Aerospace Team ONLINE
UPDATE #10 - February 6, 1998
After our upliftinging live event with Brent Wellman which is archived at http://quest.arc.nasa.gov/ltc/test1.html some of you are, no doubt, thinking: "What could top that?" Don't worry, we still have a few surprises for you! We are going to spell out the instructions for participating in the Design and Essay Contests soon and you can look forward to a few weeks more of the Wind Tunnel test journals, also we hope to have some journals from the engineers and astronauts about the next shuttle simulation at the Verticle Motion Simulator. Speaking of the wind tunnel test journals from Fanny Zuniga, I hope you are finding these interesting. We are striving for the right balance between technical and understandable. If you have any questions about these journals you can submit them through email. There is a special category for these questions and they will be archived at http://quest.arc.nasa.gov/aero/question/twelve/
UPCOMING CHAT SCHEDULE
Wednesday, February 12, 9:00 a.m.-10:00 a.m. Pacific Time: Ross Shaw, Wind Tunnel Test Engineer Ross has run several interesting tests here at Ames and recently worked as a Test Systems Engineer on the Lunar Propsector Project. For registration information go to http://quest.arc.nasa.gov/aero/chats/#chatting Please read Ross's biography prior to joining this chat. http://quest.arc.nasa.gov/aero/team/shaw.html Thursday, February 19, 10:00 a.m.-11:00 a.m. Pacific Time: Ray Oyung, Research Coordinator for the Fatigue Countermeasures Program For registration information go to http://quest.arc.nasa.gov/aero/chats/#chatting Ray's studying the effects of sleep loss and jet lag on pilots. Read his biography prior to joining this chat. http://quest.arc.nasa.gov/aero/team/oyung.html
AN ORDINARY WEEK IN THE CAREER OF AN AEROACOUSTICS ENGINEER
Monday, November 17, 1997: 8:00 a.m.: I arrive at work, turn on my computer and make coffee. Nothing works at NASA without a computer or coffee. The first 30 minutes of the morning is spent reading and answering E-mail and phone messages. 9:00 a.m.: I attend an engineering class televised from Stanford University. This is very convenient for engineers at NASA. We can go to school by watching the class live over the television rather than having to drive all the way to campus. I have been going to this class three times a week for two months. 10:30 a.m.: I sit in on a presentation by Dr. Vern Rossow. Vern Rossow is the senior scientist in our branch. Engineers are always presenting their ideas to their co-workers. We in turn ask questions about his findings and discuss the conclusions of his work. We also point out any problems he may have overlooked, but we're usually very nice about it. Lunch time: I go for a run around NASA and work out at the gym. Since I might be sitting around all day in front of the computer, it's nice to get out and get some exercise. 1:00 p.m.: I finish writing up a data file for our array processing software. This data file includes information on the 100 microphones we have installed in our microphone array. The array is an aluminum wall with microphones mounted in a special pattern somewhat like the arms of an octopus. The wall will be mounted inside a wind tunnel. The array allows us to "see" sound. We can point the array at a model in a wind tunnel and make color pictures of the sound. This allows us to pinpoint the areas on the airplane model that make the most noise. 5:00 p.m.: I finish the day by writing a brief report for my company telling them what work I have been doing for the last couple of weeks. Since my company is providing services for NASA, it is important that they know the type of work that their employees are doing for their customers. 6:00 p.m.: Off to karate class. Tuesday, November 18, 1997: 8:00 a.m.: I arrive at work and go immediately to watch another class over the television. 10:00 a.m.: I make coffee of course and then I spend most of the day collecting information for another engineer, Dr. Dale Ashby. His project is to prepare for a wind tunnel test in 1999. In this test, a very large model of a jet liner will be placed in the 40-by 80-Foot Wind Tunnel. This wind tunnel is one of the largest in the world. The airplane model is almost 60 feet long so the wind tunnel has to be big. During this test we will be using the microphone array to measure the noise that the airplane's wings make during landing. This is very important because as jet liners get larger and their engines get quieter, the noise created by the wings, flaps and landing gear becomes more significant. My job is to give Dale all the information he needs to measure the noise of the model including a list of equipment we need, what type of noise measurements we want to make and who will be helping out with the test. Often the planning and preparation for a wind tunnel test can take three or four years. Lunchtime: I play volleyball with some friends at lunch. I'm setting the ball much better but I still need to work on my overhand serves. 3:00 p.m.: I help out with setting up the microphone array in our lab. I have spent most of the last year helping to design the array. Now that the array has been built, I have been spending a lot of time installing the microphones in the aluminum plate and making sure everything works. Wednesday, November 19, 1997: 8:00 a.m.: Remember: NOTHING works at NASA without a computer or coffee. 9:00 a.m.: Off to class. 10:00 a.m.: Cool news! I received my first patent. A patent is one of the great milestones of an engineer's career. The patent, which I share with three other people, is for an invention that can reduce noise when microphones are used in a wind tunnel. 11:00 a.m.: I am called away to help troubleshoot some difficulties with the array setup. Nothing ever goes as planned and complicated pieces of equipment like the microphone array have a lot of electronic parts that don't always work like they are supposed to. I set up a speaker to test the array. The speaker can really crank because we are using a 300 Watt stereo amplifier, but for this type of test that kind of noise will not be necessary. I also designed a round aluminum horn to connect with the speaker and provide a uniform sound source. 2:00 p.m.: I continue working to provide information for Dale's project. 6:00 p.m.: I spend most of the rest of the evening writing a newsletter for the AIAA. That's the American Institute of Aeronautics and Astronautics. A "friend" of mine volunteered me for the job of Newsletter Editor. This task usually takes a few hours each month but it's a chance to write articles, create artwork, and support my profession. Thursday, November 20, 1997: 8:00 a.m.: Off to class. 10:00 a.m.: I gather with the other members of our microphone array team for our weekly meeting. At this meeting we discuss how the project is progressing. A complex project like the microphone array requires a team effort and the meeting is a great way to get advice and ideas from the other team members. 11:30 a.m.: I take time out for a long run around the base. Most of us at NASA get some kind of exercise at lunch. It might be soccer, rollerblading, hockey, aerobics, running, cycling or weight-lifting. After a good workout, I can eat my lunch at my desk while I work. 1:00 p.m.: I spend the rest of the day working on Dale's project and I prepare for a future meeting where we will discuss the noise measurements we need to do for Dale's test. This work includes making detailed computer drawings of test setups, making a list of required equipment and composing a list of measurements. I enjoy taking an idea and creating a detailed drawing on the computer. Even more exciting is seeing that drawing turned into reality. We have many tools and instruments at NASA designed for very special purposes including speakers, microphones and models. Many of those tools started out as an image on my computer screen. 6:30 p.m.: I attend an AIAA dinner meeting. The AIAA has a meeting every month, where engineers and scientists talk about everything from designing airplanes to the exploration of Mars. This night's speaker, Dr. Michael Drory, gave an interesting talk on using artificial diamonds for aerospace applications. Friday, November 21, 1997: 8:00 a.m.: I make coffee. We are running out of coffee and it's probably my turn to buy more. This is a critical situation. 9:00 a.m.: I attend the televised class. The final exam is only two weeks away. I hope to do well. 10:00 a.m.: I'm getting back to a project I had put off for awhile. Sometimes I have to juggle projects according to their priority. A task that may have seemed important yesterday may have to be put on the back burner when a more urgent opportunity appears. This project is a computer code that we will use to record and process the noise from a starter pistol. We will use the starter pistol, which fires blanks, to calibrate the 40- by 80-Foot Wind Tunnel after the modification of its test section is complete. The wind tunnel test section has been lined with acoustic fiberglass to eliminate echoes. We will fire the pistol and use the computer code to record any echoes. We also have a small cannon we can use. It is very loud in the test section and a lot of fun to fire off! 4:00 p.m.: I help with testing the microphone array. We are preparing for a demonstration of the array next week. It should work nicely.
[Editor's Note: Fanny is the Project Manager for an upcoming test of
a future supersonic airliner. She has
MOVING TO THE WIND TUNNEL
By Fanny Zuniga
January 30, 1998 Tuesday and Wednesday: Early this week we weren't quite ready to put the model in the tunnel. We had a lot of trouble getting all of the details ready, mostly details about getting our software to talk to every instrument on the model and record the information accurately. We also had trouble with the automatic warning system that we will use to make sure that the model doesn't generate more force than either the balance, the model itself, or the mounting posts can handle. We can't start our test without this important safety system working. Fortunately, the test that is currently in the tunnel wanted more time. So everyone agreed last Friday that we would start a few days late and try to make up the lost days sometime during the 5 weeks of our test. So we have set our sights on a Thursday move into the tunnel....... Starting last week my team has been working two shifts; we have day and night teams. This is one way we can cover a lot of ground in a short amount of time. In fact, we will operate on two shifts throughout the entire test. That means there are two complete teams of tunnel operators, model mechanics, researchers, electricians, instrumentation technicians, etc! No, we don't clone people, so this demands a lot of communication between all of the people on each shift. We take lots of notes! Thursday: On Thursday we were ready to move our model upstairs and install it in the tunnel. There is a lot of stuff going on - enough to keep 20 people busy 16 hours a day. Installing the model in the tunnel is an exciting moment for a wind tunnel test team! There's no way I can tell you about all of it. We have to take our computer program off of the computers downstairs and copy it to the computers in the control room. Meanwhile, our model was lifted off the bottom half of the supporting posts, leaving the top half of both posts attached to the balance inside the model. All of the electrical cables from our instruments run down through the hollow rear post; they had been connected, under the floor, to the computers in the prep room. Now they are hanging out of the model and will be connected to the computer upstairs. The bottom half of the posts were pulled out of the floor and taken upstairs too. Next our model was placed on a cart and taken up to the test section in a big freight elevator. You might wonder how we got our big model into the wind tunnel. There is a door in the side of the test section so people can go in and change parts of the model or fix problems. Unfortunately, the model won't fit through that door. So we actually rotated the test section 90 degrees - the whole thing is on a giant turntable. We then put an overhead crane into it, picked up the model with the crane, and carried it in. The bottom halves of the support posts were set into the floor of the tunnel. We held the model over those posts and fed all of the instrument cables through the rear post so they can run out of the tunnel and plug into electronic "black boxes" that will read the electrical signals. After the cables were fed through, we finally mounted the model on the posts and bolted everything down. We next checked that the model could reach the full range of tilt angles (which we call "angle of attack"). Last, we rotated the test section back into line with the rest of the tunnel so the air can flow through the test section. Everyone is glad to have reached this major milestone in our test. The next big milestone is actually turning on the wind after everything is checked out! Friday: We moved all of the software onto computers in the control room, and all of our instrument cables were plugged into the electronics as well. We are doing a lot of checks to make sure everything is OK. We even hung some weight on the model to do one last check load to see if our balance was talking properly to the new computer. Cameras, strobe lights, and computers are being put into place for the mini-tuft imaging system. The tufts were glued onto the left hand wing, but didn't stick well enough. The whole job had to be redone. I'm really tired and looking forward to the weekend! We got a lot done, and with luck we will turn the wind on in the tunnel for the first time next week! By the way, check out http://george.arc.nasa.gov/jit/projects/12FT_WT/ to learn more about this wind tunnel. And for the curious out there, http://aocentral.arc.nasa.gov/ describes some of the other wind tunnels at NASA Ames Research Center (which, by the way, is located near San Francisco, California).
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