Dark Eagles: A History of the Top Secret U.S. Aircraft Page 7

  Finally, on April 27, the weather looked good, and Powers and the support crew headed for Peshawar. The overflight was to begin at 6:00 A.M. the next morning. Powers and the backup pilot were awakened at 2:00 A.M., but almost immediately weather forced a scrub. Powers went through the same routine the next morning, but again weather forced a scrub, this time for forty-eight hours. It was not until Sunday, May 1, the last authorized day, that the weather cleared enough to allow the flight to be made. A last-minute communications problem delayed the takeoff until 6:26 A.M. This invalidated the precomputed navigation data.

  As Powers crossed the Soviet border, he found the weather was worse than expected. A solid cloud cover extended below him. An hour and a half into the flight, Powers spotted the first break in the clouds. The plane was slightly off course and Powers corrected his heading. Far below, Powers could see the contrail of a Soviet fighter. He knew the U-2 was being tracked.

  The clouds cleared again when the U-2 reached Tyuratam. Several large thunderheads hid the pad area, but the surrounding area was clear. The clouds closed in again until about three hours into the overflight. As they began to clear, Powers could see a town. Using the plane's radio compass, Powers took a bearing on a Soviet radio station and corrected his course again. About fifty miles south of Chelyabinsk, the clouds finally broke and Powers could see the snowcapped Urals.[93]

  At this point, Powers's plane, Article 360, suffered an autopilot failure.

  The aircraft's nose pitched up. Powers disconnected the autopilot, retrimmed the aircraft, and flew it manually for several minutes. He then reengaged the autopilot, and the plane flew normally. After ten or fifteen minutes, the pitch control again went full up. This could not continue, so Powers left the autopilot disconnected. He now faced the daunting task of hand flying the plane. The weather was now clear, however, and the plane was nearing the halfway point. Powers decided to press on rather than turning back.[94]

  The U-2 was approaching Sverdlovsk at an altitude of 72,000 feet when it was picked up on Soviet radar. A prototype Su-9 fighter, still in testing and not even armed, was ordered to ram the U-2. The pilot was u n a b l e to spot the U-2, however, and flew far past it. Two MiG 19s were also sent up, but with a maximum altitude of 66,000 feet, they could not reach the U-2.

  As yet, Powers was unaware of these intercept attempts. He had just completed a 90-degree turn and was lining up for the next photo run. As he wrote entries in his logbook, an SA-2 battery opened fire.[95] One of the missiles exploded below and behind the U-2. Powers saw an orange flash.

  The shock wave damaged the right stabilizer. The U-2 held steady for a moment, then the stabilizer broke off, the U-2 flipped over on its back, and the wings broke off.[96] Powers struggled to escape from the tumbling forward fuselage. He was unable to trigger the plane's destruct system. At 15,000 feet, he was able to escape and parachute to a landing. Powers was captured almost immediately.

  The Soviets did not realize they had shot down the U-2. The MiG 19 pilots saw the explosion, but thought the SAM had self-destructed after a miss. On the ground, the fluttering debris from the U-2 filled the radar screens with echoes, but the Soviets thought it was chaff being ejected from the U-2 to confuse the radar. At least three SAM sites continued to fire — reportedly fourteen SA-2s in all. An SA-2 hit one of the MiG 19s, killing its pilot, Sergei Safronov. Soon after the MiG was hit, the destruction of the U-2 was confirmed.[97]

  The confusion of the Soviet air defenses was echoed by that of U.S. intelligence. The Soviet radio transmissions had been intercepted. They were interpreted as indicating the U-2 had gradually descended for a half hour before being shot down. It was assumed the U-2 had flamed out. A cover story was issued that an unarmed civilian weather plane had crossed the Soviet border after the pilot had reported problems with his oxygen system.

  Several days later, Khrushchev revealed that Powers had been captured and had confessed to spying. As Eisenhower feared, the U-2 wreckage was put on display in Moscow. Eisenhower made the unprecedented admission that he had personally authorized the overflights. No head of state had ever before admitted that his country spied in peacetime. The Paris Summit ended when Khrushchev demanded Eisenhower apologize for the overflights. Eisenhower would only give a promise that no future overflights would be made. Powers underwent a show trial and was sentenced to ten years. He was exchanged in February 1962 for a Soviet spy. He later worked for Lockheed as a U-2 test pilot.[98]

  The U-2 detachments were brought home following the loss of Powers's aircraft. The number of CIA U-2 pilots was cut from about twenty-five to only seven.[99] The Detachment D headquarters squadron moved from the Ranch to North Base at Edwards Air Force Base in June 1960. The Lockheed test operation was moved to Burbank.[100] Groom Lake was about to become home for the greatest Dark Eagle ever built.

  CHAPTER 3

  The Archangel from Area 51

  The A-12 Oxcart

  What is called "foreknowledge" cannot be elicited from spirits, nor from gods, nor by analogy with past events, nor by calculations. It must be obtained from men who know the enemy situation.

  Sun Tzu ca. 400 B.C.

  The December 24, 1962, issue of Aviation Week and Space Technology carried an editorial titled "Laurels for 1962." It was a listing of significant accomplishments for the previous year. The sixth item was one of the magazine's most significant scoops. It read: "Clarence (Kelly) Johnson of Lockheed Aircraft for his continued ingenuity in the 'Skunk Works.'"[101]

  Behind those bland words was the greatest achievement of aeronautical technology. The program had already been under way for six years. The full dimension of the achievement of this greatest of the Dark Eagles would not be revealed for another three decades.

  Despite the success of the U-2, its top speed of just over 400 knots was slower than that of some World War II prop fighters. It could only survive through height. With development of the SA-2 SAM, this was no longer enough. Well before Powers was shot down, it was clear any U-2 successor would have to fly both higher and faster. Much faster.

  SUN TAN

  There had been early, pre-U-2 studies of high-speed reconnaissance aircraft. One was by Bell aircraft of the "RX-1," a second-generation X-l rocket-powered research aircraft with camera equipment. In the early 1950s, the X-1A reached a speed of Mach 2.44 and an altitude of 90,440 feet, both world records. The RX-1 would be carried to the target area by a 47 bomber; it would then be released, make the overflight, and be retrieved. It does not appear the idea progressed beyond the concept stage.[102]

  A somewhat more practical idea was the air force-AVRO Canada's Project Y, also called WS-606A. This was a vertical-takeoff and landing (VTOL) aircraft that used six Armstrong-Siddeley Viper jet engines, a CF-105 fuselage, and a disk-shaped wing. It was 37 feet long, with a dish-span of 29 feet. The top speed was Mach 3 to 4, with a maximum altitude of 95,000-plus feet. The combat radius was a mere 800 nautical miles in the VTOL mode. Although WS-606A had 1-A priority for a time in the mid-1950s, […] problems […] of the Various air force-CIA Black airplanes, WS-606A remains unique in that it was the only one to involve a foreign contractor.

  What proved to be the most serious of these early attempts grew out of early 1950s work on aircraft fueled by liquid hydrogen. In early 1956, Johnson proposed to the air force a study design for a hydrogen-powered reconnaissance aircraft called the CL-400. It had a top speed of Mach 2.5, an altitude of 100,000 feet, and a range of 2,200 nautical miles. Johnson said he could have the prototype ready in eighteen months.

  The CL-400 would be a huge aircraft—164.8 feet long with a wingspan of 83.8 feet. It used a T-tail and a retractable vertical fin that spanned nearly 30 feet. The fuselage was nearly 10 feet in diameter. The plane's two engines were located on the wingtips. It used a bicycle-type landing gear with the outriggers retracting into the engine pods. In shape, the CL-400 resembled a scaled-up F-104. The plane's insulated tanks held 21,440 pounds of liquid hydrogen. It had a crew of two and 1,500 po
unds of reconnaissance equipment.

  Lieutenant General Donald Putt, the deputy chief of staff for development, was very impressed with the CL-400 proposal and indicated that the air force wanted such a high-speed aircraft within two or three years (the expected operating lifetime of the U-2). In February 1956, Pratt and Whitney was selected to build the engines, and Lockheed was given a contract for two prototypes. This was soon followed by a contract for six production CL-400s. By April, a full three months before the first U-2 overflight of the USSR, work on the project was under way. Lieutenant Colonel John Seaberg, who had set in motion the U-2, was named to manage the liquid hydrogen tanks, airframe, and systems. Major Alfred J. Gardner was to manage the engines, while Capt. Jay R. Brill would work on the logistical problems of producing, transporting, and storing liquid hydrogen.

  The CL-400 was to be a Black airplane, due to the advanced technology and the need for rapid development. It was classified Top Secret (Codeword) and only twenty-five people had full access to the project. To speed development, near complete power to issue contracts was given to the managers. The project number was changed regularly and some contracts were written by other air force offices to hide their connection with the CL-400.

  At contractors' plants, CL-400 personnel were isolated from other employees. The project was given the code name "Sun Tan."[103]

  Johnson saw the development of Sun Tan as more than aeronautical; the plane would require the routine production and transport of huge quantities of liquid hydrogen. Ben R. Rich, the Skunk Works engineer with dual responsibility for propulsion and hydrogen handling, liked to talk about "acre-feet" of liquid hydrogen (code named "SF-1" fuel). This was at a time when the Mechanical Engineering Handbook described it as only a laboratory curiosity.

  A major concern was the danger of hydrogen fire and explosion. The vivid images of the destruction of the Hindenberg were very much in mind.

  The tests were done at Fort Robertson, a converted bomb shelter near the Skunk Work's. Surprisingly, in many cases, the liquid hydrogen simply escaped without ignightng in sixty-one attempts to cause an explosion, only two' succeeded.' When" a fire did occur, the fireball quickly dissipated. In contrast, gasoline fires did much more damage. Clearly, with proper care, liquid hydrogen was a practical fuel.

  Despite the high level of security that enveloped Sun Tan, several incidents occurred, funny in retrospect, that threatened to expose the project.

  All of these related to the use of liquid hydrogen. The first such hydrogen "leak" occurred when a female Skunk Works engineer (a rarity in the 1950s) attended a conference on hydrogen. Another engineer recognized her and began to wonder why Lockheed was interested in liquid hydrogen.

  Another problem was the semitrailer used to transport liquid hydrogen.

  Because of the light weight of liquid hydrogen (one gallon weighed one pound), the vehicle had only a single axle instead of the two a trailer of this size normally required. The single-axle arrangement attracted undue attention every time it went through state weighing stations. At one weigh station, a trailer was found to be 100 pounds overweight, and the driver was ordered to unload the excess. The air force had to go to the governor to get the load released. The Sun Tan group thought about painting on a second axle but quickly realized this would be too obvious. When the new trailer was built, it had two axles, the second purely for cover.

  A third incident occurred during construction of a liquid hydrogen plant near Pratt and Whitney's Florida test facility. Its cover was as a "fertilizer plant," but word soon spread that the facility produced hydrogen. A local civil defense official became alarmed that a hydrogen bomb was being built in the area. It took a delegation of security officials to convince him to keep quiet.

  Use of liquid hydrogen affected every part of the CL-400. It boiled at negative 423 degrees F, yet, at Mach 2.5, the plane's skin would reach 746 degrees F. The liquid hydrogen would have to be protected from this heat.

  The fuel lines, which would have to pass through the hot wing structure before reaching the engines, had a vacuum-jacketed insulation. Tests of the insulation were done at Fort Robertson using five ovens. Heat tests were also run on the engines, booster pumps, valves, controls, and other components.[104]

  While the Skunk Works was designing the CL-400, Pratt and Whitney was conducting tests on the hydrogen-fueled engine. The initial work, code-named "Shamrock," was to convert a J57 engine to burn hydrogen. The modifications worked very well; the engine could be throttled down until the fan blades were spinning slowly enough to be counted. The throttle could then be smoothly opened to full power.

  The success of the modified J57 encouraged development of the Model 304 engine that would power the CL-400. On a normal jet engine, fuel is sprayed directly into the combustion chamber. With the Model 304 engine, the liquid hydrogen first passed through a heat exchanger. This contained nearly five miles of stainless steel tubing. The liquid hydrogen was heated by the exhaust, going from negative-423 degrees F to 1,340 degrees F and changing from a liquid to a hot gas. The hydrogen gas was fed through a turbine, which spun the compressor fans and liquid hydrogen pump via a reduction gear. Some of the hydrogen was sprayed out the burners and ignited. The rest was sent to an afterburner.

  The first runs of the 304 engine began on September 11, 1957. In all, twenty-five and a half hours of operation with liquid hydrogen were completed during the next year. Despite failures with the turbines, heat exchanger, and bearing, the development was seen as progressing satisfactorily.[105]

  The CL-400 would never get to test its wings, however. By October 1957, the Sun Tan project had effectively ended. The problem was the plane's short range. The end came when Johnson was visited by Assistant Air Force Secretary James H. Douglas Jr. and Lt. Gen. Clarence A. Irvine. They asked how much "stretch" was in the CL-400. Johnson told them only 3 percent.

  The plane was a flying thermos bottle. The only space was the cockpit, and fuel could not be carried in the hot wing structure. Douglas and Irvine asked Pratt and Whitney how much improvement could be made in the 304's fuel efficiency. The answer was only 5 or 6 percent over five years.[106]

  To increase the CL-400's range, its size would have to be increased considerably. The Skunk Works looked at planes as long as a football field.

  This made the plane even less practical, and Johnson urged that Sun Tan be canceled. The air force was also short of money for several higher-priority projects, and there were doubts Eisenhower would approve overflights.

  With this, the project ended. The prototype CL-400s were canceled in October 1957, although the engine tests continued through 1958. The formal cancellation was made in February 1959. In all, between $100 and $250 million had been spent. Not until 1973 was the Sun Tan project revealed.[107]

  Sun Tan was only one thread in a number of post-U-2 ideas. After the failure of the Dirty Bird U-2s, Johnson studied a large flying-wing design.

  The span of the swept-back wings was larger than that of the U-2. It was powered by two jet engines fed from a nose intake. Fins were located near the wing tips. In overall shape, it resembled the World War II Go 229 German fighter. The design was capable of very high altitudes, but still at relatively low speeds.

  GUSTO

  It was not until the fall of 1957 that the emerging high-speed reconnaissance aircraft program began to coalesce. Bissell arranged for a study of how a plane's speed, altitude, and radar cross section affected its probability of being shot down. The study found that supersonic speeds greatly reduced the chances of radar detection. The aircraft would need a top speed of Mach 3, to fly at altitudes over 80,000 feet, and to incorporate radar-absorbing material.[108]

  To achieve such speeds was a nearly impossible task. At this time, there had been only one manned Mach 3 flight. On September 27, 1956, the X-2 rocket-powered research aircraft reached Mach 3.196, equivalent to 2,094 mph. The plane went out of control, killing the pilot, Capt. Milburn Apt.[109]

  Even this had been a bri
ef, rocket-powered sprint. The reconnaissance aircraft would need to maintain these speeds for a prolonged time, while being subjected to more severe airframe heating than on Sun Tan.

  To put in perspective what was required, the plane would have a sustained speed 60 percent higher than the m a x i m u m dash speed of any jet then operational. It would have to fly 70 percent higher and have 500 percent better range. Speeds above Mach 2 were unknown territory. The only large, high-speed aircraft was the B-58, and its flight control system was overly complicated, once being described as "designed standing up in a hammock." Nothing then in existence could be used to build such an airplane.[110]

  If these speeds could be reached, however, it would vastly complicate the problem facing Soviet air defenses. A U-2 flying directly toward an SA-2 SAM site would be detected about ten minutes before reaching it and would be in range for about five minutes. A Mach 3 aircraft would have a warning time of less than two minutes. Only twenty seconds would elapse from the time the aircraft entered the site's range, until it was too close to be fired on. The SA-2 would then have to chase the plane as it flew away from the site. With the missile's top speed of Mach 3.5, it would be a dead heat."[111]

  Speed would greatly reduce the reaction time of air defenses. Use of radar-absorbing material would further reduce the range at which the plane could be detected.

  An airplane with these capabilities would be very expensive — far more than the U-2 had been. A clear assessment of the plane's feasibility was needed. (Sun Tan had, by this time, proven to be a "wide-body dog.") Bissell put together a panel to provide this assessment. The chairman was Dr. Land, and the panel included two aerodynamic experts and a physicist.