The greatest exponent of the flying wing was John K Northrop who, along with 3 other men, helped found the Lockheed Company. After founding his own company, Northrop continued to experiment with flying wings and successfully flew the N-1M ‘Jeep’ in 1940. The Army Air Force Chief, General ‘Hap’ Arnold encouraged Northrop to investigate whether the flying wing principle could be applied to heavy bomber aircraft.
The XB-35 was the first flying wing bomber developed by Northrop and had a wing span of 172 feet. Two XB-35 prototypes were ordered by the Army Air Force in 1941and the aircraft first flew in Jun 1946. The XB-35 was a spectacular aircraft powered by 4 P&W Wasp Major engines each with double turbo superchargers driving eight coaxial counter-rotating four bladed pusher propellers. For self defence it was planned to equip the aircraft with 7 remote-control gun turrets firing a total of twenty 50 caliber machine guns. However, only the first two aircraft were propeller driven - the advent of the jet engine allowed the Army Air Force to instruct Northrop to install 8 Allison J-35-A-5 in the second and third aircraft and these were designated YB-49s and the aircraft first flew in Oct 1947. The YB-49 had a top speed of 520 mph a ceiling of 42,000ft and a range of 4450 miles. As a bomber it was capable of carrying a 10,000lb bomb load 4000 miles. However, this was less than half the range of the B-36 and what the Air Force was really looking for was a very long-range bomber. Although the YB-49 was over 100mph quicker than the XB-35, the early inefficient jet engines limited the effective range.
Nevertheless, after 20 months testing, it was decided that a reconnaissance role best suited the aircraft and a contract for 30 RB-49s was placed and it was decided to convert 10 B-35 aircraft to YRB-49 reconnaissance aircraft. Unfortunately, on 5 Jun 1948 the second YB-49 prototype piloted by Capt Glen Edwards crashed whilst descending after conducting CG stability tests at 40,000ft. Although the exact cause of the accident was never determined, it is believed that the aircraft exceeded the maximum permitted airspeed and broke up as a result. Muroc Air Base was later re-named Edwards Air Force base in honour of Capt Edwards. Sadly this crash lead to doubts about the whole flying wing programme. The first YB-49 was later destroyed in a high-speed taxiing accident at Edwards leaving the YRB-49A as the only flying wing still in operation.
The YRB-49A was a modified XB-35 converted to be a strategic reconnaissance aircraft with a top speed of around 550mph at 40,000ft and a range of 3500 miles. It was powered by 4 Allison J-35-A-19 engines buried in the wing . Two more J-35 engines were suspended in pods below the wing to allow room for more fuel in the wings, in addition, the engine pylons were designed to act as vertical stabilisers. To further help overcome stability problems, four vertical stabilisers were fitted to the trailing edge of the wing. Photographic equipment was installed in the tail cone bay to the rear of the centre section. The aircraft first flew on 4 May 1950, but encountered stability problems and plans were made to install a Honeywell stability device similar to that used by the Boeing B-47 Stratojet. However, when the aircraft was flown to the Northrop facility at Ontario International Airport in 1952 funding for the aircraft was suddenly dropped and after remaining in storage eventually in Oct 1953 the Air Force ordered that the YRB-49A be scrapped.
The YRB-49A was well ahead of its time and certainly had stability problems. However, these could have been resolved if sufficient funding had been made available. The Air Force wanted the faster Boeing B-47 Stratojet and the long-range Convair B-36 Peacemaker and the budget just didn’t stretch to the YRB-49A as well. Another factor may well have been the appointment to the Truman administration of a Secretary of the Air Force, Stuart Symington. Allegedly, it was later intimated to John Northrop that the Air Force would buy a number of B-49s if he agreed to Convair taking over Northrop and the merged company then building the aircraft - Northrop declined the offer and soon after the flying wings were cancelled.
That the YRB-49A would have made a very effective reconnaissance platform if its stability problems had been resolved is in little doubt. Furthermore, if the ‘stealthy’ characteristics of a flying wing had been identified, the aircraft might have been developed further by burying the pod-mounted engines in the wing. In this configuration, even with the small vertical stabilisers, the YRB-49A would have been very difficult to spot on radar and may well have lead to the development of a B-2 Spirit bomber many years earlier.