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  Partner: UNT Libraries Government Documents Department
 Collection: Technical Report Archive and Image Library
Tank tests of Model 36 flying boat hull

Tank tests of Model 36 flying boat hull

Date: March 1, 1938
Creator: Allison, John
Description: N.A.C.A. Model 36, a hull form with parallel middle body for half the length of the forebody and designed particularly for use with stub wings, was tested according to the general fixed-trim method over the range of practical loads, trims, and speeds. It was also tested free to trim with the center of gravity at two different positions. The results are given in the form of nondimensional coefficients. The resistance at the hump was exceptionally low but, at high planing speeds, afterbody interference made the performance only mediocre.
Contributing Partner: UNT Libraries Government Documents Department
Tank tests of models of floats for single-float seaplanes First series.

Tank tests of models of floats for single-float seaplanes First series.

Date: April 1, 1936
Creator: Parkinson, J B
Description: Large models of the Mark V and Mark VI floats used for single float seaplanes (National Advisory Committee for Aeronautics (NACA) models 41-A and 41-B, respectively) were tested in the NACA tank to provide general test data for typical single floats and a basis for possible improvements of their form. The resistance of model 41-B was greater than that of model 41-A, either when free to trim or at the best trim angle for each. The resistance of model 35-B (a pointed step hull tested free to trim) was less than either of the models at the hump speed, greater at intermediate planing speeds, and less at the speeds and loads near get-away, although the spray was generally worse owing to the absence of transverse flare. The results of the fixed-trim tests of model 41-A were cross plotted to obtain data at the angle for zero trimming moment and at the best trim angle. The trims assumed by models 41-A and 41-B, when tested free to trim, were found to be excessive at the hump speed. The corresponding trim of model 35-B was found to be approximately 3 degrees lower because of the lower angle of afterbody keel used in ...
Contributing Partner: UNT Libraries Government Documents Department
Tank tests of models of flying boat hulls having longitudinal steps

Tank tests of models of flying boat hulls having longitudinal steps

Date: July 1, 1936
Creator: Allison, John M & Ward, Kenneth E
Description: Four models with longitudinal steps on the forebody were developed by modification of a model of a conventional hull and were tested in the National Advisory Committee for Aeronautics (NACA) tank. Models with longitudinal steps were found to have smaller resistance at high speed and greater resistance at low speed than the parent model that had the same afterbody but a conventional V-section forebody. The models with a single longitudinal step had better performance at hump speed and as low high-speed resistance except at very light loads. Spray strips at angles from 0 degrees to 45 degrees to the horizontal were fitted at the longitudinal steps and at the chine on one of the two step models having two longitudinal steps. The resistance and the height of the spray were less with each of the spray strips than without; the most favorable angle was found to lie between 15 degrees and 30 degrees.
Contributing Partner: UNT Libraries Government Documents Department
Tank tests of NACA model 40 series of hulls for small flying boats and amphibians

Tank tests of NACA model 40 series of hulls for small flying boats and amphibians

Date: January 1, 1937
Creator: Parkinson, John B & Dawson, John R
Description: The NACA model 40 series of flying-boat hull models consists of 2 forebodies and 3 afterbodies combined to provide several forms suitable for use in small marine aircraft. One forebody is the usual form with hollow bow sections and the other has a bottom surface that is completely developable from bow to step. The afterbodies include a short pointed afterbody with an extension for the tail surfaces, a long afterbody similar to that of a seaplane float but long enough to carry the tail surfaces, and a third obtained by fitting a second step in the latter afterbody. The various combinations were tested in the NACA Tank by the general method over a suitable range of loadings. Fixed-trim tests were made for all speeds likely to be used and free-to-trim tests were made at low speeds to slightly beyond the hump speed. The characteristics of the hulls at best trim angles have been deduced from the data of the tests at fixed trim angles and are given in the form of nondimensional coefficients applicable to any size hull.
Contributing Partner: UNT Libraries Government Documents Department
Tank Tests of the Effect of Rivet Heads, etc., on the Water Performance of a Seaplane Float, Special Report

Tank Tests of the Effect of Rivet Heads, etc., on the Water Performance of a Seaplane Float, Special Report

Date: June 4, 1936
Creator: Parkinson, J. B. & Robertson, J. B., Jr.
Description: A 1/3.5 full-size model of the Mark V float of the Bureau of Aeronautics, Navy Department, was tested in the NACA tank both with smooth painted bottom surfaces and with roundhead rivets, plate laps, and keel plates fitted to simulate the actual bottom of a metal float. The augmentation in water resistance due to the added roughness was found to be from 10-12% at the hum speed and from 12-14% at high speeds. The effect of the roughness of the afterbody was found to be negligible except at high trims. The model data were extrapolated to full size by the usual method which assumes the forces to vary according to Froude's law, and in the case of the smooth model by a method of separation that takes into account the effect of scale on the frictional resistance. It was concluded that the effect of rivet heads on the takeoff performance of a relatively high-powered float seaplane is of little consequence but that it may be of greater importance in the case of more moderately powered flying boats.
Contributing Partner: UNT Libraries Government Documents Department
Tank tests of three models of flying-boat hulls of the pointed-step type with different angles of dead rise - NACA model 35 series

Tank tests of three models of flying-boat hulls of the pointed-step type with different angles of dead rise - NACA model 35 series

Date: January 1, 1936
Creator: Dawson, John R
Description: The results of tank tests of three models of flying-boat hulls of the pointed-step type with different angles of dead rise are given in charts and are compared with results from tests of more conventional hulls. Increasing the angle of dead rise from 15 to 25 degrees: had little effect on the hump resistance; increased the resistance throughout the planning range; increased the best trim angle; reduced the maximum positive trimming moment required to obtain best trim angle; and had but a slight effect on the spray characteristics. For approximately the same angles of dead rise the resistance of the pointed-step hulls were considerably lower at high speeds than those of the more conventional hulls.
Contributing Partner: UNT Libraries Government Documents Department
Tank tests of three types of afterbodies on a flying-boat model with basic hull length-beam ratio of 10.0

Tank tests of three types of afterbodies on a flying-boat model with basic hull length-beam ratio of 10.0

Date: March 1, 1948
Creator: Garrison, Charlie C & Clement, Eugene P
Description: None
Contributing Partner: UNT Libraries Government Documents Department
Tank tests of twin seaplane floats

Tank tests of twin seaplane floats

Date: October 1, 1928
Creator: Herrman, H; Kempf, G & Kloess, H
Description: The following report contains the most essential data for the hydrodynamic portion of the twin-float problem. The following points were successfully investigated: 1) difference between stationary and nonstationary flow; 2) effect of the shape of the step; 3) effect of distance between floats; 4) effect of nose-heavy and tail-heavy moments; 5) effect of the shape of floats; 6) maneuverability.
Contributing Partner: UNT Libraries Government Documents Department
Tank tests of two floats for high-speed seaplanes

Tank tests of two floats for high-speed seaplanes

Date: November 1, 1933
Creator: Bell, Joe W
Description: At the request of the Bureau of Aeronautics, Navy Department, a study of the design of floats especially suitable for use on high-speed seaplanes was undertaken in the N.A.C.A. tank. This note give the results obtained in tests of one-quarter full-size models of two floats for high-speed seaplanes. One was a float similar to that used on the Macchi high-speed seaplane which competed in the 1926 Schneider Trophy races, and the other a float designed at the N.A.C.A. tank in an attempt to improve on the water performance of the Macchi float. The model of the latter showed considerably better water performance than the model of the Macchi float.
Contributing Partner: UNT Libraries Government Documents Department
Tank tests of two models of flying-boat hulls to determine the effect of ventilating the step

Tank tests of two models of flying-boat hulls to determine the effect of ventilating the step

Date: February 1, 1937
Creator: Dawson, John R
Description: The results of tests made in the N.A.C.A. tank on two models of flying-boat hulls to determine the effect of ventilating the step are given graphically. The step of N.A.C.A. model 11-C was ventilated in several different ways and it was found that the resistance of the normal form is not appreciably affected by artificial ventilation in any of the forms tried. Further tests made with the depth of the step of model 11-C reduced likewise show no appreciable effect on the resistance from ventilation of the step. Tests were made on a model of the hull of the Navy P3M-1 flying-boat hull both with and without ventilation of the step. It was found that the discontinuity which is obtained in the resistance curves of this model is eliminated by ventilating the step.
Contributing Partner: UNT Libraries Government Documents Department