In 1965, when the United States first began to take a full scale role in the war in Southeast Asia, the Air Force was called on to provide direct fire support and airlift to the ground forces. Men and planes adapted admirably, ultimately flying more missions, dropping more bombs, and delivering more men and supplies, with a lower loss rate, than in any previous conflict. The aircraft involved in this war ranged from ancient lumbering propeller planes to sleek supersonic jets.
Jet fighter pilots, trained for nuclear war, flew observation planes at 100 mph; fighter-bombers and B-52's designed for nuclear strikes, dropped iron bombs on enemy troops; training planes served as fighter-bombers; transport planes were employed as gunship's, dropped flares, and defoliated thick jungle underbrush; and radar used for scoring practice bombing from ground was used in reverse to direct fighter and bomber to their targets. These and other peculiarities form the basis of the jet age Air Force conducting a limited war against an enemy fighting an insurgency in a jungle environment. The study of this war, particularly that portion fought in the skies of South Vietnam in the years 1965 to 1968, has much to teach those who will apply air power into the twenty-first century.
The gun, which was to become the M-61, trailed the development of the M-39, but was ready for operation by 1956. The M-39 represented a substantial improvement over the .50-caliber. The M-39 delivers fifty percent more rate of fire than the .50-caliber, but the M-61 delivers four times the number of rounds in the same amount of time. Equally important, the old machine guns and the M-39 use a reciprocating motion whereas, the M-61 gained reliability in air-to-air operation by employing a rotary motion.
The only aircraft to come close for the air superiority role in conventional warfare was the F-100, which came along too soon for the M-61, therefore was equipped with four M-39s. The F-104 and F-105 were the first two planes equipped with the M-61 Gatling gun. The F-4 was brought into the Air Force inventory for the air superiority role without a gun, but by the onset of the Vietnam War the fighter employed the M-61 Gatling gun carried externally in the SUU-16 pod.
In the earlier wars, the only air-to-air armament was the .50-caliber machine gun. But in Vietnam, the F-4E, for example, had a standard air-to-air configuration consisting of 630 round of 20 mm, four AIM-7 radar-guided Sparrow missiles and four AIM-9 heat-seeking Sidewinder missiles. With this variety of weapons our F-4s were capable of bringing an enemy aircraft under fire at distances ranging from five to ten miles down to a thousand feet.
The Sparrow could be fired from any direction relative to the target aircraft. However, visual identification was required. Therefore, our aircraft forfeited their initial advantage of being able to detect a MIG at the thirty-five mile range in order to launch their missile. Without the visual identification requirement the F-4s could have radar locked on the enemy aircraft from three to five miles.
The AIM-7 was designed as an anti-bomber weapon and didn't have the broad range for firing or maneuverability that is needed in a fighter versus-fighter engagement. However, the AIM-9 kill rate was somewhat better, about twenty-percent, during the latter part of the 1965-1968 campaign.
The Air Force F-4E with an internal gun didn't make its debut in the war until 1968. Consequently most of the kills by the Air Force were made with Sparrow and Sidewinder missiles against MIG-17s and MIG-21s. During the 1972 campaign, fifty-percent of the kills were made with guns. However, it was standard procedure to fire missiles as a deterrent, this tended to bias the statistical base on the relative effectiveness of missiles for this time period.Sparrow (AIM-7) long-range air-to-air missile