BT308, the Avro Lancaster prototype, at RAF Ringway, 9 January 1941. (Avro Heritage Museum)Captain Harry Albert (“Sam”) Brown, O.B.E. (Photograph courtesy of Neil Corbett, Test & Research Pilots, Flight Test Engineers)
9 January 1941: Test pilot Captain Harry Albert (“Sam”) Brown, O.B.E., (1896–1953) makes the first flight of the Avro Lancaster prototype, BT308, at RAF Ringway, Cheshire, England, south of Manchester.
Throughout World War II, 7,377 of these long range heavy bombers were produced for the Royal Air Force. The majority were powered by Rolls-Royce or Packard Merlin V-12 engines—the same engines that powered the Supermarine Spitfire and North American P-51 Mustang fighters.
The bomber was designed by Roy Chadwick, F.R.S.A., F.R.Ae.S., the Chief Designer and Engineer of A. V. Roe & Company Limited, based on the earlier twin-engine Avro Manchester Mk.I. Because of this, it was originally designated as the Manchester Mk.III, before being re-named Lancaster. Chadwick was appointed Commander of the Most Excellent Order of the British Empire, 2 June 1943, for his work.
The first prototype, BT308, was unarmed and had three small vertical fins.
Avro 683 Lancaster prototype BT308, shortly after the first flight at RAF Ringway, Manchester, England, 9 January 1941. (A.V.Roe via R.A.Scholefield) Photograph is from The R.A. Scholefield Collection and is used with permission.
With the second prototype, DG595, the small center vertical fin was deleted and two larger fins were used at the outboard ends of a longer horizontal tailplane. DG595 was also equipped with power gun turrets at the nose, dorsal and ventral positions, and at the tail.
Avro Lancaster DG595, the second protoype of the Royal Air Force four-engine long range heavy bomber. This armed prototype has the twin-tail arrangement of the production aircraft. (Test & Research Pilots, Flight Test Engineers)Air Ministry clearance form for Avro 683 Lancaster BT308. Shown on page 1 are the aircraft’s engine type and serial numbers.Air Ministry test flight clearance form, Page 2. This form is signed by the airplane’s designer, Roy Chadwick, 5 January 1941.
The first production model, Lancaster Mk.I, was operated by a crew of seven: pilot, flight engineer, navigator/bombardier, radio operator and three gunners. It was a large, all-metal, mid-wing monoplane with retractable landing gear. It was 68 feet, 11 inches (21.001 meters) long with a wingspan of 102 feet, 0 inches (31.090) meters and an overall height of 19 feet, 6 inches (5.944 meters). The Mk.I had an empty weight of 36,900 pounds (16,738 kilograms) and its maximum takeoff weight was 68,000 pounds (30,909 kilograms).
BT308 and early production Lancasters were equipped with four liquid-cooled, supercharged, 1,648.96-cubic-inch-displacement (27.01 liter), Roll-Royce Merlin XX single overhead camshaft (SOHC) 60° V-12 engines, which were rated at 1,480 horsepower at 3,000 r.p.m. to 6,000 feet (1,829 meters). The Merlins drove three-bladed de Havilland Hydromatic quick-feathering, constant-speed airscrews (propellers), which had a diameter of 13 feet, 0 inches (3.962 meters), through a 0.420:1 gear reduction.
DG595 was used for performance testing at the Aeroplane and Armament Experimental Establishment (A&AEE) at Boscombe Down. The Mark I had a maximum economic cruise speed of 267 miles per hour (430 kilometers per hour) at 20,800 feet (6,340 meters), and a maximum speed of 286 miles per hour (460 kilometers per hour) at 20,000 feet (6,096 meters) at a gross weight of 45,300 pounds (20,548 kilograms).¹ Its service ceiling was 20,000 feet (6,096 meters) at 64,500 pounds (29,257 kilograms). It had a range of 2,530 miles (4,072 kilometers) with a 7,000 pound (3,175 kilogram) bomb load.
The Lancaster was designed to carry a 14,000 pound (6,350 kilogram) bomb load, but modified bombers carried the 22,000 pound (9,979 kilogram) Grand Slam bomb. For defense, the standard Lancaster had eight Browning .303-caliber Mark II machine guns in three power-operated turrets, with a total of 14,000 rounds of ammunition.
According to the Royal Air Force, “Almost half all Lancasters delivered during the war (3,345 of 7,373) were lost on operations with the loss of over 21,000 crew members.”
Only two airworthy Avro Lancasters are in existence.
The Royal Air Force Battle of Britain Memorial Flight Avro Lancaster Mk.I, PA474. This airplane was built in 1945 by Vickers Armstongs Ltd. at Broughton, Wales, United Kingdom. (Battle of Britain Memorial Flight)The Canadian Warplane Heritage Museum’s Avro Lancaster Mk.X FM213, flies formation with an Royal Canadian Air Force CF-188 Hornet. The bomber is marked VR A and nicknamed “Vera.” FM213 was built by Victory Aircraft Ltd., Malton, Ontario, Canada. (Canadian Warplane Heritage Museum)
The Lockheed XP-80 prototype, 44-83020, at Muroc Army Air Field, 8 January 1944. (Lockheed Martin Aeronautics Company)Milo Garrett Burcham
8 January 1944: At Muroc Army Air Field (later to become Edwards Air Force Base), the Lockheed Aircraft Corporation’s chief engineering test pilot, Milo Garrett Burcham, took the prototype Model L-140, the Army Air Forces XP-80 Shooting Star, 44-83020, for its first flight.
Tex Johnston, who would later become Boeing’s Chief of Flight Test, was at Muroc testing the Bell Aircraft Corporation XP-59 Airacomet. He wrote about the XP-80’s first flight in his autobiography:
Early on the morning of the scheduled first flight of the XP-80, busload after busload of political dignitaries and almost every general in the Army Air Force arrived at the northwest end of the lake a short distance from our hangar. Scheduled takeoff time had passed. I was afraid Milo was having difficulties. Then I heard the H.1B fire up, and he taxied by on the lake bed in front of our ramp. What a beautiful bird—another product of Kelly Johnson, Lockheed’s famed chief design engineer—tricycle gear, very thin wings, and a clear-view bubble canopy. Milo gave me the okay sign.
This was the initial flight of America’s second jet fighter, and what a flight it was. Milo taxied along in front of generals and politicians, turned south and applied full power. I could see the spectators’ fingers going in their ears. The smoke and sand were flying as the engine reached full power, and the XP-80 roared down the lake. Milo pulled her off, retracted gear and flaps, and held her on the deck. Accelerating, he pulled up in a climbing right turn, rolled into a left turn to a north heading, and from an altitude I estimated to be 4,000 feet[1,219 meters] entered a full-bore dive headed for the buses. He started the pull-up in front of our hangar and was in a 60-degree climb when he passed over the buses doing consecutive aileron rolls at 360 degrees per second up to 10,000 feet [3,048 meters]. He then rolled over and came screaming back. He shot the place up north and south, east and west, landed and coasted up in front of the spectators, engine off and winding down. I have never seen a crowd so excited since my barnstorming days. I returned to the office and dictated a wire to [Robert M.] Stanley [Chief Test Pilot, Bell Aircraft Corporation] “WITNESSED LOCKHEED XP-80 INITIAL FLIGHT STOP VERY IMPRESSIVE STOP BACK TO DRAWING BOARD STOP SIGNED, TEX“ I knew he would understand.
—Tex Johnston: Jet-Age Test Pilot, by A.M. “Tex” Johnston with Charles Barton, Smithsonian Books, Washington, D.C., 1 June 1992, Chapter 5 at Pages 127–128.
A few minor problems caused Burcham to end the flight after approximately five minutes but these were quickly resolved and flight testing continued.
The XP-80 was the first American airplane to exceed 500 miles per hour (805 kilometers per hour) in level flight.
Clarence L. “Kelly” Johnson with a scale model of a Lockheed P-80A-1-LO Shooting Star. Johnson’s “Skunk Works” also designed the F-104 Starfighter, U-2, A-12 Oxcart and SR-71A Blackbird. (Lockheed Martin Aeronautics Company)
The Lockheed XP-80 was designed by Clarence L. “Kelly” Johnson and a small team of engineers that would become known as the “Skunk Works,” in response to a U.S. Army Air Corps proposal to build a single-engine fighter around the de Havilland Halford H.1B Goblin turbojet engine. (The Goblin powered the de Havilland DH.100 Vampire F.1 fighter.)
Lockheed Aircraft Corporation was given a development contract which required that a prototype be ready to fly within just 180 days.
Milo Burcham, on the left, shakes hands with Clarence L. Johnson following the first flight of the Lockheed XP-80, 8 January 1944. (Lockheed Martin Aeronautics Co.)
The XP-80 was a single-seat, single-engine airplane with straight wings and retractable tricycle landing gear. Intakes for engine air were placed low on the fuselage, just forward of the wings. The engine exhaust was ducted straight out through the tail. For the first prototype, the cockpit was not pressurized but would be on production airplanes.
As was customary for World War II U.S. Army Air Forces aircraft, the prototype was camouflaged in non-reflective Dark Green with Light Gull Gray undersides. The blue and white “star and bar” national insignia was painted on the aft fuselage, and Lockheed’s winged-star corporate logo was on the nose and vertical fin. Later, the airplane’s radio call, 483020 was stenciled on the fin in yellow paint. The number 20 was painted on either side of the nose in large block letters. Eventually the tip of the nose was painted white and a large number 78 was painted just ahead of the intakes in yellow block numerals. Early in the test program, rounded tips were installed on the wings and tail surfaces. This is how the XP-80 appears today.
The highly-polished Dark Green and Light Gull Gray Lockheed XP-80 prototype parked at Muroc Dry Lake, 1944 (Lockheed Martin Aeronautics Co.)
The XP-80 is 32 feet, 911/16 inches (9.9997 meters) long with a wingspan of 37 feet, ⅞-inch (11.2998 meters) and overall height of 10 feet, 21/16 inches (3.1004 meters). It had a Basic Weight for Flight Test of 6,418.5 pounds (2,911.4 kilograms) and Gross Weight (as actually weighed prior to test flight) of 8,859.5 pounds (4,018.6 kilograms).
The Halford H.1B Goblin used a single-stage centrifugal-flow compressor, sixteen combustion chambers, and single-stage axial-flow turbine. It had a straight-through configuration rather than the reverse-flow of the Whittle turbojet from which it was derived. The H.1B produced 2,460 pounds of thrust (10.94 kilonewtons) at 9,500 r.p.m., and 3,000 pounds (13.34 kilonewtons) at 10,500 r.p.m. The Goblin weighed approximately 1,300 pounds (590 kilograms).
Cutaway illustration of the Halford H.1B Goblin turbojet engine. (FLIGHT and AIRCRAFT ENGINEER)
The XP-80 has a maximum speed of 502 miles per hour (808 kilometers per hour) at 20,480 feet (6,242 meters) and a rate of climb of 3,000 feet per minute (15.24 meters per second). The service ceiling is 41,000 feet (12,497 meters).
Unusual for a prototype, the XP-80 was armed. Six air-cooled Browning AN-M2 .50-caliber machine guns were placed in the nose. The maximum ammunition capacity for the prototype was 200 rounds per gun.
The Halford engine was unreliable and Lockheed recommended redesigning the the fighter around the larger, more powerful General Electric I-40 (produced by GE and Allison as the J33 turbojet). The proposal was accepted and following prototypes were built as the XP-80A.
Lockheed built 1,715 P-80s for the U.S. Air Force and U.S. Navy. They entered combat during the Korean War in 1950. A two-seat trainer version was even more numerous: the famous T-33A Shooting Star.
Lockheed XP-80 Shooting Star 44-83020 was used as a test aircraft and jet trainer for several years. In 1949, it was donated to the Smithsonian Institution. 44-83020 is on display at the Jet Aviation exhibit of the National Air and Space Museum. It was restored beginning in 1976, and over the next two years nearly 5,000 man-hours of work were needed to complete the restoration.
The prototype Lockheed XP-80 Shooting Star, s/n 140-1001, 44-83020, at the Smithsonian Institution National Air and Space Museum. (NASM)
The prototype Tupolev Tu-144, CCCP-68001, during its first flight, 31 December 1968. The chase plane is a Mikoyan-Gurevich MiG-21I, which was modified to use the same wing profile as the Tu-144. (Tupolev PJSC, via Kazan National Research Technical University)
31 December 1968: At Zhukovsky Airport, located on the banks of the Moskva River, 22 miles (36 kilometers) southeast of central Moscow, the prototype Tupolev Tu-144 supersonic airliner took off on its first flight. Tupolev Design Bureau test pilot Eduard Vaganovich Elyan (Эдуа́рд Вага́нович Еля́н ) was the aircraft commander. The prototype, known as Izdeliye 044, carried the Soviet registration number CCCP-68001.
The flight lasted 37 minutes. The new airplane was reported as responsive and easy to fly. There were no significant problems.
This test flight took place two months before the first flight of the rival Aérospatiale Concorde supersonic airliner.¹
The Tupolev Tu-144 was prototype large four-engine double-delta-winged supersonic transport aircraft with a “droop” nose for improved low speed cockpit visibility. The airplane was assembled at Zhukovsky Airport from parts manufactured at the Tupolev Experimental Design Bureau plant (also known as OKB-156, or MMZ Opyt). It was flown by a flight test crew of four. The prototype completed 9 October 1968.
Izdeliye 044 was 59.50 meters (195 feet, 2.5 inches) long, with a wingspan of 27.65 meters (90 feet, 8.6 inches) and overall height of 11.35 meters (37 feet, 2.9 inches). The wing had an approximate area of 438 square meters (4,715 square feet). At the root, the double delta wing had a chord of 35.60 meters (116 feet, 9.6 inches). The fuselage was cylindrical with an external diameter of 3.00 meters (9 feet, 10.1 inches). The prototype had a maximum takeoff weight (MTOW) of 160,000 kilograms (352,740 pounds).
CCCP-68001 first went supersonic 5 June 1969. It reached Mach 2.02 on 26 May 1970. The highest speed reached by the prototype was Mach 2.30, and its highest altitude, 16,960 meters (55,643 feet). Izdeliye 044 made a total 180 flight hours over 120 flights. Its final flight took place 27 April 1973. The prototype was scrapped at Zhukovsky.
e Tupolev Tu-144 prototype rollout. (Tupolev PJSC)
Izdeliye 044 was powered by four Kuznetsov NK-144 engines with a maximum thrust of 171.6 kilonewtons (38,577 pounds thrust) per engine. Its maximum thrust while supersonic was 127.5 (28,663 pounds thrust). The NK-144 is a two-spool, axial-flow turbofan engine with afterburner. It uses a 2-stage fan section, 14-stage compressor section (11 high- and 3 low-pressure stages), and a 3-stage turbine (1 high- and 2 low-pressure stages). The NK-144 is 5.200 meters (17 feet, 0.7 inches) long, 1.500 meters (4 feet, 11.1 inches) in diameter and weighs 2,827 kilograms (6,233 pounds). (The prototype had all four engines placed side by side along the aircraft centerline).
Tupolev Tu-144 engines mounted side by side. (Tupolev PJSC)
The Tu-144 was intended to carry 120 passengers on international flights. It was designed to have a cruise speed of 2,200 kilometers per hour (1,367 miles per hour), a maximum speed of 2,443 kilometers per hour (1,518 miles per hour), and service ceiling of 18,500 meters (60,696 feet). Its planned range was 2,920 kilometers (1,814 statute miles).
Tupolev Tu-144 under construction. (Tupolev PJSC, via Kazan National Research Technical University)
The production Tupolev Tu-144 aircraft was lengthened 6.2 meters (20 feet, 4.1 inches), added canards, had changes to wing which included shortening the chord at the root 2.10 meters (6 feet, 10.7 inches), increasing the span 0.35 meters (1 foot, 1.8 inches), drooping and squaring off the wing tips, a significant increase in wing area, changes to engine placement and shape of the nacelles, and the location of the landing gear. The engines were upgraded to the improved NK144A.
The Tupolev Tu-144 was the first supersonic transport to enter service, 26 December 1975.² In actual commercial service, the Tu-144 was extremely unreliable. It was withdrawn from service after a total of just 102 commercial flights, including only 55 passenger flights.
A total of 17 Tu-144s were built, including one pre-production aircraft, five Tu-144S series production aircraft, and ten improved Tu-144Ds with Kolosev RD-36-51A engines. One of the Tu-144Ds, RA-77114, was converted to a Tu-144LL for the United States National Aeronautics and Space Administration (NASA). This airplane made its last flight in 1999.
Colonel Eduard Vaganovich Elyan
Eduard Vaganovich Elyan was born at Baku, Azerbaijan Soviet Socialist Republic, 20 August 1926. From 1938 he lived in Norilsk, Russian Soviet Federative Socialist Rrepublic, a recently established mining settlement in Krasnoyarsk Krai, approximately 185 miles (300 kilometers) north of the Arctic Circle. (Norilsk is now a large, closed city). He also lived in Moscow and Sverdlovsk.
Elyan attended the Sverdlovsk Air Force School in 1944, and entered the Soviet military in June of that year. He underwent initial pilot training at the 9th Military Aviation School at Buguruslan, Orenburg Oblast, Russia, then Borisglebsk Military Aviation School of Pilots, Voronezh Oblast, graduating in 1948. He remained there as a flight instructor until 1951.
From 1951 to 1953, Elyan attended the test pilot school at Zhukovsky. He then began working at the Flight Research Institute at Zhukovsky, in 1953.
From March 1958 through August 1960, Elyan served as a test pilot for the Sukhoi Design Bureau (OKB-51). He then went on to the Tupolev OKB, remaining there until December 1981.
In 1967, Elyan was named an Honored Test Pilot of the Soviet Union. In 1969, the Fédération Aéronautique Internationale (FAI) awarded him the Paul Tissandier Diploma for his accompliushments in aviation. On 26 April 1971, Elyan was named Hero of the Soviet Union, awarded the order of Lenin and the Gold Star Medal.
Tupolev Tu-144D CCCP-77111 on fire, 23 May 1978.
On 23 May 1978, Elyan made an emergency belly landing of a Tu-144D, CCCP-77111, in an open field near Yegoryevsk. During the airliner’s sixth test flight, a fuel leak started a fire in the right wing. Three engines had to be shut down in succession and it was impossible to return to Ramenskoye Airport, where the flight had originated. The Tu-144D touched down at about 380 kilometers per hour (236 miles per hour). Two crewmen were killed when the nose cone collapsed on impact. The aircraft continued to burn after landing. The six survivors escaped. Elyan was seriously injured.
Wreckage of Tupolev Tu-144D CCCP-77111. (Tu-144 SST)
Elyan stopped test flying in 1982. He worked as an engineer for Mikoyan OKB. He retired in 1996.
Eduard Vaganovich Elyan died at Rostov-on-Don 6 April 2006. His remains were buried at the Northern Cemetery there.
grave
¹ See This Day in Aviation for 2 March 1969 at https://www.thisdayinaviation.com/2-march-1969/
² See This Day in Aviation for 26 December 1975 at https://www.thisdayinaviation.com/26-december-1975/
The first production Mikoyan-Gurevich MiG-15 (SV), No. 101003. (Mikoyan Design Bureau)
31 December 1948: One year and one day after the first flight of the MiG I-310 S01 prototype, the first production Mikoyan-Gurevich MiG-15, serial number 101003, made its first flight. The production aircraft were based on the third I-310 prototype, S03. No. 101003 was designated МиГ-15(CB) (MiG-15 SV), and was retained by Mikoyan OKB for testing.
The MiG-15 is a single-seat, single-engine turbojet-powered fighter interceptor, designed to attack heavy bombers. Designed for high-subsonic speed, the wings were swept aft to 35° at 25% chord and had 2° anhedral. The wings were very thin to minimize aerodynamic drag and used “fences” to control air flow. The horizontal stabilizer was swept 40°, and the vertical fin, 55.7°.
Rolls-Royce Nene Mk.I and Mk.II turbojet engines had been used in the three I-310 prototypes. The British engine was reverse-engineered by Vladimir Yakovlevich Klimov and manufactured at Factory No. 45 in Moscow as the RD-45F. The engine produced a maximum 22.26 kilonewtons of thrust (5,004 pounds of thrust). It was improved and designated VK-1. Most MiG-15s used this engine.
The production fighter was 10.10 meters (33 feet, 2 inches) long, with a wingspan of 10.08 meters (33 feet, 1 inch) and height of 3.17 meters (10 feet, 5 inches). The total wing area was 20.60 square meters (222 square feet). The interceptor’s empty weight was 3,247 kilograms (7,158 pounds), and its takeoff weight was 4,917 kilograms (10,840 pounds).
The MiG-15 had a cruise speed 974 kilometers per hour (605 miles per hour, 0.79 Mach). Its maximum speed was 1,047 kilometers per hour (565 knots, or 651 miles per hour)—0.99 Mach—at low altitude, and 1,031 kilometers per hour (557 knots, 641 miles per hour, 0.97 Mach) at 5,000 meters (16,404 feet). The maximum rate of climb was 2,520 meters per minute (8,268 feet per minute), and its service ceiling was 15,100 meters (49,541 feet). The fighter had a practical range of 1,335 kilometers (830 miles).
Armament consisted of one Nudelman NS-37 37 mm cannon with 40 rounds of ammunition, and two Nudelman-Rikhter NR-23 23 mm cannon with 80 rounds per gun.
The first MiG 15, 101003, was built at Factory No. 1. Full scale production was considered so important that four other aircraft types were discontinued so that their factories could be used to build MiG-15s. They were also license-built in Poland and Czechoslovakia. More than 18,000 MiG-15s have been built. It has served in the air forces of at least 44 countries.
The MiG-15 soon entered combat in the Korean War. It scored its first air-to-air victory, 1 November 1950, when First Lieutenant Fiodor V. Chizh shot down a U.S. Air Force F-51 Mustang.
Soviet technicians service a Mikoyan-Gurevich MiG-15bis of the 351st Fighter Aviation Regiment at Antung Air Base, China, mid-1952. (Unattributed)
Boeing Model 307 Stratoliner with all engines running, Boeing Field, Seattle, Washington, circa 1939. (San Diego Air & Space Museum Archives)
31 December 1938: Boeing Model 307 Stratoliner NX19901 made its first flight at Boeing Field, Seattle, Washington. The test pilot was Eddie Allen, with co-pilot Julius A. Barr.
The Model 307 was a four-engine commercial airliner that used the wings, tail surfaces, engines and landing gear of the production B-17B Flying Fortress heavy bomber. The fuselage was circular in cross section to allow for pressurization. It was the first pressurized airliner and because of its complexity, it was also the first airplane to include a flight engineer as a crew member.
Boeing 307 Stratoliner NX19901 with both propellers on right wing feathered. (Boeing)
The Associated Press news agency reported:
Test Of Big Craft Begins
SEATTLE, Dec. 31—(AP)—The world’s first plane, designed for flying in the sub-stratosphere, the new Boeing “Stratoliner”, performed “admirably” in a 42-minute first test flight in the rain today.
The big ship, with a wingspread of 107 feet, three inches, climbed to 4,000 feet, the ceiling, and cruised between here, Tacoma and Everett. Speed was held down to 175 miles an hour.
“The control and stability and the way it handled were very nice,” Edmund T. Allen, pilot, said. “She performed admirably.”
The 33-passenger ship was built to fly at altitudes of 20,000 feet.
No more tests are planned until next week. The supercharging equipment for high altitude flights will be installed later.
—Arizona Republic, Vol. IL, No. 228, Sunday, 1 January 1939, Page 2, Column 4
Boeing Model 307 Stratoliner NX19901 taking of at Boeing Field, Seattle, Washington. (San Diego Air & Space Museum Archives)
Giant ‘Stratoliner” Wheeled From Factory, On First Flight
SEATTLE, Dec. 31—(AP)—The newest thing in aviation—a giant, 33-passenger stratoliner named and built by Boeing Aircraft Company—met enthusiastic approval of its test pilot today after preliminary test runs.
Scarcely 24 hours after it left the factory, the newest Boeing plane tested its wings yesterday. Test Pilot Edmund T. Allen taxied the plane along the ground, gunned it a bit and flew it in the air a short time at an altitude from 15 to 30 feet.
Allen did not class the short hop as the ship’s maiden flight, which he said formally remained to be made, probably within a week.
He said the big ship, minus general airplane characteristics, would not require any super-airports as the demonstration showed it would be able to take off and land at any ordinary-sized field.
The stratoliner has four 1,100-horsepower motors which will enable it to cruise at an altitude of four miles at a speed of more than four miles a minute.
Most unusual feature of the silver colored plane is the shape of the cabin, which bears a distinct resemblance to a metal dirigible. The cabin is circular throughout its length of 74 feet, four inches.
The shape was adopted because of the necessity of sealing the cabin so passengers can enjoy low-level atmospheric conditions while soaring at high altitudes. The door, instead of opening outwards, is opened from the inside, so that the higher air pressure in the cabin will keep it sealed.
The stratoliner’s wings compare in design with the Boeing flying fortresses but because of the larger cabin, the wing span is 107 feet, three inches, greater than that of the bombers, the new plane’s height is 17 feet, three inches.
“Outside of scientific and engineering circles the substratosphere has been generally regarded as something far away and mystical, but now it is being brought ‘down to earth,’ C. L. Engtvedt, president of Boeing said.
“The stratoliner will fly below the true stratosphere, but above the heavy air belt that brews surface weather conditions. Here we get most of the benefits of the stratosphere without getting into complex problems of flight in the extremely rare atmosphere and low temperature of the true stratosphere,” he said.
Engtvedt predicted stratosphere type planes would lend a tremendous stimulus to the growth of air transportation.
The first three stratoliners are being built for pan-American airways. Six more are in the course of construction for buyers whose identity has not been announced.
—Eugene Register-Guard, Vol. 95, No. 1, January 1, 1939 at Page 3, Columns 5 and 6
On March 18, 1939, during its 19th test flight, the Stratoliner went into a spin, then a dive. It suffered structural failure of the wings and horizontal stabilizer when the flight crew attempted to recover. NX19901 was destroyed and all ten persons aboard were killed.¹
Boeing 307 Stratoline NX19901. (Boeing)Boeing Model 307 Stratoliner NX19901. (San Diego Air & Space Museum Archives)Boeing 307 Stratoliner NX19901, right rear quarter. (San Diego Air & Space Museum Archives, Catalog #:01_00091289)Boeing Model 307 Stratoliner NX19901. The engine cowlings have been removed. The inboard right engine is running. The arrangement of passenger windows differs on the right and left side of the fuselage. (San Diego Air & Space Museum Archives)
The Boeing Model 307 was operated by a crew of five and could carry 33 passengers. It was 74 feet, 4 inches (22.657 meters) long with a wingspan of 107 feet, 3 inches (32.690 meters) and overall height of 20 feet, 9½ inches (6.337 meters). The wings had 4½° dihedral and 3½° angle of incidence. The empty weight was 29,900 pounds (13,562.4 kilograms) and loaded weight was 45,000 pounds (20,411.7 kilograms).
The cockpit of a Boeing 307 Stratoliner, photographed 12 March 1940. (Boeing)Cutaway illustration of a Boeing Model 307 Stratoliner. (NASM SI-89-4024)
The airliner was powered by four air-cooled, geared and supercharged, 1,823.129-cubic-inch-displacement (29.875 liter) Wright Cyclone 9 GR-1820-G102 9-cylinder radial engines with a compression ratio of 6.7:1, rated at 900 horsepower at 2,200 r.p.m., and 1,100 horsepower at 2,200 r.p.m. for takeoff. These drove three-bladed Hamilton-Standard Hydromatic propellers through a 0.6875:1 gear reduction in order to match the engine’s effective power range with the propellers. The GR-1820-G102 was 4 feet, 0.12 inches (1.222 meters) long, 4 feet, 7.10 inches (1.400 meters) in diameter, and weighed 1,275 pounds (578 kilograms).
Boeing Model 307 Stratoliners under construction. (SDASM Archives Catalog #: 00061653)
The maximum speed of the Model 307 was 241 miles per hour (388 kilometers per hour) at 6,000 feet (1,828.8 meters). Cruise speed was 215 miles per hour (346 kilometers per hour) at 10,000 feet (3,048 meters). The service ceiling was 23,300 feet (7,101.8 meters).
Boeing Model 307 Stratoliner NX19901 with all engines running. (San Diego Air & Space Museum Archives, Catalog #: 01_00091291)A Transcontinental and Western Airlines (TWA) Boeing 307 Stratoliner with cabin attendants. (Trans World Airlines)
As a result of the crash of NX19901, production Stratoliners were fitted with a vertical fin similar to that of the B-17E Flying Fortress.
Pan American Airways’ Boeing 307 Stratoliner NC19903, photographed 18 March 1940. Note the new vertical fin. (Boeing via Goleta Air and Space Museum)
During World War II, TWA sold its Stratoliners to the United States government which designated them C-75 and placed them in transatlantic passenger service.
Boeing C-75 Stratoliner “Comanche,” U.S. Army Air Corps serial number 42-88624, formerly TWA’s NC19905. (San Diego Air & Space Museum Archives, Catalog # 01_00091316)Two TWA stewardesses with a Boeing 307 Stratoliner, circa 1950. (San Diego Air & Space Museum)
In 1944, the 307s were returned to TWA and they were sent back to Boeing for modification and overhaul. The wings, engines and tail surfaces were replaced with those from the more advanced B-17G Flying Fortress. The last one in service was retired in 1951.
Of the ten Stratoliners built for Pan Am and TWA, only one remains. Fully restored by Boeing, NC19903 is at the Stephen F. Udvar-Hazy Center of the Smithsonian Institution.
The only existing Boeing Model 307 Stratoliner, NC19903, Clipper Flying Cloud, at the Smithsonian Institution National Air and Space Museum, Steven F. Udvar-Hazy Center. (Photo by Dane Penland, National Air and Space Museum, Smithsonian Institution)
¹ Please see This Day in Aviation for 18 March 1939 at: https://www.thisdayinaviation.com/18-march-1939/
