A continuing study of altitude determination deficiencies of the Service Aircraft Instrumentation Package (SAIP).


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., United States Naval ReserveApproved for public release; distribution is unlimited

Similar works

Full text


Calhoun, Institutional Archive of the Naval Postgraduate School

Provided a free PDF time updated on 5/26/2016View original full text link

Having an issue?

Is data on this page outdated, violates copyrights or anything else? Report the problem now and we will take corresponding actions after reviewing your request.