50 Matching Results

Search Results

Results: 1 - 24 next
open access

Effect of spark-timing regularity on the knock of engine performance

Description: Tests on a high-speed single-cylinder engine are described. The regularity of the spark timing was varied by driving the timer from different engine shafts. A simple and reasonably accurate method of determining the spark timing is described. The results show that irregular spark timing may cause large errors in tests of the knocking properties of fuels. For the engine tested, it was found that a change of one crankshaft degree in spark restart was equivalent to an 0.85 inch Hg change in allowa… more
Date: May 1938
Creator: Biermann, Arnold E.
Partner: UNT Libraries Government Documents Department
open access

Tables of Stiffness and Carry-Over Factor for Structural Members Under Axial Load

Description: "Tables of stiffness and carry-over factor are presented for members in which the cross section and axial load do not vary along the length of the member. These tables are of use in solving problems in the stability of structural members under axial load as well as in application of the Cross method of moment distribution when the effects of axial load in the members are considered. The interval between successive values of the argument is small enough to make interpolation unnecessary in engin… more
Date: June 1938
Creator: Lundquist, Eugene E. & Kroll, W. D.
Partner: UNT Libraries Government Documents Department
open access

Hydrodynamic and Aerodynamic Tests of Four Models of Outboard Floats: (N.A.C.A. Models 51-A, 51-B, 51-C, and 51-D)

Description: Four models of outboard floats (N.A.C.A. models 51-A, 51-B, 51-C, and 51-D) were tested in the N.A.C.A. tank to determine their hydrodynamic characteristics and in the 20-foot wind tunnel to determine their aerodynamic drag. The results of the tests, together with comparisons of them, are presented in the form of charts. From the comparisons, the order of merit of the models is estimated for each factor considered. The best compromise between the various factors seems to be given by model 51-D.… more
Date: December 1938
Creator: Dawson, John R. & Hartman, Edwin P.
Partner: UNT Libraries Government Documents Department
open access

A flight investigation of the reduction of aileron operating force by means of fixed tabs and differential linkage, with notes on linkage design

Description: Flight tests were made to demonstrate the particularity of employing fixed tabs in conjunction with a suitably designed differential linkage to reduce the force required to operate ailerons. The tests showed the system to be practicable with tabs of the inset type. The relative ineffectiveness of attached tabs for changing the aileron floating angle rendered them unsuitable. Experience gained in the investigation has indicated that the use of the system is limited to maximum deflections of one … more
Date: June 1938
Creator: Soulé, H. A. & Hootman, James A.
Partner: UNT Libraries Government Documents Department
open access

The increase in frictional resistance caused by various types of rivet heads as determined by tests of planing surfaces

Description: "The increase in the frictional resistance of a surface caused by the presence of rivet heads was determined by towing four planing surfaces of the same dimensions. One surface was smooth and represented a surface without rivet heads or one with perfectly flush countersunk rivets. The other three surfaces were each fitted with the same number of full-size rivet heads but of a different type arranged in the same pattern on each surface" (p. 1).
Date: May 1938
Creator: Truscott, Starr & Parkinson, J. B.
Partner: UNT Libraries Government Documents Department
open access

The effect of air-passage length on the optimum fin spacing for maximum cooling

Description: The effect on cooling of baffle length with optimum cylinder finning is discussed. Results from tests of several streamlined cylinders are given. It is shown that by employing several baffles the cooling can be increased several times.
Date: May 1938
Creator: Brevoort, Maurice J.
Partner: UNT Libraries Government Documents Department
open access

Wind-Tunnel Tests of a Clark Y Wing Having Split Flaps With Gaps

Description: "Tests were made of the Clark Y wing having split flaps with a gap between the flap and the lower surface of the wing. Lift, drag, and pitching moments were measured for the wing with three different sizes of flap. It was found that any gap between the flap and the wing reduced the lift, the drag, and the pitching moments, but that the center-of-pressure movement and the ratio of lift to drag were little affected" (p. 1).
Date: May 1938
Creator: Wenzinger, Carl J.
Partner: UNT Libraries Government Documents Department
open access

Wind-Tunnel Tests of Carburetor-Intake Rams

Description: "An investigation was conducted in the NACA 20-foot wind tunnel of the ramming effect of three general types of carburetor intake rams for radial engines, namely, the internal constant area type, the external constant area type, and the external expanding type. The rams were installed on a radial air- cooled engine nacelle, and tests were made with and without the propeller operating. The results indicated that the external types having entrances near the front of the engine cowling gave the gr… more
Date: January 1938
Creator: Highley, Frank H.
Partner: UNT Libraries Government Documents Department
open access

Fatigue Testing of Wing Beam by the Resonance Method

Description: "Preliminary fatigue tests on two aluminum-alloy wing-beam specimens subjected to reversed axial loading are described. The motion used consists in incorporating one or two reciprocating motors in a resonance system of which the specimen is the spring element. A description is given of the reciprocating motors, and of the method of assembling and adjusting the vibrating system" (p. 1).
Date: August 1938
Creator: Bleakney, William M.
Partner: UNT Libraries Government Documents Department
open access

Wind-tunnel investigation of rectangular and tapered NACA 23012 wings with plain ailerons and full-span split flaps

Description: An investigation was made to determine the aerodynamic properties of rectangular and tapered NACA 23012 wings with plain ailerons and a full-span split flap, the flap retracting ahead of the ailerons. Measurements were made of lift and drag and of pitching, rolling, yawing, and hinge moments for all conditions of full-span flaps neutral and deflected at different chord locations. The results of the tests showed that a 0.20c(sub w) full span split flap located at approximately the 0.75c(sub w) p… more
Date: August 1938
Creator: Wenzinger, Carl J. & Ames, Milton B., Jr.
Partner: UNT Libraries Government Documents Department
open access

Improvement of aileron effectiveness by the prevention of air leakage through the hinge gap as determined in flight

Description: "A flight investigation was made of the increase in effectiveness of ailerons that can be obtained by preventing flow of air through the wing at the hinges and of the possibility of reducing the aileron operating force by replacing ailerons having normal open hinge gaps with narrower but equally effective ailerons having sealed hinge gaps. Tests were made with a Fairchild 22 airplane with two sizes of plain unbalanced ailerons, one set having a chord equal to 0.18c, and the other chord equal to… more
Date: January 1938
Creator: Soulé, H. A. & Gracey, W.
Partner: UNT Libraries Government Documents Department
open access

Gyroscopic Instruments for Instrument Flying

Description: The gyroscopic instruments commonly used in instrument flying in the United States are the turn indicator, the directional gyro, the gyromagnetic compass, the gyroscopic horizon, and the automatic pilot. These instruments are described. Performance data and the method of testing in the laboratory are given for the turn indicator, the directional gyro, and the gyroscopic horizon. Apparatus for driving the instruments is discussed.
Date: September 1938
Creator: Brombacher, W. G. & Trent, W. C.
Partner: UNT Libraries Government Documents Department
open access

The effects of partial-span plain flaps on the aerodynamic characteristics of a rectangular and a tapered Clark Y wing

Description: An investigation was made to determine the aerodynamic characteristics of tapered and rectangular wings with partial-span plain flaps. Two Clark Y airfoils equipped with center section and with tip-section flaps were tested. The results showed that the aerodynamic characteristics of partial-span plain flaps were, in general, similar to those of split flaps of the same span, but that the lift and the drag were less for the wing with plain flaps than for the wing with split flaps of comparable si… more
Date: September 1938
Creator: House, R. O.
Partner: UNT Libraries Government Documents Department
open access

Spinning characteristics of wings 5: N.A.C.A. 0009, 23018, and 6718 monoplane wings

Description: Three rectangular monoplane wings having rounded tips were tested on the N.A.C.A. spinning balance in the 5-foot vertical wind tunnel. The airfoil sections used were the N.A.C.A. 0009, 23018, and 6718. The aerodynamic characteristics of the models and a prediction of the angles of sideslip for steady spins are given. There is included an estimate of the yawing moment that must be furnished by parts of the airplane to balance the inertia couples and wing yawing moments for spinning equilibrium. … more
Date: January 1938
Creator: Bamber, M. J. & House, R. O.
Partner: UNT Libraries Government Documents Department
open access

Free-spinning wind-tunnel tests of a low-wing monoplane with systematic changes in wings and tails 3: mass distributed along the wings

Description: Report presenting an investigation of 24 wing-tail combinations with the weight moved from the center of gravity toward the wing tips so that the distribution of mass along the wings was increased. Results regarding the effects of wings, effects of tail arrangement, effects of control setting, relationships between spin characteristics, and comparison with results for basic loading are provided.
Date: September 1938
Creator: Seidman, Oscar & Neihouse, A. I.
Partner: UNT Libraries Government Documents Department
open access

Tests of N-85, N-86 and N-87 Airfoil Sections in the 11-Inch High Speed Wind Tunnel

Description: "Three airfoils, the N-85, the N-86, and the N-87, were tested at the request of the Bureau of Aeronautics, Navy Department, to determine the suitability of these sections for use as propeller-blade sections. Further tests of the NACA 0009-64 airfoil were also made to measure the aerodynamic effect of thickening the trailing edge in accordance with current propeller practice. The N-86 and the N-87 airfoils appear to be nearly equivalent aerodynamically and both are superior to the N-85 airfoil"… more
Date: September 1938
Creator: Stack, John & Lindsey, W. F.
Partner: UNT Libraries Government Documents Department
open access

The N.A.C.A. Optical Engine Indicator

Description: An optically recording engine-pressure indicator of simple and rugged construction has been developed for use in high-pressure and high temperature combustion research. This instrument is of the diaphragm type and has a natural frequency of about 10,000 cycles per second.
Date: January 1938
Creator: Tozier, Robert E.
Partner: UNT Libraries Government Documents Department
open access

Flow observations with tufts and lampblack of the stalling of four typical airfoil sections in the NACA variable-density tunnel

Description: From Summary: "A preliminary investigation of the stalling processes of four typical airfoil sections was made over the critical range of the Reynolds Number. Motion pictures were taken of the movements of small silk tufts on the airfoil surface as the angle of attack increased through a range of angles including the stall. The boundary-layer flow also at certain angles of attack was indicated by the patterns formed by a suspension of lampblack in oil brushed onto the airfoil surface. These obs… more
Date: October 1938
Creator: Abbott, Ira H. & Sherman, Albert
Partner: UNT Libraries Government Documents Department
open access

Preliminary Fatigue Studies on Aluminum Alloy Aircraft Engines

Description: "Preliminary information on the complex subject of the fatigue strength of fabricated structural members for aircraft is presented in the test results obtained on several different types of airship girders subjected to axial tension and compression in a resonance fatigue machine. A description of this machine as well as numerous photographs of the fatigue failures are given. There is also presented an extended bibliography on the subject of fatigue strength" (p. 1).
Date: February 1938
Creator: Goodyear-Zeppelin Corporation
Partner: UNT Libraries Government Documents Department
open access

The Pressure Available for Ground Cooling in Front of the Cowling of Air-Cooled Airplane Engines

Description: "A study was made of the factors affecting the pressure available for ground cooling in front of a cowling. Most of the results presented were obtained with a set-up that was about one-third full scale. A number of isolated tests on four full-scale airplanes were made to determine the general applicability of the model results. The full-scale tests indicated that the model results may be applied qualitatively to full-scale design and quantitatively as a first approximation of the front pressure… more
Date: November 1938
Creator: Stickle, George W. & Joyner, Upshur T.
Partner: UNT Libraries Government Documents Department
open access

Scavenging a Piston-Ported Two-Stroke Cylinder

Description: "An investigation was made with a specially designed engine to determine the scavenging characteristics of a large number of inlet-port shapes and arrangements and the optimum port arrangement and timing for this particular type of engine. A special cylinder construction permitted wide variations in timing for this particular type of engine. A special cylinder construction permitted wide variations in timing as well as in shape and arrangement of both the inlet and exhaust ports" (p. 1).
Date: November 1938
Creator: Rogowski, A. R. & Bouchard, C. L.
Partner: UNT Libraries Government Documents Department
open access

Tank Tests of Model 36 Flying Boat Hull

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 inter… more
Date: March 1938
Creator: Allison, John M.
Partner: UNT Libraries Government Documents Department
open access

Discharge Characteristics of a Simulated Unit Injection System

Description: "Rate-of-discharge curves that show the discharge characteristics of an injection system having a very short fuel passage are presented. The rate of discharge closely follows the rate of displacement of the injection-pump plunger for open nozzles in which the maximum calculated pressures at the orifice do not exceed a certain value, which is dependent on the particular injection pump. With small orifices and high pump speeds, the rate of discharge does not follow the rate of plunger displacemen… more
Date: November 1938
Creator: Marsh, Edred T.
Partner: UNT Libraries Government Documents Department
open access

Tests of a Contra-Propeller for Aircraft

Description: "Tests of an 8-blade contra-propeller of 32-inch diameter in combination with a 4-inch, 36-inch diameter adjustable pitch, metal propeller at pitch setting of 15, 25, 35, and 45 degrees at 0.75 R were made. The tests showed a significant increase in effective thrust of the combination over that of the propeller alone for value V/nD somewhat below those for maximum efficiency and without a corresponding increase of power absorbed. From 1/2 percent to 2-1/2 percent in propulsive efficiency was th… more
Date: November 1938
Creator: Benson, William M.
Partner: UNT Libraries Government Documents Department
Back to Top of Screen