Wind-Tunnel Investigation of a Number of Total-Pressure Tubes at High Angles of Attack - Subsonic, Transonic, and Supersonic Speeds
Abstract
The effect of inclination of the airstream on the measured pressures of 54 total-pressure tubes has been determined for angles of attack up to 60 deg and over a Mach number range from 0.26 to 1.62. The investigation was conducted in five wind tunnels at the Langley Aeronautical laboratory. For simple, nonshielded tubes, the usable angular range was found to depend on the external shape of the nose section, the size of the impact opening (relative to the tube diameter), and the shape of the internal chamber behind the impact opening. The best combination of these design features (that is, a tube having a cylindrical nose shape, an impact opening equal to the tube diameter, and a 30 deg conical chamber) produced the highest usable range (about 28 deg at a Mach number of 0.26) of any of the nonshielded tubes. In cases where a usable angular range larger than +/- 28 deg is required, a much higher range may be obtained with shielded tubes. The usable range of a tube with a shield having a conical entry, for example, is about +/- 41 deg at a Mach number of 0.26. Changing the shape of the entry of the shield to a highly curved section increases the usable range to about +/- 63 deg, the highest of any of the tubes tested. The throats of these tubes were vented through the walls of the shield, a design feature permitting end-mounting of the tube on a horizontal boom. For airspeed applications where it is not essential that the tube have a large negative angle-of-attack range, the usable range may be extended to higher positive angles of attack by means of a leading-edge slant profile. For slant profiles up to 20 deg, the usable range at positive angles of attack can be extended by about 1 deg for each degree of slant. The effect of Mach number on both unshielded and shielded tubes was found to be considerable. For most of the unshielded tubes the usable range increased with Mach number, whereas that of the shielded tubes decreased with Mach number.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 01, 1956
- Accession Number
- ADA377664
Entities
People
- William Gracey
Organizations
- National Aeronautics and Space Administration