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 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 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

NACA Technical Notes

"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-heat-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" (p. 1)

NACA Technical Notes

"A study has been made of the heat requirement for the cyclic de-icing of hollow steel propellers fitted with external blade heating shoes. Solutions to the equations for the heat flow in cyclic heating of propellers were obtained, using an electrical analogy. The study showed how the energy requirement for propeller de-icing with existing blade shoes could be decreased, and illustrated the effect of blade-shoe design on the energy requirement. It was demonstrated, for example, that by increasing the heating intensity and decreasing the heating period from those currently used the energy requirement could be decreased in the order of 60 percent" (p. 1)

NACA Technical Notes

"Measurements of propeller efficiency loss due to ice formation are supplemented by an analysis to establish the magnitude of efficiency losses to be anticipated during flight in icing conditions. The measurements were made during flight in natural icing conditions; whereas the analysis consisted of an investigation of changes in blade-section aerodynamic characteristics caused by ice formation and the resulting propeller efficiency changes. Agreement in the order of magnitude of efficiency losses to be expected is obtained between measured and analytical results" (p. 1)

NACA Wartime Reports

Report presenting an investigation of a thermal ice-prevention system for a C-46 cargo airplane, which involved flight tests in dry-air and natural-icing conditions at two different laboratories. The purpose of the investigation was to determine the effectiveness of the C-46 airplane ice-prevention system and to continue the develop of thermal ice-prevention equipment. Results regarding the wing outer panel, wing tips, wing center panel, horizontal stabilizers, vertical fin, windshields, ice-removal tests, unprotected surfaces, and heat exchangers are provided

NACA Technical Notes

Note presenting a verification of previously derived equations for calculating the rate of heat transfer from airfoils in icing conditions, which have come about as a result of an investigation of the meteorological conditions conducive to the formation of ice on aircraft and a study of the process of airfoil thermal ice prevention. The results indicated that knowledge of these components has increased to a point where the design of heated wings on a fundamental, wet-air basis can now be undertaken with reasonable certainty