The North Vietnamese also sought to end the drone flights through political means. When the Paris Peace Talks opened, the North Vietnamese demanded an end to all reconnaissance flights. This was described as the first order of business: the halt must be "without delay" and "definite and unconditional," and continuation of the talks was dependant on U.S. acceptance of the demand.[272] This effort also proved ineffective. United States reconnaissance flights continued to monitor North Vietnamese activities.
These reconnaissance photos showed that, within two weeks of the bombing halt, the North Vietnamese had repaired all the bombed-out bridges between the seventeenth and nineteenth parallels. Roads had also been made passable, and troop and truck traffic had quadrupled to some four hundred trucks per day.[273]
The next version of the 147S family made its debut in November 1968.
This was the 147SRE night reconnaissance drone. They were equipped with a near infrared strobe. In flight, this was visible as a small red light; it was hard to see unless someone looked directly at it, making the drone much harder to track than the white-light strobe on the NRE. The film was geared to near infrared, and the camera had a filter to cut down the effects of haze. A doppler navigation system also provided better accuracy than the NRE.
The first flight, by 147SRE-1, was made on November 7, 1968. A total of five flights were made in November and six more in December. Missions were flown in the predawn hours, when activities were just starting. When compared to photos taken later in the day, this would give an indication of activities.
The December 19 flight of SRE-2 was an adventure. As it flew over a SAM site, it was fired on. The camera photographed the SAM overtaking the drone, then exploding behind it as the SAM hit the ground. A second SAM was launched, which passed so close the photo was burned out by the exhaust flame. The flight was intended to cover the Haiphong docks and seaplane base, then turn west to cover an airfield near Hanoi. The doppler system was not set correctly, however, and the turns were coming late. This caused the drone to fly to an area northwest of Haiphong, where it missed colliding with a ridgeline seven times. The photos showed it only ten or twenty feet above the trees. The final 147SRE flight was made in October 1969.
Although the SREs were successful, less use was made of the system than was possible. The photo interpreters were not trained in analyzing the near infrared images. Many times targets were missed.[274]
A total of 340 drone missions were launched in 1968. Of these, 205 were 147S drones, while only 67 were 147H high-altitude flights. Clearly, there was a shift in operations. The original concept of high-altitude, covert reconnaissance, similar to that of the CIA U-2 overflights, had been replaced by the much simpler low-altitude mission.
In January 1969, the 147SC was introduced. The SC drones had a cross-correlation doppler radar and a digital programmer to improve navigation accuracy. Of the total of 437 launches made in 1969, 307 were SC drones, known as "Buffalo Hunters." They provided photos with a three-to-five-inch resolution and were used to provide technical intelligence. In contrast to the huge numbers of SC drones, there were only twenty-one high-altitude 147H missions during 1969. These were conducted between January and June; it would be seven months before another was flown.[275]
The drone program did suffer losses, but throughout the war the North Vietnamese grossly inflated the American losses. On April 19, 1969, they reported shooting down a drone, which they claimed was the 3,278th U.S. aircraft downed over the north.[276] In fact this total was more than twice the true number. The actual drone loss rate in 1969 was 24 percent. Even if hit, the drones often survived. During H-58's seven flights during 1969, it was damaged twice. SC-75, dubbed "Myassis Dragon," was hit seven times by shell fragments during its eighth mission. After recovery, SC-75 was "awarded" a Purple Heart. (SC-75 was finally "killed in action" on its tenth mission.)[277]
Up to this point, the drones had been solely an air force operation. The navy had access to the information, but thought it was not timely enough.
Now the navy wanted to test the idea of drones being launched from ships.
This would give the task force commander the ability to cover targets immediately. A contract was issued to modify several SC drones for surface launch. These were the 147SKs; they used the SC's 29-foot fuselage, but with 15-foot wings (two feet longer than the SC's).
Test launches were done from Point Mugu and from the U.S.S. Bennington before deployment off Vietnam. The drone got its initial boost from a rocket, which would burn out and separate. An E-2A aircraft would guide the flight to the initial point, where the drone's own system would take over and fly the programmed mission. After it was completed, a midair recovery would be made. The program was code-named "Belfry Express."
For the operational missions, three 147SK drones were loaded aboard the U.S.S. Ranger. The first flight was made on November 23, 1969, to cover North Vietnam's Highway 1, which ran parallel to the coast a few miles inland. SK-5 was launched successfully, but the carrier was two miles out of position. This meant the ground track was shifted, and the drone photographed an area two miles seaward of Highway 1.
A second mission was flown on November 27, which followed the planned route. The third Belfry Express mission was made on November 30. This time, a midair recovery was made by an air force helicopter. After landing on the Ranger's deck, the pilot climbed out with a large American flag and announced, "I claim this island for the United States Air Force!"
By February 10, 1970, fifteen Belfry Express missions had been flown.
SK-5 was launched on mission sixteen and ran into problems. The tracking beacon could not be picked up, and the drone was lost. When the drone ran out of fuel, a radio signal to deploy the parachute was transmitted. A helicopter was sent to its estimated position, but nothing was found.
Several days later, the Chinese announced they had "shot down" SK-5 over Hainan Island. This was the 20th drone to be lost over China. A newspaper report said, "A broadcast from Canton describing the downing of the plane said that the craft 'cunningly' changed altitude as it veered over Hainan but 'could never escape the eyes of our radar operators.' Chinese Navy men were said to have 'shot down' this U.S. pirate plane at once 'while cherishing infinite loyalty to our great leader Chairman Mao and harboring bitter hatred for the U.S. aggressors.'"
A total of fifteen more Belfry Express missions were flown after SK-5's capture. The three missions of April 18, 22, and 27, 1970, were particularly effective, providing photos of SAM and antiaircraft gun sites at Vinh and Than Hoa, as well as railroads, bridges, pipelines, truck parks, storage yards, and anchorage areas. The only disappointment was the loss of SK-3 on April 24. The mission was successfully flown, but the drag and main parachutes failed to deploy.
The final flight, by SK-10, was made on May 10, 1970. After a near perfect mission, the main parachute failed to open, and the drone was destroyed. The problem was later traced to salt water contamination of the parachute actuation circuit cable. On this note, Belfry Express, and the navy experience with drone reconnaissance, ended.[278]
Although the 147S family made up the bulk of flights in 1969, the year also saw introduction of the final high-altitude drone — the 147T. It had been ordered in early 1967 as successor to the 147H. It used the basic 147H airframe and camera but had a new engine that increased the maximum altitude to 75,000 feet. The 147T also carried the Rivet Bouncer SA-2 jammer and the radar-absorbing inlet coating.
273
Gene Roberts, "Enemy Increases Convoys in North,"