UPDATE #16 - March 20, 1998
CHATS - WHY THE INTERNET IS DIFFERENT THAN BOOKS
Sometimes teachers say they don't want to teach with computers because they want students to know the joy of curling up with a book. This we all know is a wonderful pleasure no child should be denied. Computers connected to the Internet offer children different and new pleasures - the opportunity to interact with NASA experts and other children. This is a wonderful way to reinforce their reading and writing skills with the added the excitement of talking to real NASA experts. This may stimulate and challenge young minds to unimaginably great endeavors. Certainly many of the Aerospace Team Experts credit television coverage of the Apollo missions as their initial inspiration. We've asked several Aerospace Team members to be available to interact with your classrooms. So here's your chance to participate. Tuesday, March 24, 10:00 a.m.- 11:00 a.m. Pacific Time: Stephen Jaeger, Aeroacoustics Engineer Stephen develops tools for measuring aircraft noise. He also conducts acoustics research on wind tunnel models of supersonic jets, airliners and aircraft engines. In fact his latest journal contains pictures of some of the tools he uses during test and in another journal you can hear the recorded sounds of his test and see a video interview of Stephen in the 7 x 10' wind tunnel. http://quest.arc.nasa.gov/aero/team/fjournals/jaeger/ Registration information is at http://quest.arc.nasa.gov/aero/chats/#chatting Read his biography prior to joining this chat. http://quest.arc.nasa.gov/aero/team/jaeger.html Tuesday, March 31, 10:00 a.m.- 11:00 a.m. Pacific Time: Andrew Hahn, Conceptual Aircraft Designer Andrew designs aircraft concepts. He uses physics every day in his job. Registration information is at http://quest.arc.nasa.gov/aero/chats/#chatting Read his biography prior to joining this chat. http://quest.arc.nasa.gov/aero/team/hahn.html Thursday, April 2, 1998 11:00 a.m.- 12:00 p.m. Pacific Time: Rabi Mehta, Senior Project Scientist, Rabi is an expert in the aerodynamics of sports balls from cricket balls to golf balls. Registration information is at http://quest.arc.nasa.gov/aero/chats/#chatting Read his biography prior to joining this chat. http://quest.arc.nasa.gov/aero/team/rabi.html Tuesday, April 14, 10:00 a.m.- 11:00 a.m. Pacific Time: Dave Korsmeyer, Senior Project Scientist Dave is a project manager who develops advanced information technology and systems like near real time remote access to wind tunnel data. Registration information is at http://quest.arc.nasa.gov/aero/chats/#chatting Read his biography prior to joining this chat. http://quest.arc.nasa.gov/aero/team/korsmeyer.html Thursday, April 30, 1:00 p.m.- 2:00 p.m. Pacific Time: Estela Hernandez, Flight Simulation Engineer Estela is a flight simulation engineer. She uses math to build computer models that simulate flying airplanes. This chat will be in English and Spanish. Registration information is at http://quest.arc.nasa.gov/aero/chats/#chatting Read her biography prior to joining this chat. http://quest.arc.nasa.gov/aero/team/hernandez.html
PRIZES FOR EARLY CONTEST ENTRIES
As you know we are holding two contests: "Draw a Picture of an Airplane" and "Write an Essay Describing the Airplane You Would Like to Design", http://quest.arc.nasa.gov/aero/events/index.html An early bird prize will be awarded to entries received by March 30, 1998.
SMART FILTERS NEEDED
As part of Aerospace Team Online, NASA experts answer personal email questions from students and teachers. Since these experts are very busy, we use volunteers (called Smart Filters) to help minimize the expert work load. These Smart Filters read the incoming mail and determine if the answer to the question already exists. (This is where the smart part comes in!) If so they respond with that answer. If not, they send the question onto experts; once the experts reply, the Smart Filter does some minor editing and then forwards to the original questioner and also places the answer online for all to see.(It's exciting to be the first person to see the answer!) The job of a Smart Filter requires certain skills, including: - good written communication abilities - an ability to follow detailed directions - an ability to navigate the Internet to find information - a self-directed nature to continue to follow through quickly to new messages Our current and past Smart Filters have had fun helping NASA provide this service. While participating, they've learned a lot about the aeronautics and planes. We need to identify several new Smart Filters for Aerospace Team Online. If you would like to join our team, please send a note to Barb Weimann at firstname.lastname@example.org
[Editor's Note: Robert Jercinovich is an instrumentation engineer in the 12' Wind Tunnel. He knows how to make instruments take measurements in the wind tunnel. Read his bio at http://quest.arc.nasa.gov/aero/team/jercinovich.html ]
TURN DOWN THAT NOISE
by Robert Jercinovich
This may sound like a familiar command to some of us. Not only does this word apply to some forms of music, but it also can be a reference to electromagnetic interference. As an Instrumentation Engineer you may be called upon to turn down the noise, but that won't mean adjusting the volume. An Instrumentation Engineers job during a wind tunnel test is to insure the customer gets the best quality data attainable. Our secondary goal is to ensure that the instrumentation measuring the phenomena operates reliably and consistently. Immediately after the installation of the Technology Concept Aircraft model in the test section, problems arose. A preliminary look at the data reveals that the Rolling Moment gage is showing a standard deviation of 140 counts over a 0.7 sec span of acquired data. This is the equivalent of 37 ft-lbs for a gage with a maximum capacity of 2000 ft-lbs, or a 1.85% error band. This is not music to the researchers ears. With errors this large it would be pointless to continue. The Instrumentation team springs into action. We commence the search for the source of our problems. Instrumentation engineers get to use lots of electronic equipment. We are used a spectrum analyzer in an attempt to characterize the noise. Again we see the rolling moment gage of the balance, only this time it's in the frequency domain. The balance is used to measure the forces and moments the model is experiencing. What we see from the graph is 165 mVp @ every 10 Khz. This is riding atop a channel that has a maximum output of 1.6 mV/V. So, the noise has a magnitude of a hundred of the desired signal. Now we eliminate the institutional data system, and continue the search with our own toys. As we delve deeper for the source of the noise, reaching into the belly of the tunnel, the wiring looks like intestines down here. We have isolated the culprit, a digital stepper motor used to control the model position. We need the motor to position the model, but we can't tolerate this level of EMI. So, we unleash the weapons of Instrumentation: by-pass capacitors, an external power source, and shielding and grounding. The capacitors alone reduce the level of noise to 60 mVp. The test team test is happy again, and the test can continue.
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