Two families of large, long-range, propeller-driven transports dominated U.S. airlines, as well as many foreign airlines, until the jet transport began to appear in significant numbers toward the end of the 1950's. These families of aircraft, which served on both long-range domestic and international routes, were the Douglas DC-6 and DC-7 series and the Lockheed Constellation series. Both were derived from aircraft developed during World War II; they had four supercharged engines and pressurized cabins, and both series underwent large increases in size, power, and weight during their development history.
At the end of the war, Douglas could claim to be the largest aircraft manufacturer in the United States. But soon after, the company had to fight hard to remain competitive. Its major competitor and rival was Lockheed, which came out with its four-engine Constellation airliner series to challenge Douglas's primacy in the commercial market. The Lockheed Constellation, which went into military service late in WWII, boasted cabin pressurization and superior performance in comparison to the DC-4. Douglas had the four-engine DC-4, but it did not have a pressurized cabin, was slower, and could carry fewer people.
Donald Douglas realized that his company needed a competitive model, and it needed one in a hurry. Although the DC-4 did not have pressurization, it had been designed with that prospect in mind, and this legacy quickly became part of plans for a postwar successor, designated the DC-6. Even before the end of the war, Donald Douglas signed off on the start of design studies for the new plane, which had the same wings as the DC-4 but incorporated a stretched fuselage, new engines, and other embellishments.
The first DC-6 became airborne in 1946 and entered service with American Airlines only a year later. Douglas had more success meeting the Lockheed Constellation competition with its DC-6. The plane was very successful and around 700 were built. It emerged as the most economical of the piston-powered airliners of the period. With its higher performance, increased accommodation, greater payload and pressurized cabin, it was a natural evolution of the DC-4. The DC-6 made its first flight on June 29, 1946, and CAA certificated the plane nine months later. The Douglas DC-6 was one of the first airplanes to fly a regularly scheduled around-the-world route. Although the DC-6 had the same wingspan as the DC-4, its engines helped it fly 90 mph faster than the DC-4, carry 3,000 pounds more payload and fly 850 miles farther. The aircraft, the first Douglas plane with a pressurized cabin, could seat approximately 50 passengers. The DC-6 could maintain the cabin pressure of 5,000 feet while flying at 20,000 feet.
The DC-4 was followed by the DC-6, DC-6B, DC-7, DC-7B and DC-7C. The Douglas aircraft grew from 44 seats (DC-4) to 105 seats (DC-7C). The much larger DC-7 can be distinguished from the smaller DC-4 and DC-6 models by square windows, with three being forward of the wing (DC-4 has round windows), and four-blade propellers (DC-4 & DC-6 have three-blade propellers). The DC-6 is similar to the DC-7 as it has the same wingspan and square windows but is about 1 foot shorter in length and has smaller engines. The DC-6 has three-blade propellers (DC-7 has four-blade propellers) and may or may not have windows (1 or 2) ahead of the wing. The DC-4 has the same wingspan as the DC-6 and DC-7 models but is considerably shorter in length. It can be identified by the round windows and three-blade propellers. The "Super" DC-4 is a stock model that has been converted to operate with larger engines.
American Airlines and United Airlines ordered the commercial DC-6 in 1946, and Pan American Airways used the DC-6 to start tourist-class service across the North Atlantic. The Douglas DC-6 was first delivered to United and American airlines in November 1946 and which entered service on April 27, 1947 with United Airlines. The well-appointed, pressurized cabin made passengers happy because the airliner's ceiling of 28,000 feet allowed it to fly above storms and avoid choppy weather en route. Moreover, at higher altitudes, the "thinner" air actually caused less aerodynamic friction, and the plane's radial engines drove it along at speeds of 300 mph. Various seating arrangements accommodated 48 to 86 passengers.
On October 24, 1947 In-flight fire caused the crash of a United Air Lines DC-6 at Bryce Canyon, Utah, with the loss of all 52 persons aboard. On Nov 11, another in-flight fire caused an American Airlines DC-6 to make an emergency landing at Gallup, N.M. Immediately following this second incident, the three airlines using DC-6 aircraft voluntarily withdrew them from service. The CAB determined that the fires had been caused by fuel leaking into the cabin heater system through an air intake scoop. After the problem had been remedied, the DC-6 returned to service in March 1948.
The larger, all-cargo DC-6A first flew Sept. 29, 1949. Using Douglas DC-6As, Pan American World Airways inaugurated the first all-cargo air service across the North Atlantic on Jan 5, 1952. The larger capacity DC-6B, which could seat up 102 people, first flew Feb. 10, 1951. The DC-6B featured seating for 54 to 102 passengers, higher cruise speed, and generally better performance-often called one of the most economical and efficient airliners ever built. Operators in the United States and all over the world tended to agree; including several dozen military versions, over 700 of the DC-6 types were delivered. In 1952, Pan American used the Douglas airliner to launch the first scheduled around-the-world flight, a journey of 83 hours.
After the Korean War broke out in 1951, the military ordered DC-6As modified as either C-118A "Liftmaster" personnel carriers, as the Navy's R6D transports or as MC-118As for aeromedical evacuation. During its 11-year production run between 1947 and 1959, Douglas built a total of 704 DC-6s, 167 of them military versions. By 1998, the DC-6 was still flying with smaller airlines around the world.
In responding to the Eisenhower administration's decision in 1957 to provide clandestine support to the Tibetan resistance, the intelligence community quickly encountered its first major obstacle. Without the expertise and equipment to conduct long-range clandestine air missions it needed just to get to Tibet, the program appeared doomed before it had even started. Prior to 1959, Detachment 2's largest aircraft, a four-engined C-118 transport, had been frequently used for flights conducted by Civil Air Transport, a CIA proprietary airline operating throughout Asia. And CAT had indeed been busy during the earlier stages of the cold war. CAT had by 1959 completed numerous overflights of mainland China and Tibet.
For the Tibetan operation, the C-118 was loaded on Okinawa with Communist-bloc weapons and supplies already rigged for parachute drop over guerrilla strongholds in Tibet. Proceeding to Clark Air Base in the Philippines to pick up fuel and long-range communication specialists, the plane then overflew Indochina en route to its final destination at Kermatola, an abandoned World War II airfield located 20 miles north of Dacca, in East Pakistan. From Kermatola, the Air America** crews would take the C-118 on the final run north into Tibet. Unfortunately, Detachment 2 had only one C-118. And by 1958, the Tibetan resistance movement was growing dramatically, outstripping in the process Detachment 2's inadequate air support.
Worse still, the C-118's power limitations at Tibetan altitudes limited its payload to an unsatisfactory 9,000 pounds per flight. Even with the C-118's limited payload, the loss of even one of its four engines over Tibet's jagged mountains would make the loss of the aircraft and its American crew virtually inevitable, taking with them in the process any hope of maintaining "plausible denial" of US support. By early 1959, the inadequacy of the C-118 had become so obvious to all that top priority was placed on finding a replacement aircraft.
Exercise BIG SLAM/PUERTO PINE in March 1960 was the first of the so-called strategic mobility exercises conducted on a large scale. A total of 21,000 troops and 11,000 tons of cargo were airlifted from 14 bases in the United States to Puerto Rico, and return, in a 15-day period. While the numbers seemed impressive at the time, the troops were from a large assortment of Strategic Army Corps units, not an integral fighting force; the cargo was miscellaneous, not organic divisional battle equipment; and the distance from the CONUS to Puerto Rico was short compared to real-world military strategy. Rated a highly "successful failure," BIG SLAM did dramatize the deficiencies of a C-118/C-124 type of force, while at the same time providing a vivid glimpse of what combat airlift could be.
Exercise LONG PASS, in February 1961, by spanning the Pacific, remedied the range deficiency of the Puerto Rico scenario, but it had to make a corresponding trade-off in the size of the force airlifted. Slightly more than 1000 Army troops and 1000 tons of cargo were carried from the CONUS to the Philippines and back, while 200 troops and less than 100 tons went from Hawaii to Clark AB. With some added Tactical Air Command personnel and equipment, the total force package came to 1700 troops and 1400 tons. It was a brave attempt by C-118s, C-124s, and C-133s, but still only a veiled hint of the genuine possibility of airlift.
After the devastating earthquakes and quake-generated tidal waves in Chile late in May 1960, the Chilean Government appealed to the U.S. State Department for assistance. Acting quickly in response to this appeal, the Joint Chiefs of Staff, on 25 May, authorized the U.S. Army to airlift two fully staffed and completely equipped field hospitals to the disaster area to assist in the evacuation and care of the injured and to help prevent outbreaks of epidemic diseases. Each hospital was augmented by an Engineer Corps water purification unit, a Quartermaster Corps laundry detachment, and a Signal Corps communications team. The airlift, which involved about 1,230,000 pounds of Army supplies and equipment and 550 Army personnel, required the use of 59 giant transport aircraft of the Military Transport Service (C-124 Globemasters and C-118's). It was the Army's largest emergency airlift since the Lebanon Operation in 1958.
In 1974, the Secretary of Defense initiated airlift consolidation transferring the Navy's Tactical Air Support mission along with the Navy's C-118s, C9s, and CT-39s to the Air Force. After a Navy reclama, the Navy was allowed to keep the 20 CT-39s and the 12 C-9s already delivered or under construction as administrative/command support aircraft. All future C-9 procurement was canceled, the Navy's tactical airlift mission was transferred to the Air Force and the Naval Reserve C-118s were to cease operation by the end of Fiscal (FY) 1977. Largely due to the efforts of the Naval Reserve Association and Congressman Bill Chappell of Florida, Congress restored C-118 operating funds in the FY'78 and FY'79 budgets after two successive DOD budgets reiterated the airlift consolidation premise that the Navy did not require its own airline, and that MAC could perform the mission.
In 1978 a Commercial OMEGA Navigation System (ONS) Litton LTN 201, was flight tested to determine the suitability of the system to meet the commercial specifications and the Navy's long-range overwater navigation requirements for the C-118 aircraft. The ONS on the C-118 aircraft had a position error of less than 1 nautical mile (commercial spec error no greater than 7 nautical miles) for the three areas of operation, CONUS, Caribbean and Mediterranean. Signal to noise ratio readings indicate six stations were available for navigation at all times. Seven stations are the maximum number of stations which can be used for navigation due to algorithms in the LTN 201. In the Mediterranean area, seven stations were available for navigation in 85% of the samples taken. No point estimates can be made on the reliability of the ONS. With approximately 150 flight hours, there were no failures. A Commercial OMEGA Navigation System will satisfy the long-range overwater navigation requirement in the Atlantic, Caribbean, and Mediterranean for the C-118 aircraft.
The mid-1980's were years of transition and farewells. The retirement of the U.S. Navy's last C-118 Liftmaster, after 33 years of service, brought forward its replacement, the McDonnell Douglas C-9 "Skytrain" operated by Fleet Logistics Support Squadron 46 (VR-46). Fleet Logistics Support Squadron Five Four (VR-54) was commissioned 01 June 1991. The establishment of VR-54 was actually the re-birth of a previous squadron of the same designation, which was also based at NAS JRB New Orleans. The first VR-54, which flew C-118 transport aircraft, was commissioned on 01 October 1972. With the introduction of the then technologically advanced C-9 transport aircraft into the fleet, the C-118 was subsequently retired on 06 January 1981, and as a result VR-54 was decommissioned on 28 February 1981.
The peculiar nature of counterinsurgency operations in Vietnam, required modification of the usual concepts of hospital usage in a combat area. Based on experience gained in World War II and the Korean War, the US Air Force initially used returning assault or cargo aircraft for casualty evacuation. The system worked well during the early stages of the Vietnam War, because the number of sick and wounded was relatively low. As troop strength increased and combat operations became more intense, the system grew progressively less satisfactory. The requirements for evacuation often coincided with the most urgent needs for resupply, although not always at the same location. The old system was therefore abandoned in favor of a new one in which aircraft were, regularly used specifically for evacuation purposes.
In 1965, patients were loaded into C-118 and C-130 aircraft and were flown to Clark Air Force Base, Republic of the Philippines; from there, they were evacuated further. By late 1967, improved hospitalization in Vietnam and the advent of C-141 jets allowed direct evacuation of some patients to off-shore hospitals in Japan, and others to CONUS. The 903d Aeromedical Evacuation Squadron scheduled the first regular in-country evacuation flights in 1967. By late 1969, the number of regular scheduled flights had increased to 188. The assault aircraft initially used for aeromedical evacuation were supplemented, in early 1968, by C-118 cargo aircraft specifically modified for evacuation missions.
The 29th DC-6 was ordered by the Air Force, adapted as the Presidential aircraft and designated the VC-118. It was delivered on July 1, 1947, and called The Independence after President Harry Truman's hometown, Independence, Missouri. Andrews Air Force Base is a major military airfield just minutes from Washington, DC. Andrews is known for its special air mission -- the transportation of senior government and military leaders. President Harry S. Truman was the first to fly a presidential flight out of Andrews in 1946. President John F. Kennedy's official aircraft, a C-118, permanently transferred from Washington National in 1962, and Andrews officially became the home of "Air Force One."
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