LONG BEACH, Calif., Feb. 16, 1977 -- A McDonnell Douglas YC-15 jet prototype modified with a new engine and longer wing for additional research returned to the skies today to begin the second phase of its flight test program.
McDonnell Douglas plan at Long Beach
"YC-15", "McDonnell Douglas" logos on aircraft.
Aircraft Commander Ken Lewis and crew board YC-15.
Front view of YC-15, panning left to right to new General Electric/SNECMA engine on wing.
Ground crew pulls wheel chocks; pan to YC-15 nose.
YC-15 on ramp ready for takeoff.
Nose wheels roll as taxi-out begins; zoom back to see whole aircraft, moving to runway.
YC-15 taxis past; new engine in foreground.
YC-15 takeoff roll and lift-off.
YC-15 in flight wit extended wing, new engine.
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Background: LONG BEACH, Calif., Feb. 16, 1977 -- A McDonnell Douglas YC-15 jet prototype modified with a new engine and longer wing for additional research returned to the skies today to begin the second phase of its flight test program.
The wide-cabin Air Force transport, first of two STOL (short takeoff and landing) prototypes built here by McDonnell Douglas, took off from the Long Beach Municipal Airport and flew to the company flight development facility in Yuma, Arizona for the expanded Advance Medium STOL Transport (AMST) technology program.
The occasion also marked the first flight of the new French-American engine, the CFM-56, jointly developed by the General Electric Aircraft Engine Group and SNECMA. The new high-bypass ratio engine, installed in the left outboard position, is in the 22,000-pound (9979.2 kg) thrust class. This compares to the 16,000 pounds (7257.6 kg) of thrust of each of the three remaining Pratt & Whitney JT8D-17 turbofans.
The long-range wing, designed to enhance the strategic airlift augmentation capability of the YC-15, is 22 feet (6.7) longer and has an area 367 square feet (34.09 sq m) greater than the original wing. Span of the larger wing is 132 feet 7 inches (40.4 m), and wing area is 2107 square feet (195.7 sq m).
The second YC-15 prototype, scheduled to resume flight testing within several weeks, will have a Pratt & Whitney JT8D-209 refan engine in the left outboard statio in place of one of its JT8D-17 engines. Takeoff thrust of the JT8D-209 is rated at 18,000 pounds (8164.8 kg). This aircraft also will be test-flown at Yuma.
During the Phase II program, the Air Force and McDonnell Douglas will evaluate the range and payload-lifting advantages of the larger wing. In addition, the CFM-56 and the JT8D-209 engines will be evaluated, along with their compatibility with the YC-15 and its externally blown flap powered lift system.
It was this lift system which produced the impressive STOL performance of the YC-15 during Phase I, reducing takeoff and landing distances to well within the 2000-foot (609.6 m) criterion for tactical missions.
For YC-15 number two, other flight test goals will include the evaluation of an engine thrust management system and of a digital SCAS (stability and control augmentation system) in place of an analog SCAS.
Marvin D. Marks, YC-15 vice president-program manager for McDonnell Douglas, said the Phase II flight development program is scheduled to last approximately two months. During phase one, completed last year, the two YC-15s made 292 flights totalling 553.4 hours.
"During the first phase," Marks said, "basic design of the YC-15 was proven. Phase II is designed to provide the Air Force and the company with additional data for evaluating STOL technology and its application to future tactical and strategic airlift requirements."
The AMST program is directed by the Air Force Systems Command's Aeronautical Systems Division, Wright-Patterson AFB, Ohio.