Force agreement. Prior to the Air Force assumption of the Caribou, most were already under centralized management under Military Assistance Command, Vietnam, and were participating in the Southeast Asia airlift effort. However, one-fourth to one-half of their resources were dedicated to specific Army support. The 7th Air Force in Vietnam, which had been upgraded from the 2d Air Division on 2 April 1966, was severely critical of the Army's method of operation of its Caribou assets. They believed that the Caribou should be incorporated into the Air Force managed Southeast Asia airlift and consequently be more productive from a ton-mile basis.
The Army traded the Caribou for an end to all restrictions on helicopters. It is for this reason, many consider the Caribou to be the most significant aircraft in Army Aviation history.
The Army kept several prototypes, Tail #59-3079 being the fifth prototype. The yellow and white paint scheme represents the Golden Knights colors, the Army's Parachute Team, who used this plane from 1973 to 1985.
|Join the GlobalSecurity.org mailing list|