4 August 1971: At its Cascina Costa plant, near the Aeroporto di Milano-Malpensa, northwest of Milan, Italy, Agusta test pilot Ottorino Lancia made the first flight of the prototype Agusta A109 Hirundo, serial number 7101. Also on board was one of the helicopter’s designers, Paolo Bellevita.
The Agusta A109 is an 8-place, light, twin-engine helicopter with a four-blade, fully-articulated main rotor and retractable landing gear. It can be flown by one pilot and carry up to seven passengers. The helicopter is certified for flight in visual meteorological conditions. It was certified by Italy’s Ente Nazionale per l’Aviazione Civile (ENAC) on 28 May 1975, and by the U.S. Federal Aviation Administration the following month. The first production helicopters were delivered in 1976.
The original production variant A109 was 10.71 meters (35 feet, 2 inches) in length. The fuselage had a maximum width of 2.88 meters (9 feet, 5 inches) and the helicopter’s overall height was 3.30 meters (10 feet, 10 inches). The maximum gross weight was 2,450 kilograms, or 5,400 pounds.
The main rotor diameter of the A109 is 11.00 meters (36 feet, 1 inch), and turns counter-clockwise, as seen from above. (The advancing blade is on the helicopter’s right side.) In normal operation, the main rotor turns 365–385 r.p.m. (95–100%). In autorotation, the range is 346–424 r.p.m. (90–110%). The two-bladed semi-rigid tail rotor had a diameter of 2.03 meters (6 feet, 8 inches). It is positioned on the left side of the tail boom in pusher configuration. The tail rotor turns clockwise, when seen from the helicopter’s left side. (The advancing blade is below the axis of rotation.)
The A109 was powered by two Allison 250-C20B turboshaft engines. They are rated at 346 shaft horsepower (113% torque), each, for takeoff (five minute limit). With one engine inoperative (OEI), the maximum power of the remaining engine is 400 shaft horsepower (five minute limit) and 385 shaft horsepower, maximum continuous power.
The A109’s maximum speed (VNE) is 168 miles per hour (270 kilometers per hour). The maximum operating altitude is 15,000 feet (4,572 meters). The helicopter’s total useable fuel capacity is 550.0 liters (145.3 gallons).
The A109 remains in production in both civil and military variants. It is produced in Italy by Leonardo S.p.A. (formerly, AgustaWestland) and in China by Jiangxi Change Agusta Helicopter Co., Ltd.
3 August 1972: During a 45-minute test flight at Edwards Air Force Base, the McDonnell Douglas YF-15A-1-MC Eagle prototype, 71-0280, went supersonic for the first time, reaching Mach 1.5.
An air-superiority fighter, the F-15 entered service with the United States Air Force in 1975. More than 1,500 fighter, two-seat trainer, and two-seat F-15E Strike Eagle fighter-bombers have been built by McDonnell Douglas and Mitsubishi. It is operated by allied air forces around the world and is expected to remain in front line service until 2025.
28 July 1935, At Boeing Field, Seattle, Chief Test Pilot Leslie Ralph (“Les”) Tower and Louis Waite took off on the maiden flight of the Boeing Model 299, NX13372, a prototype four-engine long range heavy bomber. For approximately one-and-a-half hours, Tower flew back and forth between Tacoma and Fort Lewis. When he landed, he said, “It handles just like a little ship—a little bigger, of course.”
The Boeing Model 299 was a four-engine bomber operated by a crew of eight. It was designed to meet a U.S. Army Air Corps proposal for a multi-engine bomber that could carry a 2,000 pound (907 kilogram) bomb load a distance of 2,000 miles (3,219 kilometers) at a speed greater than 200 miles per hour (322 kilometers per hour). Design of the prototype began in June 1934 and construction was started 16 August 1934. The Air Corps designated it B-299, and later, XB-17. It did not carry a military serial number, being marked with civil registration NX13372.
The Model 299 was 68 feet, 9 inches (20.955 meters) long with a wingspan of 103 feet, 9–3/8 inches (31.633 meters) and height of 14 feet, 11–5/16 inches (4.554 meters). Its empty weight was 21,657 pounds (9,823 kilograms). The maximum gross weight was 38,053 pounds (17,261 kilograms).
The prototype was powered by four air-cooled, supercharged, 1,690.537-cubic-inch-displacement (27.703 liter) Pratt & Whitney Hornet S1E-G nine-cylinder radial engines with a compression ratio of 6.5:1. The S1E-G was rated at 750 horsepower at 2,250 r.p.m., and 875 horsepower at 2,300 r.p.m. for takeoff, using 87-octane gasoline. They turned 11 foot, 6 inch (3.505 meters) diameter, three-bladed, Hamilton Standard Hydromatic constant-speed propellers through a 3:2 gear reduction. The S1E-G was 4 feet, 1.38 inches (1.254 meters) long, 4 feet, 6.44 inches (1.383 meters) in diameter and weighed 1,064 pounds (483 kilograms)
In flight testing, the Model 299 had a cruise speed of 204 miles per hour (328 kilometers per hour) and a maximum speed of 236 miles per hour (380 kilometers per hour) at 10,000 feet (3,048 meters). The service ceiling was 24,620 feet (7,504.2 meters). Its maximum range was 3,101 miles (4,991 kilometers). Carrying a 2,573 pounds (1,167 kilograms) load of bombs, the range was 2,040 miles (3,283 kilometers).
The XB-17 could carry eight 500 pound (226.8 kilogram) bombs in an internal bomb bay. Defensive armament consisted of five air-cooled Browning .30-caliber machine guns.
NX13372 was destroyed when it crashed on takeoff at Wright Field, Dayton, Ohio, 30 October 1935. An Army Air Corps pilot making his first familiarization flight neglected to remove the control locks. This incident led directly to the creation of the ”check list” which is used by all aircraft crew members.
Designated XB-17 by the Army Air Corps, this airplane and the YB-17 pre-production models that followed would undergo several years of testing and improvement before entering production as the B-17 Flying Fortress, a legendary airplane of World War II. By the end of the war 12,731 B-17s had been built by Boeing, Douglas and Lockheed Vega.
Leslie Ralph Tower was born at Sisseton, South Dakota, 21 January 1903. He was the first of three children of Ralph R. Tower, a farmer who would later serve as a state senator for Montana, and Mayme Amanda Johnson Tower, a Swedish immigrant.
Les Tower attended high school at Polson, Montana, graduating in 1922. He then attended the University of Washington, where he studied engineering. He was a member of the Radio Club.
Tower enlisted in the United States Army as an aviation cadet, training at Brooks and Kelly airfields in Texas. He then served with the 2nd Bombardment Squadron at Langley Field, Virginia.
In 1925 Tower started working for Boeing as a draftsman, but soon began test flying new airplanes, which included the B-9 bomber and the Model 247 commercial airliner. He also demonstrated and delivered Boeing airplanes around the world.
On 20 August 1935, Tower and Louis Wait flew the Model 299 from Seattle to Dayton, approximately 2,100 miles, in 9 hours, 3 minutes, averaging 233 miles per hour (375 kilometers per hour).
Les Tower was aboard the XB-17 as an observer during the 30 October flight. He saw that the control locks had not been released and tried to reach them, but was unable. In the fire that followed the crash, Tower suffered severe burns to his face, right arm and both legs.
Leslie Ralph Tower died of his injuries 19 November 1935 at Miami Valley Hospital in Dayton. His remains were transported by train, escorted by Army airplanes, and were buried at Lakeview Cemetery, Polson, Montana.
27 July 1972: McDonnell Douglas Chief Experimental Test Pilot Irving L. Burrows made the first flight of the prototype YF-15A-1-MC Eagle, 71-0280, at Edwards Air Force Base, California.
The F-15A Eagle is a single-seat, twin-engine air superiority fighter, built by the McDonnell Douglas Corporation at St. Louis, Missouri. The fighter has outstanding acceleration and maneuverability. It is 63 feet, 9 inches (19.431 meters) long, with a wingspan of 42 feet, 9.75 inches (13.049 meters) and overall height of 18 feet, 7.5 inches (5.677 meters).
The wings’ leading edges are swept to 45°. The angle of incidence is 0°. The wings have 1° anhedral. The total wing area is 608 square feet (56.5 square meters).
The F-15A has an empty weight of 25,780 pounds (11,694 kilograms), and maximum takeoff weight of 44,497 pounds (20,184 kilograms).
The fighter was powered by two Pratt & Whitney JTF22A-25A (F100-PW-100) turbofan engines. The F100 is a two-spool, axial-flow afterburning 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 has a maximum continuous power rating of 12,410 pounds of thrust (55.20 kilonewtons) and intermediate rating of 14,690 pounds (65.34 kilonewtons), (30 minute limit). Its maximum power rating is 23,840 pounds (106.05 kilonewtons) with afterburner (5 minute limit). The F100-PW-100 is 16 feet, 4.3 inches (4.986 meters) long, 3 feet, 10.5 inches (1.181 meters) in diameter, and weighs 3,179 pounds (1,442 kilograms).
The Eagle is a Mach 2.5+ fighter. The cruise speed of the F-15A Eagle is 502 knots (578 miles per hour/930 kilometers per hour). It has a maximum speed of 1,434 knots (1,650 miles per hour/2,656 kilometers per hour) at 45,000 feet (13,716 meters)—Mach 2.503. The service ceiling is 63,050 feet (19,218 meters). It can climb 67,250 feet per minute (342 meters per second), and with a thrust-to-weight ratio of 1.15:1, the fighter could climb straight up.
The The F-15A’s combat radius is 638 nautical miles (734 statute miles/1,182 kilometers). Its maximum ferry range is 2,362 nautical miles (2,718 statute miles/4,374 kilometers).
The F-15A is armed with one General Electric M61A1 Vulcan 20mm rotary cannon with 938 rounds of ammunition, four AIM-7F Sparrow radar-guided missiles and four AIM-9E/L Sidewinder infrared-homing missiles. The fighter could also carry a variety of bombs.
There were 12 pre-production F-15 aircraft, serial numbers 71-0280–71-0291. 384 F-15A fighters were built from 1972 to 1979, before production switched to the improved F-15C. The last F-15A Eagle in U.S. Air Force service, F-15A-19-MC 77-0098, was retired from the Oregon Air National Guard, 16 September 2009.
The first YF-15A, 71-0280, is on display at Lackland Air Force Base, Texas.