Daily Archives: June 11, 2024

11 June–4 August 1971

Sheila Scott on the wing of her Piper PA-23-250 Aztec D, Mythre, G-AYTO, 1971. (NASA)
Sheila Scott on the wing of her Piper PA-23-250 Aztec D, Mythre, G-AYTO, 1971. (NASA)

11 June 1971: Sheila Scott O.B.E. (née Sheila Christine Hopkins) departed Nairobi, Kenya, on her third solo around-the-world flight. On this flight she used a new airplane, a twin-engine Piper PA-23-250 Aztec D which she named Mythre. It carried United Kingdom registration G-AYTO. Scott used a NASA navigation and locator communication system to constantly relay her position to a Nimbus weather satellite, and from there to a ground station.

Sheila Scott's Piper PA-23-250 Aztec D, G-ATYO. Mythre.
Sheila Scott’s Piper PA-23-250 Aztec D, G-ATYO, Mythre, at Kidlington Airport, Oxfordshire, England, 1971. (Tim R. Badham)

Sheila Scott planned to not only fly around the world, but to fly from the Equator, over the North Pole, and back to the Equator again. She flew her Aztec from London, England, to Nairobi, Kenya, where she began the Equator–North Pole–Equator portion of the flight.

Scott took off from Nairobi on 11 June 1971 and headed northward to Khartoum, Sudan; Bengazi, Libya; Malta; arriving back at London on 21 June. From there she continued to Bodø, Norway; Andøya, Norway; Station Nord, Greenland; across the North Pole on 28 June; then southward to Barrow, Alaska; arriving at Anchorage, Alaska, on 3 July; San Francisco, California, to Honolulu, Hawaii, on 11 July. She recrossed the Equator heading south to Canton Island. On 23 July, Mythre arrived at Nadi, Viti Levu, Fiji, and then flew on to Noumea, New Caledonia. After a stop at Townsville, Queensland, Scott arrived at Darwin, Northern Teritory, Australia, 1 August. From there she continued to Singapore; Madras, India; Karachi, Pakistan; Bahrain; Athens, Greece; and finally completed her journey at London on 4 August. The trip took 55 days.

During the circumnavigation, Sheila Scott set seven Fédération Aéronautique Internationale (FAI) World Records for Speed Over a Recognized Course: Andøya, Norway, to Station Nord, Greenland, 213.61 kilometers per hour (132.73 miles per hour) ¹; Nord to Barrow, Alaska, 183.73 km/h (114.16 mph) ²; San Francisco, California, to Honolulu, Hawaii, 236.56 km/h (146.99 mph) ³; Darwin, Northern Territory, Australia, to London, England, 160.19 km/h (99.54mph). ⁴ Three of these records remain current. ⁵

Ms. Scott’s airplane was a 1971 Piper 23-250 Aztec (“Aztec D”), serial number 27-4568. The airplane was assigned the United Kingdom registration G-AYTO on 3 March 1971. The Aztec D was a six-place twin-engine light airplane based on the earlier PA-23-235 Apache, with a larger cabin and more powerful engines. It was of all-metal construction and had retractable tricycle landing gear. The Aztec D is 31 feet, 2.625 inches (9.516 meters) long with a wingspan of 37 feet, 1.750 inches (11.322 meters) and overall height of 10 feet, 3.875 inches (3.146 meters). The wing has 5° dihedral. The Aztec D has an empty weight of 3,042 pounds (1,380 kilograms) and a gross weight of 5,200 pounds (2,359 kilograms).

The Aztec D is powered by two air-cooled, fuel-injected, 541.511-cubic-inch-displacement (8.874 liter) AVCO Lycoming IO-540-C4B5 6-cylinder, horizontally-opposed, direct-drive engines. The -C4B5 has a compression ratio of 8.5:1 and a Maximum Continuous Power/Takeoff rating of 250 horsepower at 2,575 r.p.m. It weighs 374 pounds (170 kilograms). The engines drive two-bladed Hartzell constant-speed propellers with a diameter of 6 feet, 2 inches (1.880 meters).

The PA-23-250 Aztec D has a maximum structural cruising speed (VNO) of 172 knots (198 miles per hour/319 kilometers per hour) at 7,500 feet (2,286 meters) and maximum speed (VNE) of 216 knots 249 miles per hour (400 kilometers per hour). The service ceiling is 19,800 feet (6,035 meters). With standard fuel capacity of 144 gallons (545 liters) the airplane’s range is 1,055 miles (1,698 kilometers). Mythre carried an auxiliary fuel tank in the passenger cabin.

After the around-the-world flight, Scott returned Mythre to the Piper Aircraft Company at Lock Haven, Pennsylvania, for overhaul. Following Tropical Storm Agnes in June 1972, the Piper factory was flooded to a depth of 16 feet (4.9 meters) and Scott’s airplane, along with many others and much of the tooling for aircraft manufacture, was destroyed.

Sheila Scott's Piper Aztec, Mythre, over the North Pole, by Paul Couper, 2008
“Sheila Scott over the Top—Piper Aztec,” by Paul Couper, Guild of Aviation Artists, 2008. 62 × 52 centimeters, oil/acrylic.

This painting is available from the Guild of Aviation Artists at:


Sheila Christine Hopkins was born 27 April 1922 at 12 Park Avenue, Worcester, Worcestershire, England. She was the daughter of Harold Reginald Hopkins and Edyth Mary Kenward Hopkins.

Miss Hopkins married Rupert Leamon Bellamy at Kensington, in late 1945. The marriage was dissolved in 1950.

Sheila Scott had been a nurse at Haslar Naval Hospital during World War II. She was an actress on the stage, in films and on television. In 1959 she followed a lifetime ambition and learned to fly. She owned or leased several airplanes which she entered in races or used to establish flight records.

Scott was a commercial pilot, rated in single and multi-engine airplanes, seaplanes and helicopters. She was a member of The Ninety-Nines, founding and serving as governor of the British branch. She was also a member of the Whirly-Girls and the International Association of Licensed Women Pilots.

Sheila Scott was the author of I Must Fly and On Top of the World (Barefoot With Wings in the United States).

Sheila Scott, O.B.E., died of cancer at Royal Marsden Hospital, Chelsea, London, 20 October 1988, at the age of 66 years. ¹

Sheila Scott, Officer of the Most Excellent Order of the British Empire, 12 March 1968. (AP/Worth)

¹ FAI Record File Numbers 4622, 4623

² FAI Record File Number 14203

³ FAI Record File Numbers 4626, 4627

⁴ FAI Record File Numbers 4624, 4625

⁵ FAI Record File Numbers 4622, 4626, 14203

© 2020, Bryan R. Swopes

11 June 1957

Convair XSM-65A Atlas 4A launch, 11 June 1957. (U.S. Air Force)

11 June 1957, 4:37 p.m., EST, (20:47 UTC): The Convair XSM-65A Atlas, number 4A, lifted off from Launch Complex 14 at the Cape Canaveral Auxiliary Air Force Station in Florida. This was the first launch of a prototype Atlas intercontinental ballistic missile.

At T+26 seconds, the number two engine lost thrust. The rocket began to tumble and at T+50 seconds, the destruct signal was sent by the range safety officer. The Atlas had reached a peak altitude of approximately 9,800 feet (2,987 meters).

Convair Atlas 4A is launched from the Cape Canaveral Auxiliary Air Force Station 11 June 1957. (San Diego Air & Space Museum Archives, Catalog #:14_015602)

Despite the missile’s destruction, the first flight test of the XSM-65A (also known as Atlas A) was actually considered to be a success. The engines had started normally, the launch pad release mechanism functioned as intended, and perhaps most importantly, the lightweight structure of the missile body withstood the forces experienced during the launch.

Following data analysis of the short flight, engineers determined that engine exhaust had circulated back into the engine’s thrust section, causing it to overheat. The propellant ducts were not sufficiently shielded from the heat and began to collapse. This reduced the flow of the liquid oxygen to the engine, effectively throttling it back.

Atlas 4A had been previously tested at Convair’s static test facility in Sycamore Canyon, east of MCAS Miramar, in the Scripps Ranch area of San Diego, California. It is possible that Atlas 4A had suffered internal damage during test firing.

Static test stands for Atlas rockets at Convair’s Sycamore Canyon Test Facility, near San Diego, California. (siloworld.net)

The Atlas A was a prototype for an intercontinental ballistic missile, designed to test the structure, engines and launch system. Unlike the production Atlas, Atlas A used only two engines. The missile was designed and built by the Convair Astronautics Division of General Dynamics at San Diego, California.

Atlas A 4A

Atlas A was 76 feet, 11 inches (23.444 meters) long and 11 feet (3.353 meters) in diameter. At liftoff the missile weighed 180,666 pounds (81,949 kilograms), and at burnout 17,721 pounds (kilograms).

The Atlas is primarily constructed of very thin stainless steel sheet. Rather than using a supporting internal structure, the rocket used “balloon tanks” so that it could be built with minimal weight. The fuel and oxidizer tanks supported the outer skin, but could only do so when pressurized. When the rocket was not fueled, these tanks were pressurized with nitrogen at 5 pounds per square inch (34 kilopascals). If left unpressurized, the rocket would collapse under its own weight.

Atlas A 4A before erection at Launch Complex 14 (Drew Ex Machina)

Atlas 4A was powered by two Rocketdyne XLR-89-1 engines, which produced 271,432 pounds of thrust (1,207 kilonewtons) at takeoff, burning RP-1, a highly refined kerosene, with liquid oxygen. The two engines shared a single turbopump to provide the fuel. Early versions of this engine had a conical exhaust nozzle, while improved models used a bell-shaped nozzle. Production Atlas missiles added a Rocketdyne LR105-NA sustainer engine which continued to accelerate the missile after the LR-89 booster engines were jettisoned. Because of this configuration, the Atlas was known as a “1½-stage rocket.” The LR105 produced 60,473 pounds of thrust (269 kilonewtons) at Sea Level.

Yaw, pitch and roll control of the Atlas after the booster section was jettisoned was provided by two smaller Rocketdyne LR101 vernier thrusters, producing 1,060 pounds of thrust (4.7 kilonewtons) at Sea Level.

Convair XSM-65A Atlas 4A at Launch Complex 14, 11 June 1957. (NASA 19570611-004A-0408)
Atlas A 4A, Launch Complex 14, Cape Canaveral Air Force Station, Florida. (U.S. Air Force)
Three-view diagram of Convair Atlas A. (Drew Ex Machina)
Atlas A MA-1 with two Rocketdyne LR-89-1 engines. (Rocketdyne)

The SM-65A Atlas ICBM became operational 31 October 1959. The rockets were housed in underground “silos,” or hardened above ground shelters located throughout the continental United States. These missiles carried a single W-49 thermonuclear warhead with a yield of 1.44 megatons. The W-49 was designed by the Los Alamos Scientific Laboratory (LASL) and is believed to be a development of the earlier B-28 two-stage radiation-implosion bomb. It incorporated a 10-kiloton W-34 warhead as a gas-boosted fission primary, and had a one-point-safe safety system. The warhead had a diameter of 1 foot, 8 inches (0.508 meters) and length of 4 feet, 6.3 inches (1.379 meters). It weighed 1,665 pounds (755 kilograms).

An unexpected side effect of the Atlas missile programs was the development by the Rocket Chemical Company of its Water-Displacing Formula 40, popularly known by its trade name of WD-40. This universal lubricant was used on the stainless steel surfaces of the Atlas to prevent rust and corrosion.

© 2023, Bryan R. Swopes

11 June 1937

Amelia Earhart’s Lockheed Electra 10E NR16020 in Africa. (Purdue University Libraries, Archives and Special Collections)

11 June 1937: Leg 13. Amelia Earhart and Fred Noonan flew the Lockheed Electra 10E Special, NR16020, from Gao, French Sudan, to Fort-Lamy, French Equatorial Africa, a distance of 910 nautical miles (1,047 statute miles/1,685 kilometers), landing at 1:55 p.m. G.M.T.

“As usual, our arising at Gao was before dawn, a start made notable by a marvelous breakfast, whose chief d’oeuvre was a mushroom omelet supplemented with cups of fine French chocolate. Thence our revised route took us to Fort Lamy about a thousand miles away. On this day’s flying to Lamy and the next, we crossed stretches of country barren beyond words, a no-man’s land of eternal want, where the natives cling tenaciously to an existence almost incomprehensible to westerners. . . .”

Amelia Earhart

Great Circle route from Gao, French Sudan, to Fort-Lamy, French Equatorial Africa, 910 nautical miles (1,047 statute miles/1,685 kilometers). Great Circle Mapper)

© 2019, Bryan R. Swopes

11 June 1926

Ford Tri-Motor 4-AT-1, photographed at Ford Airport, Dearborn, Michigan, 5 June 1926. Note the open cockpit. (The Henry Ford)

11 June 1926: The first production Ford 4-AT-A Tri-Motor, serial number 4-AT-1, flew for the first time at Ford Airport, Dearborn, Michigan. It was registered NC2435.

Designed and built by the Stout Metal Airplane Division of the Ford Motor Company as a commercial passenger transport, the Ford Tri-Motor was a high-wing monoplane with fixed landing gear, similar to the Fokker F.VII/3m. One engine was mounted at the nose, and two more were suspended under the wings. It had a crew of three and could carry up to eight  passengers in a completely enclosed cabin.

A distinctive feature of the Tri-Motor’s construction was the corrugated metal skin which was used to provide strength and rigidity. Corrugated skin panels had been used on the Junkers F.13 in 1919. When Ford began marketing the Tri-Motor in Europe, Junkers sued for patent infringement and won. Ford counter-sued in a different court, and Junkers won again.)

Changes to production airplanes came quickly and no two of the early Tri-Motors were exactly alike.

Ford Tri-Motor 4-AT-1, photographed at Ford Airport, Dearborn, Michigan, 5 June 1926. (The Henry Ford)

The Ford 4-AT-A was 49 feet, 10 inches (15.189 meters) long with a wingspan of 74 feet, 00 inches (22.555 meters) and height of 11 feet, 9 inches (3.581 meters). It had an empty weight of 5,937 pounds (2,693 kilograms) and gross weight of 9,300 pounds (4,218 kilograms).

The 4-AT-A was powered by three air-cooled, normally-aspirated 787.26-cubic-inch-displacement (12.90 liter), Wright Aeronautical Corporation Model J-4 Whirlwind 9-cylinder radial engines. The J-4 Whirlwind had a compressionn ration of 5.3″1 producing 215 h.p. at 1,800 r.p.m., each, and turning two-bladed propellers. The J-4 Whirlwind was 34.0 inches (0.864 meters) long, 44.0 inches (1.118 meters) in diameter, and weighed 475 pounds (215 kilograms).

The Tri-Motor 4-AT-A could cruise at 95 miles per hour (153 kilometers per hour) and a maximum speed of 114 miles per hour (184 kilometers per hour). Its service ceiling was 15,000 feet (4,572 meters) and it had a range of 500 miles (805 kilometers).

This photographg shows four of teh first six Ford Trimotoes at dearborn, Michigan, 27 June 1927. Left to right, 4-AT-3, NC3041, the third built; 4-AT-6, NC2492, the sixth Trimotor; U.S. Navy A-7526, the fourth 4-AT; and 4-AT-1, NC2435, the very first Ford Trimotor built. (Vintage Air)
This photograph shows four of the first six Ford Tri-Motors at Ford Airport, Dearborn, Michigan, 27 June 1927. Left to right, 4-AT-3, NC3041, the third built; 4-AT-6, NC2492, the sixth Tri-Motor; U.S. Navy A-7526, the fourth 4-AT; and 4-AT-1, NC2435, the very first Ford Tri-Motor built. (Vintage Air)

This airplane was very popular at the time and was the foundation for many commercial airlines.  Several were also in military service. Between 1926 and 1933, Ford built 199 Tri-Motors. Though advances in aeronautics quickly made the Tri-Motor obsolete, its ruggedness and simplicity kept it in service around the world for decades.

The very first production Ford Tri-Motor was operated by Ford’s airline, Ford Air Transport Service. It was re-registered NC1492. At 8:45 a.m., 12 May 1928, 4-AT-1 stalled on takeoff at Dearborn. The airliner crashed and caught fire. Pilots William Alexander Munn, 32, and Earl Kenneth Parker, 31, were killed.

Ford 4-AT-B, serial number 4-AT-19, registration NC5092, owned by the Standard Oil Company of California. San Diego Air and Space Museum Archives).
Ford 4-AT-B, serial number 4-AT-19, civil registration NC5092, owned by the Standard Oil Company of California. (San Diego Air and Space Museum Archive)

© 2018, Bryan R. Swopes