The first Lockheed YF-12A interceptor, 60-6934, flown by James D. Eastham, lands at Groom Lake, Nevada, after its first flight, 7 August 1963. (U.S. Air Force)James D. Eastham (1918–2016)
7 August 1963: The first Lockheed YF-12A interceptor, 60-6934, took off from a top secret air base at Groom Lake, Nevada, on its first flight. Lockheed test pilot James D. Eastham was at the controls.
Three YF-12A prototypes s were built. They were Mach 3+ interceptors developed from the Central Intelligence Agency “Oxcart” Lockheed A-12 reconnaissance airplane.
The interceptors were equipped with a very effective Hughes fire control system and armed with three Hughes AIM-47 Falcon air-to-air missiles. In 1965 the U.S. Air Force placed an order for 93 F-12B interceptors for the Air Defense Command, but Secretary of Defense Robert McNamara continually refused to release the funds which Congress had appropriated. Eventually the contract was cancelled.
In testing, a YF-12A launched a Falcon missile while flying at Mach 3.2 at 74,000 feet (22,555 meters). It successfully intercepted and destroyed a target drone flying at only 500 feet (152 meters).
Lockheed YF-12A 60-6934 at Groom Lake, Nevada. (Central Intelligence Agency via Burbank Aviation Museum)
On 1 May 1965, YF-12A 60-6936, flown by Colonel Robert L. Stephens and Lieutenant Colonel David Andre, set a world speed record of 2,070.101 miles per hour (3,331.505 kilometers per hour) and a sustained altitude record of 80,257.86 feet (22,677 meters).
Lockheed YF-12A 60-6934 in flight. (U.S. Air Force)
60-6934 was damaged beyond repair in a runway accident at Edwards Air Force Base, 14 August 1966. Part of the airplane was salvaged and used to construct the only SR-71C, 64-17981, a two-seat trainer. The third YF-12A, 60-6936, was destroyed when the crew ejected during an inflight fire near Edwards AFB, 24 June 1971. The only remaining YF-12A, 60-6935, is in the collection of the National Museum of the United States Air Force, Wright-Patterson AFB, Ohio.
Lockheed YF-12A 60-6934. (U.S. Air Force)Clarence L. (“Kelly”) Johnson, Director of Lockheed’s Advanced Development Projects (“the Skunk Works”) with the first YF-12A interceptor, 60-6934. (Lockheed Martin)
A prototype Grumman XTBF-1 torpedo bomber. (Ray Crupi Collection)
7 August 1941: Grumman Aircraft Engineering Corporation chief engineer and test pilot, Robert Leicester (“Bob”) Hall, took the XTBF-1, a prototype torpedo bomber, for its first flight. He quickly returned to the airfield. The airplane was seriously over-weight, its center of gravity was too far aft, and it was unstable in the yaw axis.
The first XTBF-1, U.S. Navy Bureau of Aeronautics serial number (“Bu. No.”) 00373, was modified to correct these faults. The engine mount was revised, moving the engine farther forward. A triangular fillet was added to the top of the fuselage in front of the vertical fin, and the weight was reduced.
Grumman XTBF-1 Bu.No. 00373. Note the dorsal fillet. (Northrop Grumman)
On 28 June 1942, 00373 caught fire during a test flight. Its crew safely bailed out but the prototype was destroyed.
The second prototype XTBF-1 was sent to the National Advisory Committee for Aeronautics Langley Memorial Aeronautical Laboratory at Hampton, Virginia, for testing in the 30- × 60-foot Full Scale Tunnel.
The second Grumman XTBF-1 prototype in the NACA Full Scale Tunnel. (NASA)
Before the airplane’s first flight, the U.S. Navy had ordered 286 production aircraft. In October 1941, the type was officially named “Avenger.” The first production airplane, Bu. No. 000393, made its first flight on 15 December 1941.
A flight crew boards a Grumman TBF-1 Avenger torpedo bomber, circa late 1941–early 1942. (Rudy Arnold Collection, Smithsonian Institution, National Air and Space Museum NASM-XRA-0780)
The Grumman Model 40, designated TBF-1 Avenger by the United States Navy, was a single engine torpedo bomber designed to operate from aircraft carriers. Initially it had a four-man crew: pilot, navigator, radio-operator/gunner and ball turret gunner. The TBF was 40 feet, 11½ inches (12.484 meters) long with a wingspan of 54 feet, 2 inches (16.510 meters) and height of 16 feet, 4¼ inches (4.991 meters).
Grumman TBF Avenger three-view illustration with dimensions. (U.S. Navy)
The XTBF-1 was powered by an air-cooled, supercharged, 2,603.943-cubic-inch-displacement (42.671 liters) Wright Cyclone 14 GR2600B698 (R-2600-8) two-row, fourteen-cylinder radial engine with a compression ratio of 6.9:1. The R-2600-8 was rated at 1,500 horsepower at 2,400 r.p.m., and 1,700 horsepower at 2,800 r.p.m. at Sea Level for Takeoff. The engine drove a 13 foot, 1 inch diameter ( meters), three-bladed Hamilton Standard constant speed propeller through a 0.5625:1 gear reduction unit. The R-2600-8 was 5 feet, 4.91 inches (1.649 meters) long, 4 feet, 6.26 inches (1.378 meters) in diameter, and weighed 1,995 pounds (904.9 kilograms).
A Grumman TBF-1 Avenger, mid-1942. (Hans Groenhoff Collection, Smithsonian Institution, National Air and Space Museum NASM-HGC-906)
The first production B-52A takes off from Boeing Field, 5 August 1954. (Boeing)
5 August 1954: The first production Boeing B-52A Stratofortress, B-52A-1-BO 52-001, made its first flight from Boeing Field, Seattle, Washington.
Boeing B-52A Stratofortress 52-001 rollout, 18 March 1954. (Boeing)
The B-52A differed from the XB-52 and YB-52 in that its cockpit was arranged for side-by-side seating, rather than the B-47-type tandem arrangement of the prototypes. It also had an inflight refueling system allowing it to receive fuel from an airborne KC-97 tanker.
Boeing B-52A Stratofortress 52-001 takes off from Boeing Field, 4 August 1954. (U.S. Air Force 021001-O-9999G-015)
52-001 was used as a service test aircraft along with sister ships 52-002 and 52-003. It was used to test the shorter vertical fin of the B-52G. It was permanently grounded at Chanute Air Force Base in the early 1960s.
Boeing B-52A-1-BO Stratofortress 52-001 during its first flight, 5 August 1954. (U.S. Air Force)
A prototype Agusta A109 Hirundo hovering in ground effect. (Agusta)
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).
A prototype Agusta A109 Hirundo in ground effect hover. (Agusta)
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.
Boeing Model 299 X13372, photographed during its first flight, 28 July 1935. (The Boeing Company)Boeing’s Chief Test Pilot Leslie R. Tower.
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, X13372,¹ 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 experimental registration X13372.
The Boeing Model 299 with Mount Rainier. (U.S. Air Force)
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)
Boeing Model 299. (U.S. Air Force)
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).
Boeing 299 X13372, all engines running.
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.
Nose turret of the Boeing Model 299, photographed 24 July 1935. (The Boeing Company)
X13372 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.
Waist gun position of the Boeing 299. (The Boeing Company)
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.
Boeing Model 299 X13372, designated XB-17, at Wright Field, Ohio, 1935. (U.S. Air Force)
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.
¹ At that time, experimental and restricted category aircraft were prohibited from displaying the letter “N” at the beginning of their registration mark.
