21st of October 1947
Updated: Oct 21, 2021
It was on this day in aviation history that the flying wing, the Northrop YB-49 took off for the first time from Northrop Field in California, USA.
Northrop YB-49 42-102367 airborne for the first time.
With the Northr0p YB-49 project Northrop continued on the path of the flying wing project, the Northrop XB-35 and YB-35 projects. The two YB-49's were actually modified / converted YB-35 test aircraft.
Where the YB-35 was powered by P&W Wasp Major (R-4360-21) the YB-49 was powered by 8 Allison J35-A-15 turbojet engines. The YB-49 had a configuration that was unusual for the time. It was a true flying wing as everything was contained in the wing, cockpit, engines, landing gears and armament. With the absence of a tailplane, 4 small vertical fins provided the necessary yaw stability.
The results of the first test flight were so positive that it immediately was clear that this design had a lot more potential than its piston-powered ancestor. the first prototype set an unofficial endurance record by maintaining an altitude of more than 40.000 feet (12.200) meters for 6 1/2 hours.
A serious setback to the program occurred on the 5th of June 1948 when the second prototype of the YB-49 broke up in flight. Both outer wings broke off from the centre section of the aircraft. The exact cause is unknown, rumours at the time were saying that the aircraft was pulled out of a dive too sharply. All crew members (5) lost their lives the pilot Major Daniel Forbes and the Co-pilot Captain Glen Edwards had One of the broken-off wing sections
US Air Force Bases named after them. Forbes Air Force Base (currently operating as Topeka Regional) in Kansas and Edwards Air Force Base in California, In February 1949 Prototype #1 flew from Muroc Air Force Base (Currently known as Edwards Air Force Base) to Andrews Air Force Base, Washington DC, in 4 hours and 25 minutes. The return flight nearly ended in disaster when 4 of the eight engines had to be shut down due to oil pressure issues. After a successful emergency landing, it was found that the engines were not serviced after the flight from California to Washington DC. Industrial sabotage was suspected but not proven. The program came to an abrupt halt when the remaining prototype was lost during high-speed taxi tests on the 15th of March 1950. The nose wheel developed a severe shimmy, causing the nose gear to collapse., The ensuing fire completely destroyed the aircraft. Also in this incident industrial sabotage was suspected as the taxi trial was done with a full fuel load, which was abnormal. The program was cancelled the same day. The legacy of the YB-49 is carried on in the B-2 Stealth Bomber, during the development of this modern-day flying wing results from the Y-49 program were incorporated in the B-2. Early on in the YB-49 it already became clear that the aircraft had a very small radar cross-section. Something that was used in the development of the B-2. Specifications of the YB-49;
Length: 53 ft 1 in (16.18 m)
Wingspan: 172 ft 0 in (52.43 m)
Height: 15 ft 2 in (4.62 m)
Wing area: 4,000 sq ft (370 m2)
Empty weight: 88,442 lb (40,117 kg)
Gross weight: 133,569 lb (60,586 kg)
Max takeoff weight: 193,938 lb (87,969 kg)
Powerplant: 8 × Allison J35-A-15 turbojet engines, 4,000 lbf (18 kN) thrust each
Maximum speed: 493 mph (793 km/h, 428 kn)
Cruise speed: 365 mph (587 km/h, 317 kn)
Range: 9,978 mi (16,058 km, 8,671 nmi) maximum
Combat range: 1,615 mi (2,599 km, 1,403 nmi) with 10,000 lb (4,536 kg) bombload
Service ceiling: 45,700 ft (13,900 m)
Rate of climb: 3,785 ft/min (19.23 m/s)
Wing loading: 33 lb/sq ft (160 kg/m2)
Guns: 4 × .50 in (12.7 mm) machine guns (to be mounted in rotating "stinger" tail cone on all production aircraft)
Bombs: 16,000 lb (7,260 kg) of ordnance