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Aviation History
1951
1951 - 2161.PDF
544 FLIGHT Mr. Stout's striking conception of a supersonic blended-hull configuration incorporating a 6O-<0y deadrise. HrGH-SPEED HYDRODYNAMICS . . . bridle-towed dynamically similar model was constructed in order to obtain a preliminary check on the hydrodynamic characteristics of the configuration. Preliminary towing tests were highly encouraging; after a series of minor revisions and adjustments in the step and spray-dam design, it was concluded that spray could be controlled adequately at the design gross weight, and that hydrodynamic stability was satisfactory. From these preliminary tests it was determined that the spray dam obtained its effectiveness by violently agitating the main spray blister and mixing it thoroughly with air. This aerated mass was deflected downwards with great force in a high-velocity jet and, because of the high content of entrained air, this water mass penetrated the free water surface with little or no rebound or reflection. Mr. Stout then reviewed the application of the basic cri- teria to an actual full-scale subsonic design. This led to the XP5Y-1 flying-boat which, fitted with four Allison T-40 turboprops, first flew in April, 1950. Initial flight tests cor- responded to the model results very closely; in fact, the hydrodynamic characteristics were of sufficient excellence to justify flying the aircraft at its design gross weight on its seventh flight, at which time it established the world's endurance record for turboprop aircraft. Dealing with the adaptation of transonic aircraft design to water-based operation, the lecturer said that it was obvious from the outset that extensive aerodynamic refinement of known hydrodynamic forms would result in poor hydro- dynamic performance without ever fully obtaining the aero- dynamic cleanliness required for transonic flight. It appeared logical, therefore, to start with an ideal aerodynamic con- figuration and, by means of extensive hydrodynamic re- search, to develop new principles and applications; these although different in concept, would result in the same de- gree of seaworthiness and stability normally associated with the best hulls of conventional forms. By this reasoning, it was obvious that the basic configura- tion must consist of a smooth, unbroken form using sections of high critical Mach number throughout. In order to secure elementary flotation it would also be necessary to supply sufficient volume of body so that engines, air intakes, jet exhausts and personnel would not be inundated. The com- bination of these two fundamental requirements and the liminary data obtained from the XB-46 studies, led logically to the blended wing/hull configuration. It was determined that straight transverse and buttock sections could be employed without altering the critical Mach number of the form. As a result of these geometric considerations it was also established that this elementary flotation body, by virtue of its inherently low centre of gravity and high water-plane inertia, would have static transverse ship stability, i.e., it would float upright without recourse to auxiliary devices such as wing-tip floats. By this means it became apparent that a true aerodynamic form could meet adequately, or in some cases exceed, many established hydrodynamic design criteria. Mr. Stout then discussed die four-year research programme devoted to the hydrodynamic characteristics of nine separate blended-hull configurations known as the "Skate" project. He included such items as the latitude that existed for the optimum selection of planing surface proportions, the in- fluence of linear warping, and details of the retractable spray dam and main step. He then referred to supersonic developments, saying that in view of the broad background and experience that had been gained with the Convair XF-92A 60 deg delta-wing land-based aircraft, it was natural that such an aerodynamic configuration should be employed in the supersonic hydro- dynamic-research programme. To account for the increased impact loads due to a higher take-off speed, the deadrise was increased to give the same structural load required for conventional design. With the power loadings that would be available, it was the lecturer's opinion that high-deadrise hulls held out great promise for successful rough-water operation at high planing speeds. Mr. Stout concluded by saying that the supersonic approach so far discussed might not be the most desirable solution to the problem. It had been presented more as an example of the line of thought that would provide a solution, rather than as the fact. With the research programme well into considerations of supersonic design, it was safe to say that the probability of achieving the original objective of this effort was excellent, and it was not too early to take serious cognisance of the existence of this versatile new weapon and give high-speed water-based aircraft serious consideration in strategic planning. YOUR BALL, SIRT HE following news story from Montreal not only seems too good for the spike (editorial home of lost causes), but even deserves printing exactly as received :— A man who claims to have helped build the "fantastic flying ball" which four northern New York state residents said they saw, says it is a plastic, egg-shaped balloon measuring about six feet across and powered by an electric motor. The ball, press report from Hogansburgh, N.Y., said, was seen to land and take off and vanish in the air over Massena, N.Y. A man who gave his name as Arthur Greenwood called press associations and said he helped one Edward of Toronto build the thing. Greenwood said he lived in New Toronto, a Toronto suburb. Greenwood said the contraption is a motorized balloon capable of speeds up to 210 miles an hour. It could take off almost vertically while "hanging" on its electrically-driven propeller. On its flight Tuesday, Greenwood said, it "took off from a secrethiding place near Ancaster (near Hamilton, Ontario) and returned to another hiding place near Toronto." Further, it would be flown over Niagara Falls at the week-end. After giving these details, the man hung up. He called back 10 minutes later, saying : "I ran out of nickels, I forgot to say it has a range of only 450 miles. The motor is light—only 269 pounds." He then hung up. STUDYING RUSSIAN AIRCRAFT A CCORDING to the Cornell Aeronautical Laboratory, which **• has been making a detailed examination of a Yak fighter and an Il-io ground-attack machine, Russian aircraft design is as good as American. A spokesman of the laboratory is quoted as ss3Vin6> "Where excellent workmanship counts in respect to performance, Russian workmanship is as good, and in some cases better, thiffl ours." He added that the Yak was evidently built by people who knew aircraft construction as well as any American manufacturer. No detailed information concerning the Mig-15 jet fighter now under examination at the Wright-Patterson Air Force isase Dayton, Ohio, has yet been released.
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