Dark Eagles: A History of the Top Secret U.S. Aircraft
Curtis Peebles
An extraordinary history of the United States' top secret military aircraft from WWII to the Gulf War and the missions they flew. Since 1941 the United States has produced a series of 'black' aeroplanes — planes developed, tested, and operated in deep secrecy. Years, even a decade or more, would pass before their existence was made public. The impact of these 'Dark Eagles' has been profound. The first introduced America to the jet age. The next revolutionised the way intelligence was gathered. Another pushed aviation technology to its farthest limits. This is the extraordinary history of the Top Secret U.S. aircraft programmes: including the first, XP-59A Airacomet, the famous U-2, the stealthy F-177A, and so many more.
Curtis Peebles
Dark Eagles: A History of the Top Secret U.S. Aircraft
Introduction
On February 3, 1964, Lockheed test pilot James D. Eastham reached a speed of nearly Mach 3.3 at an altitude of 83,000 feet during the test flight of a new aircraft. This was a world's record for a jet-powered aircraft. For ten minutes, the plane held this speed. This epic flight was the culmination of five years of effort, frustration, and, finally, success. There was not one word about this singular achievement in that evening's newspapers. There was no mention of the event on the television news. No articles were published about the flight in the technical press. As far as the larger world knew, it had never happened.
This was because the airplane did not officially exist.
For the past five decades, some of the most significant advances in aerospace technology were made by airplanes that the larger world knew nothing about. Since 1941, the United States has produced a series of "Black" airplanes — planes developed, tested, and operated in deep secrecy. Years, even a decade or more, would pass before their existence was made public.
Some remain secret still.
The impact of these Dark Eagles has been profound. The first introduced America to the jet age. The next revolutionized the way intelligence was gathered. Another pushed aviation technology to its farthest limits. A series of unmanned reconnaissance drones would venture to places too dangerous for conventional aircraft. One group would change U.S. aerial combat techniques and training. The latest series would fundamentally alter the role of airpower and strategic bombing, leading the way to the Coalition victory in the Gulf War. Each would do things most engineers thought impossible.
CHAPTER 1
The First Black Airplane
The XP-59A Airacomet
… come like the wind, go like the thunder.
Sun Tzu, ca. 400 B.C.
On the cool morning of October 1, 1942, a group of Bell Aircraft Company engineers prepared their new plane for its first flight. Finally, shortly after noon, the XP-59A stood ready. The aircraft had a midposition straight wing and tricycle landing gear. The tail was on a raised boom, while the center section of the fuselage seemed to bulge. The plane was painted dark olive green with dark gray undersides and had the U.S. insignia of a white star in a blue circle. It had no serial number. The XP-59A's design owed much to Bell's earlier P-39 and P-63. But in one aspect, this first Dark Eagle had nothing in common with any aircraft of the previous four decades of American aviation technology. It was the plane that separated all that was from all that would follow.
The XP-59A had no propeller.
BIRTH OF THE JET AGE
The events that set in motion development of the first U.S. Black airplane had begun more than a decade before. In 1928 Royal Air Force (RAF) Pilot Officer Frank Whittle, then only twenty, realized that the conventional propeller engine was Hearing its performance limit. To fly faster, a larger, more powerful engine was needed. Such an engine would burn more fuel, thus requiring a larger, heavier airframe and canceling out any gain. As a plane flew higher, it flew into thinner air. This resulted in a loss of engine power. Propellers, as they approached supersonic speed, also lost efficiency.
The high-speed planes of the 1930s, such as the GeeBee racer, were little more than the biggest possible engine attached to the smallest possible airframe. They flew fast, but, like the GeeBee, often proved lethal.[1]
Whittle proposed the idea of using a gas turbine to power an aircraft.
Incoming air would be compressed, then mixed with fuel and ignited. The hot gas would be vented out an exhaust pipe to produce thrust. This offered speeds and altitudes far beyond the reach of propeller-driven fighters and bombers. Whittle submitted his idea to the British Air Ministry, which promptly rejected it as unattainable. For the next seven years, Whittle struggled to find money to build his "Whittle Unit." It was not until 1937 that the Air Ministry agreed to a small study contract, and it was another year before the money was actually provided.
In March 1939, the first Whittle jet engine was making test-bed runs. In the meantime, Nazi Germany had absorbed Austria and taken over Czechoslovakia. With war clouds looming over Europe, a few far-sighted individuals realized the strategic advantages of jet aircraft. In July 1939, Whittle was given a contract to develop the W.I jet engine, which would power the experimental Gloster E28/39 Pioneer aircraft. Two months later, Germany invaded Poland and World War II began. By the following summer, Hitler was the master of Europe, and England stood alone. In the sky above London, the RAF and the Luftwaffe fought the Battle of Britain to decide the fate of Western Civilization.
As these monumental events were being played out, Whittle and a small group of engineers were working in an empty factory near Coventry, England. The engine that was built was unlike any power plant ever flown before. A conventional aircraft engine operated at 2,000 rpm. The W.l's turbine spun at 17,750 rpm. The temperatures inside the combustion chambers were also far higher than those of piston engines.
Equally daunting was the political situation. With London in flames and England needing every Spitfire it could produce, Lord Beaverbrook, head of the Ministry of Aircraft Production, stripped the W.I of its priority order.
By this time, however, Whittle had gained powerful supporters who were able to convince Beaverbrook to restore the W.1's priority.[2]
By the spring of 1941, the first E28/39 aircraft was finished and Whittle delivered a "lash-up" prototype engine, the W.1X. (The X indicated it was not to be flown, but only used for taxi tests.) The taxi tests were made on April 7 and 8, 1941, by Flight Lieutenant P. E. G. Sayer, Gloster's chief test pilot.
In the final series, the aircraft lifted off on three short hops. On May 15, the E28/39 was ready for its first flight. Due to poor weather, it was delayed.
Finally, at 7:35 P.M., Sayer took off for a seventeen-minute flight. It was the culmination of more than a decade of efforts by Whittle. The Air Ministry did not bother to send an official photographer to record the event.[3]
THE JET ENGINE COMES TO AMERICA
The Battle of Britain had ended in victory for England, but it was clear that the country lacked the industrial capacity to defeat Nazi Germany on its own.
The only option was to share military technology with America, including jet engines. On April 11, 1941, U.S. Army Air Corps Chief Maj. Gen. Harold
"Hap" Arnold arrived in England to examine jet propulsion projects. Arnold quickly realized what Whittle had achieved — the E28/39 could outfly a Spitfire, then the fastest British aircraft. Every aircraft the army air corps and navy were building or planning was about to be made obsolete.
In late May, General Arnold formally requested access to jet engine technology. Initially, the British provided only a nine-page secret memo describing the engine. On July 15, the British agreed
to release the Whittle engine to the United States "subject to special care being taken to safeguard its secrecy." To meet this requirement, the concept of the "Black airplane" would be developed.[4]
On September 4, 1941, General Arnold met with senior Army Air Forces (AAF) and War Department officials. Also on hand were four General Electric representatives. Arnold opened a safe and pulled out several reports.
After discussing the recommendation that the United States embark on a crash program to mass-produce the engine, General Arnold said, "Gentlemen, I give you the Whittle engine — consult all you wish and arrive at any decision yo'u please — just'so long as General Electric accepts a contract to build 15 of them."
It was also agreed that Bell Aircraft would build three prototype jet fighters. Because of the low thrust of the Whittle engine, it would have to be a twin-engine design. Unlike the experimental E28/39, it would be intended as an operational fighter. Bell was picked for several reasons. Bell's Buffalo, New York, plant was near General Electric's Schenectady and Lynn, Massachuetts engine plants. Bell's engineering and design staff were not overloaded with existing contracts. This was important, as General Arnold had imposed a one-year deadline. Larry Bell, president of the company, had a reputation for undertaking unusual projects and could be counted on to keep close watch on the effort. That evening, Arnold's office contacted Larry Bell and asked that he and his chief engineer, Harland M. Poyer, come to Washington, D.C. On September 5, they were briefed on the jet engine and were asked to build the airplane. They agreed.[5]
On September 22, the British Air Commission told the U.S. Secretary of War, Henry L. Stimson, that all information on jet engines would be released. The British provided one engine (the old W.1X used in the taxi tests) and a set of manufacturing drawings for the W.2B, an advanced version of the original W.1 engine. On October 1, 1941, the engine and drawings were loaded on a B-24 at Prestwick, Scotland, and flown west across the Atlantic. The plane arrived the next day at Boiling Field in Washington, B.C.
Then began a standoff; customs agents demanded to inspect the cargo. It took two days before they relented and agreed only to count the three crates, which were sent on, finally, to the General Electric plant in Boston.[6]
THE SECRET SIX DESIGN A BLACK AIRPLANE
When Poyer returned from the September 5 meeting, he selected a small group of engineers and called them to Larry Bell's office. They were sworn to secrecy, then briefed on the project. Larry Bell told them they would design the first U.S. jet fighter. The group, quickly dubbed the "Secret Six," were Poyer, Robert Wolf, E. P. Rhodes, Jim Limage, H. L. Bowers, and Brian Sparks. This established the pattern for later Black airplanes — they were developed by a very small group, using streamlined procedures and working on a tight schedule.
The project was protected by layers of secrecy and deception, far beyond the normal secrecy involved in building a new aircraft. All information on jet technology was classified "Special Secret." This was the predecessor to today's "Top Secret (Codeword)" and "Special Access" classifications. The designation XP-59A was an example of such "cover." The original XP-59 was a single-seat, twin-boom pusher fighter. Preliminary design work had been done and a wooden mock-up had been built. By reusing the designation and adding an A, it was made to seem to be only a revised version of the old plane.
The Secret Six had a preliminary proposal and a one-twentieth scale model of the aircraft ready in two weeks. General Arnold approved the design. On September 30, 1941, an eight-month, fixed-fee contract was signed for three XP-59A aircraft, a wind-tunnel model, and data. The total price was $1,644,431. The XP-59As were described only as "twin engine, single place interceptor pursuit models." The contract required that General Electric engines be used, but otherwise Bell had a free hand in determining the plane's configuration.
It was clear from the start that the project would have to be done outside Bell's existing development-production facilities. The first drawings were done at an old Fierce-Arrow factory on Elmwood Avenue in Buffalo. Before long, the work was moved to a four-story building owned by the Ford Motor Company at Main and Rodney Streets. As the Secret Six moved into the second floor, a Ford dealership was still selling cars on the first floor. The dealership was soon eased out, and the machine shop and storage areas were set up on the first floor. To ensure security, all entrances to the "Main Street Plant" were guarded, and special passes were required to enter the building. The metal window frames were welded shut, and the first- and second-floor window panes were painted over.[7]
Once again, the XP-59A introduced an aspect of later Black airplane development. The contractor was now split into a "White" half (which conducted normal production) and a "Black" half, for secret work. The Black company was a duplicate of the larger White part, with its own design and production facilities. These facilities were isolated — both physically and in terms of secrecy — from the main company.
The Secret Six were embarking on an unknown sea. They were about to reinvent the airplane, yet the only information they had initially on the jet engine was a single, freehand one-twentieth scale sketch. There was nothing about the specific dimensions, weight, thrust, attachment points, accessories, cooling, inflow and outflow — just a drawing the size of a cigarette pack.
Another difficulty was the expectation that the XP-59A could be directly converted into an operational fighter, skipping the test aircraft step. This was made more difficult by the low thrust of the jet engines. The XP-59A's thrust-to-aircraft-weight ratio was lower than contemporary fighters.
The secrecy of the program also complicated development. Outside wind tunnels could not be used. (The one exception was the use of the Wright Field low-speed tunnel to refine the engine inlet design.) The Secret Six could not consult with outside technical experts or contractors. They had to either build equipment in-house or use off-the-shelf hardware.
The secrecy problems became more complex once fabrication of the first XP-59A began on January 9, 1942. Much of the work was done in the machine shop at the Main Street Plant. However, large parts had to be made at the main Bell plant. The drawings were purposely mislabeled — the engine exhaust pipes, for example, were "heater ducts" (a full fourteen inches in diameter).
As construction of the prototype continued in March and April 1942, more man power was needed. People began to "disappear." Desks and drawing boards were now empty. When the "lost ones" met their ex-co-workers at social events and meetings, they were asked what they were doing. It reached the point that the XP-59A personnel were discouraged from attending such outside activities.[8]
As the Secret Six worked on the prototype, General Electric was producing the engine. Once the W.1X was delivered to Boston, General Electric constructed a special test cell in Building 34 North at the River Works Plant. Dubbed "Fort Knox," it was constructed of reinforced concrete and had a heavy steel door. The engine was viewed through a small slit. The exhaust was vented out a sixty-four-foot unused chimney. The W.1X was ignited for the first time on October 16, 1941.
General Electric then began building the production W.2B engines. As with the XP-59A, cover designations were used. The engine was called "I-A turbosupercharger." General Electric was then producing aircraft superchargers in the A through F series; calling it the "I-A" made it seem to be the eighth in this series. General Electric found that the drawings were not complete. They also suggested changes in the gear train and accessories, a new alloy, and modified compressor blades. Even so, it was still a copy of the W.2B. The first test I-A engine made a brief run on March 18, 1942.[9] It was another thirty days before the problems were ironed out and the engine reached 1,250 pounds of thrust. To help work out the problems, Whittle, now an RAF wing commander, came to the United States in early June and remained until the first week of August. By that time, the first two production I-A jet engines were shipped to Bell. They were installed in the prototype XP-59A and final assembly began.[10]
MUROC — A NEST FOR THE DARK EAGLE
/> Having gone to these extraordinary lengths to keep the XP-59A secret, it was clear the plane could not be test flown from the Bell plant in Buffalo. An isolated site would be needed to ensure secrecy during the highly visible test flights. In early 1942, Lt. Col. Benjamin W. Chidlaw and Maj.
Ralph R. Swofford Jr. made a tour of possible sites. They selected the Muroc Bombing and Gunnery Range on Rogers Dry Lake, in the Mojave Desert of California.
Rogers Dry Lake is a flat expanse some sixty-five square miles in area.
The site was originally settled by Clifford and Effie Corum in 1910. The little desert community that soon grew on the edge of the lake bed was named Muroc (Corum spelled backward). In September 1933, the army air corps set up a gunnery range on the lake bed. With the attack on Pearl Harbor, a base was built at the south end of the lake bed to train B-24, B-25, and P-38 crews. Out on the lake bed the "Muroc Maru" was built — a false-front mock-up of a Japanese Mogam/n'-class heavy cruiser — to act as a bombing target."The site was isolated, far from any major city.
In mid-May 1942, Bell was told Muroc would be the test site. The flight test facility was constructed on the north end of the lake bed, about five miles from Muroc Field. In later years, the two areas would become known as "North Base" and "South Base." North Base consisted of a large portable hangar (which had lost many parts in its travels), a two-story barracks, and a mess hall. Water came from a two-hundred-foot-deep well and was stored in a wooden tank. The ground control for the test flights was a two-way radio and an old recorder set up on the ramp. Transport was provided by two Bell-owned station wagons.[11]
Larry Bell told Robert M. Stanley, Bell Aircraft's chief test pilot, that the company was building a jet aircraft and that he would fly it. This was the first time Stanley had heard of the project. Stanley arrived at North Base on August 20, 1942. He found that progress on the buildings had been slow, and the contractor said there was little chance of completing the work by mid-September. As it turned out, the barracks was completed by the deadline, while the hangar lacked only the floor and electrical wiring. With the prototype aircraft about to arrive, the civilian contractors were sent away, and Stanley and the Bell crew finished the work. They built to last — a half century later, the original XP-59A hangar is still in use at North Base, and is still used for Black airplanes.
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