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 Decade: 1940-1949
 Year: 1941
 Collection: National Advisory Committee for Aeronautics Collection
Design of nozzles for the individual cylinder exhaust jet propulsion system

Design of nozzles for the individual cylinder exhaust jet propulsion system

Date: April 1, 1941
Creator: Voss, Fred
Description: None
Contributing Partner: UNT Libraries Government Documents Department
Comparison of Vee-Type and Conventional Tail Surfaces in Combination with Fuselage and Wing in the Variable-Density Tunnel

Comparison of Vee-Type and Conventional Tail Surfaces in Combination with Fuselage and Wing in the Variable-Density Tunnel

Date: July 1, 1941
Creator: Greenberg, Harry
Description: The pitching and the yawing moments of a vee-type and a conventional type of tail surface were measured. The tests were made in the presence of a fuselage and a wing-fuselage combination in such a way as to determine the moments contributed by the tail surfaces. The results showed that the vee-type tail tested, with a dihedral angle of 35.3 deg, was about 71 percent as effective in pitch as the conventional tail and had a yawing-moment to pitching-moment ratio of 0.3. The conventional tail, the panels of which were all congruent to those of the vee-type tail, had a yawing-moment to pitching-moment ratio of 0.48. These ratios are in fair agreement with values calculated by methods shown in this and previous reports. The values of the measured moments were reduced from 15 to 25 percent of the calculated value by fuselage interference.
Contributing Partner: UNT Libraries Government Documents Department
Effects of some present-day airplane design trends on requirements for lateral stability

Effects of some present-day airplane design trends on requirements for lateral stability

Date: June 1, 1941
Creator: Bamber, Millard J
Description: None
Contributing Partner: UNT Libraries Government Documents Department
Methods of analyzing wind-tunnel data for dynamic flight conditions

Methods of analyzing wind-tunnel data for dynamic flight conditions

Date: October 1, 1941
Creator: Donlan, C J & Recant, I G
Description: The effects of power on the stability and the control characteristics of an airplane are discussed and methods of analysis are given for evaluating certain dynamic characteristics of the airplane that are not directly discernible from wind-tunnel tests alone. Data are presented to show how the characteristics of a model tested in a wind tunnel are affected by power. The response of an airplane to a rolling and a yawing disturbance is discussed, particularly in regard to changes in wing dihedral and fin area. Solutions of the lateral equations of motion are given in a form suitable for direct computations. An approximate formula is developed that permits the rapid estimation of the accelerations produced during pull-up maneuvers involving abrupt elevator deflections.
Contributing Partner: UNT Libraries Government Documents Department
Spin tests of two models of a low-wing monoplane to investigate scale effect in the model test range

Spin tests of two models of a low-wing monoplane to investigate scale effect in the model test range

Date: May 1, 1941
Creator: Donlan, Charles C
Description: None
Contributing Partner: UNT Libraries Government Documents Department
The calculation of span LCAD distributions of swept-back wings

The calculation of span LCAD distributions of swept-back wings

Date: December 1, 1941
Creator: Mutterperl, William
Description: Span load distributions of swept-back wings have been calculated. The method used was to replace the wing with a bound vortex at the quarter-chord line and to calculate the downwash due to the system of bound and trailing vortices to conform at the three-quarter-chord line to the slope of the flat-plate wing surface. Results are given for constant-chord and 5:1 tapered plan forms, for sweep-back angles of 0 degrees, 30 degrees, and 45 degrees, and for aspect ratios of 3, 6, and 9. Some comments on the stalling of swept-back wings are included.
Contributing Partner: UNT Libraries Government Documents Department
Supplement to Comparison of automatic control systems

Supplement to Comparison of automatic control systems

Date: August 1941
Creator: Oppelt, W
Description: This analysis deals with the indirect regulator, wherefrom the behavior of the direct regulator is deduced as a limiting case. The prime mover is looked upon as "independent of the load": a change in the adjusting power (to be applied) for the control link (as, for example, in relation to the adjusting path (eta) with pressure valves or the rudder of vessels) does not modify the actions of the prime mover. Mass forces and friction are discounted; "clearance" also is discounted in the transmission links of the regulator.
Contributing Partner: UNT Libraries Government Documents Department
Tests of the NACA 0025 and 0035 airfoils in the full-scale wind tunnel

Tests of the NACA 0025 and 0035 airfoils in the full-scale wind tunnel

Date: January 1, 1941
Creator: Bullivant, W Kenneth
Description: This report presents the results of an investigation conducted in the NACA full-scale wind tunnel to determine the aerodynamic characteristics of the 6 by 36-foot rectangular NACA 0025 and 0035 airfoils. The aerodynamic characteristics of the plain airfoils with rounded and square tips were determined by force tests through a complete angle-of-attack range, in addition, the profile drag was determined by the momentum method. The transition points on the airfoils were located by boundary-layer determinations with small total-head and static tubes. Each airfoil was also tested with a 0.20c full-span split flap. Tuft surveys were included to show the progressive breakdown of flow with increasing angles of attack. Previously published data from tests of the NACA 0009, 0012, and 0018 airfoils in the full-scale tunnel have been included in the summary curves.
Contributing Partner: UNT Libraries Government Documents Department
Wind-tunnel investigation of spoiler, deflector, and slot lateral-control devices on wings with full-span split and slotted flaps

Wind-tunnel investigation of spoiler, deflector, and slot lateral-control devices on wings with full-span split and slotted flaps

Date: January 1, 1941
Creator: Wenzinger, Carl J & Rogallo, Francis M
Description: Report presents the results of an extensive investigation made in the NACA 7 by 10-foot wind tunnel of spoiler, deflector, and slot types of lateral-control device on wings with full-span split and slotted flaps. The static rolling and yawing moments were determined for all the devices tested, and the static hinge moments and the time response were determined for a few devices of each type.
Contributing Partner: UNT Libraries Government Documents Department
Internal-flow systems for aircraft

Internal-flow systems for aircraft

Date: January 1, 1941
Creator: Rogallo, F M
Description: An investigation has been made to determine efficient arrangements for an internal-flow system of an aircraft when such a system operates by itself or in combination with other flow systems. The investigation included a theoretical treatment of the problem and tests in the NACA 5-foot vertical wind tunnel of inlet and outlet openings in a flat plate and in a wing.
Contributing Partner: UNT Libraries Government Documents Department
Wind-tunnel investigation of an NACA 23012 airfoil with several arrangements of slotted flaps with extended lips

Wind-tunnel investigation of an NACA 23012 airfoil with several arrangements of slotted flaps with extended lips

Date: January 1, 1941
Creator: Lowry, John G
Description: An investigation was made in the NACA 7- by 10-foot wind tunnel to determine the effect of slot-lip location on the aerodynamic section characteristics of an NACA 23012 airfoil with a 30-percent-chord slotted flap. Tests were made with slot lips located at 90 and 100 percent of the airfoil chord and with two different flap shapes. The results are compared with a slotted flap previously developed by the National advisory Committee for Aeronautics with a slot lip located at 83 percent of the airfoil chord. The extension of the slot lip to the rear increased the section lift and pitching-moment coefficients. Comparisons made on a basis of pitching moment for a given tail length show that the Fowler type flap, lip extended to trailing edge of the airfoil, has the greatest section lift coefficient. For moderate tail lengths, 2 to 3 chord lengths, there was only a slight difference between the previously developed slotted flap and the slotted flap with slot lip extended to 90 percent of the airfoil chord. Of the three flaps tested, the Fowler flap had the lowest drag coefficient at high lift coefficients. The extension of the lower surface at the leading edge of the slot ...
Contributing Partner: UNT Libraries Government Documents Department
Wind-tunnel investigation of the effect of vertical position of the wing on the side flow in the region of the vertical tail

Wind-tunnel investigation of the effect of vertical position of the wing on the side flow in the region of the vertical tail

Date: April 1, 1941
Creator: Recant, Isidore G & Wallace, Arthur R
Description: None
Contributing Partner: UNT Libraries Government Documents Department
Pressure distribution over NACA 23012 airfoil with a slotted and a split flap

Pressure distribution over NACA 23012 airfoil with a slotted and a split flap

Date: January 1, 1941
Creator: Harris, Thomas A & Lowry, John G
Description: A pressure-distribution investigation has been conducted in the NACA 4 by 6-foot vertical wind tunnel to determine the air loads on an NACA 23012 airfoil in combination with a 25.66-percent-chord slotted flap and a 20-percent-chord split flap. Pressures were measured on both the upper and the lower surfaces of the main airfoil and the flaps for several angles of attack and at several flap settings. The data, presented as pressure diagrams and as graphs of the section coefficients for the flap alone and for the airfoil-flap combinations, are applicable to rib and flap design for a combination of a thick airfoil and a slotted or a split flap. The results of previous tests of a NACA 23012 airfoil with a slotted flap are compared with the present results.
Contributing Partner: UNT Libraries Government Documents Department
A simplified theoretical method of determining the characteristics of a lifting rotor in forward flight

A simplified theoretical method of determining the characteristics of a lifting rotor in forward flight

Date: January 1, 1941
Creator: Bailey, F J , Jr
Description: Theoretical derived expressions for the flapping, the thrust, the torque, and the profile drag-lift ratio of nonfeathering rotor with hinged, rectangular, linearly twisted blades are given as simple functions of the inflow velocity and the blade pitch. Representative values of the coefficients of each of the terms in these expressions are tabulated for a series of specified values of the tip-speed ratio. Analysis indicates that the tabulated values can be used to calculate, with reasonable accuracy, the characteristics of any rotor of conventional design.
Contributing Partner: UNT Libraries Government Documents Department
Preignition characteristics of several fuels under simulated engine conditions

Preignition characteristics of several fuels under simulated engine conditions

Date: January 1, 1941
Creator: Spencer, R C
Description: The preignition characteristics of a number of fuels have been studied under conditions similar to those encountered in an engine. These conditions were simulated by suddenly compressing a fuel-air mixture in contact with an electrically heated hot spot in the cylinder head of the NACA combustion apparatus. Schlieren photographs and indicator cards were taken of the burning, and the hot-spot temperatures necessary to cause ignition under various conditions were determined.
Contributing Partner: UNT Libraries Government Documents Department
Analysis and prediction of longitudinal stability of airplanes

Analysis and prediction of longitudinal stability of airplanes

Date: January 1, 1941
Creator: Gilruth, R R & White, M D
Description: An analysis has been made of the longitudinal stability characteristics of 15 airplanes as determined in flight. In the correlation of satisfactory and unsatisfactory characteristics with determined values, the derivative that expresses the ratio of static-restoring moments to elevator-control moments was found to represent most nearly the stability characteristics appreciated by the pilots. The analysis was extended to study the effects of various design features on the observed stability characteristics. Design charts and data are included that show the effects on longitudinal stability of relative positions of wing and tail, fuselage size and location, engine nacelles, and horizontal-tail arrangements.
Contributing Partner: UNT Libraries Government Documents Department
Wind-tunnel investigation of effect of interference on lateral-stability characteristics of four NACA 23012 wings, an elliptical and a circular fuselage and vertical fins

Wind-tunnel investigation of effect of interference on lateral-stability characteristics of four NACA 23012 wings, an elliptical and a circular fuselage and vertical fins

Date: January 1, 1941
Creator: House, Rufus O & Wallace, Arthur R
Description: Report presents the results of a wind-tunnel investigation of the effect of wing-fuselage interference on lateral-stability characteristics made in the NACA 7 by 10-foot wind tunnel on four fuselages and two fins, representing high-wing, low-wing, and midwing monoplanes. The fuselages are of circular and elliptical cross section. The wings have rounded tips and, in plan form, one is rectangular and the three are tapered 3:1 with various amounts of sweep. The rate of change in the coefficients of rolling moment, yawing moment, and lateral force with angle of yaw is given in a form to show the increment caused by wing-fuselage interference for the model with no fin and the effect of wing-fuselage interference on fin effectiveness. Results for the fuselage-fin combination and the wing tested alone are also given.
Contributing Partner: UNT Libraries Government Documents Department
The problem of cooling an air-cooled cylinder on an aircraft engine

The problem of cooling an air-cooled cylinder on an aircraft engine

Date: January 1, 1941
Creator: Brevoort, M J & Joyner, U T
Description: An analysis of the cooling problem has been to show by what means the cooling of an air-cooled aircraft engine may be improved. Each means of improving cooling is analyzed on the basis of effectiveness in cooling with respect to power for cooling. The altitude problem is analyzed for both supercharged and unsupercharged engines. The case of ground cooling is also discussed. The heat-transfer process from the hot gases to the cylinder wall is discussed on the basis of the fundamentals of heat transfer and thermodynamics. Adiabatic air-temperature rise at a stagnation point in compressible flow is shown to depend only on the velocity of flow.
Contributing Partner: UNT Libraries Government Documents Department
Propeller analysis from experimental data

Propeller analysis from experimental data

Date: January 1, 1941
Creator: Stickle, George W & Crigler, John L
Description: The operation of the propeller is analyzed by the use of the distribution of forces along the radius, combined with theoretical equations. The data were obtained in the NACA 20-foot wind tunnel on a 4-foot-diameter, two-blade propeller, operating in front of four body shapes, ranging from a small shaft to support the propeller to conventional NACA cowling. A method of estimating the axial and the rotational energy in the wake as a fractional part of the propeller power is given. A knowledge of the total thrust and torque is necessary for the estimation.
Contributing Partner: UNT Libraries Government Documents Department
Lateral control required for satisfactory flying qualities based on flight tests of numerous airplanes

Lateral control required for satisfactory flying qualities based on flight tests of numerous airplanes

Date: January 1, 1941
Creator: Gilruth, R R & Turner, W N
Description: Report presents the results of an analysis made of the aileron control characteristics of numerous airplanes tested in flight by the National Advisory Committee for Aeronautics. By the use of previously developed theory, the observed values of pb/2v for the various wing-aileron arrangements were examined to determine the effective section characteristics of the various aileron types.
Contributing Partner: UNT Libraries Government Documents Department
Plate method of ground representation for wind-tunnel determination of elevator effectiveness in landing

Plate method of ground representation for wind-tunnel determination of elevator effectiveness in landing

Date: September 1, 1941
Creator: Recant, I G
Description: None
Contributing Partner: UNT Libraries Government Documents Department
A high-speed motion-picture study of normal combustion, knock and preignition in a spark-ignition engines

A high-speed motion-picture study of normal combustion, knock and preignition in a spark-ignition engines

Date: January 1, 1941
Creator: Rothrock, A M; Spencer, R C & Miller, Cearcy D
Description: Combustion in a spark-ignition engine was investigated by means of the NACA high-speed motion-picture cameras. This camera is operated at a speed of 40,000 photographs a second and therefore makes possible the study of changes that take place in the intervals as short as 0.000025 second. When the motion pictures are projected at the normal speed of 16 frames a second, any rate of movement shown is slowed down 2500 times. Photographs are presented of normal combustion, of combustion from preignitions, and of knock both with and without preignition. The photographs of combustion show that knock may be preceded by a period of exothermic reaction in the end zone that persists for a time interval of as much as 0.0006 second. The knock takes place in 0.00005 second or less.
Contributing Partner: UNT Libraries Government Documents Department
Flow coefficients of monosleeve valves

Flow coefficients of monosleeve valves

Date: January 1, 1941
Creator: Waldron, C D
Description: The flow coefficients of the intake and the exhaust ports of a sleeve-valve cylinder were measured by attaching the cylinder to a large tank and measuring the changes in pressure and temperature in the tank that were caused by short periods of air flow through the valve ports. The derivation of the equations on which the flow coefficients are based is given. The distribution of total pressure in the arms of the sleeve-valve intake manifold was measured. The arms are found to have as little as 75 percent of the total pressure within the manifold entrance.
Contributing Partner: UNT Libraries Government Documents Department
Pressure available for cooling with cowling flaps

Pressure available for cooling with cowling flaps

Date: January 1, 1941
Creator: Stickle, George W; Naiman, Irven & Crigler, John L
Description: Report presents the results of a full-scale investigation conducted in the NACA 20-foot tunnel to determine the pressure difference available for cooling with cowling flaps. The flaps were applied to an exit slot of smooth contour at 0 degree flap angle. Flap angles of 0 degree, 15 degrees, and 30 degrees were tested. Two propellers were used; propeller c which has conventional round blade shanks and propeller f which has airfoil sections extending closer to the hub. The pressure available for cooling is shown to be a direct function of the thrust disk-loading coefficient of the propeller.
Contributing Partner: UNT Libraries Government Documents Department
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