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n HISTORICAL PERSPECTIVE A need for speed

Mach 0.8 to 1.2 and above the speed of powerful turbine engine available. To mit- Skystreak taught lots sound, respectively). The U.S. Army Air igate as much risk as possible, the team Forces took responsibility for supersonic kept the design simple, using a conven- about flight near research—which resulted in Chuck Yea- tional straight wing rather than the new ger breaking in the Bell and mostly unproven . The the sound barrier X-1 on Oct. 14, 1947. That historic event 5,000-lb.-thrust (22-kilonewton) Allison overshadowed the highly successful re- J35-A-11 engine filled the fuselage, leav- By Michael Lombardi search conducted by the pilots who flew ing just enough room to house instrumen- s World War II was coming to a the Douglas D-558-1 Skystreak to the edge tation and a pilot in a cramped cockpit. close, advances in high-speed aero- of the sound barrier while capturing new Because of the lack of knowledge about Adynamics were rapidly progressing world speed records. the survivability of a high-altitude, high- beyond the ability of the wind tunnels of The D-558-1 was developed by the speed bailout, Douglas engineers designed the day, prompting a dramatic expansion Douglas Company, today a part a jettisonable nose section that could pro- of flight-test research and experimental of Boeing, at its El Segundo (Calif.) tect the pilot until a safe bailout speed was aircraft. Division. It was designed by a team led reached. The National Advisory Commit- by Ed Heinemann, Douglas’s legendary The small wings had just enough room tee for Aeronautics, the predeces- chief engineer, and D-558 project engi- to store 230 gallons (871 liters) of jet fuel sor to NASA, joined with the U.S. neer Robert Donovan. and the specially designed narrow wheels military to further the research of tran- The basic design philosophy was to with high-pressure tires that were required sonic and supersonic flight (categorized as build the smallest plane around the most to fit inside the minimal wheel wells of the

 August 2007 BOEING FRONTIERS n HISTORICAL PERSPECTIVE

some piston-powered World War II air- air speed record in 24 years. planes in high-speed dives—most notably Four days later, Marion Carl, a major in the P-38 Lightning. the U.S. Marine Corps and a World War II The pilots who volunteered to fly these ace, squeezed into the tiny cockpit of the research planes understood the tremen- second Skystreak and bettered Caldwell’s dous risks involved in literally becoming record, with an average speed of 650.7 pioneers flying into the unknown. Their mph (1,047 kilometers per hour). courage and, at times, sacrifice made an The three Skystreaks would continue A need for speed undeniable contribution to the safety of jet to research flight, through flights travel. made by May, Caldwell and Carl, as well One of those courageous pilots was as by future X-15 pilot Scott Crossfield. Douglas company Gene May. Today the fully restored Skystreak No. 1 Between 1947 and 1949, May flew more can be seen on display at the National Mu- transonic flights than any other pilot. He seum of Naval Aviation in Pensacola, Fla. flew not only the D-558-1 but also the Bell Skystreak No. 2 was lost along with NACA As shown in this head-on view, the X-1, in which he became the sixth person pilot Howard Lilly, the first NACA pilot to D-558-1 Skystreak featured a clean and to break the sound barrier. He retired from be killed in the line of duty. Skystreak No. simple design. That design reflected the flight testing in 1949 after proving the 3 was recently restored by the Carolinas simple philosophy for this aircraft: Build Douglas D558-2 Skyrocket. Aviation Museum in Charlotte, N.C. the smallest plane around the most On April 15, 1947, May took the The D-558-1 Skystreak and its suc- powerful turbine engine available. Skystreak up for its first flight. Over the cessor, the D-558-2 Skyrocket—the first next four months, he pushed the bright manned aircraft to reach twice the speed red jet to its operational limits, flying up of sound—are a proud part of a heritage of to 30,000 feet (9,100 meters) at a speed of high-speed innovation at Boeing that also Mach 0.85. includes other record-breaking research The testing amounted to 24 short flights, aircraft, such as the triple-sonic XB-70, totaling only 9 hours and 32 minutes. But the hypersonic (Mach 5 and above) X-15 the team concluded that the Skystreak plane and the Space Shuttle. had proved itself ready for an attempt at Today Boeing continues its legacy of the world speed record—and handed the leadership in high-speed flight research plane over to the U.S. Navy. with the hypersonic X-43A Hyper-X that On Aug. 20, 1947, at Rogers Dry has reached speeds in excess of Mach 7. Lake Speed Course in Muroc, Calif. This program expanded our knowledge (known today as Edwards Air Force of high-speed flight that someday could Base), Cmdr. Turner Caldwell Jr. took allow airline passengers to measure their the Skystreak for its first record-breaking transoceanic flights in minutes rather than flight. Caldwell averaged 640.7 mph (1,031 hours. n kilometers per hour), breaking an ear- [email protected] lier record by 17 mph (27 kilometers per hour) and giving the Navy its first world B oeing A r c hi v es photos

. Later, 50-gallon (190-liter) wing- tip tanks were added that increased the plane’s range from 490 miles to 833 miles (789 kilometers to 1,340 kilometers). With a bright gloss-red finish to assist in visual tracking, and not being much more than a long tube with wings, the D-558-1 earned affectionate nicknames such as “The Flying Stove Pipe” and “The Crim- son Test Tube.” The first pilots of the Skystreak included (from In 1947, when the Skystreak first flew, left) U.S. Marine Corps there were a number of unknowns in tran- Maj. Marion Carl, Douglas sonic flight. Of great concern was com- test pilot Gene May and pressibility, or the compression of air U.S. Navy Cmdr. Turner around an airplane as it passes through a Caldwell Jr. . The effects of could vary greatly based on the design of the airplane and could result in slight buf- feting all the way to loss of control. Indeed, this phenomenon had been experienced by

BOEING FRONTIERS August 2007