The year saw the debut of the final two members of the 147S family, the 147SD and SDL. The SD was designed with an improved navigation system with an accuracy of 1.1 miles per 100 miles. (The SC's accuracy was 3 percent.) The SD also had an improved radar altimeter, a new cooling system to cope with low-altitude flight in hot tropical weather, and external tanks to extend the range. The first 147SD mission was flown in June.
The other was the SDL. This was a 147SD equipped with a Loran radio-navigation system, which provided even greater accuracy. The first two missions had actually been flown in August 1972, but both were lost. The cause was traced to interference from the navigation system. Normally, the drone would bank up to a maximum angle. Once at this point, the guidance system would not accept any further bank commands. It was found that the Loran was generating an override signal to the roll control; the bank angle increased and the drone went out of control.
Survivability of these last-generation drones was also phenomenal. By November of 1973 there had been 100 launches without a loss. The 147SC drones were designed for an average lifetime of two and a half missions each. They would far surpass this. The record holder was 'Tom Cat,' with 68 missions, each covering an average of twelve targets. The runners-up were 'Budweiser' (63 missions), 'Ryan's Daughter' (52 missions), and 'Baby Buck' (46 missions). A 147SC/TV flew 42 missions, an SD made 39, while an SDL made 36 missions.
The final eighteen months of drone operations — between 1974 and early June 1975—saw a total of 518 flights. From the start, it was discovered that the North Vietnamese were violating the peace agreement. Troops, tanks, and SAMs poured into the South. The United States, its spirit broken by the war and increasingly obsessed with the Watergate scandal, was both unwilling and unable to do more than issue feeble protests.
By early 1975, the North Vietnamese began their final offensive. The South Vietnamese army was driven back, while the U.S. Congress cut off all aid. By late April, Saigon was surrounded. The United States began an evacuation, and South Vietnamese aircraft and helicopters began to flee.
The final 147S-series mission was flown on April 30, 1975—the day Saigon fell.
With the fall of Saigon, the 147SC and SD drones were put into storage.
The 147TF drones continued a little longer. The final flight was made on June 2, 1975. Then they, too, were stored. Although some in Congress objected to the loss of so valuable a capability, the decision stood.
The story of the Model 147 drones was an amazing chapter in the history of U.S. Black aircraft. Using the existing Firebee drone gave it flexibility, while new versions were developed on a short-time scale at low cost. The result was a reconnaissance capability that was unmatched by manned aircraft. In all, 3,435 drone missions were flown against Communist China, North Vietnam, and North Korea. Of these, 1,651 were by 147SC drones. A total of about 1,000 147SC drones were built, in nineteen different versions.
A total of 578 drones were lost—251 were confirmed kills, the vast majority to North Vietnamese air defenses. Another 80 were possible losses to enemy action, 53 were lost in the recovery sequence, 30 in retrieval, and the remainder in other ways.[288] The drones survived the heaviest air defenses built up to that time. One drone had an SA-2 explode within twenty to thirty feet of it and still made it home. One of the high-altitude drones evaded eight MiG intercepts, three air-to-air missile firings, and nine SA-2 launches.[289]
Their accomplishments were many and varied. They had provided the first photographs of North Vietnamese SA-2 construction, MiG 21s, and helicopters; arming and fuze data on the SA-2; and the only low-altitude BDA coverage of Linebacker. The total number of photos they took, over areas too physically or politically dangerous for manned aircraft, is estimated to be 145 million.
The photos these Dark Eagles brought back cast a long shadow. For more than a decade after the defeat in Vietnam, the images of collapse and failure raised doubts about the ability and even competence of the U.S. military. In the years to follow, it was depicted as unable to win and equipped with weapons that did not work.
Until another Dark Eagle, and a night of thunder.
CHAPTER 5
Orphaned Eagle
The Model 154 Firefly
… of the four seasons, none lasts forever; of the days, some are long and some short, and the Moon waxes and wanes.
Despite the failures of the Model 136 and Lucy Lee proposals to gain approval, Ryan Aeronautical remained interested in an advanced drone. There was only so much growth in the basic Firebee airframe. Also, a greater altitude and range, as well as further reductions in radar cross section, would need a completely new design.
The target area for the advanced drone was Communist China. The nuclear test site at Lop Nor, as well as the reactors and reprocessing plants, were beyond the reach of the 147 drones. Even the U-2s were hard-pressed to cover these targets. The losses suffered by Nationalist Chinese U-2 pilots made a long-range drone program that much more attractive.
With most of Ryan's efforts directed toward the 147 program, work on the advanced drone remained at a low level. Understanding how shape affected radar return was one major area of study. Unlike the 147 drones, which relied on radar-absorbing blankets, the new design would use shape to make it hard to detect. From time to time, the advanced drone was proposed to the air force, but a place could not be found for it in their plans or funding.
The CIA expressed an interest to Ryan about developing a separate drone program, and a formal proposal was put together. It was given the designation Model 150 'Red Book.' Ryan felt uncomfortable about going 'behind the back' of the air force with the proposal, and told the CIA that if they did not respond within thirty days, Ryan would feel free to deal with the air force. Within a week the CIA rejected the Model 150 proposal, suggesting Ryan talk to the air force about the project. The CIA had its own, very different, drone project.
Ryan renamed the project 'Blue Book,' which sounded better and was less suggestive of a project aimed at Communist China. The Model 150 was also revised to the Model 151 through the Model 154 designs. After several years of work and proposals, Ryan felt the time was right for a major effort.
This included a formal briefing at SAC Headquarters by the company's founder, T. Claude Ryan. By this time, the 147G drones were conducting overflights of China, and the 147H was beginning development, so the presentation was successful. Because this was a whole new aircraft, rather than a simple conversion of an existing target drone, a design competition was started.
The competition pitted North American Aviation against Ryan. North American had set up a separate division to undertake drone work. Additionally, Northrop tried to enter the emerging competition, but the air force refused its proposal. The range and altitude requirements for the drone were similar to what Ryan had proposed, and the company felt confident its design would be selected. North American put up a strong challenge, and for a time it seemed likely to win. Ryan emerged victorious, however, and won the development contract in June 1966.[290]
THE MODEL 154 FIREFLY
The new drone was called the Model 154 Firefly. The fuselage resembled that of the Model 136, with the engine over the fuselage and inward-canted fins. The sloped, flat sides were designed with reduced radar return in mind.
The fins were tilted inward to both reduce radar return and shield the exhaust. Much of the airframe was made of plastic, which also absorbed radar signals. Infrared suppression was provided by placing the engine above the fuselage and mixing the hot exhaust with cool intake air. Active ECM equipment would provide further protection.
The total length was 34.2 feet, while the swept-back wings spanned 47.68 feet. The 154 had a maximum altitude between 72,000 and 78,000 feet. As with the 147 drones, it would be launched by a DC-130 and recovered in midair by a helicopter. It was equipped with a KA-80A camera able to provide coverage along a 1,720-mile strip.
