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 Collection: Technical Report Archive and Image Library
Tank tests of a model of a flying-boat hull having a longitudinally concave planing bottom

Tank tests of a model of a flying-boat hull having a longitudinally concave planing bottom

Date: November 1, 1935
Creator: Parkinson, J B
Description: The NACA model 11-B, which has a longitudinally concave planing bottom forward of the step, was tested over a wide range of loading. The results of the tests are presented as curves of resistance and trimming moment plotted against speed for various trim angles and as curves of resistance coefficient at best trim angle, and trimming-moment coefficient. The characteristics of the form at the optimum trim are compared with those of NACA model 11-C which has the same form with the exception of a planing bottom longitudinally straight near the step. Photographs of the models being towed in the tank are included for a comparison of the spray patterns. At the best angles of trim in each case model 11-B has lower resistance at high speeds, a higher maximum positive trimming moment near the hump speed, and a more favorable spray pattern than of model 11-C.
Contributing Partner: UNT Libraries Government Documents Department
Tank tests of a model of a flying-boat hull with a fluted bottom

Tank tests of a model of a flying-boat hull with a fluted bottom

Date: March 1, 1935
Creator: Dawson, John R
Description: A 1/5-scale model of a flying-boat hull having flutes in the bottom both forward and aft of the step (NACA model 19) was tested to determine its water performance. The model was also tested after the successive removal of the flutes on the afterbody and forebody. The results from these tests are compared with those from tests of a model of the hull of the Navy PN-8 flying boat and it is concluded that the fluted-bottom model and its modifications are inferior to the model of the PN-8.
Contributing Partner: UNT Libraries Government Documents Department
Tank tests of a model of one hull of the Savoia S-55-X flying boat -N.A.C.A. Model 46

Tank tests of a model of one hull of the Savoia S-55-X flying boat -N.A.C.A. Model 46

Date: February 1, 1938
Creator: Allison, John M
Description: A model of one of the twin hulls of the Italian Savoia S-55-X flying boat (N.A.C.A. Model 46) was tested in the N.A.C.A. tank according to the general method. The data obtained from these tests cover a broad range of speeds, loads, and trims and are given in nondimensional form to facilitate their use in applying this form of hull to any other flying boat or comparing it's performance with the performance of any other hulls. The results show that the resistance characteristics at best trim of this model are excellent throughout the speed range. In order to compare the performance of the S-55-X hull with that of the 35, a pointed-step hull developed at the N.A.C.A. tank, the data are used in the computations of take-off example of a twin-hull, 23,500-pound flying boat. The calculations show that the S-55-X hull has better take-off performance.
Contributing Partner: UNT Libraries Government Documents Department
Tank tests of a model of the NC flying-boat hull - N.A.C.A. model 44

Tank tests of a model of the NC flying-boat hull - N.A.C.A. model 44

Date: May 1, 1936
Creator: Bell, Joe W
Description: A 1/7.06 full-size model of the NC-type hull was tested in the N.A.C.A. tank by both the general method and the specific or free-to-trim method. The results of the tests are given in curves plotted as non dimensional coefficients and are compared with the test results of N.A.C.A. model 11-A. The NC model (N.A.C.A. model 44) shows higher resistance than model 11-A at hump speed but lower resistance at high speeds. Model 44 has a higher best trim angle at the jump and a lower maximum positive trimming moment than model 11-A. At high speeds the best trim angle and the trimming moments of the two models are approximately the same.
Contributing Partner: UNT Libraries Government Documents Department
Tank tests of a powered dynamic model of a flying boat having an afterbody length-beam ratio of 4.7-Langley tank model 203C-1

Tank tests of a powered dynamic model of a flying boat having an afterbody length-beam ratio of 4.7-Langley tank model 203C-1

Date: October 1, 1945
Creator: Haar, Marvin I
Description: None
Contributing Partner: UNT Libraries Government Documents Department
Tank Tests of a Powered Model of a Compression Plane, NACA Model 171A-2

Tank Tests of a Powered Model of a Compression Plane, NACA Model 171A-2

Date: July 1, 1948
Creator: Mottard, Elmo J. & Ruggles, Robert D.
Description: The compression plane is intended for operation on or close to the surface of the water, and has a hull with a concave bottom which forms the upper surface of a tunnel into which air is forced under pressure to support part of the load. The results of the tests made in Langley tank no. 1 include values of the horizontal forces, trimming moment, and static pressure in the tunnel for a wide range of loads and speeds and two power conditions, and are presented in the form of curves against speed with load as a parameter. The results are scaled up to 10 times the model size for three conditions at which the model is self-propelled at a steady speed. Lift is obtained from the static pressure of air in the tunnel. In general, the ratio of the gross load to the total resistance increases with increase in load and decrease in speed. This ratio varies between l-7 and 5.7 at high speeds and has a maximum value of 7. The total resistance is nearly the same for both power conditions except at low speeds and heavy loads. No abrupt change in forces on the hull or flow around ...
Contributing Partner: UNT Libraries Government Documents Department
Tank Tests of an Alternate Hull Form for the Consolidated Vultee PB2Y-3 Airplane

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

Date: November 6, 1946
Creator: Land, Norman S. & Posner, Jack
Description: 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 ot the production design. In addition the take-off and landing stability of the model with the alternate hull were satisfactory.
Contributing Partner: UNT Libraries Government Documents Department
Tank tests of auxiliary vanes as a substitute for planing area

Tank tests of auxiliary vanes as a substitute for planing area

Date: February 1, 1934
Creator: Parkinson, John B
Description: The results of towing tests made on two models at the request of the Bureau of Aeronautics, Navy Department, are presented. The first model represents the hull of the U.S. Navy PN-8 flying boat, in which the sponsors of the original hull are removed and auxiliary lifting vanes are fitted at the chines immediately forward of the main step. The tests showed that the altered form gave a large increase in hump resistance and a very undesirable spray formation through a large part of the speed range.
Contributing Partner: UNT Libraries Government Documents Department
Tank tests of flat and v-bottom planning surfaces

Tank tests of flat and v-bottom planning surfaces

Date: November 1, 1934
Creator: Shoemaker, James M
Description: Four planing surfaces, all having beams of 16 inches and lengths of 60 inches but varying in dead rise by 10 degrees increments from 0 degrees to 30 degrees, were tested in the N.A.C.A. tank. The results cover a wide range of speed, loads, and trim angles, and are applicable to a variety of problems encountered in the design of seaplanes. The data are analyzed to determine the characteristics of each surface at the trim angle giving minimum resistance for all the speed and loads tested. A planing coefficient intended to facilitate the application of the results to design work is developed and curves of resistance, wetted length, and center of pressure are plotted against this coefficient. Several examples, showing the application of the test data to specific design problems are included.
Contributing Partner: UNT Libraries Government Documents Department
Tank tests of model 11-G flying-boat hull

Tank tests of model 11-G flying-boat hull

Date: June 1, 1935
Creator: Parkinson, J B
Description: The NACA model 11-G flying-boat hull, a modification of NACA model 11-A was tested over a range of loadings. The planing bottom of model 11-G has a variable-radius flare, or concavity, at the chines in contrast to the straight V planing bottom of model 11-A. The results are given as curves of resistance and trimming moment plotted against speed for various angles of trim. The characteristics of the form at the optimum angles of trim are given in non-dimensional form as curves of resistance coefficient, best trim angle, and trimming-moment coefficient plotted against speed coefficient. As compared with the original form, model 11-G is shown to have higher resistance at all loads and speeds and higher maximum trimming moments at heavy loads. The spray pattern, however, is generally more favorable, indicating that the service performance of model 11-A would be improved by some form of chime flare.
Contributing Partner: UNT Libraries Government Documents Department