Effects of Ice Formations on Airplane Performance in Level Cruising Flight (open access)

Effects of Ice Formations on Airplane Performance in Level Cruising Flight

"A flight investigation in natural icing conditions was conducted by the NACA to determine the effect of ice accretion on airplane performance. The maximum loss in propeller efficiency encountered due to ice formation on the propeller blades was 19 percent. During 87 percent of the propeller icing encounters, losses of 10 percent or less were observed" (p. 1).
Date: May 1948
Creator: Preston, G. Merritt & Blackman, Calvin C.
System: The UNT Digital Library
Investigation of Effectiveness of Air-Heating a Hollow Steel Propeller for Protection Against Icing 1: Unpartitioned Blades (open access)

Investigation of Effectiveness of Air-Heating a Hollow Steel Propeller for Protection Against Icing 1: Unpartitioned Blades

From Summary: "An investigation to determine the effectiveness of icing protection afforded by air-heating hollow steel unpartitioned propeller blades has been conducted In the NACA Cleveland icing research tunnel. The propeller used was a production model modified with blade shank and tip openings to permit internal passage of heated air. Blade-surface and heated-air temperatures were obtained and photographic observations of Ice formations were made with variations In icing intensity and heating rate to the blades. For the conditions of Icing to which the propeller was subjected, it was found that adequate ice protection was afforded with a heating rate of 40 1 000 Btu per hour per blade."
Date: May 1948
Creator: Mulholland, Donald R. & Perkins, Porter J.
System: The UNT Digital Library
Investigation of Effectiveness of Air-Heating a Hollow Steel Propeller for Protection Against Icing. 2: 50% Impartitioned Blades (open access)

Investigation of Effectiveness of Air-Heating a Hollow Steel Propeller for Protection Against Icing. 2: 50% Impartitioned Blades

From Summary: "The icing protection afforded an internal air-heated propeller blade by radial partitioning at 50-percent chord to confine the heated air to the forward half of the blade was determined in the NACA Cleveland icing research tunnel. A modified production-model hollow steel propeller, was used for the investigation. Temperatures of the blade surfaces for several heating rates were measured under various tunnel icing conditions. Photographic observations of ice formations on blade surfaces and blade heat-exchanger effectiveness were obtained."
Date: May 1948
Creator: Perkins, Porter J. & Mulholland, Donald R.
System: The UNT Digital Library
Investigation of Effectiveness of Air-Heating a Hollow Steel Propeller for Protection Against Icing. 3: 25% Partitioned Blades (open access)

Investigation of Effectiveness of Air-Heating a Hollow Steel Propeller for Protection Against Icing. 3: 25% Partitioned Blades

From Summary: "The icing protection obtained from an internally air-heated propeller blade partitioned to confine the heated air forward of 25-percent chord was investigated in the NACA Cleveland icing research tunnel. A production-model hollow steel propeller was modified with an Internal radial partition at 25-percent chord and with shank and tip openings to admit and exhaust the heated air. Temperatures were measured on the blade surfaces and in the heated-air system during tunnel icing conditions. Heat-exchanger effectiveness and photographs of Ice formations on the blades were obtained."
Date: May 1948
Creator: Mulholland, Donald R. & Perkins, Porter J.
System: The UNT Digital Library
Impingement of Water Droplets on NACA 65(1)-208 and 65(1)-212 Airfoils at 4 Degrees Angle of Attack (open access)

Impingement of Water Droplets on NACA 65(1)-208 and 65(1)-212 Airfoils at 4 Degrees Angle of Attack

"The trajectories of droplets in the air flowing past NACA 65(1)-208 airfoil and an NACA 65(1)-212 airfoil, both at an angle of attack of 4 degrees, were determined. The amount of water in droplet form impinging on the airfoils, the area of droplet impingement, and the rate of droplet impingement per unit area on the airfoil surface affected were calculated from the trajectories and are presented. The amount, extent, and rate of impingement of the NACA 65(1)-208 airfoil are compared with the results for the NACA 65(1)1-212 airfoil" (p. 1).
Date: May 1953
Creator: Brun, Rinaldo J.; Gallagher, Helen M. & Vogt, Dorothea E.
System: The UNT Digital Library
Statistical Study of Aircraft Icing Probabilities at the 700- and 500- Millibar Levels over Ocean Areas in the Northern Hemisphere (open access)

Statistical Study of Aircraft Icing Probabilities at the 700- and 500- Millibar Levels over Ocean Areas in the Northern Hemisphere

From Summary: "A statistical study is made of icing data reported from weather reconnaissance aircraft flown by Air Weather Service (USAF). The weather missions studied were flown at fixed flight levels of 500 millibars (18,000 ft) and 700 millibars (10,000 ft) over wide areas of the Pacific, Atlantic, and Arctic Oceans. This report is presented as part of a program conducted by the NACA to obtain extensive icing statistics relevant to aircraft design and operation. The thousands of in-flight observations recorded over a 2- to 4-year period provide reliable statistics on icing encounters for the specific areas, altitudes, and seasons included in the data."
Date: May 1957
Creator: Perkins, Porter J.; Lewis, William & Mulholland, Donald R.
System: The UNT Digital Library
Droplet Impingement and Ingestion by Supersonic Nose Inlet in Subsonic Tunnel Conditions (open access)

Droplet Impingement and Ingestion by Supersonic Nose Inlet in Subsonic Tunnel Conditions

"The amount of water in cloud droplet form ingested by a full-scale supersonic nose inlet with conical centerbody was measured in the NACA Lewis icing tunnel. Local and total water impingement rates on the cowl and centerbody surfaces were also obtained. All measurements were made with a dye-tracer technique" (p. 1).
Date: May 1958
Creator: Gelder, Thomas F.
System: The UNT Digital Library
Notes on the Theory of the Accelerometer (open access)

Notes on the Theory of the Accelerometer

Report discusses several types of accelerometers and how they function. Methods for reducing error and determining the source of the error, including the best placement for the device, are included.
Date: May 1920
Creator: Warner, E. P.
System: The UNT Digital Library
The Problem of the Helicopter (open access)

The Problem of the Helicopter

Report discussing some of the issues regarding the design and operation of helicopters and the theoretical basis behind them. Some particular issues covered include propeller blade design, helicopters in forced descent, horizontal travel, and stability and control.
Date: May 1920
Creator: Warner, E. P.
System: The UNT Digital Library
Airplane Superchargers (open access)

Airplane Superchargers

Discussed here are the principles and operation of aircraft engine superchargers used to maintain and increase engine power as aircraft encounter decreases in the density of air as altitude rises. Details are given on the design and operation of the centrifugal compressors. A method is given for calculating the amount of power needed to drive a compressor. The effects of the use of a compressor on fuel system operation and design are discussed. Several specific superchargers that were in operation are described.
Date: May 1921
Creator: Noack, W. G.
System: The UNT Digital Library
On a New Type of Wind Tunnel (open access)

On a New Type of Wind Tunnel

Discussed here is a new type of wind tunnel, its advantages, the difficulties attendant upon its use, and the special methods required for its operation. The main difference between the new type of wind tunnel and the ones now in operation is the use of a different fluid. The idea is to diminish the effect of viscosity.
Date: May 1921
Creator: Munk, Max
System: The UNT Digital Library
Sylphon diaphragms : a method for predicting their performance for purposes of instrument design (open access)

Sylphon diaphragms : a method for predicting their performance for purposes of instrument design

Here, the purpose is to show that the characteristic performance of a syphon diaphragm can be predicted from a knowledge of its stiffness and of its dimensions. The proof is based on a mathematical analysis of this type of diaphragm, together with enough experimental data to prove the validity of the assumptions and the sufficiency of the analysis. Equations are developed for the performance of syphons under various conditions of loading, both for concentrated loads and for hydrostatic pressure.
Date: May 1922
Creator: Eaton, H. N. & Keulegan, G. H.
System: The UNT Digital Library
Notes on Propeller Design III: The Aerodynamical Equations of the Propeller Blade Elements (open access)

Notes on Propeller Design III: The Aerodynamical Equations of the Propeller Blade Elements

The air flow and the air force created by all elements of the propeller blades lying in a ring located between two concentric circles around the propeller axis are independent of what happens in other rings.
Date: May 1922
Creator: Munk, Max M.
System: The UNT Digital Library
Notes on Propeller Design 4: General Proceeding in Design (open access)

Notes on Propeller Design 4: General Proceeding in Design

The choice of the numbers of revolutions and of the diameter, the distribution of thrust, and the values of the constants in the aerodynamical equations of the propeller are discussed.
Date: May 1922
Creator: Munk, Max M.
System: The UNT Digital Library
N.A.C.A. control position recorder (open access)

N.A.C.A. control position recorder

Report discussing a new instrument is described which is capable of simultaneously recording the position of the three controls of an airplane. The records are taken photographically on a standard N.A.C.A. film drum and the instrument can be quickly installed in any airplane.
Date: May 1922
Creator: Norton, F. H.
System: The UNT Digital Library
Notes on the Design of Latticed Columns Subject to Lateral Loads (open access)

Notes on the Design of Latticed Columns Subject to Lateral Loads

"No rational column formula has yet been developed which gives results which are sufficiently precise for the design of airplane members, and consequently it is necessary to fall back upon experimental testing. In order to derive the maximum benefit from experiments, however, it is necessary that the experiments be guided by theory. It is the object here to modify existing formulae that may be obtained with a minimum number of tests" (p. 1).
Date: May 1922
Creator: McCarthy, Charles J.
System: The UNT Digital Library
Airplane Performance as Influenced by the Use of a Supercharged Engine (open access)

Airplane Performance as Influenced by the Use of a Supercharged Engine

"The question of the influence of a supercharged engine on airplane performance is treated here in a first approximation, but one that gives an exact idea of the advantage of supercharging. Considered here is an airplane that climbs first with an ordinary engine, not supercharged, and afterwards climbs with a supercharged engine. The aim is to find the difference of the ceilings reached in the two cases" (p. 1).
Date: May 1920
Creator: de Bothezat, George
System: The UNT Digital Library
Relation of Rib Spacing to Stress in Wing Planes (open access)

Relation of Rib Spacing to Stress in Wing Planes

The stress relations to the fabric and the rib consequent upon a change of spacing between ribs in a wing plane are discussed. Considering the wing plane as a static structure, and ignoring the question of aerodynamic efficiency, it appears that the unit stress in the rib and fabric will remain constant for constant p if the linear dimensions of both rib and fabric are increased alike, viz., if wing and fabric remain geometrically similar. Since the bulge and the structural dimensions remain geometrically similar, the whole distended plane remains so, and hence should have the same pressure distribution and efficiency.
Date: May 1920
Creator: Zahm, A. F.
System: The UNT Digital Library
Further Experimental Studies of Area Suction for the Control of the Laminar Boundary Layer on a Porous Bronze NACA 64A010 Airfoil (open access)

Further Experimental Studies of Area Suction for the Control of the Laminar Boundary Layer on a Porous Bronze NACA 64A010 Airfoil

Note presenting a low-turbulence wind-tunnel investigation of an NACA 64A010 airfoil with a porous surface to determine the reduction in section total-drag coefficient that might be obtained at large Reynolds numbers by the use of area suction. This report primarily deals with additional tests of the same airfoil model equipped with a porous skin of lower porosity.
Date: May 1950
Creator: Braslow, Albert L. & Visconti, Fioravante
System: The UNT Digital Library
Analysis of Circular Shell-Supported Frames (open access)

Analysis of Circular Shell-Supported Frames

From Summary: "This paper deals with the single problem if circular shell-supported frames subjected to concentrated loadings. A mathematical attack is developed and presented in the form of nondimensional-coefficient curves."
Date: May 1944
Creator: Wignot, J. E.; Combs, Henry & Ensrud, A. F.
System: The UNT Digital Library
The Effect of Wind Tunnel Turbulence Upon the Forces Measured on Models (open access)

The Effect of Wind Tunnel Turbulence Upon the Forces Measured on Models

These tests were undertaken to find the effect of turbulence in the air stream upon the lift and drag forces measured on models in the four-foot wind tunnel at the Massachusetts Institute of Technology. Maximum lifts and minimum drags were measured on Gottingen-387 and R.A.F.-15 airfoils, minimum drag on a streamlined strut, and the static pressure gradients for different conditions of turbulence were investigated. The results show that the scale of the turbulence (as defined in this report) has a marked effect upon the measured forces on models tested in the tunnel as well as on the pressure gradient, and it is recommended that further investigation of the phenomena be made with the aid of smoke and small wind vanes.
Date: May 1924
Creator: LePage, W. L. & Nichols, J. T.
System: The UNT Digital Library
Note on the Pressure Distribution Over the Hull of Elongated Airships With Circular Cross Section (open access)

Note on the Pressure Distribution Over the Hull of Elongated Airships With Circular Cross Section

"This note, prepared for the National Advisory Committee for Aeronautics, contains the demonstration that the pressure around the circular cross section of an elongated airship, plotted against the diameter of symmetry, can be expected to be represented by a straight line" (p. 1).
Date: May 1924
Creator: Munk, Max M.
System: The UNT Digital Library
High Altitude Flying (open access)

High Altitude Flying

This note investigates the effect of high altitude or low atmospheric pressure upon the operation of an engine and the effect of the low pressure and lack of oxygen and of the very low temperatures upon the pilot and upon the performance of the airplane itself.
Date: May 1924
Creator: King, Paul B. & Carroll, Thomas
System: The UNT Digital Library
A method of determining the dimensions and horsepower of an airship for any given performance (open access)

A method of determining the dimensions and horsepower of an airship for any given performance

A simple and easily applied method of calculating the dimensions and horsepower necessary for an airship to have any given performance is described and illustrated by examples. The method includes means for estimating the changes in performance or in size when modifications or new features are introduced into a design, involving increase or saving in weights, or changes in resistance or propulsive efficiency.
Date: May 1924
Creator: Burgess, C. P.
System: The UNT Digital Library