1 February 1975: Major Roger J. Smith, United States Air Force, a test pilot assigned to the F-15 Joint Test Force at Edwards AFB, California, flew the McDonnell Douglas F-15A-6-MC 72-0119, Streak Eagle, to its eighth Fédération Aéronautique Internationale (FAI) and U.S. National Aeronautic Association time-to-altitude record.
From brake release at Grand Forks Air Force Base, North Dakota, at 913 feet (278 meters) above Sea Level, the F-15 reached 30,000 meters (98,425 feet) in 3 minutes, 27.799 seconds.
This was the eighth time-to-altitude record set by Streak Eagle in 17 days.
FAI Record File Num #8520 [Direct Link]
Status: ratified – retired by changes of the sporting code
Class: C (Powered Aeroplanes)
Sub-Class: C-1 (Landplanes)
Category: Not applicable
Group: 3 : turbo-jet
Type of record: Time to climb to a height of 30 000 m
Performance: 3 min 27.799s
Course/Location: Grand Forks, ND (USA)
Claimant Roger J. Smith (USA)
Aeroplane: McDonnell Douglas F-15
Engines: 2 Pratt & Whitney F-100
The flight profiles for the record attempts were developed by McDonnell Douglas Chief Developmental Test Pilot, Charles P. “Pete” Garrison (Lieutenant Colonel, U.S. Air Force, Retired).
Streak Eagle carried only enough fuel for each specific flight. It was secured to the hold-back device on the runway and the engines were run up to full afterburner. It was released from the hold-back and was airborne in just three seconds.
When the F-15 reached 428 knots (793.4 kilometers per hour), the pilot pulled up into an Immelmann turn, holding 2.5 Gs. Streak Eagle would arrive back over the air base in level flight at about 32,000 feet (9,754 meters), but upside down. Rolling right side up, Streak Eagle continued accelerating to Mach 1.5 while climbing through 36,000 feet (10,973 meters). It would then accelerate to Mach 2.2 and the pilot would pull the fighter up at 4.0 Gs until it reached a 60° climb angle. He held 60° until he had to shut down the engines to prevent them from overheating in the thin high-altitude atmosphere.
After reaching a peak altitude and slowing to just 55 knots (63 miles per hour, 102 kilometers per hour), the airplane was pushed over into a 55° dive. Once it was below 55,000 feet (16,764 meters) the engines would be restarted and Streak Eagle returned to land at Grand Forks.
Streak Eagle is a very early production F-15A-6-MC Eagle, a single-seat, twin-engine air superiority fighter. It is 63 feet, 9 inches (19.431 meters) long with a wingspan of 42 feet, 9½ inches (13.043 meters) and overall height of 18 feet, 5½ inches (5.626 meters). The F-15A has an empty weight of 27,000 pounds (12,247 kilograms) and its maximum takeoff weight (MTOW) is 66,000 pounds (29,937 kilograms).
The F-15A is powered by two Pratt & Whitney JTF22A-25A (F100-PW-100) afterburning turbofan engines capable of producing 14,670 pounds of thrust (65.255 kilonewtons), and 23,830 pounds (105.996 kilonewtons), each, with afterburner. The F100 is a two-spool, axial-flow turbine engine with a 3-stage fan section; 10-stage compressor; single chamber combustion section; and 4-stage turbine (2 low- and 2 high-pressure stages). The F100-PW-100 is 191 inches (4.851 meters) long, 46.5 inches (1.181 meters) in diameter, and weighs 3,035 pounds (1,376.7 kilograms).
The cruise speed of the F-15A Eagle is 570 miles per hour (917 kilometers per hour). It has a maximum speed of 915 miles per hour (1,473 kilometers per hour) at Sea Level, and 1,650 miles per hour (2,655 kilometers per hour) at 36,000 feet (10,973 meters). The service ceiling is 65,000 feet (19,812 meters). It can climb in excess of 50,000 feet per minute (254 meters per second), and with a thrust-to-weight ratio of 1.15:1, could climb straight up. The Eagle’s combat radius is 1,222 miles (1,967 kilometers).
The F-15A is armed with one General Electric M61A1 Vulcan 20mm rotary cannon with 940 rounds of ammunition, four AIM-7 Sparrow radar-guided missiles and four AIM-9 Sidewinder heat-seeking missiles.
384 F-15A Eagles were built before production shifted to the improved F-15C version. As F-15Cs became operational, the F-15As were transferred to Air National Guard units assigned to defend continental U.S. airspace. The last F-15A was retired from service in 2009.
Streak Eagle was specially modified for the record attempts. Various equipment that would not be needed for these flights was eliminated: The flap and speed brake actuators, the M61A1 Vulcan 20 mm cannon and its ammunition handling equipment, the radar and fire control systems, unneeded cockpit displays and radios, and one generator.
Other equipment was added: A long pitot boom was mounted at the nose with alpha and beta vanes, equipment for the pilot’s David Clark Company A/P-225-6 full pressure suit, extremely sensitive accelerometers and other instrumentation, extra batteries, an in-cockpit video camera aimed over the pilot’s shoulder, and perhaps most important, a special hold-down device was installed in place of the fighter’s standard arresting hook.
These changes resulted in an airplane that was approximately 1,800 pounds (817 kilograms) lighter than the standard production F-15A. This gave it a thrust-to-weight ratio of 1.4:1.
Because Streak Eagle was a very early production airplane its internal structure was weaker than the final production F-15A standard. It was considered too expensive to modify it to the new standard, so it was transferred to the National Museum of the United States Air Force at Wright-Patterson Air Force Base, Ohio, in December 1980.
© 2017 Bryan R. Swopes
Source: This Day in Aviation