Measurements of Temperature Variations in the Atmosphere Near the Tropopause With Reference to Airspeed Calibration by the Temperature Method
Abstract
Detailed measurements of pressure and temperature were made in constant-speed level flight, in low-speed climbing flight, and in a high-speed dive and pull-up with a jet fighter airplane for the purpose of obtaining information on the accuracy of the temperature method of air-speed calibration (NACA TN 2046). The measurements were made near the tropopause over land in the vicinity of Langley Field, Va., on clear days with few or no clouds. The data were taken by means of a thermometer, described in the present paper, which was designed by the Langley Instrument Research Division to meet the low-lag, high-recovery requirements of the temperature method. Measurements made in low-speed climbs indicated that the variations of temperature with pressure were very smooth when the lapse rate was close to adiabatic and several temperature-pressure surveys agreed closely, although spaced several minutes apart with no effort made to repeat the surveys in the same position in the air mass. On the other hand, when the lapse rate was small (between isothermal and NACA standard for air below the tropopause), variations of temperature with pressure were irregular and changed erratically with time and distance. Evaluation of the airspeed calibration of the jet fighter made when the conditions were least unfavorable to the method showed an undesirably large scatter of the static-pressure error of about +/- 2.5 percent of impact pressure at a Mach number of about 0.8.
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 01, 1952
- Accession Number
- ADA377043
Entities
People
- Harry H. Ricker Jr
- Lindsay J. Lina
Organizations
- National Aeronautics and Space Administration