An Investigation Utilizing an Electrical Analogue of Cyclic Deicing of Hollow Steel Propellers with Internal Electric Heaters

A study has been made of the heating requirements for the cyclic de?icing of hollow steel propellers fitted with two types of internal electric heaters. Solutions to the transient?teat?flow equations depicting the cyclic de?icing of propellers were obtained by use of an electrical analogy. The study showed the impracticability of using an internal tubular heater and illustrated the advantages of employing an internal shoe?type heater, which distributes the heat more evenly to the blade surface. The importance of minimizing the thermal inertia of the system was demonstrated, and the magnitude of reductions in the total energy requirement made possible through reductions in the heating period was indicated

The Calculated and Measured Performance Characteristics of a Heated-Wire Liquid-Water-Content Meter for Measuring Icing Severity

Ground tests have been made of an instrument which, when assembled in a more compact form for flight installation, could be used to obtain statistical flight data on the liquid-water content of icing clouds and to provide an indication of icing severity. The sensing element of the instrument consists of an electrically heated wire which is mounted in the air stream. The degree of cooling of the wire resulting from evaporation of the impinging water droplets is a measure. of the liquid-water content of the cloud. Determination of the value of the liquid-water content from the wire temperature at any instant requires a knowledge of the airspeed, altitude, and air temperature. An analysis was made of the temperature response of a heated wire exposed to an air stream containing water drops. Comparisons were made of the liquid-water content as measured with several heated wires and absorbent cylinders in an artificially produced cloud. For one of the wires, comparative tests were made with a rotating-disk icing-rate meter in an icing wind tunnel. From the test results, it was shown that an instrument for measuring the concentration of liquid water in an air stream can be built using an electrically heated wire of known temperatureresistance characteristics, and that the performance of such a device can be predicted using appropriate theory. Although an instrument in a form suitable for gathering statistical data in flight was not built, the practicability of constructing such an instrument was illustrated. The ground-test results indicated that a flight heated-wire instrument would be simple and durable, would respond rapidly to variations in liquid-water content, and could be used for the measurement of water content in clouds which are above freezing temperature, as well as in icing clouds

Airborne Simulation of Shuttle/ Spacelab Management And Operation

As part of a continuing study to develop and demonstrate low-cost techniques for management and operation of Spacelab, the CV-990 airborne laboratory at the NASA Ames Research Center was used to conduct in-depth, real-time Spacelab simulations. This ASSESS (Airborne Science/Spacelab Experiments System Simulation) project involved an extensive cooperative effort of NASA and the European Space Agency (ESA). An international Spacelab operation was completed in which a scientific payload was selected to conduct studies in upper atmospheric physics and infrared astronomy with principal investigators from France, the Netherlands, England, and several groups in the United States. Two experiment operators from Europe and two from the United States were selected to live aboard the aircraft along with a Mission Manager for a 6-day period and operate the experiments in behalf of the principal scientists. Extensive data were obtained in overall management of a complex international payload; experiment preparation, testing, and integration; training for proxy operators in space; data handling; multi-experimenter use of common experimenter facilities; multiexperiment operation by experiment operators; selection criteria for Spacelab experiment operators; and schedule requirements to prepare for such a Spacelab mission

The Calculation of the Heat Required for Wing Thermal Ice Prevention in Specified Icing Conditions

Flight tests were made in natural icing conditions with two 8-ft-chord heated airfoils of different sections. Measurements of meteorological variables conducive to ice formation were made simultaneously with the procurement of airfoil thermal data. The extent of knowledge on the meteorology of icing, the impingement of water drops on airfoil surfaces, and the processes of heat transfer and evaporation from a wetted airfoil surface have been increased to a point where the design of heated wings on a fundamental, wet-air basis now can be undertaken with reasonable certainty

NACA Technical Notes

A procedure proposed for use in the design of air-heated systems for the continuous prevention of ice formation on airplane components is set forth. Required heat-transfer and air-pressure-loss equations are presented, and methods of selecting appropriate meteorological conditions for flight over specified geographical areas and for the calculation of water-drop-impingement characteristics are suggested. In order to facilitate the design, a simple electrical analogue was devised which solves the complex heat-transfer relationships existing in the thermal-system analysis

NACA Research Memorandums

Memorandum presenting an investigation of a flight version of the NACA heated-wire liquid-water-content instrument, which was constructed and flight tested in natural icing conditions. Data obtained simultaneously with rotting multicylinders indicated that reliable flight measurements of liquid-water content could be made with the heated-wire instrument

NACA Research Memorandums

Memorandum presenting an investigation made with an electrical heat-flow analog to determine the effect of internal modifications to a wing leading edge on the surface-temperature rise and temperature distribution for conditions of transient aerodynamic heating at high supersonic speeds. Results regarding the leading-edge temperature rise, influence of conduction on leading-edge temperature for skins of uniform thickness, and surface-temperature distribution are provided

NACA Restricted Bulletins

Report discusses the results of an investigation to compare the discharge characteristics of an alcohol feed ring and a standard alcohol discharge nozzle when utilized to supply anti-icing alcohol to the propeller-blade feed shoes on a Curtiss-Wright C-46 cargo airplane. The equipment used, testing practices, and results of the alcohol flow distribution are described