1948 07 9670642 20Mi SofMontgomery Ala 144 (Project Blue Book case file)

Flying Fuselages (Torpedo or Cigar-Shaped Body)

While the cigar or torpedo shaped body represents an efficient form for the fuselage of an airplane or the body of a guided missile, in neither case has it been used as a primary lift producing surface. However, an extension of the Pradtl theory of lift indicates that a Cuse-lage of the dimensions reported by the Eastern Airlines pilots in the Montgomery, Alabama, incident could support a gross weight of approximately 12,000 pounds at an arbitrarily chosen stalling speed of 150 miles per hour, conservatively estimated. The Pradtl theory probably gives very conservative values of maximum lift for bodies of this shape. If a lift coefficient twice as great where used (such a value has been given by a German scientist from Austria of his wind tunnel researches in Germany), a gross weight of 24,000 pounds could be supported at the assumed stalling speed.

b. Although the craft sighted by and was reported to be without wings or fins, it is possible it could have been equipped with extensible wings for take-off and landing, contained within the fuse-lage. In such a case a wing span of nearly 90 feet would be possible. If an aspect ratio of 5 were used (18 ft. mean aerodynamic chord), and if the wing design incorporated slots and flaps, the wing could support 115,000 pounds at a stalling speed of 150 mph. It is possible that the fuse-lage could also contribute lift with this arrangement, depending upon the incidence of the wing. This type of aircraft could also be partially supported in the take-off and landing condition by the vertical component of the jet thrust, if the landing and take-off took place with the fuse-lage axis, or the jet stream direction in a vertical or nearly vertical attitude. The further possibility that an extensible rotor, concealed within the fuse-lage, could have been used, would provide another method for landing and take-off that would allow wingless flight at very high speed. Such a design could result in a relatively large duration of flight and corresponding range.

c. While no stabilizing fins were apparent on the "flying fuselage" reported by and, it is possible that vanes with in the jet, operated by a gyro-servo system could have provided static stability, longitudinally and laterally. The same vanes could also have been used for accomplishing static balance or trim, as well as control for manuvering. A square tailed body of the type re-ported with the center of gravity sufficiently far forward can develop, approximately, a neutral stability and the possibility exists that definite static stability could be produced by a judicious use of flow-control slots located somewhere along the fuselage.

d. The above estimates regarding weight, controllability, stability, etc, are not intended to represent deductions regarding the exact nature of the torpedo or cigar-shaped aircraft which were sighted by the military pilots, and others, and are merely statements of possibilities, which are intended to show that such an aircraft could support and control itself by aerodynamic means. The propulsive system of this type of vehicle would appear to be a jet or rocket engine. The specific fuel consumption of engines of this type would be rather high. This, coupled with the fact that aerodynamic lift