Flight Test Results from the Rake Airflow Gage Experiment on the F-15B
- Created: Tuesday, 01 November 2011
The primary goal is to identify the relationship between free stream and local mach number in the low supersonic regime.
The results are described of the Rake Airflow Gage Experiment (RAGE), which was designed and fabricated to support the flight test of a new supersonic inlet design using Dryden’s Propulsion Flight Test Fixture (PFTF) and F-15B testbed airplane (see figure). The PFTF is a unique pylon that was developed for flight-testing propulsion-related experiments such as inlets, nozzles, and combustors over a range of subsonic and supersonic flight conditions.
NASA Dryden F-15B research test bed with Propulsion Flight Test Fixture pylon and Rake Airflow Gage Experiment rake during flight test." class="caption" align="right">The objective of the RAGE program
was to quantify the local flowfield at the
aerodynamic interface plane of the
Channeled Centerbody Inlet Experiment (CCIE). The CCIE is a fixed representation
of a conceptual mixed-compression
supersonic inlet with a translating
biconic centerbody. The primary
goal of RAGE was to identify the relationship
between free-stream and local
Mach number in the low supersonic
regime, with emphasis on the identification
of the particular free-stream Mach
number that produced a local Mach
number of 1.5. Measurements of the
local flow angularity, total pressure distortion,
and dynamic pressure over the
interface plane were also desired.
The experimental data for the RAGE program were obtained during two separate research flights. During both flights, local flowfield data were obtained during straight and level acceleration segments out to steady-state test points. The data obtained from the two flights showed small variations in Mach number, flow angularity, and dynamic pressure across the interface plane at all flight conditions. The data show that a free-stream Mach number of 1.65 will produce the desired local Mach number of 1.5 for CCIE. The local total pressure distortion over the interface plane at this condition was approximately 1.5%. At this condition, there was an average of nearly 2° of downwash over the interface plane. This small amount of downwash is not expected to adversely affect the performance of the CCIE inlet.
This work was done by Michael Frederick and Nalin Ratnayake of Dryden Flight Research Center. DRC-009-018