The start of 147H operations in the spring of 1967 coincided with an increase in the number and intensity of U.S. airstrikes on North Vietnam.
The first targets hit were power plants in the Hanoi-Haiphong area. By mid-June, 85 percent of North Vietnam's electrical capacity had been destroyed. In late July, attacks were approved on more targets within Hanoi and Haiphong. Starting on September 4, navy planes began cutting rail, road, and canal links to isolate Haiphong. In the end, the 1967 bombing effort proved futile. The North Vietnamese put out "peace feelers," and President Johnson ordered a bombing halt of targets in central Hanoi. The pattern reverted to that of 1965-66—a greatly reduced scale with frequent interruptions.
On January 31, 1968, the Viet Cong launched attacks in cities throughout South Vietnam — the Tet Offensive had begun. At home, protest rallies grew and became both more violent and more pro-North Vietnam. On March 31, President Johnson halted all bombing north of the nineteenth parallel. Peace talks opened in Paris on May 13, and on November 1, Johnson ordered a halt to all bombing of North Vietnam.[260]
The 147Hs were also continuing overflights of Communist China, now engulfed by the madness of Mao Tse-tung's "Great Proletariat Cultural Revolution."[261] On April 30, 1967, the shooting down of a drone over south China was announced.[262] Another announcement followed on June 12.[263] A total of fourteen drones had been shot down by the end of 1967. A fifth Nationalist Chinese U-2 was also shot down on September 9, 1967. The pilot, Capt. Tom Hwang Lung Pei, was killed when an SA-2 hit his plane.[264] In early 1968, it was decided to end the Nationalist Chinese U-2 overflights, due to the risk. From now on, the 147H drones would carry the burden of watching China.
The new role had a cost — on January 20, 1968, the Chinese shot down 147H-25. The Peking Review's announcement reflected the political madness sweeping China: "The Air Force of the heroic Chinese People's Liberation Army, which is boundlessly loyal to Chairman Mao Tse-tung's thought and Chairman Mao's proletarian revolutionary line, shot down a U.S. imperialist pilotless high-altitude military reconnaissance plane when it intruded into China's air space over southwest China for reconnaissance and provocation." In March 1968, a "bad streak" of three drone losses over China brought to eighteen the number of drones lost on China overflights since November 1964. Despite this, the 147H's loss rate was below that of the 147B and G drones.[265]
THE DEFINITIVE DRONE — THE 147S BUFFALO HUNTER
December 1967 saw the debut of the first of a family of low-altitude drones, a series that would form the backbone of the final years of 147 operations. The 147J was not the ideal low-altitude drone. Its long, flexible wings, originally built for the high-altitude 147G, were somewhat unstable at low altitude and prevented the 147J from making sharp turns. The 147NPs and NQs were a quick, short-term effort.
There was a need for a low-cost drone specifically designed for the low-altitude mission. Ryan was told that if they could produce a cheap drone to replace the 147J, the production run would amount to several hundred, compared to only thirty to forty of the other models.
In building the new drone, Ryan went back to the basic Firebee design.
The Firebee's 13-foot wing was used; this was much cheaper than the long wing of the G and J models. The fuselage was 29 feet long and carried a redesigned camera system. Rather than two cameras, as on the 147J, the new drone had a single camera. This provided an 80 percent increase in coverage. The contract for the new 147S drone was issued in December 1966. Unit cost was about $160,000—40 percent less than that of the G and J drones.[266]
It would take a year to get the 147S into operation. Five of the last 147Gs were modified to test the new "poly-profile" low-altitude control system. In the first test of the system, the drone flew into the water. There was a lag in the system, with corrections coming too late. It took six weeks to develop a fix for the problem. It was known as the "Polly Get Well Kit."
When the 147S test flights were completed, there were a number of proposals for modifications which would give it additional capabilities. These included antiflutter kits, different yaw rate gyros, multiple altitude settings, radar altimeters, and a digital programmer. It was decided to group the changes in production blocks. All the drones in a specific block would have identical configurations.
The first such block was the 147SA. A total of forty were produced. The first operational mission was made in December 1967. The drone's camera could produce photos with a one-foot resolution along a sixty-mile-long strip of North Vietnam. In some cases, objects as small as six inches could be identified. On one mission, a stack of truck tires in a storage yard was photographed. The trademark could be read.
Most of the 147SA missions were directed at the main bridges around Hanoi. These were under repair, and it was necessary to have regular coverage. Other targets were supply lines and SAM sites. In some cases, winds or navigation problems would cause the drone to go off the track, but the targets of opportunity picked up would often be more valuable.
The early 147SA missions were very successful, and, in March 1968, a second block of forty drones was ordered. The 147SB carried the multiple altitude control system (MACS). The 147SB could be programmed to fly at three different altitude settings between 1,000 and 20,000 feet. It could also vary between the three settings throughout the mission, making it much less predictable. The drone was also equipped with new yaw gyros that allowed tighter, more precise turns.
The first 147SB missions were flown in March 1968, overlapping with the 147SAs. One early mission was flown by a pair of drones over Haiphong Harbor. The Soviets claimed one of their freighters had been tor-pedoed by the United States as it entered the harbor. The drone unit was ordered to photograph the ship to see if it had been damaged. The drones' flight paths were to cross over the ship. The two drones flew as programmed and returned with photos looking directly into the cargo hold.
They showed no damage at all. The North Vietnamese, however, caused some damage when they opened fire at the low-flying drones. Shooting at a nearly flat trajectory, the shells hit the ground throughout the harbor area.
The 147S drones were the source of a number of "war stories." None matched the adventure of 147SB-12 on October 6, 1968. After launch, the MACS had a problem and rather than flying at an altitude of 1,500 feet, the drone flew at 150 feet above the ground. Its programmed flight path took it under a line of high-tension power lines. The photo showed the tower looming above the drone, while on the ground, people were looking upward at the low-flying plane. The unit commander posted the photo on the bulletin board with a note saying, "The FAA frowns on this bullshit!"[267]
Such achievements were not without cost. With the partial bombing halt on March 31, the drones became a prime target. Flying at 1,000 to 1,200 feet, they were taking heavy losses. On April 21, SA-17 was lost over Haiphong.[268] On June 8, a drone was reported shot down over Hanoi.[269]
A change in profile was necessary — the drones were set to fly at 500 feet and 500 knots. This put them below the m i n i m u m altitude of heavy antiaircraft guns, while the high speed made them difficult to hit with light antiaircraft guns or small arms.[270] Still, by late 1968, the North Vietnamese had shot down a total of about forty of the drones.[271]
261
"Chinese Pilots Guided by the Thoughts of Mao,"