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Multidisciplinary
Design, Analysis, and
Optimization Branch
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EDUCATIONAL ACTIVITIES: THE NASA AEROQUIZ
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Week of 6/7/99:
Q:
During Apollo 14's outbound flight to the moon, astronauts Shepard, Mitchell,
and Roosa had trouble docking their command module to the lunar module --
a maneuver necessary to extract it from the Saturn third stage. They did
finally dock with it, and they avoided having to fly a simplified lunar
reconnaissance mission without a landing.
But there were concerns that the docking problem could occur a second
time: when Shepard and Mitchell were coming back from the moon's surface.
What contingency plans did NASA have in the event of a failed dock?
A:
In the event of a docking failure, Shepard and Mitchell would have had
to suit up, go outside, tether the spacecraft together, and transfer
themselves and all of the moon rocks to the command module. This emergency
procedure was practiced in water tank simulations.
No one got the correct answer!
- The Aeroquiz Editor
Week of 6/14/99:
Q:
In order to comply with Federal Aviation Regulations, a commercial airplane
must satisfy landing gear strength requirements. Drop tests are performed
in controlled laboratory settings, where the gear to be tested is placed in
a mechanical jig. The jig slams the gear down onto a surface with a force
and speed comparable to an actual aircraft landing. How is the forward
speed of the aircraft simulated in these tests?
A:
In a drop-style aircraft landing gear test, the wheel/tire assembly is
rotated at a high speed by an electric motor in the reverse direction
with respect to normal tire rotation due to ground contact. The rotation
speed is equal to the expected rpm of the tire after contact with the
runway at the desired landing speeds to be simulated in the test. In
such a test, the wheel/tire assembly is connected to the motor by a
chain/sprocket arrangement.
Congratulations to Stephen W. Jackson.
Week of 6/21/99:
Q:
The first really serious effects of aerodynamic compressibility on
airplanes were encountered in high-speed dives of fighter airplanes in
World War Two. When pilots put their airplanes in steep, terminal velocity
dives starting from about 30,000 feet, they were often unable to recover.
In these dives, supersonic flow and shock waves formed on the upper
surface of the relatively thick wings, causing flow separation. The
separated flow, in turn, reduced the elevator effectiveness. The control
force necessary to recover from the dive was sometimes beyond the strength
of the pilot. At times, however, one of the things that sometimes allowed
pilots to pull out of these dives was the higher air temperature encountered
at lower altitudes. Why?
A:
At lower altitudes and higher air temperatures, the speed of sound is
faster than it would be in the thin air at higher altitudes, which is
well known to be colder. The speed of an aircraft as a percentage of
the speed of sound is lower at lower altitudes and/or sea level, which
means a reduction or elimination of shock waves, supersonic airflow, and
control-reducing airflow separations.
Congratulations to Stephen W. Jackson.
Week of 6/28/99:
Q:
When we think of Harley-Davidson, we usually think of style, function,
sound, feel, chrome, a legendary heritage, and the open road. Would you
think of flying at 330,000 feet at speeds approaching Mach five? Why?
A:
Raytheon Aircraft currently manufactures the AQM-37C: a small, supersonic,
expendable target missile. It is propelled by the LR64 liquid-fueled
rocket motor, made by Harley-Davidson, and is capable of producing 860 pounds
of thrust. The AQM-37 provides air-to-air weapons training for pilots or
for surface-to-air missile crews. The AQM-37C has recently been upgraded
for use as a ballistic missile target. During exercises in 1996,
the missile flew at altitudes of 235,000 feet with a range of 105 miles.
Terminal velocities were Mach 4. Air launches at Mach 1.5 at an altitude of
50,000 feet extend the envelope to altitudes of 330,000 feet with a
range of 265 miles with terminal velocities near Mach 5.
Congratulations to Daniel Shedd.
If anyone has the H-D catalog number for the LR64, let me know.
I'd have the fastest FXSTC on the block!
- The Aeroquiz Editor.
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