Lieutenants Lowell H. Smith and John P. Richter, Air Service, U.S. Army. (U.S. Air Force)
The first successful aerial refueling took place on June 27, 1923, when a DH-4B, Air Service serial number A.S. 23-462, carrying Lieutenants Virgil S. Hine and Frank W. Seifert passed gasoline through a hose to another DH-4B which was flying beneath them carrying Lieutenants Lowell H. Smith and John P. Richter.
Hine and Smith piloted their respective airplanes while Seifert and Richter handled the refueling. A 50 foot (15.24 meter) hose with manually-operated quick-acting valves at each end was used. During the refueling, 75 gallons (284 liters) of gasoline was passed from the tanker to the receiver.
Smith and Richter landed after 6 hours, 38 minutes, when their airplane developed engine trouble. Only one refueling had been completed but that had demonstrated the feasibility of the procedure.
A DH.4B flown by Lieutenant Lowell H. Smith and Lieutenant John P. Richter receives gasoline from another DH.4B, A.S. 23-462, flown by Lieutenants Virgil S. Hine and Frank W. Seifert at Rockwell Field, San Diego, California, 27 June 1923. (U.S. Air Force)
For their accomplishment, all four officers were awarded the Distinguished Flying Cross.
The Airco DH.4 was a very successful airplane of World War I, designed by Geoffrey de Havilland. It was built by several manufacturers in Europe and the United States. The DH-4B was a rebuilt DH.4 with fuel capacity increased to 110 gallons (420 liters). The DH-4B was 30 feet, 6 inches (9.296 meters) long with a wingspan of 43 feet, 6 inches (13.259 meters) and height of 10 feet, 4 inches (3.150 meters). Loaded weight of the standard DH-4B was 3,557 pounds (1,613.4 kilograms).
In place of the Rolls-Royce Eagle VII V-12 of the British-built version, Army Air Service DH-4s were powered by a water-cooled, normally-aspirated, 1,649.336-cubic-inch-displacement (27.028 liter) Liberty L-12 single overhead cam (SOHC) 45° V-12 engine with a compression ratio of 5.4:1. The Liberty produced 408 horsepower at 1,800 r.p.m. The L-12 as a right-hand tractor, direct-drive engine. It turned turned a two-bladed fixed-pitch wooden propeller. The Liberty 12 was 5 feet, 7.375 inches (1.711 meters) long, 2 feet, 3.0 inches (0.686 meters) wide, and 3 feet, 5.5 inches (1.054 meters) high. It weighed 844 pounds (383 kilograms).
The Liberty L12 aircraft engine was designed by Jesse G. Vincent of the Packard Motor Car Company and Elbert J. Hall of the Hall-Scott Motor Company. This engine was produced by Ford Motor Company, as well as the Buick and Cadillac Divisions of General Motors, The Lincoln Motor Company (which was formed by Henry Leland, the former manager of Cadillac, specifically to manufacture these aircraft engines), Marmon Motor Car Company and Packard. Hall-Scott was too small to produce engines in the numbers required.
The DH-4B had a maximum speed of 128 miles per hour (206 kilometers per hour), service ceiling of 19,600 feet (5,974 meters) and range of 400 miles (644 kilometers).
The first mid air refueling near San Diego, California, 27 June 1923. (U.S. Air Force)
Convair B-36A-1-CF 44-92004, the first B-36A built. (U.S. Air Force)
26 June 1948: The 7th Bombardment Wing, Very Heavy, at Carswell Air Force Base, Fort Worth, Texas, received the United States Air Force’s first Consolidated-Vultee Aircraft Corporation (“Convair”) B-36A, a six-engine, very long range heavy bomber. Its mission was to serve as a nuclear-capable deterrent until the Boeing B-52 Stratofortress came into service five years later. A total of 22 B-36As were delivered by February 1949. These were not armed and were used for crew training. Most were later converted by Convair to RB-36E reconnaissance bombers, beginning in 1950.
The B-36A differed from the XB-36 prototype in several areas, but two features were the most apparent: The cockpit had been completely revised and now covered by a large dome. The single-wheel main landing gear was replaced by four-wheel bogies to better spread the airplane’s weight over the runway surface.
A crew of thirteen airmen with their Convair B-36A-10-CF Peacemaker, 44-92013, at Carswell AFB, 1949. (LIFE Magazine via Jet Pilot Overseas)
The B-36A was 162.1 feet (49.4 meters) long with a wingspan of 230.0 feet (70.1 meters) and overall height of 46.8 feet (14.3 meters). The wings had 2° dihedral, an angle of incidence of 3° and -2° twist. The wings’ leading edges were swept aft to 15° 5′. The airplane’s total wing area was 4,772 square feet (443.33 square meters). Its empty weight was 135,020 pounds (61,244 kilograms). The combat weight was 212,800 pounds (96,524 kilograms) and maximum takeoff weight (MTOW) was 310,380 pounds (140,786 kilograms).
Convair B-36A 44-92015 at Carswell Air Force Base.
The initial production version of the Peacemaker was powered by six air-cooled, supercharged, 4,362.5 cubic-inch-displacement (71.489 liter) Pratt & Whitney Wasp Major R-4360 Pusher (R-4360-25) four-row, 28-cylinder radial engines rated at 2,500 horsepower at 2,550 r.p.m. at 37,000 feet (11,278 meters), and 3,000 horsepower at 2,700 r.p.m. for takeoff. Each engine drove a 19-foot (5.791 meter) three-bladed propeller through a 0.381:1 gear reduction. The R-4360-25 was 9 feet, 1.75 inches (2.788 meters) long and 4 feet, 4.50 inches (1.334 meters) in diameter. It weighed 3,483 pounds (1,580 kilograms).
Convair B-36A 44-92015
The six radial engines gave the bomber a maximum speed of 300 knots (345 miles per hour/556 kilometers per hour) at 31,600 feet (9,632 meters). It took 53 minutes for the giant airplane to climb to an altitude of 20,000 feet (6,396 meters). The service ceiling for the B-36A was 39,100 feet (11,918 meters), and combat ceiling was 35,800 feet (10,912 meters). The ferry range was 9,136 miles (14,702 kilometers).
The B-36As initially carried no defensive armament. The maximum bomb load was seventy-two 1,000 pound bombs (total, 72,000 pounds/32,659 kilograms) carried in four internal bomb bays. With a bomb load of 10,000 pounds (4,536 kilograms), the B-36A had a combat radius of 3,370 nautical miles (3,878 miles/6,241 kilometers).
Designed during World War II when nuclear weapons were unknown to aeronautical engineers, the bomber was designed to carry up to 86,000 pounds (39,009 kilograms) of conventional bombs. It could carry a single 43,600 pound (19,777 kilogram) T-12 Cloudmaker, a conventional explosive earth-penetrating bomb, or, later, several Mk.15 thermonuclear bombs. By combining the bomb bays, one Mk.17 15-megaton thermonuclear bomb could be carried.
The sixteenth B-36A, 44-92020, after conversion to the RB-36E reconnaissance configuration. (U.S. Air Force)
The RB-36E reconnaissance bomber carried a crew of 22. The radial engines were upgraded to R-4360-41s which increased takeoff horsepower with water injection to 3,500 at 2,700 r.p.m. at Sea Level. Four General Electric J47-GE-19 turbojet engines were added in two two-engine pods at the outer end of each wing. These changes significantly increased the airplane’s maximum speed and altitude capability and reduced the required takeoff distance by 25%. Fourteen reconnaissance cameras were installed. There were four additional radomes on the belly and numerous external antennas for electronic intelligence gathering.
The empty weight of the RB-36E increased to 164,238 pounds (74,497 kilograms) and the maximum takeoff weight to 370,000 pounds (167,829 kilograms).
The maximum speed of the RB-36E was 363 knots (418 miles per hour/672 kilometers per hour) at 38,200 feet (11,643 meters). Its service ceiling was 46,400 feet (14,143 meters).
The reconnaissance bomber carried eighty 188 pound (85.3 kilogram) T-56 photo flash bombs. Defensive armament consisted of sixteen M24A1 20 mm autocannon in five remotely-operated turrets. 9,200 rounds of ammunition were carried.
Between 1946 and 1954, 384 B-36 Peacemakers were built. They were never used in combat. Only five still exist.
The first Consolidated-Vultee B-36A, 44-92004, was flown to Wright Field, Dayton, Ohio, for structural testing. Redesignated YB-36A, it was tested to destruction.
Convair YB-36A 44-92004 under structural testing at Wright Field. (U.S. Air Force)
The name, “Peacemaker,” was suggested by a Convair employee. It is a reference to the Colt Model 1873 Single-Action Army® revolver, the classic “six-shooter” of the American frontier, which is also known as the Peacemaker®.
U.S. Air Force Douglas C-47 Skytrain transports unloading supplies at Flughafen Berlin-Templehof, Berlin, 1948. (U.S. Air Force)
26 June 1948: 32 United States Air Force Douglas C-47 Skytrain transports flew 80 tons of supplies to Berlin, the first day of the Berlin Airlift.
At the height of the Cold War, the Union of Soviet Soviet Socialist Republics, occupying eastern Germany following World War II, blockaded the Allied portions of the city of Berlin, cutting off all transportation by land and water. This was followed by the building of the Berlin Wall. The western part of the city was now completely isolated. Josef Stalin hoped to force Britain, France and the United States to abandon Berlin, giving the communists complete control of the devastated country.
Soviet T-55 tanks at Checkpoint Charlie, one of just three access points to the Allied sectors of Berlin. (Central Intelligence Agency)
General Curtis LeMay was asked to transport the needs of the city by air. It was calculated that they would need to supply seventeen hundred calories per person per day, giving a grand total of 646 tons of flour and wheat, 125 tons of cereal, 64 tons of fat, 109 tons of meat and fish, 180 tons of dehydrated potatoes, 180 tons of sugar, 11 tons of coffee, 19 tons of powdered milk, 5 tons of whole milk for children, 3 tons of fresh yeast for baking, 144 tons of dehydrated vegetables, 38 tons of salt and 10 tons of cheese. In total, 1,534 tons were needed daily to keep the over two million people alive. Additionally, the city needed to be kept heated and powered, which would require another 3,475 tons of coal and gasoline.
A U.S. Air Force Douglas C-54 Skymaster on approach to land at Flughafen Berlin-Templehof.
At the height of the airlift, one airplane was landing every 30 seconds. By the end, more supplies were arriving by air than had previously come by rail. The airlift ended 30 September 1949.
2,326,406 tons of food, medicine and coal had been delivered.
101 aviators lost their lives.
A Douglas C-47 Skytrain clears the rooftops after takeoff from Berlin-Templehof. (Unattributed)
26 June 1942: The Grumman XF6F-1, Bureau of Aeronautics serial number (Bu. No.) 02981, prototype for the Navy and Marine Corps F6F Hellcat fighter, with Grumman’s Chief Engineer and Test Pilot Robert Leicester Hall flying, made a 25-minute first flight at the Grumman Aircraft Engineering Corporation plant, Bethpage, Long Island, New York.
The first Hellcat was powered by an air-cooled, supercharged, 2,603.737-cubic-inch-displacement (42.688 liters) Wright Aeronautical Division Twin Cyclone GR2600B676 (R-2600-10) two-row, 14-cylinder radial engine. This engine had a compression ratio of 6.9:1 and required 100-octane aviation gasoline. The R-2600-10 was rated at 1,500 horsepower at 2,400 r.p.m. at Sea Level, and 1,700 horsepower at 2,600 r.p.m. for takeoff. It turned a three-bladed Curtiss Electric propeller through a 0.5625:1 gear reduction. The R-2600-10 was 4 feet, 6.26 inches (1.378 meters) in diameter and 6 feet, 2.91 inches (1.903 meters) long. It weighed 2,115 pounds (959 kilograms).
Beginning with the second prototype, Bu. No. 02982, the Pratt & Whitney Double Wasp SSB2-G (R-2800-10) 18-cylinder engine became the standard powerplant. The R-2800-10 was an air-cooled, supercharged, 2,804.4-cubic-inch-displacement (45.956 liter), twin-row 18-cylinder radial engine with water injection. The engine had a compression ratio of 6.65:1 and was rated at 1,550 horsepower at 2,550 r.p.m. at 21,500 feet (6,553 meters), and 2,000 horsepower at 2,700 r.p.m. for takeoff, burning 100-octane gasoline. The engine drove a three-bladed Hamilton Standard Hydromatic constant-speed propeller with a diameter of 13 feet, 1 inch (3.988 meters) through a 2:1 gear reduction. The R-2800-10 was 4 feet, 4.50 inches (1.334 meters) in diameter, 7 feet, 4.47 inches (2.247 meters) long, and weighed 2,480 pounds (1,125 kilograms), each. The engine weighed 2,480 pounds (1,125 kilograms).
Grumman XF6F-1 Hellcat Bu. No. 02981 in flight. (Northrop Grumman)
The first prototype was quickly re-engined to the Pratt & Whitney radial and redesignated XF6F-3. Bob Hall flew it with the new engine on 30 July 1942. A few weeks later, 17 August, the Hellcat’s new engine failed and Hall crash-landed at Crane’s Farm. The airplane was moderately damaged and Hall was seriously injured.
Grumman XF6F-3 Bu. No. 02981 after crash landing in a field at Crane’s Farm, Long Island, New York, 17 August 1942. (Northrop Grumman)
The airplane was rebuilt and continued in the test program. It was eventually converted to the XF6F-4 with a two-speed turbocharged Pratt & Whitney Double Wasp 2SB-G (R-2800-27) which produced 2,000 horsepower at 2,700 r.p.m. It was armed with four 20 mm cannon.
The first prototype Hellcat was converted to the XF6F-4 configuration, seen here at NACA, Langley Field, Virginia in 1944. (NASA)
The Grumman F6F-3 Hellcat is single-place, single-engine fighter designed early in World War II to operate from the U.S. Navy’s aircraft carriers. It is a low wing monoplane monoplane of all metal construction. The wings can be folded against the sides of the fuselage for storage aboard the carriers. Landing gear is conventional, retractable, and includes an arresting hook.
The F6F-3 is 33 feet, 7 inches (10.236 meters) long with a wingspan of 42, feet 10 inches (12.842 meters) and overall height of 14 feet, 5 inches (4.394 meters) in three-point position. It has an empty weight of 9,207 pounds (4,176 kilograms) and gross weight of 12,575 pounds (5,704 kilograms).
A Grumman F6F Hellcat ready for takeoff from an Essex-class aircraft carrier, circa 1943. (U.S. Navy)
The F6F-3 Hellcat was powered by a Pratt & Whitney Double Wasp SSB2-G (R-2800-10W) engine with water injection, rated at 2,000 horsepower at 2,700 r.p.m. for takeoff, using 100/130 octane aviation gasoline. The normal power rating was 1,550 horsepower at 2,550 r.p.m. at 22,500 feet (6,858 meters). The engine drove a three-bladed Hamilton Standard Hydromatic constant-speed propeller with a diameter of 13 feet, 1 inch (3.988 meters) through a 2:1 gear reduction. The engine weighed 2,480 pounds (1,125 kilograms).
Two Grumman F6F-3 Hellcat fighters, Summer 1943. (U.S. Navy)
In clean configuration, the F6F-3 had a maximum speed of 321 miles per hour (517 kilometers per hour) at Sea Level, and 384 miles per hour (618 kilometers per hour) at 18,000 feet (5,486 meters). It could climb to 10,000 feet (3,048 meters) in 3.2 minutes, and to 20,000 feet (6,096 meters) in 7.0 minutes. The service service ceiling was 38,800 feet (11,826 meters). It had a combat radius of 335 nautical miles (386 miles/620 kilometers). The maximum ferry range was 1,540 miles (2,478 kilometers).
The Hellcat’s armament consisted of six air-cooled Browning AN-M2 .50-caliber machine guns, mounted three in each wing, with 2,400 rounds of ammunition.
The Grumman Hellcat was the most successful fighter of the Pacific war, with a kill-to-loss ratio of 19:1. It was in production from 1942 to 1945 and remained in service with the United States Navy until 1956. A total of 12,275 were built by Grumman at Bethpage. This was the largest number of any aircraft type produced by a single plant.
High humidity creates visible propeller tip vortices as this Grumman F6F-3 Hellcat prepares to takeoff from USS Yorktown (CV-10), November 1943. (U.S. Navy)
Robert Leicester Hall
Robert Leicester Hall was born at Taunton, Massachussetts, 22 August 1905. He was the son of Bicknell Hall, a mechanical engineer, and Estella Beatrice Lane Hall.
Hall attended the University of Michigan, graduating in 1927 with Bachelor of Science degree in Mechanical Engineering (B.S.M.E.).
In 1929 he went to work for the Fairchild Airplane Manufacturing Company at Farmingdale, New York. While there, Hall met his first wife, Eugenie, a secretary at the plant. They were married in 1930, and lived in a rented home on St. James Avenue, Chicopee City, Massachusetts. Their son, Robert Jr., was born 5 November 1931.
Granville Brothers Gee Bee Model Z, NR77Y, City of Springfield.
Also in 1931, Hall began working for Granville Brothers Aircraft at Springfield, Massachusetts. He designed the Gee Bee Model Z Super Sportster air racer. He left Granville Brothers in 1933 to go to work for the Stinson Aircraft Company in Dayton, Ohio. There he designed the Stinson Reliant.
A Stinson SR-8E Reliant, NACA 94, at the Langley Research Center, 5 August 1936. (NASA)
In 1936, Bob Hall became the Chief Engineer for the Grumman Aircraft Engineering Corporation, Bethpage, Long Island, New York. He designed the F4F Wildcat, F6F Hellcat, F7F Tigercat, and F8F Bearcat fighters, and the TBF Avenger torpedo bomber. As corporate vice president, he supervised the design of the F9F Panther and Cougar jet fighters.
Hall married his second wife, Rhoda C. Halvorsen, 18 January 1939, at New York City, New York.
Hall retired from Grumman in 1970. Two of his sons, Eric and Ben Hall, founded Hall Spars and Rigging of Bristol, Rhode Island.
Robert Leicester Hall died at Newport, Rhode Island, 25 February 1991, at the age of 85 years.
Grumman F6F-3 Hellcat, Bu. No. 4778, Long Island, New York, circa 1942. (Rudy Arnold Collection/NASM)
Grumman F6F-3 Hellcat Bu. No. 26108, Long Island, New York, circa 1943. (Rudy Arnold Collection/NASM)
Northrop XB-35 taking off at Northrop Field, Hawthorne, California. (U.S. Air Force)Max R. Stanley (Photograph courtesy of Neil Corbett, Test and Research Pilots, Flight Test Engineers))
25 June 1946: Northrop Aircraft, Inc., experimental test pilot Max R. Stanley, flight test engineer Dale Schroeder and Orva H Douglas, Jr., flight engineer, made the first flight of the Northrop XB-35 “Flying Wing,” serial number 42-13603. They took off from the factory’s airfield at Hawthorne, California, and flew the prototype bomber to Muroc Army Air Field (now, Edwards Air Force Base). The initial flight lasted 55 minutes.
The Los Angeles Times reported:
Gigantic Flying Wing Triumphs in First Flight
Northrop 110,000-Pound Superbomber Soars 44 Minutes, makes Perfect Landing
Unleashed into the future, a huge and spectral devilfish bellowed up from the earth yesterday and soared eastward toward the morning sun—Northrop’s malevolent Flying Wing superbomber on her maiden test flight, Forty-four minutes later the ship made a perfect landing at Muroc Army Airfield.
Eerie, almost supernatural, she trundled to the west end of Northrop’s mile-long Hawthorne runway as the sun burned away the morning mists.
Thundering Take-off
For 45 minutes she stood motionless, a 172-foot knife blade, while her four 3000 h.p. engines turned eight coaxial pusher propellers into life.Then at 10:29 a.m. her whirling blades fused into blurred disks. Her thunder enveloped the field.
Interminably she seemed to hug the ground as Test Pilot Max Stanley held her charging 110,000 pounds down past the hangars, past the flight line, past the midfield control tower.
Monster Leaves Ground
For 30 thudding heartbeats—and as many seconds—the fantastic silver monster strained at the shackles of earth, hurtling at more than 100 m.p.h. toward the end of the runway.
Then at 3000 feet Stanley eased back the yoke. Sunlight skipped beneath the spinning wheels and the Wing lifted into her element under perfect control.
Vanishes Into Haze
In another 60 seconds she vanished into the haze, her wheels still down as Stanley gently tested her sinews. Below, and to the right of his bubble canopy, Co-pilot Fred C. Bretcher stared ahead through plexiglas in the leading edge, and just aft of the pilot, Engineer O. H. Douglas watched her pulse in the needles of scores of instruments.
In an easy climb, Stanley took the superbomber to 10,000 feet over the flat lands between the San Gabriel Mountains and the sea and then banked her slowly north and inland toward Muroc.
Settles to Runway
At the Muroc test field, the strip was cleared and ready. Spectators watched the incredible ship circle once and then gently settle to the runway as gently as a tuft of cotton and roll to stop in 3000 feet.”She handled beautifully,” grinned Stanley.
The outgrowth of years of engineering, she followed the secret testing of a parade of small wings, and her designer, John K. Northrop, is confident she’ll carry more bombs farther and faster than any other airplane ever built.
Fourteen more of the giants will be built under Northrop’s contract with the Army.
—Los Angeles Times, Vol. LXV, Wednesday Morning, 26 June 1946, Page 1, Columns 5 and 6
The Los Angeles Daily News reported:
Flying wing passes tests
Everybody who had anything to do with it was happy today over the 44-minute maiden flight of Northrop’s flying wing.
The bat-like plane, a 104-ton monster bomber, met all expectations during the 85-mile flight from Northrop Field to Muroc Army Air Base.
“The wing handled just as I expected it would,” veteran test pilot Max Stanley declared after landing the giant ship. “We were delighted with its performance and the plane fully came up to our expectations.”
Officials of Northrop Aircraft, who witnessed the initial take-off, said the flight had justified their confidence in the wing.
The ship, a tailess airplane with a bat-like appearance, is the latest in a series of 15 Northrop designed flying wings and was built at a cost of $13,000,000 for the army.
—Daily News, Wednesday, 26 June 1946, Page 3, Column 1
The flight test crew of the Northrop XB-35 at Northrop Field, Hawthorne, California, 1946. Left to right, Dale Schroeder, flight test engineer; Orva H Douglas, Jr., flight engineer; and Max Stanley, test pilot. (Unattributed)
The XB-35 was designed as an aerodynamically efficient heavy bomber. It had a very unusual configuration for an aircraft of that time. There was no fuselage or tail control surfaces. The crew compartment, engines, fuel, landing gear and armament was contained within the wing. It was 53 feet, 1 inch (16.180 meters) long, with a wingspan of 172 feet (52.426 meters) and overall height of 20 feet, 1 inch (6.121 meters). The prototype weighed 89,560 pounds (40,624 kilograms) empty, with a gross weight of 180,000 pounds (81,647 kilograms).
The Wing defined the airplane. It had an aspect ratio of 7.4:1. The wing’s root chord was 37 feet, 6 inches (11.430 meters). The wing was 7 feet, 1.5 inches (2.172 meters) thick at the root. The tip chord was 9 feet, 4 inches (2.844 meters). There was 0° angle of incidence at the root, with -4° of twist, and 0° 53′ dihedral. The leading edge was swept aft 26° 57′ 48″, and the trailing edge, 10° 15′ 22″. The wing’s total area was 4,000 square feet (371.6 square meters).
This view of the first prototype Northrop XB-35, 42-13603, the “Flying Wing,” on the ramp at Muroc Air Force Base shows the pusher arrangement of four-bladed contra-rotating propellers. In the background, a turbojet-powered Northrop YB-49 is in a steep bank. (U.S. Air Force)
The XB-35 was powered by four air-cooled, supercharged and turbocharged 4,362.49 cubic-inch-displacement (71.49 liter) Pratt & Whitney Wasp Major TSB1P-RGD (R-4360-17 or -21) four-row 28-cylinder radial engines with a compression ratio of 7:1. The R-4360-17 was rated at 2,500 horsepower at 2,550 r.p.m at 40,000 feet (12,192 meters), and 3,000 horsepower at 2,700 r.p.m., for takeoff. It could maintain the takeoff rating to an altitude of 40,000 feet (12,192 meters) for Military Power. The engines were mounted completely inside the wing and were connected to a remote propeller drive unit by drive shafts. The engines were direct drive, while the propeller gear boxes had a 0.381:1 reduction ratio. The R-4360-17 was 5 feet, 7.00 inches (1.702 meters) long, 4 feet, 4.50 inches (1.334 meters) in diameter, and weighed 3,306 pounds (1,499.6 kilograms).
Northrop XB-35 42-13603 in flight with early contra-rotating propellers. (U.S. Air Force)
The propellers were dual three-bladed contra-rotating assemblies located in pusher configuration at the wing’s trailing edge. (These were quickly changed to four-bladed propellers, which were smoother in operation and more efficient.)
Northrop XB-35 42-13603. (U.S. Air Force)
The XB-35 had a cruising speed of 183 miles per hour (295 kilometers per hour) at 39,700 feet (12,100 meters) and maximum speed was 391 miles per hour (629 kilometers per hour) at 35,000 feet (10,668 meters). With a crew of nine, and another six relief crewmembers, the bomber had a range of 8,150 miles (13,116 kilometers).
The production Northrop B-35 would have been armed with twenty .50-caliber machine guns for defense and a maximum bomb load of 51,200 pounds (23,223 kilograms).
Underside of a Northrop XB-35. (U.S. Air Force)
The XB-35 was plagued by unresolved problems with the propeller gear boxes which eventually forced Jack Northrop to ground the aircraft until the engine and propeller manufacturers could come up with a solution, which was to change from piston to turbojet engines. That version became the YB-49. Because of the continuing problems, though, 42-13603 was grounded after only 19 flights, and with its sister ship, XB-35 42-38323, was scrapped in August 1949.
