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Artistic drawing of Northrop B-49
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. |
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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.
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"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." |
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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. |
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Probably the most glowing Wright-Field report on an airplane design by U.S. Army Air Corps - U.S.A.F. was reflected in General Arnold's September 19, 1939 letter to Secretary of War.
----start of General Arnold's letter to Secretary of War Woodring---
September 19, 1939
The basic principle of the lifting fuselage as developed by V. J. Burnelli since 1919 is now in such an advanced stage that it is extremely important for the Air Corps to experiment further with it with a view to reducing it to military practice.
From studies of the research made by the Burnelli Co., the NACA and the Air Corps the military adaptability of the basic design has the following advantage over the orthodox streamlined deadweight fuselage.
- The coefficient of drag is the lowest known for any useful airplane today.
- The coefficient of lift is greater.
- The lifting fuselage has distinct advantages for the installation of power plants, bombs, armament and all other accessories over the streamlined fuselage.
- From wind tunnel tests already conducted by the NACA and NYU the performance is exceptionally' good in every phase.
- The design embodies extremely good factors of safety--considerably higher than the streamlined fuselage type.
- The design is simple of construction and in the opinion of the Air Corps lends itself to high speed production better than any design and therefore the valuable time element involved in all production contracts can be taken advantage of to its fullest extent.
- It is apparently a cheaper airplane to build because of the time element referred to in 6 above.
It is to be remembered that Mr. Burnelli was the first to reduce to practice the use of smooth skin surface on airplanes in cooperation with the Material Division under Maj. Carl Green's supervision.
We understand that the present company has no affiliation with the British Company manufacturing under the Burnelli patents. We are informed by the company that the British have built one commercial article under the designs of a ship built by Mr. Burnelli in 1929, and that this design only resembles the designs submitted to the Air Corps in basic principles. We also understand that this airplane was tested at Farnsborough by the RFC with excellent results, substantiated by a cable from the British manufacturer, a copy of which we have.
We have also seen articles in various British technical magazines that are extremely flattering to the basic design involved and the report of the test pilot, Mr. Clyde Pangborn, would indicate that the design embodies extremely good flying qualities under all conditions of a very severe flight test required by the RFC.
It is, therefore, the opinion of the Air Corps that this project should be carried through to its fullest experimental possibilities and probably to the ultimate conclusion for the purchase of a prototype.
I am informed by the Burnelli Company that in an effort to cooperate with the Air Corps they have proceeded with the required work and at this moment it is seventy percent completed.
In my opinion it is essential, in the interest of the national defense, that this procurement be authorized.----end of General Arnold's letter to Secretary of War Woodring---
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"The Committee recommends that the Air Corps inform both the Central Aircraft Corporation and V.J. Burnelli Airplanes, Inc., and any other concern which may later possible become interested in the Burnelli 'lifting fuselage', that this design is of no interest to the Air Corps and that for this reason, no further correspondence, consultations, or reviewing of data embodying this design will ever again be considered by the Air Corps or the Materiel Division." |
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Post Title → Burnelli or Northrop Flying Wing
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