In one of his postings, the skeptical Boeing engineer made comments which showed that he didn't understand the difference between the Northrop FLYING-WING and the Burnelli LIFTING-BODY principle of design as he lumped the two together. The text below which was posted to the Vortex list explains the difference.

---- Begin Original Message ------------
---- From: Chalmers H. Goodlin

NORTHROP:

---Beginning of Harry Schultz letter segments---

The accompanying 3-view drawings of the Northrop B-49 and a contemporary Burnelli clearly reveal the distinction between the 2 approaches to the flying wing. Burnelli concentrates 60% of the structural weight around the passenger cabin to which is attached the landing gear and engines, the fuel tanks being isolated in the outer wings [Click here for illustrating diagrams]. Because of longer load paths, Northrop distributes the structure throughout the span and places the passengers, engines and fuel tanks all virtually in the same container, the landing gear being attached to fuel tank supporting structure. When the Burnelli UB-14 crashed, the fuselage remained intact; there was no fire and the crew survived without injury. In the Northrop B-49 crash, the entire airplane broke into fragments and 5 crew were killed. There is little change in the payload weight capability of the two designs, but when examined from the standpoint of floor area and internal volume, the difference is enormous. Because of this, Burnelli design lends itself to both military and commercial applications without restrictions, but Northrop could only be viable for specific military use.

USAF reports said the B-49 was extremely unreliable and very difficult to fly on a bombing mission because of continual yawing and pitching caused by control arrangements. Burnelli's RB-1 and RB-2 (1921 / 1924) had their control arrangements fixed adjacent to trailing edge of wing-shaped fuselage, a practice later adopted by Northrop, but flight operation of these aircraft disclosed directional and longitudinal stability were marginal. Thus when Burnelli built the CB-16 in 1928, he mounted twin-booms from the airfoil fuselage to carry rudders and elevator an appropriate distance rearward, this practice culminating in near perfect flight stability in all axes. Consequently, Burnelli maintained the twin-boom appendage in all following aircraft with the intent to gradually merge it into the pure Burnelli flying wing, as aircraft grew larger. Ironically, the B-49 flight test results proved the correctness of the brilliant Burnelli concept (Burnelli photo gallery). This superiority was also confirmed in NACA report TN1649 [5 MB PDF] issued in October 1948, summarizing NACA full-scale wind tunnel tests at Langley Field of a twin-boom Burnelli type with an all-wing tailless design, which stated:

"The maximum trimmed lift coefficient of 1.31 for the twin boom airplane and 1.03 for the all-wing plane gave stalling speeds at sea level of 82 and 92 mph respectively. The investigation indicated both planes will have essentially the same performance in range and climb rate, but reduction in drag for the twin-boom plane at high-lift coefficients represented increased performance over the all-wing plane in take-off. The elevator of the twin-boom plane ranged from -0.0055 to -0.0072 per degree for all conditions tested and was about twice that of the all wing configuration. The twin-boom plane will have about a 7% shorter take-off run and requires about 9% less distance to clear a 50ft obstacle than the all-wing plane. If both planes are designed to meet the same stall speed, the total wing area required will be reduced over 20%, or 1/5th, thereby permitting the outboard wing panels to be of reduced chord and thickness, with corresponding reduction of drag and weight of wing structure. Also, flaps of higher lift qualities can be employed on the air-foil body and wings with the twin boom design because of the greater longitudinal stability and control."

---End of Harry Schultz letter segments---

Finally, the fact that Northrop misappropriated Burnelli's 1940s technology in constructing the B-2 again shows that Burnelli was always right and proves that the Northrop flying wing was wrong.