B-49 Flying Wing

By on Monday, September 17th, 2007

The B-49 Flying Wing was the jet-propelled version of Northrop Company’s XB-35 bomber, which did not show enough capability to stay on in the US Air Force active inventory. The XB-35 attained a maximum speed of 391 mph and the fuselage provided 4,000 square feet of lifting area. The aircraft carried 18,000 gallons of fuel and had a range of 10,000 miles with a 41,200 pound bomb load. The authority wanted more. Northrop therefore incorporated eight Allison J35 engines, each delivering 3,750 pounds of thrust and named the aircraft as B-49 Flying wings. The engines were to be fed by intakes cut into the leading edges of the wing. The new build engine gave the aircraft a top speed of 510 mph, or more than 100 mph faster than its predecessor.

General concept of a jet powered flying wing offered many potential including increased range and speed; efficient airframe; considerable weight-lifting capability; and smaller aircrew. The payload of the aircraft could be distributed evenly along the entire span, eliminating heavy internal bracing. Similarly, bomb bays no longer had to be confined to a narrow fuselage tube, but could be spread across the underside of the wing. The YB-49 was a sleek airplane, upper surfaces marred only by four wing fences and small auxiliary fins. Manufacturer added Wing fences to control the span wise movement of air toward the wingtips. Since the addition of jet power promised a marked improvement in the performance of the flying wing, work on the YB-35 project was abandoned and plans were made to convert all the YB-35 airframes beyond the first to YB-49 configuration. The airframes for the second and third YB-35 (42-102367 and 42-102368) were selected for modification to YB-49 configuration. For long flights, an additional off-duty crew of six members could be carried in quarters in the tail cone just aft of the flight section.

The YB-49 initially showed great promise, but flight testing soon revealed that it also had a lot of things to worry about. It had problems with the engineering design and with the jet propulsion. The YB-49 proved to be clearly inadequate for the higher speeds needed for a jet bomber; as a result, it flew about 100 mph slower than the contemporary XB-47. Additionally, the bomb bays of the aircraft were too small for carrying the nuclear weapons. The cockpit layout was ill-designed; there were no ejection seats. To leave the aircraft, the pilot had to rotate his seat 90 degrees, lower it several feet, and walk to a hatch 15 feet away. The co-pilot’s seat was at the leading edge giving a poor view.

Stability problems were identified, which could not be corrected with the existing technology of that time. The manufacturer failed to foresee the critical control requirements, especially for a system that could anticipate and correct problems before the pilot was aware of them. The Air Force’s realized that the YB-49 was sloppy in turns, and took quite a long time to steady up for an effective bombing run. Making things worse, it could not provide the necessary margin of flight safety.

Northrop test pilots flew the first YB-49 for almost 200 hours, accumulated in some 120 flights. Air Force pilots completed about 70 hours of flight time in the first YB-49, totaled in some 20 flights. The second YB-49 carried out some 24 flights with Northrop crews for a total of about 50 hours.

Capt. Glen W. Edwards wrote in his dairy that “YB-49 was the darndest airplane I’ve ever tried to do anything with. Quite uncontrollable at times”. He eventually died on June 5, 1948, when the aircraft departed from controlled flight and broke apart in the sky northwest of the base. Col. Albert Boyd, commander of Muroc in late 1949, renamed the base after Capt. Glen W. Edwards. On Dec. 8, 1949, Muroc Air Force Base was officially designated as Edwards Air Force Base.

In spite of the crash, the Air Force still had sufficient confidence in the YB-49 that they continued with plans for the conversion of nine of the remaining eleven YB-35 airframes to a basically similar RB-35B strategic reconnaissance configuration with 8 jet engines, with another airframe to be used as a static test vehicle. In addition, orders were placed for 30 new RB-49s to be built from scratch. On March 15, 1950, during a testing of the aircraft’s stabilizer response, the nose wheel started an aggressive shimmy. Before the aircraft was brought back under control, the nose landing gear collapsed.

The Northrop than modified the YB-49 Flying Wing bomber and named it YRB-49A with inclusion of six jet engines. The six engines were installed in pods below the wing, making room for more fuel. The YRB-49A promised a 400-mph cruise speed at 35,000 feet. It had camera equipment installed in the center and aft-fuselage. The center fuselage was tailored for a radar navigation system. The gunner’s bubble was also deleted.

On May 4, 1950, the YRB-49A made its maiden flight. Only thirteen flights were carried out before the aircraft was put into storage. It was flown one more time on 26 April 1951 from short term storage facilitiies at Edwards AFB to long term storage at Northrop’s Ontario airport, California. It was finally scrapped in the late 1953. None of the airframes were saved for museums or display purposes.

The movie ‘War of the Worlds’ filmed in 1952 used stock footage of one of the YB-49s. In the movie, it was the plane which delivered a nuclear bomb onto the attacking Martian force. Many people confuse this plane with the B-2 stealth comber, which was basically developed much later.

The B-49 was replaced by the more conventional B-36.

It is rather fair to say that Northrop’s YB-49 was simply a generation ahead of its time. In other words, wrong plane at the wrong time.

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