Search NASA⌕ Search

Engineering topics

Shoemaker, James M

Publications and source records attributed to Shoemaker, James M.

11 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1934

Tank tests of flat and v-bottom planning surfaces

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.

Shoemaker, James M↗
NASA NTRS1934

Complete tank tests of two flying-boat hulls with pointed steps - N.A.C.A. Models 22-A and 35

This note presents the results of complete tank test of N.A.C.A. Models 22-A and 35, two flying-boat hulls of the deep pointed-step type with low dead rise. Model 22-A is a form derived by modification of Model 22, the test results of which are given in N.A.C.A. Technical Note No. 488. Model 35 is a form of the same type but has a higher length-beam ratio than either Model 22 or 22-A. Take-off examples are worked out using data from these tests and a previous test of a conventional model applied to an arbitrary set of design specifications for a 15,000-pound flying boat. The comparison of these examples shows both pointed-step models to be superior to the conventional form, and Model 35 to be the better of the two. Model 35 is applied to a hypothetical 100,000-pound flying boat of the twin-hull type and performance calculations are made both for take-off and range. The results indicate that the high performance of this type of hull will enable the designer to use higher wing and power loadings than are found in current practice, with a resulting increase in range and pay load.

Shoemaker, James M↗
NASA NTRS1934

A complete tank test of a flying-boat hull with a pointed step -N.A.C.A. Model No. 22

The results of a complete tank test of a model of a flying-boat hull of unconventional form, having a deep pointed step, are presented in this note. The advantage of the pointed-step type over the usual forms of flying-boat hulls with respect to resistance at high speeds is pointed out. A take-off example using the data from these tests is worked out, and the results are compared with those of an example in which the test data for a hull of the type in general use in the United States are applied to a flying boat having the same design specifications. A definite saving in take-off run is shown by the pointed-step type.

Shoemaker, James M↗
NASA NTRS1934

Tank tests of a family of flying-boat hulls

This report presents towing tests made in the N.A.C.A. tank of a parent form and five variations of a flying-boat hull. The beams of two of the derived forms were made the same as that of the parent and the lengths changed by increasing and decreasing the spacing of stations. The lengths of the two others of the derived forms were made the same as that of the parent while the beams were changed by increasing and decreasing the spacing of buttocks, all other widths being changed in proportion. The remaining derived form has the same length and beam as the parent, but the lines of the forebody were altered to give a planing bottom with no longitudinal curvature forward of the step. The test data were analyzed to determine the minimum resistance and the angle at which it occurs for all speeds and loads. The results of this analysis are given in the form of non dimensional curves for each model. The effect of variation in over-all size, as indicated by a "complete" test on any given hull, is pointed out. The effect of changing length alone by the spacing of buttocks, as well as the effects of the changes in length-beam ratio and longitudinal curvature that result from these operations are discussed. The difficulties encountered in interpreting test results of systematic families derived by the method used are emphasized. Further studies are suggested in which changes in the variable under consideration would not be obscured by secondary changes in other important variables.

Shoemaker, James M↗
NASA NTRS1934

The effect of trim angle on the take-off performance

Data obtained at the N.A.C.A. tank from tests on the models of three flying-boat hulls - N.A.C.A. models 11-A, 16, and 22 - are used to demonstrate the effect of trim angle on water resistance. A specific example is taken, and data from Model 11-A are used to show that the trim angle giving the minimum water resistance will give minimum total air-plus-water resistance. Total-resistance curves for best trimmed angles and other angles are compared for the same example. The effect of wind on best trim angles and upon the take-off and run is shown by the working of an example. The possibility of using tank data on trim angles as aid in piloting is discussed, and an instrument for use in determining the trim angle of seaplanes is described. The importance of maintaining the best trim angle throughout the take-off is indicated.

Shoemaker, James M↗
NASA NTRS1933

A complete tank test of a model of a flying-boat hull-N.A.C.A. Model No.11

This note discusses the limitations of the conventional tank test of a seaplane model. The advantages of a complete test, giving the characteristics of the model at all speeds, loads, and trim angles in the useful range are pointed out. The data on N.A.C.A. Model No.11, obtained from a complete test, are presented and discussed. The results are analyzed to determine the best trim angle for each speed and load. The data for the best angles are reduced to non-dimensional form for ease of comparison and application. A practical problem using the characteristics of model no.11 is presented to show the method of calculating the take-off time and run of a seaplane from these data.

Shoemaker, James M↗
NASA NTRS1932

Tests on Thrust Augmenters for Jet Propulsion

This series of tests was undertaken to determine how much the reaction thrust of a jet could be increased by the use of thrust augmenters and thus to give some indication as to the feasibility of jet propulsion for airplanes. The tests were made during the first part of 1927 at the Langley Memorial Aeronautical Laboratory. A compressed air jet was used in connection with a series of annular guides surrounding the jet to act as thrust augmenters. The results show that, although it is possible to increase the thrust of a jet, the increase is not large enough to affect greatly the status of the problem of the application of jet propulsion to airplanes.

Jacobs, Eastman N↗
NASA NTRS1928

Preliminary biplane tests in the variable density wind tunnel

Biplane cellules using the N.A.C.A.-M6 airfoil section have been tested in the variable density wind tunnel of the National Advisory Committee for Aeronautics. Three cellules, differing only in the amount of stagger, were tested at two air densities, corresponding to pressures of one atmosphere and of twenty atmospheres. The range of angle of attack was from -2 degrees to +48 degrees. The effect of stagger on the lift and drag, and on the shielding effect of the upper wing by the lower at high angles of attack was determined.

Shoemaker, James M↗
NASA NTRS1928

Air Force Tests of Sperry Messenger Model with Six Sets of Wings

The purpose of this test was to compare six well-known airfoils, the R.A.F 15, U.S.A. 5, U.S.A. 27, U.S.A. 35-B, Clark Y, and Gottingen 387, fitted to the Sperry Messenger model, at full scale Reynolds number as obtained in the variable density wind tunnel of the National Advisory Committee for Aeronautics; and to determine the scale effect on the model equipped with all the details of the actual airplane. The results show a large decrease in minimum drag coefficient upon increasing the Reynolds number from about one-twentieth scale to full scale. Maximum lift coefficient was increased with increasing scale for all the airfoils except the Gottingen 387, for which it was slightly decreased. A comparison is made between the results of these tests and those obtained from tests made in this tunnel on airfoils alone. (author)

Shoemaker, James M↗
NASA NTRS1923

Preliminary study of the damping factor in roll

This paper constitutes a general theoretical discussion of the damping factor in roll, together with the results of wind tunnel tests on the continuous rolling of U.S.A. 30 airfoil.

Shoemaker, James M↗