Among the most badly handled, most interesting, most distorted, and most eclectic of aerospace history subjects isthe origin of the use of the circular, elliptical and annular wing platforms (shapes) in aircraft design.
A quick review of the writer's memory and library reveal that more than 50 aircraft have been designed, and/or built, using an ellipse or circle as a wing configuration. However, this listing is by no means a complete survey, only a brief overview of what can be located at hand. In fact, there is an entire U.S. Patent subclass (Class 244, Aeronautics; Subclass 21.2 Airplane, circular) dealing with aircraft using a circular wing platform. Likewise, a number of lighter-than-air or hybrid designs have appeared in the course of aeronautical history which also use the disc shape as a basis for the gas envelopeWhat is undoubtedly the first recorded circular aircraft was the product of the fertile imagination of an 18th Century Swedish scientist, philosopher and noted theologian named Emanuel Swedenborg (1688-1772)
Born in Stockholm on Jan. 29, 1688, he was the second son of Jesper Swedenberg. The family surname was transformed to "Swedenborg" after being enobled by the King of Sweden in 1719 and following Jesper's appointment as the Bishop of Skara. From 1710 to 1714 Emanuel Swedenborg traveled extensively throughout Europe following his education at Uppsala University; visiting England, Holland, France and Germany. An avid student of astronomy and mathematics, he is known to have met with John Flamsteed and Edmund Halley. While he is known to have studied the works of Isaac Newton, there is no evidence to support the contention that Swedenborg ever knew him. Nevertheless, it was during this period in his life that Swedenborg developed many ideas which were as far ranging as a method to calculate longitude based on the position of the moon, to plans for a submarine and a practical design for an aeroplane.
On Sept. 8, 1714, Swedenborg first wrote of his idea for an aircraft to his brother-in-law, Erik Benzelius. This was later followed by a complete written description which appeared in the fourth edition of Sweden's first scientific journal, Daedulus Hyperboreus, founded by Swedenborg in the same year (1716). During this time, Charles XII of Sweden also appointed Swedenborg as Assessor Extraordinary at the Royal College of Mines, which enabled him to have significant impact on Sweden's metal-mining for the next 30 years, during which he was elevated to the position of Assessor. Moreover, his work is of great historical significance, for Daedulus Hyperboreus contains the first detailed technical description of a flying machine of any type.
Fortunately, the Stiftsoch Landesbibliotek at Linkoping (codex 14a, 1714) has Swedenborg's original manuscripts which include a sketch of Swedenborg's "Flying Saucer." The design is oval in shape; however, circular, square and rectangular planforms are also suggested in the 1716 text. The dimensions [*] of Swedenborg's aircraft are given as: 32' x 24' (603.2 sq') for an oval, 28' diameter (615.75 sq') for a circle, 25' x 25' (625 sq') for a square, and 20' x 30' (600 sq') for a rectangular surface. In all cases the central thesis of the Swedenborg ornithopter comprises of a central pilot's station measuring 6' wide, 4' long and 2' deep. Suggested materials for the pilot's basket include cork, leather and birch bark; nevertheless, both the main wing and secondary flapping wings were to be covered with sailcloth.
On both sides of the basket area are a pair of flapping wings operated by the would-be pilot. These are described as having a length of 5' and a chord of 1.5' (7.5 sq' each). A coiled spring was also to be attached to the spars of the flapping wings to enable the pilot to operate the wings with greater ease.
Furthermore, like a design suggested by DaVinci, the flapping wings were intended to function as valves with hinges at the center of the chord, folding on the up-stroke and opening on the down-stroke. With aid of what he refers to as "the power of the wind," Swedenborg believed that the muscular weakness of the pilot would be more than compensated for by this system, and that by being able to alter the incidence angle of the flapping wings, they would also provide sufficient thrust for horizontal flight. While not entirely complete, there is at least a partial divorce of the lift and thrust components of flight, as the flapping wings are clearly not intended as the primary means of aerodynamic lift. A complete separation of these two systems would not come for another 85 years when Sir George Cayley designed his first fixed-Ying aircraft in 1799.
The oval wing of Swedenborg's machine is comprised of a wooden framework with eight lateral ribs. Both lateral and longitudinal camber are employed, the curvature being maintained by four beams spaced in pairs at right angles to each other. After carefully balancing the craft to ascertain its center of gravity, Svedenborg suggested that a vertical beam measuring about 8' in length be attached to the bottom of the pilot's basket. At the bottom end, a weight of 1 lispund (18.75 lbs) was to be attached to ensure pendulum stability. To support the entire machine, and presumably prevent the central beam from piercing the bottom of the basket, four diagonal beams were apparently attached to the sides of the pilot's basket. Swedenborg states that it "would do no harm" to attach wheels to the ends of the quadruped struts, but he does not specifically indicate they were necessary.
Alas, Swedenborg's flying saucer was never to be built. He did, however, wisely suggest that the aircraft first be tested as a ballasted glider, and that it be launched from a high place. Looking across the chasm of 280 years we can see the practical, as well as the impractical, aspects of his design. His work apparently influenced no one and is all but forgotten by most aerospace historians; but since his day, a number of successful circular platform aircraft have been built and flown. Although the idea was not to be taken up again for many years, it is worth noting that there were at least a dozen circular, elliptical or annular shaped aircraft designed and/or built in the United States and Canada prior to the First World War. Among them, Dr. Bell's Ring Rite of 1908, Ringert Jongewaard's flying disc of the 1880s, Robert B. Taylor's 1842 design for a convertiplane, George Francis Myers' 1904 annular quadruplane, and the interesting McCormick-Romme "Umbrella Plane" tested at Cicero Field near Chicago from 1912 to 1914.
Last year a disc-shaped airship was displayed at Washington, D.C., by a team of Russians for the first time, so it would seem that the idea is far from permanently disappearing from the polymorphic annals of aerospace despite the high aerodynamic drag penalty of circular platforms, particularly at transonic speeds.
The flying saucer, like the "flying house" stories of the late 19th Century and the "Great Airship Flap" of 1896-1897, is based on historical fact, which has evolved into distorted cultural mythology. Yes, there are flying saucers, and I for one, am open minded enough to admit that it is entirely possible for life to have arisen on a planet orbiting a distant star. But of all the flying saucers that can be positively identified, they are definitely the products of imaginative human beings, and among those humans is one by the name of Emanuel Swedenborg, an 18th Century man who designed the progenitor of what has become a 20th Century icon.
* According to The Prehistory of Flight, p. 233, footnote 5, Sweedenborg's unit of measurement, the ell, is about 2' (24n). However, Webster's Third New International Dictionary, p. 736, states that an ell is 2.25' (27"). Based on the latter, the overall dimensions and areas would be as follows: Oval, 36' * 27', 763.4 sq'; circle, 31.5' dia, 779.3 sq'; square, 28.125', 791 sq'; rectangle, 22.5' * 33.75', 791 sq'. Additionally, the dimensions of the pilot's basket would be 6.75' * 4.5' * 2.25'. The wings would measure 5.625' * 1.6875', 9.5 sq' (ea), and the rod for the pendulum weight would be 9' in length.
· Encyclopedia Britannica, Volume 21 (Spelman-Timmins). Chicago, etc.; William Benton, 1968. pp 503-504.
· Gibbs-Smith, Charles Harvard. Sir George Cayley's Aeronautics 1796 - 1855. London; Her Majesty's Stationary Office, 1962. pp 7-10.
· Hart, Clive, Ph.D. The Dream of Flight: Aeronautics From Classical Times to the Renaissance. London, 1972.
· ibid. The Prehistory of Flight. Berkeley, California; University of California Press, 1985. pp 146-151, 223.
· Swift, E. Swedenborg, The Man and his Works. 1932.
· Sigstedt, C.S. The Swedenborg Epic. 1953.
· Tafel, R.L. Documents Concerning the Life and Character of Emanuel Swedenborg, 3 Vol. 1875-1877.
· Trobrigdge, G. Swedenborg, Life and Teaching. 1944.
· Webster's Third New International Dictionary. Chicago, London, Toronto, Geneva, Sydney, Tokyo, Manila; Encyclopedia Britannica, Inc., 1966. p 736.
· Acton, Alfred. "The Mechanical Inventions of Emanuel Swedenborg." Philadelphia, 1939. pp 20-26.
· "Machine att Flyga i Wardet Enlight Utkast av Emanuel Swedenborg." Stockholm, 1960.
· Odhner, Carl Th. "Swedenborg's Flying Machine." New Church Life, October 1909, pp 582-591.
· Odhner, Carl Th. and Hugo Lj. Odhner. "Suggestions for a Flying Machine." Aeronautical Journal, July 1910, pp 118-122.
· Swedenborq, Emanuel. "Utkast til en Machine at Flyga i Wadret." Daedulus Hyperboreus. 4, October-December 1716, pp 80-83.
· Transactions of the International Svedenborg Congress. London, 1910, pp 45-46.
· Illinois State Library. Patent Classification Index.
· Stifts-Och Landesbiblioteck. Linkoping, codex 14a, 1714.
· Swedenborg, Emanuel. Opera quaedam aut inedita aut obsoleta de rebus naturalibus I, ed. Alfred H. Stroh (Holmiae 1907), p 226.