You limited your search to:

 Decade: 1940-1949
 Year: 1947
 Month: February
 Collection: National Advisory Committee for Aeronautics Collection
Aerodynamic Characteristics at High Speeds of Full-Scale Propellers having Different Shank Designs

Aerodynamic Characteristics at High Speeds of Full-Scale Propellers having Different Shank Designs

Date: February 13, 1947
Creator: Maynard, Julian D.
Description: Tests of two 10-foot-diameter two-blade propellers which differed only in shank design have been made in the Langley 16-foot high-speed tunnel. The propellers are designated by their blade design numbers, NACA 10-(5)(08)-03, which had aerodynamically efficient airfoil shank sections, and NACA l0-(5)(08)-03R which had thick cylindrical shank sections typical of conventiona1 blades, The propellers mere tested on a 2000-horsepower dynamometer through a range of blade-angles from 20deg to 55deg at various rotational speeds and at airspeeds up to 496 miles per hour. The resultant tip speeds obtained simulate actual flight conditions, and the variation of air-stream Mach number with advance ratio is within the range of full-scale constant-speed propeller operation. Both propellers were very efficient, the maximum envelope efficiency being approximately 0,95 for the NACA 10-(5)(08)-03 propeller and about 5 percent less for the NACA 10-(5)(08)-03R propeller. Based on constant power and rotational speed, the efficiency of the NACA 10-(05)(08)-03 propeller was from 2.8 to 12 percent higher than that of the NACA 10-(5)(08)-03R propeller over a range of airspeeds from 225 to 450 miles per hour. The loss in maximum efficiency at the design blade angle for the NACA 10-(5)(08)-03 and 10-(5)(08)-03R propellers vas about 22 and 25 percent, ...
Contributing Partner: UNT Libraries Government Documents Department
Analytical comparison of a standard turbojet engine, a turbojet engine with a tail-pipe burner, and a ram-jet engine

Analytical comparison of a standard turbojet engine, a turbojet engine with a tail-pipe burner, and a ram-jet engine

Date: February 10, 1947
Creator: Krebs, Richard P & Palasics, John
Description: None
Contributing Partner: UNT Libraries Government Documents Department
Application of the analogy between water flow with a free surface and two-dimensional compressible gas flow

Application of the analogy between water flow with a free surface and two-dimensional compressible gas flow

Date: February 1, 1947
Creator: Orlin, W James; Lindner, Norman J & Bitterly, Jack G
Description: The theory of hydraulic analogy, that is, the analogy between water flow with a free surface and two-dimensional compressible gas flow and the limitations and conditions of the analogy are discussed. A test run was made using the hydraulic analogy as applied to the flow about circular cylinders at various diameters at subsonic velocities extending to the super critical range. The apparatus and techniques used in this application are described and criticized. Reasonably satisfactory agreement of pressure distributions and flow fields existed between water and airflow about corresponding bodies. This agreement indicated the possibility of extending experimental compressibility research by new methods.
Contributing Partner: UNT Libraries Government Documents Department
Bearing strength of some sand-cast magnesium alloys

Bearing strength of some sand-cast magnesium alloys

Date: February 1, 1947
Creator: Moore, R L
Description: None
Contributing Partner: UNT Libraries Government Documents Department
Calculations of the Supersonic Wave Drag of Nonlifting Wings with Arbitrary Sweepback and Aspect Ratio: Wings Swept Behind the Mach Lines

Calculations of the Supersonic Wave Drag of Nonlifting Wings with Arbitrary Sweepback and Aspect Ratio: Wings Swept Behind the Mach Lines

Date: February 21, 1947
Creator: Harmon, Sidney M & Swanson, Margaret D
Description: On the basis of a recently developed theory for finite sweptback wings at supersonic speeds, calculations of the supersonic wave drag at zero lift were made for a series of wings having thin symmetrical biconvex sections with untapered plan forms and various angles of sweepback and aspect ratios. The results are presented in a unified form so that a single chart permits the direct determination of the wave drag for this family of airfoils for an extensive range of aspect ratio and sweepback angle for stream Mach numbers up to a value corresponding to that at which the Mach line coincides with the wing leading edge. The calculations showed that in general the wave-drag coefficient decreased with increasing sweepback. At Mach numbers for which the Mach lines are appreciably ahead of the wing leading edge, the 'wave-drag coefficient decreased to an important extent with increases in aspect ratio or slenderness ratio. At Mach numbers for which the Mach lines approach the wing leading edge (Mach numbers approaching a value equal to the secant of the angle of sweepback), the wave-drag coefficient decreased with reductions in aspect ratio or slenderness ratio. In order to check the results obtained by the theory, ...
Contributing Partner: UNT Libraries Government Documents Department
Charts showing relations among primary aerodynamic variables for helicopter-performance estimation

Charts showing relations among primary aerodynamic variables for helicopter-performance estimation

Date: February 1, 1947
Creator: Talkin, Herbert W
Description: In order to facilitate solutions of the general problem of helicopter selection, the aerodynamic performance of rotors is presented in the form of charts showing relations between primary design and performance variables. By the use of conventional helicopter theory, certain variables are plotted and other variables are considered fixed. Charts constructed in such a manner show typical results, trends, and limits of helicopter performance. Performance conditions considered include hovering, horizontal flight, climb, and ceiling. Special problems discussed include vertical climb and the use of rotor-speed-reduction gears for hovering.
Contributing Partner: UNT Libraries Government Documents Department
A Comparison of the Lateral Motion Calculated for Tailless and Conventional Airplanes

A Comparison of the Lateral Motion Calculated for Tailless and Conventional Airplanes

Date: February 1, 1947
Creator: Harper, Charles W. & Jones, Arthur L.
Description: Theoretical analysts of lateral dynamic motion of tailless and conventional airplanes was made for fighter and heavy transport. Their reactions to a lateral gust and control power required by each for simple maneuvers were determined and compared. Both types of airplanes require almost identical aileron control power to perform a given maneuver; tailless airplane requires about 1-2 to 1-3 directional control power of conventional airplane. Tailless airplane also shows greatest displacement for a given disturbance and has least damping in oscillatory mode.
Contributing Partner: UNT Libraries Government Documents Department
Comparison of Wind-Tunnel Predictions with Flight Measurements of the Longitudinal-Stability and -Control Characteristics of a Douglas BTD-1 Airplane

Comparison of Wind-Tunnel Predictions with Flight Measurements of the Longitudinal-Stability and -Control Characteristics of a Douglas BTD-1 Airplane

Date: February 13, 1947
Creator: Bunnell, Mort V. & Delany, Noel K.
Description: Low Mach number longitudinal-stability and control characteristics as predicted by use of wind tunnel data from a powered 3/16-scale model are compared with flight test measurements of a Navy BTD-1 airplane. The accuracy of the wind tunnel data and the discrepancies involved in attempting to correlate with flight data are discussed and analyzed. The comparison showed that wind tunnel predictions were, in general, in good agreement with flight test data. The predicted values were for the most part sufficiently accurate to show the satisfactory and unsatisfactory characteristics in the preliminary design stage and to indicate possible methods of improvement. The discrepancies which did occur were attributed principally to physical dissimilarities between model and airplane and the instability to determine accurately the flight power conditions. The effect of Mach number was considered negligible since the maximum flight test value was about 0.5. In order to simulate more closely the flight conditions and hence obtain more accurate data for predictions, it appears desirable to perform large-scale tests of unorthodox control surfaces such as the sealed vaned elevators with which the airplane was equipped.
Contributing Partner: UNT Libraries Government Documents Department
Computed performance of a composite engine based on experimental data for a single-cylinder conventional aircraft engine converted to compression-ignition operation

Computed performance of a composite engine based on experimental data for a single-cylinder conventional aircraft engine converted to compression-ignition operation

Date: February 3, 1947
Creator: Mccoy, J Arnold & Szel, Frank
Description: None
Contributing Partner: UNT Libraries Government Documents Department
Computed Temperature Distribution and Cooling of Solid Gas-Turbine Blades

Computed Temperature Distribution and Cooling of Solid Gas-Turbine Blades

Date: February 11, 1947
Creator: Reuter, J. George & Gazley, Carl, Jr.
Description: Computations were made to determine the temperature distribution and cooling of solid gas-turbine blades.A range of temperatures was used from 1500 degrees to 2500 degrees F, blade-root temperatures from 100 degrees to 1000 degrees F, blade thermal conductivity from 8 to 220 BTU/(hr)(sq ft)(degrees F/ft), and net gas to metal heat transfer coefficients from 75 to 250 BTU/(hr)(sq ft)(degrees F).
Contributing Partner: UNT Libraries Government Documents Department
Cooling of Gas Turbines, 3, Analysis of Rotor and Blade Temperatures in Liquid-Cooled Gas Turbines

Cooling of Gas Turbines, 3, Analysis of Rotor and Blade Temperatures in Liquid-Cooled Gas Turbines

Date: February 11, 1947
Creator: Brown, W. Byron & Livingood, John N. B.
Description: A theoretical analysis of the radial temperature distribution through the rotor and constant cross sectional area blades near the coolant passages of liquid cooled gas turbines was made. The analysis was applied to obtain the rotor and blade temperatures of a specific turbine using a gas flow of 55 pounds per second, a coolant flow of 6.42 pounds per second, and an average coolant temperature of 200 degrees F. The effect of using kerosene, water, and ethylene glycol was determined. The effect of varying blade length and coolant passage lengths with water as the coolant was also determined. The effective gas temperature was varied from 2000 degrees to 5000 degrees F in each investigation.
Contributing Partner: UNT Libraries Government Documents Department
Cooling of Gas Turbines I - Effects of Addition of Fins to Blade Tips and Rotor, Admission of Cooling Air Through Part of Nozzles, and Change in Thermal Conductivity of Turbine Components

Cooling of Gas Turbines I - Effects of Addition of Fins to Blade Tips and Rotor, Admission of Cooling Air Through Part of Nozzles, and Change in Thermal Conductivity of Turbine Components

Date: February 11, 1947
Creator: Brown, Byron
Description: An analysis was developed for calculating the radial temperature distribution in a gas turbine with only the temperatures of the gas and the cooling air and the surface heat-transfer coefficient known. This analysis was applied to determine the temperatures of a complete wheel of a conventional single-stage impulse exhaust-gas turbine. The temperatures were first calculated for the case of the turbine operating at design conditions of speed, gas flow, etc. and with only the customary cooling arising from exposure of the outer blade flange and one face of the rotor to the air. Calculations were next made for the case of fins applied to the outer blade flange and the rotor. Finally the effects of using part of the nozzles (from 0 to 40 percent) for supplying cooling air and the effects of varying the metal thermal conductivity from 12 to 260 Btu per hour per foot per degree Farenheit on the wheel temperatures were determined. The gas temperatures at the nozzle box used in the calculations ranged from 1600F to 2000F. The results showed that if more than a few hundred degrees of cooling of turbine blades are required other means than indirect cooling with fins on the rotor ...
Contributing Partner: UNT Libraries Government Documents Department
Cyclic Engine Test of Cast Vitallium Turbine Buckets - I

Cyclic Engine Test of Cast Vitallium Turbine Buckets - I

Date: February 7, 1947
Creator: Farmer, Elmo & Darmara, F.N.
Description: An investigation was conducted to correlate the engine service performance of cast Vitallium turbine buckets with standard laboratory metallurgical data. Data were obtained from four I-40 turbine wheels of Timken alloy with cast Vitallium buckets. In order to accelerate bucket deterioration, the turbine wheels were subjected to 20-minute cycles consisting of 5 minutes at idle and 15 minutes at rated speed. A bucket broke on the first wheel during cycle 22 after 7 hours and 20 minutes. The broken bucket was replaced and during the third cycle after the replacement a second bucket broke after a total running time of 8 hours and 12 minutes, The first bucket failure on the second wheel occurred during cycle 29 after 9 hours and 28 minutes; no further failure occurred during 66 additional cycles. Total running time on this wheel was 31 hours and 40 minutes. The third wheel was run for 229 cycles (76 hr and 20 min, total running time) without a. failure. The fourth wheel was operated for 105 cycles (35 hr, total running time) without a failure. Examination of the bro?en buckets indicated that the failures were probably due to fatigue, Massive eutectic areas that existed near the trailing ...
Contributing Partner: UNT Libraries Government Documents Department
Development of Inboard Nacelle for the XB-36 Airplane

Development of Inboard Nacelle for the XB-36 Airplane

Date: February 11, 1947
Creator: Nuber, Robert J.
Description: A series of investigations of several 1/14-scale models of an inboard nacelle for the XB-36 airplane was made in the Langley two-dimensional low-turbulence tunnels. The purpose of these investigations was to develop a low-drag wing-nacelle pusher combination which incorporated an internal air-flow system. As a result of these investigations, a nacelle was developed which had external drag coefficients considerably lower than the original basic form with the external nacelle drag approximately one-half to two-thirds of those of conventional tractor designs. The largest reductions in drag resulted from sealing the gaps between the wing flaps and nacelle, reducing the thickness of the nacelle training-edge lip, and bringing the under-wing air inlet to the wing leading edge. It was found that without the engine cooling fan adequate cooling air would be available for all conditions of flight except for cruise and climb at 40,000 feet. Sufficient oil cooling at an altitude of 40,000 feet may be obtained by the use of flap-type exit doors.
Contributing Partner: UNT Libraries Government Documents Department
Device for measuring principal curvature and principal strains on a nearly plane surface

Device for measuring principal curvature and principal strains on a nearly plane surface

Date: February 1, 1947
Creator: Mcpherson, A E
Description: None
Contributing Partner: UNT Libraries Government Documents Department
Drag characteristics of rectangular and swept-back NACA 65-009 airfoils having aspect ratios of 1.5 and 2.7 as determined by flight tests at supersonic speeds

Drag characteristics of rectangular and swept-back NACA 65-009 airfoils having aspect ratios of 1.5 and 2.7 as determined by flight tests at supersonic speeds

Date: February 24, 1947
Creator: Alexander, Sidney R & Katz, Ellis
Description: None
Contributing Partner: UNT Libraries Government Documents Department
Drag measurements of a 34 degree swept-forward and swept-back NACA 65-009 airfoil of aspect ratio 2.7 as determined by flight tests at supersonic speeds

Drag measurements of a 34 degree swept-forward and swept-back NACA 65-009 airfoil of aspect ratio 2.7 as determined by flight tests at supersonic speeds

Date: February 20, 1947
Creator: Alexander, Sidney R
Description: None
Contributing Partner: UNT Libraries Government Documents Department
Effect of centrifugal force on the elastic curve of a vibrating cantilever beam

Effect of centrifugal force on the elastic curve of a vibrating cantilever beam

Date: February 1, 1947
Creator: Simpkinson, Scott H; Millenson, Morton B & Eatherton, Laurel J
Description: None
Contributing Partner: UNT Libraries Government Documents Department
The Effect of High Solidity on Propeller Characteristics at High Forward Speeds from Wind-Tunnel Tests of the NACA 4-(3)(06.3)-06 and NACA 4-(3)(06.4)-09 Two-Blade Propellers

The Effect of High Solidity on Propeller Characteristics at High Forward Speeds from Wind-Tunnel Tests of the NACA 4-(3)(06.3)-06 and NACA 4-(3)(06.4)-09 Two-Blade Propellers

Date: February 27, 1947
Creator: Delano, James B.
Description: Tests of two-blade propellers having the NACA 4-(3)(06.3)-06 and NACA 4-(3)(06.4)-09 blade designs (blade activity factors of 179 and 263, respectively) have been made in the Langley 8-foot high-speed tunnel through a range of blade angle from 20 degrees to 70 degrees for free-stream Mach numbers from 0.165 to 0.725 to determine the effects of high solidity and compressibility on propeller characteristics. The tests are part of a general investigation of propellers at high forward speeds. Results previously reported for similar tests of two-blade propellers having the NACA 4-308-03 and NACA 4-308-045 blade designs (blade activity factors of 87 and 133, respectively) are included for comparison. The results showed that the 0.06- and 0.09-solidity blades, although producing efficiencies of the order of 90 percent, were less efficient than blades of conventional solidity. The variation in average blade lift coefficient with solidity at a constant blade angle and advance-diameter ratio through the speed range of these tests was found to be analogous to the variation of wing lift coefficient with aspect ratio, indicating that high-solidity blades may be desirable at very high speeds. Because of power limitations of the test equipment, conclusive evidence of the possible favorable effects of increased blade ...
Contributing Partner: UNT Libraries Government Documents Department
Effects on performance of changing the division of work between increase of angular velocity and increase of radius of rotation in an impeller

Effects on performance of changing the division of work between increase of angular velocity and increase of radius of rotation in an impeller

Date: February 1, 1947
Creator: Ginsburg, Ambrose; Ritter, William K & Palasics, John
Description: None
Contributing Partner: UNT Libraries Government Documents Department
Exhaust-valve temperatures in a liquid-cooled aircraft-engine cylinder as affected by engine operating variables

Exhaust-valve temperatures in a liquid-cooled aircraft-engine cylinder as affected by engine operating variables

Date: February 1, 1947
Creator: Sutor, Alois T; Corrington, Lester C & Dudugjian, Carl
Description: None
Contributing Partner: UNT Libraries Government Documents Department
Flight Comparison of Performance and Cooling Characteristics of Exhaust-Ejector Installation with Exhaust-Collector-Ring Installation

Flight Comparison of Performance and Cooling Characteristics of Exhaust-Ejector Installation with Exhaust-Collector-Ring Installation

Date: February 14, 1947
Creator: Acker, Loren W. & Kleinknecht, Kenneth S.
Description: Flight and ground investigations have been made to compare an exhaust-ejector installation with a standard exhaust-collector-ring installation on air-cooled aircraft engines in a twin-engine airplane. The ground investigation allowed that, whereas the standard engine would have overheated above 600 horsepower, the engine with exhaust ejectors cooled at take-off operating conditions at zero ram. The exhaust ejectors provided as much cooling with cowl flaps closed as the conventional cowl flaps induced when full open at low airspeeds. The propulsive thrust of the exhaust-ejector installation was calculated to be slightly less than the thrust of the collector-ring-installation.
Contributing Partner: UNT Libraries Government Documents Department
Flight measurements of internal cockpit pressures in several fighter-type airplanes

Flight measurements of internal cockpit pressures in several fighter-type airplanes

Date: February 1, 1947
Creator: Danforth, Edward C B , III & Reeder, John P
Description: None
Contributing Partner: UNT Libraries Government Documents Department
Flight measurements of the lateral control characteristics of narrow-chord ailerons on the trailing edge of a full-span slotted flap

Flight measurements of the lateral control characteristics of narrow-chord ailerons on the trailing edge of a full-span slotted flap

Date: February 1, 1947
Creator: Sawyers, Richard H
Description: None
Contributing Partner: UNT Libraries Government Documents Department
FIRST PREV 1 2 3 NEXT LAST