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Effect of powered propellers on the aerodynamic characteristics and the porpoising stability of a dynamic model of a long-range flying boat

Description: Report discusses the results of two tests: "1) aerodynamic tests to determine the effect of the slipstream and thrust from the powered propellers on the lift and trimming-moment characteristics, and 2) hydrodynamic tests to determine the effect of the powered propellers on the range of stable locations of the center of gravity (from Introduction)." Large differences in the stable range between half-thrust and full-thrust conditions were observed. Three effects of power were also involved in the location of the stable range of the center of gravity.
Date: May 1943
Creator: Land, Norman S.
Partner: UNT Libraries Government Documents Department

The effect of afterbody length of the hydrodynamic stability of a dynamic model of a flying boat: Langley tank model 134

Description: Report presenting some model tests that will be used to guide the relation of length of afterbody and depth of step. Results indicated that an increase in length of afterbody requires an accompanying increase in depth of step to maintain adequate landing stability.
Date: October 1945
Creator: Land, Norman S.
Partner: UNT Libraries Government Documents Department

Preliminary tank tests of some hydro-ski-wheel combinations in the planing condition

Description: Report presenting an investigation of the planing characteristics of various combinations of a wheel and a hydro-ski. Models tested included at least two values of the following parameters: diameter of wheel, width of wheel, cross-section shape of wheel, fore-and-aft location of wheel, lateral location of wheel, gap between wheel and ski, rotation of wheel, and protrusion of wheel. Results regarding the general effect of a wheel, effect of wheel shape and size, effect of wheel-ski arrangement, and possible methods of reducing resistance are provided.
Date: October 6, 1952
Creator: Land, Norman S. & Fontana, Rudolph E.
Partner: UNT Libraries Government Documents Department

The landing stability of a powered dynamic model of a flying boat with a 30 degree v-step and with two depths of transverse step

Description: Report discusses tests conducted using a model of a four-engine long-range flying boat with a 30 degree V-step and two different transverse steps of comparable positions and depths. The limits of stability, landing speed, and landing characteristics of the different models are presented.
Date: February 1944
Creator: Parkinson, John B. & Land, Norman S.
Partner: UNT Libraries Government Documents Department

Preliminary tests in the NACA tank to investigate the fundamental characteristics of hydrofoils

Description: Report discusses an investigation into the hydrodynamic properties and general behavior of simple hydrofoils. The experimental results are presented as curves of the lift and drag coefficients plotted against speed for angles of attack and depths. Properly designed hydrofoil sections were determined to have excellent characteristics and a significant reduction in the speed of cavitation.
Date: September 1940
Creator: Ward, Kenneth E. & Land, Norman S.
Partner: UNT Libraries Government Documents Department

Tests of a dynamic model in NACA tank number 1 to determine the effect of length of afterbody, angle of afterbody keel, gross load, and a pointed step on landing and planning stability

Description: Report presenting testing in tank no. 1 to determine the effect of length of afterbody, angle of afterbody keel, and gross load on the limits of stable trims and landing characteristics of a model of a flying boat with conventional steps. The studies were made with four lengths of afterbody, four angles of afterbody keel, and five gross loads. Results regarding the trim limits of stability and landing stability are provided.
Date: March 1943
Creator: Land, Norman S. & Lina, Lindsay J.
Partner: UNT Libraries Government Documents Department

Flutter characteristics at transonic speeds of a 45 degree sweptback wing with and without inboard modifications at the leading and trailing edges

Description: Report presenting flutter characteristics at transonic speeds of a model of a fighter-type-airplane wing over a range of Mach numbers. The results indicated an abrupt increase in flutter speed ratio near a Mach number of 1.0, with only slight increases noted as it was increased to 1.4. Results regarding the effect of flutter-boundary shape are provided.
Date: January 9, 1957
Creator: Sellers, Thomas B. & Land, Norman S.
Partner: UNT Libraries Government Documents Department

Force Characteristics in the Submerged and Planing Condition of a 1/5.78-Scale Model of a Hydro-Ski-Wheel Combination for the Grumman JRF-5 Airplane

Description: From Summary: "Force characteristics determined from tank tests of a 1/5.78 scale model of a hydro-ski-wheel combination for the Grumman JRF-5 airplane are presented. The model was tested in both the submerged and planing conditions over a range of trim, speed, and load sufficiently large to represent the most probable full-size conditions."
Date: March 5, 1952
Creator: Land, Norman S. & Pelz, Charles A.
Partner: UNT Libraries Government Documents Department

Force characteristics in the submerged and planing condition of a 1/5.78-scale model of a hydro-ski-wheel combination for the Grumman JRF-5 airplane

Description: From Summary: "Force characteristics determined from tank tests of a 1/5.78-scale model of a hydro-ski-wheel combination for the Grumman JRF-5 airplane are presented. The model was tested in both the submerged and planing conditions over a range of trim, speed, and load sufficiently large to represent the most probable full-size conditions."
Date: July 11, 1952
Creator: Land, Norman S. & Pelz, Charles A.
Partner: UNT Libraries Government Documents Department

Methods used in the NACA tank for the investigation of the longitudinal-stability characteristics of models of flying boats

Description: Report presents the results of tests of longitudinal stability characteristics of models of several flying boats conducted in the NACA Tank No. 1. These investigations were made for the purpose of (1) determining suitable methods for evaluating the stability characteristics of models of flying boats, and (2) determining the design parameters which have an important effect on the porpoising. This report is mainly concerned with the construction of suitable models, the apparatus, and methods used in the tests. The effect of changes in some design parameters is discussed.
Date: September 9, 1942
Creator: Olson, Roland E. & Land, Norman S.
Partner: UNT Libraries Government Documents Department

Method of controlling stiffness properties of a solid-construction model wing

Description: Report presenting a method for controlling the bending and torsional stiffnesses of a solid-construction model wing. The model consists of weakening the wing by drilling holes through the wing normal to the chord plane. Results for the holes arranged in square patterns, holes arranged in miscellaneous patterns, and a consideration of some practical applications are provided.
Date: April 1955
Creator: Land, Norman S. & Abbott, Frank T., Jr.
Partner: UNT Libraries Government Documents Department

The longitudinal stability of flying boats as determined by tests of models in the NACA tank 1: methods used for the investigation of longitudinal stability characteristics

Description: Report presenting testing of dynamic models that has been helpful in the determination of the longitudinal stability characteristics on the water of a number of specific flying boats. Results regarding the constant-speed tests, accelerated runs, effect of variations in moment of inertia, effect of variations in mass moving vertically, effect of variations of depth of step, and effect of variations of gross load coefficient are provided.
Date: November 1942
Creator: Olson, Roland E. & Land, Norman S.
Partner: UNT Libraries Government Documents Department

An Investigation of Hydrofoils in the NACA Tank 1: Effect of Dihedral and Depth of Submersion

Description: Tests were conducted on hydrofoil assemblies approximating an arrangement for use under seaplanes or surface boats. A series of hydrofoils, each supported by two struts, was towed at various depths ranging from partial submersions to a depth of 5-chord lengths. At depths greater than 4 or 5 chords, the influence of the surface of the water is small; hydrofoils operating at low speed will have characteristics similar to those of airfoils of the same section.
Date: September 1942
Creator: Benson, James M. & Land, Norman S.
Partner: UNT Libraries Government Documents Department

Effects of sweepback and taper on the force and cavitation characteristics of aspect-ratio-4 hydrofoils

Description: Report presenting an investigation to determine the effects of sweepback and taper ratio on the cavitation and hydrodynamic force characteristics of hydrofoils. Four hydrofoils were used, all of which had different taper ratios and degrees of sweep. Results regarding the effect of cavitation on hydrodynamic characteristics, effect of sweep on cavitation and force characteristics, effect of taper ratio on cavitation and force characteristics, and a comparison with wind-tunnel data are provided.
Date: December 2, 1952
Creator: King, Douglas A. & Land, Norman S.
Partner: UNT Libraries Government Documents Department

Effect of afterbody length and keel angle on minimum depth of step for landing stability and on take-off stability of a flying boat

Description: From Summary: "Tests were made to fill partly the need for information on the effect of afterbody dimensions on the hydrodynamic stability of a flying boat in smooth water. The dimensions investigated were depth of step, angle of afterbody keel, and length of afterbody. An analysis of the data showed that as either the afterbody length or keel angle was increased an accompanying increase in depth of step was required in order to maintain adequate landing stability."
Date: November 13, 1947
Creator: Olson, Roland E. & Land, Norman S.
Partner: UNT Libraries Government Documents Department

Preliminary Tests in the NACA Tank to Investigate the Fundamental Characteristics of Hydrofoils

Description: A preliminary investigation made to study the hydrodynamic properties and general behavior of simple hydrofoils. Six plain, rectangular hydrofoils were tested in a tank at various speeds, angles of attack, and depths below the water surface. The results are presented as curves of the lift and drag coefficients plotted against speed for various angles of attack and depths for which the hydrofoils were tested.
Date: September 1940
Creator: Ward, Kenneth E. & Land, Norman S.
Partner: UNT Libraries Government Documents Department

Transonic flutter investigation of an all-moveable horizontal tail for a fighter airplane

Description: Report presenting an investigation of transonic flutter of a model of an all-movable horizontal tail for a fighter airplane. Characteristics of the model included an aspect ratio of 3.3, a taper ratio of 0.42, and 35 degrees of sweepback of the quarter-chord line. Information regarding analytical analysis, experimental results, and comparison with theory is provided.
Date: January 14, 1957
Creator: Land, Norman S. & Abbott, Frank T., Jr.
Partner: UNT Libraries Government Documents Department

Transonic flutter investigation of a fighter-airplane wing model and comparison with a systematic plan-form series

Description: Report presenting an investigation of the transonic flutter characteristics at zero lift of a model of a wing for a new fighter airplane. The characteristics were found to be similar to those of a comparable systematic plan-form series of models described in previous reports. Results regarding visual observations, damping, flutter-speed ratio, and ratio of experimental sustained flutter speeds to reference flutter speeds are provided.
Date: October 7, 1955
Creator: Land, Norman S. & Abbott, Frank T., Jr.
Partner: UNT Libraries Government Documents Department

The resistance of three series of flying boat-hulls as affected by length-beam ratio

Description: Report presents correlation of data obtained from several independent length-beam-ratio investigations to determine the general effect of length-beam ratio on the resistance characteristics of three series of flying-boat hulls. An optimum length-beam ratio was found beyond which no further reduction in hydrodynamic resistance occurred. The optimum ratio depended on the hull lines of any given mode series.
Date: October 1945
Creator: Land, Norman S.; Bidwell, Jerold M. & Goldenbaum, David M.
Partner: UNT Libraries Government Documents Department

Full-Scale Hydrodynamic Evaluation of a Modified Navy J4F-2 Amphibian with a 0.425-Scale XP5M-1 Hull Bottom: TED No. NACA DE325

Description: An investigation was made to evaluate the hydrodynamic qualities of a 0.425-scale model of the Navy XP5M-1 hull, which was installed on a modified Navy J4F-2 amphibian. Longitudinal and directional stability during take-off and landing, low-speed maneuverability, spray characteristics, and take-off performance were investigated. The behavior of the airplane in moderately rough water was also observed. The opinions of three pilots have been correlated with the data.
Date: December 7, 1949
Creator: Land, Norman S.; Elliott, John M. & Christopher, Kenneth W.
Partner: UNT Libraries Government Documents Department

Acceleration Measurements During Landing in Rough Water of a 1/7-Scale Dynamic Model of Grumman XJR2F-1 Amphibian - Langley Tank Model 212: TED No. NACA 2378

Description: From Summary: "Tests of a 1/7 size model of the Grumman XJR2F-1 amphibian were made in Langley tank no.1 to examine the landing behavior in rough water and to measure the normal and angular accelerations experienced by the model during these landings. All landings were made normal to the direction of wave advance, a condition assumed to produce the greatest accelerations. Wave heights of 4.4 and 8.0 inches (2.5 and 4.7 ft, full size) were used in the tests and the wave lengths were varied between 10 and 50 feet (70 and 350 ft, full size)."
Date: May 6, 1947
Creator: Land, Norman S. & Zeck, Howard
Partner: UNT Libraries Government Documents Department

Tank Tests of an Alternate Hull Form for the Consolidated Vultee PB2Y-3 Airplane

Description: From Summary: "Tests have been made in Langley tank no. I of a dynamic model of the Consolidated Vultee PB2Y-3 airplane. These tests were made using an alternate hull form, the purpose of which was to reduce the bow spray and eliminate the landing instability which are objectionable features of the production design. The major differences from the PB2Y-3 hull included a deeper step to improve the landing stability , and a lengthened forebody and increased beam to reduce the sway in the propellers and on the flaps. The tests showed that the spray characteristics of the revised hull form were much better than that to the production design. In addition the take-off and landing stability of the model with the alternate hull were satisfactory."
Date: November 6, 1946
Creator: Land, Norman S. & Posner, Jack
Partner: UNT Libraries Government Documents Department

Tank Tests of a 1/7-Size Powered Dynamic Model of the Grumman XJR2F-1 Amphibian: Spray Characteristics, Take-Off and Landing Stability in Smooth Water - Langley Tank Model 212, TED No. NACA 2378

Description: From Summary: "Tests of a model of the XJR2F-Y amphibian were made in Langley tank no. to determine the spray characteristics and the take-off and landing stability. At a gross load of 22,000 pounds full size, spray entered the propeller disk only at a very narrow range of speeds. The spray striking the flaps was not excessive and no appreciable wetting of the tail surfaces was noted. The trim limits of stability appeared to be satisfactory and the upper-limit porpoising was not violent."
Date: December 4, 1946
Creator: Land, Norman S. & Zeck, Howard
Partner: UNT Libraries Government Documents Department