X-59 Sonic Boom Test Results from the NASA Glenn 8- by 6-Foot Supersonic Wind Tunnel

A wind tunnel test was conducted to investigate near-field sonic boom pressure signatures
from a model of the X-59 Low-Boom Flight Demonstrator aircraft. A 1.62%-scale model of the
aircraft in the C612A configuration was fabricated for the wind tunnel test, which took place in
the NASA Glenn 8- by 6-Foot Supersonic Wind Tunnel in September and October 2021.

The model had provisions for two different mounting options: a swept blade strut that
attached at the top of model ahead of the inlet, and rear-entry sting that was made as one piece
with a dummy nacelle, and which had a 2”-long cylindrical segment aft of the nozzle exit before
tapering up in size. The blade strut allowed for a clean aft end of the model for evaluation of the
shocks from that region, while the sting avoided the significant distortions of the flow and shocks
from the blade strut along the top of the model. Both the sting and the strut had adapters that
attached to a force balance. The model had alternate parts for ±0.5° deflections of the flaps,
ailerons, and stabilator, and ±1° deflections of the T-tail horizontal surface.

Off-body static pressure measurements of the flow field below the model were made by use
of a pressure rail which had 420 orifices along its tip. The model was positioned at various
heights from the rail by vertical movement of the wind tunnel strut, and at various longitudinal
stations relative to the rail by means of a linear actuator mounted between the tunnel strut and
the balance. The longitudinal positioning allowed multiple pressure signatures to be obtained
along different portions of the rail. These signatures were aligned by accounting for the model
longitudinal movement and then averaged to take out the effects of tunnel flow distortions and
the interference of the rail flow field and shocks on the model pressure signatures. The test was
run at approximate Mach numbers of 1.36, 1.4, and 1.47, and the model was set at various
angles of attack and roll relative to the rail.

Plots of the model signatures for all the variations of Mach number, model angles, control
deflections, and height relative to the rail are provided throughout the report. Repeatability was
generally very good and gave confidence in the quality of the measurements. The signatures
measured at various heights from the rail provided insight into the aging of the model shocks as
they propagated from 1.2 to 3 body lengths from the model. Off-track signatures up to 45° from
centerline obtained by rolling the model gave indications of the shock flow fields across the
width of the sonic boom carpet. The deflections of the various control surfaces allowed
assessment of the boom sensitivity to the control surface movements.