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Report no. 539, Investigation of full-scale split trailing-edge wind flaps with various chords and hinge locations
178
BOOK
REVIEWS.
[J.
F. I.
equipped with the proper size of streamline wheels than when furnished with low-pressure wheels. The drag of a cantilever landing gear is as low when equipped with the proper size of streamline wheels as when equipped with lowpressure wheels and the best type of wheel fairing. Two of the landing gears tested combine, to a high degree, the structural advantages of the tripod types with the low drag of the full cantilever types. The drag of a conventional tripod landing gear with streamline wheels can be reduced about 39 per cent. by careful fairing of all strut intersections. Expanding fillets are useful in reducing landing-gear drag, especially on landing gears that are attached to wings. The drags of tail-wheel units and tail skids are, even in the worst case, almost negligible. Report No. ,536, Wind Tunnel Tests of a ro-Foot-Diameter Gyroplane Rotor, by John B. Wheatley and Carlton Bioletti. IO pages, illustrations, Washington, Superintendent of Documents, diagrams, 20 X 26 ems. 193.5. Price 5 cents. This paper presents the results of wind-tunnel tests on a model gyroplane rotor IO feet in diameter. The rotor blades had zero sweepback and zero offset; the hub contained a feathering mechanism that provided control of the rotor rolling moment, but not of the pitching moment. The rotor was tested with 4 The entire useful range of pitch settings and tip-speed blades and with 2 blades. ratios was investigated including the phase of operation in which the rotor turned very slowly, or idled. The results afford valuable information concerning the influences of pitch setting, solidity, and feathering angle upon the rotor characteristics. The feathering control appeared to be satisfactory in the normal flying range but showed a marked decrease in effectiveness at very low tip-speed ratios. A feathering angle considerably greater than the 10~ that was provided was required at high tipspeed ratios and high pitch settings to obtain zero rolling moment. Unfortunately, because the rotor hub was disproportionately large, the measured lift-drag ratios are considered to be inexact. Report No. 539, Investigation of Full-Scale Split Trailing-Edge Wind Flaps with Various Chords and Hinge Locations, by Rudolf Wallace. 26 tables, diagrams, 20 X 26 ems. Washington, pages, illustrations, Superintendent of Documents, 1935. Price 5 cents. An investigation was conducted in the N. A. C. A. full-scale wind tunnel on a small parasol monoplane equipped with three different split trailing-edge wing flaps. The object of the investigation was to determine and correlate data on the characteristics of the airplane and flaps as affected by variation in flap chord, flap deflection, and flap location along the wing chord. The chords of the flaps were IO, 20, and 30 per cent. of the wing chord and each flap was tested at deflections from 0” to 75” when located successively at 68, 80, and 88.8 per cent. of the wing chord aft of the leading edge. The investigation included force tests, pressure-distribution tests, and downwash surveys. The results give the lift, the drag, and the pitching-moment characteristics of the airplane, the flap forces and moments, the pressure distribution over the flaps and wing at one section, and the downwash characteristics of the flap and wing combinations.
Jan., 1936.1
PUBLICATIONS
RECEIVED.
179
An increase in flap chord or distance of the flap from the leading edge of the wing increased the lift of the airplane but had an adverse effect on the wing pitching moment. The L/D ratio of the airplane decreased with increase in flap deflection or l?ap chord. Flap normal-force coefficients were primarily a function of flap deflection and were relatively independent of flap chord, hinge-axis location, and airplane attitude. The location of the flap center of pressure in percentage of flap chord aft of the hinge axis remained practically constant irrespecFlap hingetive of airplane attitude and of flap deflection, chord, or location. moment coefficients varied with a power of flap chord greater than the square so that with regard to hinge moments narrow flaps were the most efficient in producing a given increase in lift.
PUBLICATIONS
RECEIVED.
The Eruption of Mt. Pelke, rgq-1932, by Frank A. Perret. 125 pages, plates, 23 X 29 ems. Washington, Carnegie Institution, 1935. A Treatise on Heat (Including Kinetic Theory of Gases, Thermodynamics and Recent Advance in Statistical Thermodynamics). Being the second and revised edition of A Text Book of Heat, by M. N. Saha and B. N. Srivastava, second Allahabad and Calcutta, edition. 815 pages, illustrations, plates, 17 X 25 ems. The Indian Press, Ltd., 1935. Photo-Electric and Selenium Cells, their Operation, Construction and Uses, by T. J. Fielding. Pittsburgh, Instru140 pages, illustrations, 12 X 20 ems. ments Publishing Company, 1935. Price $1.75. Le Champ tlectromagnttigue, par Marc Jouguet. 220 pages, illustrations, II X 17 ems. Paris, Librairie Armand Colin, 1935. Price rofr. 50. Ripertoire International des Centres de Documentation chimipue. 115 pages, 21 X 30cms. Paris. Office International de Chimie. 1935. U. S. Bureau of Mines. Monograph 6, Flow of Natural Gas Through Highpressure Transmission Lines. A joint report by T. W. Johnson and W. B. Berwald. Baltimore, Baltimore Press. 120 pages, diagrams, 15 X 23 ems. Statistical Appendix to Minerals Yearbook, 1934. 434 pages, 15 X 23 ems. Washington, Government Printing Office, 1935. Price $1.00. Minerals Yearbook, 1935. 1293 pages, 15 X 23 ems. Washington, Government Printing Office, 1935. Price $2.00. National Advisory Committee for Aeronautics, Twentieth Annual Report, 1934, including Technical Reports Nos. 475 to 507. 649 pages, illustrations, diagrams, 24 X 30 ems. Washington, Government Printing Office, 1935. Price $2.75. Technical Notes, No. 544, An Application of the Von K&m&n-Mill&an Laminar Boundary-Layer Theory and Comparison with Experiment by Albert E. von Doenhoff. II pages, figures, 20 X 26 ems. Washington, Committee. 193.5. No. 545, Tank Tests of a Model of a Flying-Boat Hull Having a Longitudinally Concave Planing Bottom by J. B. Parkinsor. IO pages, figures, 20 X 26 ems. Washington, Committee, 1935. No. 546, Comparative Tests of Pitot37 pages, figures, Static Tubes by Kenneth G. Merriam and Ellis R. Spaulding. tables, 20 X 26 ems. Washington, Committee, 1935. No. 547, Development of
BOOK
REVIEWS.
[J.
F. I.
equipped with the proper size of streamline wheels than when furnished with low-pressure wheels. The drag of a cantilever landing gear is as low when equipped with the proper size of streamline wheels as when equipped with lowpressure wheels and the best type of wheel fairing. Two of the landing gears tested combine, to a high degree, the structural advantages of the tripod types with the low drag of the full cantilever types. The drag of a conventional tripod landing gear with streamline wheels can be reduced about 39 per cent. by careful fairing of all strut intersections. Expanding fillets are useful in reducing landing-gear drag, especially on landing gears that are attached to wings. The drags of tail-wheel units and tail skids are, even in the worst case, almost negligible. Report No. ,536, Wind Tunnel Tests of a ro-Foot-Diameter Gyroplane Rotor, by John B. Wheatley and Carlton Bioletti. IO pages, illustrations, Washington, Superintendent of Documents, diagrams, 20 X 26 ems. 193.5. Price 5 cents. This paper presents the results of wind-tunnel tests on a model gyroplane rotor IO feet in diameter. The rotor blades had zero sweepback and zero offset; the hub contained a feathering mechanism that provided control of the rotor rolling moment, but not of the pitching moment. The rotor was tested with 4 The entire useful range of pitch settings and tip-speed blades and with 2 blades. ratios was investigated including the phase of operation in which the rotor turned very slowly, or idled. The results afford valuable information concerning the influences of pitch setting, solidity, and feathering angle upon the rotor characteristics. The feathering control appeared to be satisfactory in the normal flying range but showed a marked decrease in effectiveness at very low tip-speed ratios. A feathering angle considerably greater than the 10~ that was provided was required at high tipspeed ratios and high pitch settings to obtain zero rolling moment. Unfortunately, because the rotor hub was disproportionately large, the measured lift-drag ratios are considered to be inexact. Report No. 539, Investigation of Full-Scale Split Trailing-Edge Wind Flaps with Various Chords and Hinge Locations, by Rudolf Wallace. 26 tables, diagrams, 20 X 26 ems. Washington, pages, illustrations, Superintendent of Documents, 1935. Price 5 cents. An investigation was conducted in the N. A. C. A. full-scale wind tunnel on a small parasol monoplane equipped with three different split trailing-edge wing flaps. The object of the investigation was to determine and correlate data on the characteristics of the airplane and flaps as affected by variation in flap chord, flap deflection, and flap location along the wing chord. The chords of the flaps were IO, 20, and 30 per cent. of the wing chord and each flap was tested at deflections from 0” to 75” when located successively at 68, 80, and 88.8 per cent. of the wing chord aft of the leading edge. The investigation included force tests, pressure-distribution tests, and downwash surveys. The results give the lift, the drag, and the pitching-moment characteristics of the airplane, the flap forces and moments, the pressure distribution over the flaps and wing at one section, and the downwash characteristics of the flap and wing combinations.
Jan., 1936.1
PUBLICATIONS
RECEIVED.
179
An increase in flap chord or distance of the flap from the leading edge of the wing increased the lift of the airplane but had an adverse effect on the wing pitching moment. The L/D ratio of the airplane decreased with increase in flap deflection or l?ap chord. Flap normal-force coefficients were primarily a function of flap deflection and were relatively independent of flap chord, hinge-axis location, and airplane attitude. The location of the flap center of pressure in percentage of flap chord aft of the hinge axis remained practically constant irrespecFlap hingetive of airplane attitude and of flap deflection, chord, or location. moment coefficients varied with a power of flap chord greater than the square so that with regard to hinge moments narrow flaps were the most efficient in producing a given increase in lift.
PUBLICATIONS
RECEIVED.
The Eruption of Mt. Pelke, rgq-1932, by Frank A. Perret. 125 pages, plates, 23 X 29 ems. Washington, Carnegie Institution, 1935. A Treatise on Heat (Including Kinetic Theory of Gases, Thermodynamics and Recent Advance in Statistical Thermodynamics). Being the second and revised edition of A Text Book of Heat, by M. N. Saha and B. N. Srivastava, second Allahabad and Calcutta, edition. 815 pages, illustrations, plates, 17 X 25 ems. The Indian Press, Ltd., 1935. Photo-Electric and Selenium Cells, their Operation, Construction and Uses, by T. J. Fielding. Pittsburgh, Instru140 pages, illustrations, 12 X 20 ems. ments Publishing Company, 1935. Price $1.75. Le Champ tlectromagnttigue, par Marc Jouguet. 220 pages, illustrations, II X 17 ems. Paris, Librairie Armand Colin, 1935. Price rofr. 50. Ripertoire International des Centres de Documentation chimipue. 115 pages, 21 X 30cms. Paris. Office International de Chimie. 1935. U. S. Bureau of Mines. Monograph 6, Flow of Natural Gas Through Highpressure Transmission Lines. A joint report by T. W. Johnson and W. B. Berwald. Baltimore, Baltimore Press. 120 pages, diagrams, 15 X 23 ems. Statistical Appendix to Minerals Yearbook, 1934. 434 pages, 15 X 23 ems. Washington, Government Printing Office, 1935. Price $1.00. Minerals Yearbook, 1935. 1293 pages, 15 X 23 ems. Washington, Government Printing Office, 1935. Price $2.00. National Advisory Committee for Aeronautics, Twentieth Annual Report, 1934, including Technical Reports Nos. 475 to 507. 649 pages, illustrations, diagrams, 24 X 30 ems. Washington, Government Printing Office, 1935. Price $2.75. Technical Notes, No. 544, An Application of the Von K&m&n-Mill&an Laminar Boundary-Layer Theory and Comparison with Experiment by Albert E. von Doenhoff. II pages, figures, 20 X 26 ems. Washington, Committee. 193.5. No. 545, Tank Tests of a Model of a Flying-Boat Hull Having a Longitudinally Concave Planing Bottom by J. B. Parkinsor. IO pages, figures, 20 X 26 ems. Washington, Committee, 1935. No. 546, Comparative Tests of Pitot37 pages, figures, Static Tubes by Kenneth G. Merriam and Ellis R. Spaulding. tables, 20 X 26 ems. Washington, Committee, 1935. No. 547, Development of