:
Full-scale F-15 Forebody Testing
A
full-scale F-15 forebody wind tunnel test program was initiated following
the reports of high-AOA nose-slice departures seen on a fleet vehicle
at Nellis AFB. It was suspected that geometric imperfections on the
radome were the primary cause. An USAF-sponsored test program was performed
at the Langley Full Scale Tunnel
to investigate and quantify the link between the F-15’s radome
imperfections and the aerodynamic asymmetry at high angle of attack.
Several refurbished fleet radomes were fitted to the after-body plug
for testing. The test articles were also tapped and configured for surface pressure measurement.
During testing of the radome imperfections, force and moment data were
collected concurrently with surface pressure measurement on the forebody.
This capability permitted rapid correlation of measured sideforce and
yawing moment data against local flow conditions. It was concluded that
high-AOA sideforce and yawing moment asymmetries can be attributed to
minute geometric anomalies near the radome apex. These test results
supported revisions to the F-15 maintenance procedures to prevent future
high-AOA departure.
A summary of the test results can be found in AIAA2000-4104.
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