I applaud the Independent Group in
trying to work with the limited public
information to sanity-check the investi-
gation. They should be encouraged.
Kenneth H. Friberg
PORTLAND, OREGON
ROCKY ROAD FOR ROCKET ENGINES
Viewpoint writer Daniel Goure may
have good reason to look to 2015 as
the year of “The Great Rocket Engine
Competition” (AW& S T Oct. 20, p. 58).
Given past experience, the U.S. Air
Force may be facing a year of protests,
stop-work orders and delays in 2016.
John C. Bauer
MANOTICK, ONTARIONOISE TAKES CENTER STAGE
I was pleased to see several articles
devoted to airframe noise (AW& S T
Sept. 22, pp. 46-52). In the late 1960s
and early ’70s I worked for the then-
Lockheed-California Co. Althoughassigned to the acoustics department,
most of my projects came from the
advanced design organization.
One of the most rewarding was
being the acoustics principal engineer
on a Defense Department contract for
designing an ultra-quiet reconnais-
sance airplane. Of all the possible noise
sources that had to be predicted, only
“Airframe Noise,” as we called it, had
no established prediction methodology.
Several measurement programs
using aircraft operating under “idle
or near idle” power were measured,
but none unpowered, although later,
Davey Smith at Wright-Patterson AFB
conducted research on a glider.
The Defense Department funded the
external noise measurement program.
We measured five diferent aircraft—
all flying unpowered. As a direct result,
the course of external aircraft noise
regulations were forever changed.
The program is reported in a NASA
paper—CR2377, December 1974.
Gerald J. Healy
ELOY, ARIZONAPUT ‘EARS’ AT RUNWAY ENDS
“Taming Noise” take two pages to
address excessive aerodynamic noise
produced by components of flaps
and leading edges during the takeof
phase. I have lived under the flightpath
of Wichita Mid-Continent Airport
Runway 32 for 46 years. The greatest
noise created during takeof is from the
clatter of the hydraulic pumps while
raising their flaps, and from leading-
edge devices during the climb out. As a
flight heads northwest, the noise drops
to a slight hum of the engines.
A switch to electric motor power for
the flaps, leading-edge devices and land-
ing gears might be more productive.
I recommend that the NASA
engineers position themselves 2 mi.
from the runway end at a commercial
airport and listen to takeofs and ap-
proaches to figure out what is making
the most noise.
William J. Schueler
WICHITA, KANSASFeedback
12 AVIATION WEEK & SPACE TECHNOLOGY/NOVEMBER 3/10, 2014 AviationWeek.com/awst
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