An Investigation of the Drag and Pressure Recovery of a Submerged Inlet and a Nose Inlet in the Transonic Flight Range with Free-fall Models

The drag and pressure recovery of an NACA submerged-inlet model and an NACA series I nose-inlet model were investigated in the transonic flight range. The tests were conducted over a mass-flow-ratio range of 0.4 to 0.8 and a Mach number range of about 0.8 to 1.10 employing large-scale recoverable free-fall models. The results indicate that the Mach number of drag divergence of the inlet models was about the same as that of a basic model without inlets. The external drag coefficients of the nose-inlet model were less than those of the submerged-inlet model throughout the test range. The difference in drag coefficient based on the maximum cross-sectional area of the models was about 0.02 at supersonic speeds and about 0.015 at subsonic speeds. For a hypothetical airplane with a ratio of maximum fuselage cross-sectional area to wing area of 0.06, the difference in airplane drag coefficient would be relatively small, about 0.0012 at supersonic speeds and about 0.0009 at subsonic speeds. Additional drag comparisons between the two inlet models are made considering inlet incremental and additive drag

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

Report presenting flight testing to investigate the temperature gradients in the wing structure of a typical high-speed fighter airplane caused by rapid changes in surface temperatures. Reports were carried out using dive testing and measured at multiple points on the airplane

NACA Technical Notes

Report presenting flight measurements of structure temperatures occurring in the wing outer panel of the airplane in order to improve the design of thermal ice-prevention systems. Results indicate that structure temperatures increased almost in direct proportion with an increase in heated-air temperature

NACA Research Memorandums

"The drag and pressure recovery of an NACA submerged-inlet model and an NACA series I nose-inlet model were investigated in the transonic flight range. The tests were conducted over a mass-flow-ratio range of 0.4 to 0.8 and a Mach number range of about 0.8 to 1.10 employing large-scale recoverable free-fall models. The results indicate that the Mach number of drag divergence of the inlet models was about the same as that of a basic model without inlets" (p. 1)

NACA Technical Notes

Report presenting a metallurgical examination of the material used in the fabrication of a thermal ice-prevention system after 225 hours of actual flight operation of the heating installation. Only minor corrosion was noted and no impairment of tensile strength was observed

NACA Advanced Restricted Reports

Report presenting an investigation of a thermal ice-prevention system for a Curtiss-Wright C-46 airplane, which included a determination of the change in stress at various locations in the wing outer panel caused by operation of the thermal system. Curves are presented showing the chordwise variation of stress and temperature for two wing stations