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 2.2
Miramar No. 2 and El Toro Hush-Houses. Next, designs for the second
N.A.S. Miramar F-14 hush-house (Miramar No. 2) and an F-4, A-6 hush-house for
MCAS El Toro, California were completed. The important changes between
Miramar No. 1 and No. 2 included better faring of the door air inlet, a door
outlet screen to reduce flow separation on the turning vanes, sound absorptive
panels surrounding the augmenter inlet and nonperforated inconel panels in the
hottest locations on the augmenter duct sidewalls. These facilities were
checked out in 1978 and 1979, respectively, and the results were presented in
Reference [1]. Prior to full-scale facility checkout, 1/11.4 scale model
tests were run to verify that the A-6 exhaust can be captured by a 19 ft wide
x 11 ft high augmenter entrance (refer to Aero and Thermodynamic Test of a
1/11.4-Scale Hush-House Augmenter Inlet, J.L. Grunner and J.H. Berger [10]).
2.3
NARF Norfolk Depot Test Cell Diagnostic Tests. TF-30P412/414
engines run up to maximum afterburning in the NARF Norfolk, Virginia depot
cells 13 and 14 (refer to NARF-NORVA Test Cells 13 and 14 Diagnostic Tests and
Recommendations, J.L. Grunnet [4]) gave an indication of excessive turbine
station vibration while they would meet vibration limits in the older cells
next door. Noise buildup in the reverberant cell enclosure was responsible
for the high measured vibration level. Some improvement was obtained by
moving the engine as far AFT as the mounting would allow, thus minimizing the
axial distance between the engine nozzle exit and the augmenter throat and
thereby reducing the cell interior noise level.
2.4
NATC Patuxent River Hush-House. Design of a hush-house type test
and evaluation facility for NATC Patuxent, Maryland began in 1977. This
facility had to accommodate the S-3A as well as the F-14A. In addition it had
to provide a mist free environment with the aircraft enclosure and a maximum
engine inlet approach velocity within the enclosure of only 30 f/s (9.1 m/s).
These things necessitated the incorporation of a secondary air inlet located
above the augmenter entrance. Model tests were run to verify acceptable flow
capture with the S-3A (refer to 1/15-Scale Cold-Flow Model Tests of the
Patuxent River Hush-House Configuration, J.L. Grunnet [11]) and to check
augmentation and "cell" depression. Adequate performance was indicated. In
1983, after completion of the facility a complete full-scale checkout was run
(Refer to Aero-Thermo and Acoustical Data from the Postconstruction Checkout
of a Hush-House Located at NATC Patuxent River, MD, J.L. Grunnett [9]).
2.5
Test Cell Emissions Study. For a number of years the Navy has been
striving to meet local district restrictions on test cell and hush-house
exhaust plume opacity. In 1980, this culminated in a study of factors
effecting exhaust plume opacity. The study included both full-scale observa-
tions and model-scale tests. A number of guidelines for exhaust system design
were derived for minimizing plume opacity (refer to Phase I Report - The
Effect of Test Cell Exhaust System Design on Exhaust Plume Opacity- Analysis
and Observations and Phase II and III Report - The Effect of Test Cell Exhaust
System Design on Exhaust Plume Opacity--Model-Scale Plume Opacity Tests and
Design Procedures to Minimize Opacity, J.L. Grunnet and W.H. Phillips [5,12].
2.6
Miramar Hush-House Augmenter Failure Study. Long term operation of
the Miramar Numbers 1 and 2 hush-houses began to produce structural failures
in the augmenter sidewalls near the upstream end. This was believed to be due
to high wall temperatures during operation of misaligned F-14A aircraft in
maximum afterburner. Full-scale F-14A tests were run with various degrees of
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