| Popis: |
After correcting test equipment used in a previous study of the SAIP for an ambiguous grounding requirement, research was continued on aerodynamic factors affecting SAIP altitude measurement. Existing equations for incompressible flow over a cylinder and a sphere were used to model the static-pressure probe located on the front of the SAIP pod and an algorithm was derived for the computation of the pressure coefficient, Cp . Our low-speed wind tunnel data show an overpressure at the static pressure ports when the angle of attack (({>) is less than 14°. The five-inch diameter body of the SAIP, located aft of the static pressure probe, is responsible for creating a stagnation-like region at the front of the SAIP probe which envelops the static-port location. Calculation of the altitude error (AZ) using the model for Cp, corrected for compressibility, is within ± 15% of the error observed in flight at Mach 0.60. Improvements in the compressibility correction as well as analyses using an aero-panel method are suggested before sufficiently reliable fixes to the SAIP can be proposed. http://archive.org/details/acontinuingstudy1094526434 Lieutenant, United States Naval Reserve Approved for public release; distribution is unlimited. |
