Usually, the object carries special instruments to measure the forces
produced by the air on the object.
Engineers also study how the air
moves around the object by injecting smoke or dye into the tunnel and
photographing its motion around the object. Improving the flow of air
around an object can increase its lift and decrease its drag.
It saves a lot of time and money required for the testing and analysis of designs, and prototypes.
I leave you guys with this clipping from a wind tunnel testing facility at NASA:
The Flappy Plane : This phenomenon is known as Flutter in Aerodynamics. It is an unstable oscillation that can lead to destruction
Our flying observatory, called SOFIA, carries a 100-inch telescope inside a Boeing 747SP aircraft. Scientists onboard study the life cycle of stars, planets (including Pluto’s atmosphere), the area around black holes and complex molecules in space.
Once each year our flying observatory, SOFIA, its team and instruments travel to the Southern Hemisphere to Christchurch, New Zealand. From there the team studies stars and other objects that cannot be seen while flying in the Northern Hemisphere.
What We Study
We often study star formation in our Milky Way Galaxy. But from the Southern Hemisphere we can also study the lifecycle of stars in two other galaxies called the Magellanic Clouds. The Magallenic Clouds have different materials in them, which changes how stars form in these galaxies. Scientists are studying these differences to better understand how the first stars in our universe formed.
The Southern Hemisphere’s seasons are opposite from our own. When we are operating from Christchurch in June and July, it’s winter. This means that the nights are very long – ideal for our nighttime observing flights, which last approximately 10 hours.
These observations often bring us so far south that the team onboard can see the Southern Lights, also called the Aurora Australis. This is the Southern Hemisphere equivalent of the Northern Lights, or Aurora Borealis, visible near the North Pole. Auroras are caused by particles from space hitting the atmosphere near Earth’s magnetic poles. Our scientists onboard SOFIA don’t study the aurora, but they do enjoy the view.
In 1984 NASA Dryden Flight Research Center and the Federal Aviation
Administration (FAA) teamed-up in a unique flight experiment called the
Controlled Impact Demonstration (CID), to test the impact of a Boeing
720 aircraft using standard fuel with an additive designed to supress
fire. The additive FM-9, a high molecular-weight long chain polymer,
when blended with Jet-A fuel had demonstrated the capability to inhibit
ignition and flame propagation of the released fuel in simulated impact
Antimisting kerosene (AMK) cannot be introduced directly into a gas
turbine engine due to several possible problems such as clogging of
filters. The AMK must be restored to almost Jet-A before being
introduced into the engine for burning. This restoration is called
“degradation” and was accomplished on the B-720 using a device called a
“degrader”. Each of the four Pratt & Whitney JT3C-7 engines had a
“degrader” built and installed by General Electric (G.E) to break down
and return the AMK to near Jet-A quality.
In addition to the AMK research the NASA Langley Research
Center was involved in a structural loads measurement experiment which
included having instrumented dummies filling the seats in the passenger
compartment. Before the final flight on December 1, 1984, more then four
years of effort passed trying to set-up final impact conditions
considered survivable by the FAA. During those years while 14 flights
with crews were flown the following major efforts were underway: NASA
Dryden developed the remote piloting techniques necessary for the B-720
to fly as a drone aircraft; General Electric installed and tested four
degraders (one on each engine); and the FAA refined AMK (blending,
testing, and fueling a full size aircraft). The 14 flights had 9
takeoffs, 13 landings and around 69 approaches, to about 150 feet above
the prepared crash site, under remote control. These flight were used to
introduce AMK one step at a time into some of the fuel tanks and
engines while monitoring the performance of the engines. On the final flight
(No. 15) with no crew, all fuel tanks were filled with a total of
76,000 pounds of AMK and all engines ran from start-up to impact (the
flight time was 9 minutes) on the modified Jet-A.
The CID impact was spectacular with a large fireball
enveloping and burning the B-720 aircraft. From the standpoint of AMK
the test was a major set-back, but for NASA Langley, the data collected
on crashworthiness was deemed successful and just as important.
“Close-up, in-flight view of a VB-16 Douglas SBD-5 Dauntless stenciled with the names of LT(JG) George T. Glacken (pilot) and his gunner Leo Boulanger, near New Guinea, early April 1944. LT Glacken was later awarded the Navy Cross for his actions on 20 June 1944.”