ADTO # 71 - July 21, 1999
Tuesday, July 27, 9:00 a.m. Pacific Daylight Time: Phillip Luan, mechanical engineer Balances used in wind tunnel tests tell engineers how the force of the wind affects the model. Phillip is responsible for making sure that balances used for these tests are extremely accurate. He also helps determine how electrical signals received during the tests are related to the accuracy of the balances. Register for this chat at http://quest.arc.nasa.gov/aero/chats/#chatting Read Phillip's profile and field journals prior to joining this chat. http://quest.arc.nasa.gov/aero/wright/team/luan.html
Follow a Wind Tunnel Test of the Airliner of the Future Meet the people from NASA who have been planning and working to make this test happen. Read field journals from the team as the test progresses. Learn more about High Speed Research. The model goes into the tunnel, July 21, 1999. http://quest.arc.nasa.gov/aero/events/hsct.html - - - - - - - Summer Air Travel Contest This a special summer contest for Aerospace Team Online. This contest is open to all students between the grades of fourth through twelfth. The grade categories are as follows: 4th through 8th 9th through 12th For this contest, we ask students to help researchers here at NASA solve the air travel traffic problems. For more information go to http://quest.arc.nasa.gov/aero/events/contest - - - - - - - Lecture Series to be Webcast The 1999 NASA-ASEE-Stanford Summer Faculty Program seminars on "Current Research in the Aerospace Sciences" will be webcast on the Learning Technologies Channel. For more information at times visit the LTC Schedule page. http://quest.arc.nasa.gov/ltc/schedule.html July 27 - DR. DAVID KORSMEYER, Senior Project Scientist, Computational Sciences Division, NASA Ames Research Center, "NASA's Distributed Aerospace Data Management"
[Editor's Note: Mina Cappuccio is the NASA Ames research engineer on the low speed test of the High Speed Civil Transport Technology Concept Airplane model. Read her biography at http://quest.arc.nasa.gov/aero/team/cappuccio.html ]
by Mina Cappuccio
July 14, 1999 Hello, I am Mina Cappuccio and I am the NASA research engineer on the low speed test of the High Speed Civil Transport (HSCT) Technology Concept Airplane (TCA) model. This is the fifth and last test in a series of tests with this particular model. A little history: The first two tests were done in the 14' by 22' wind tunnel at NASA Langley Research Center. The TCA-3 test was done in the Twelve-Foot Pressure Wind Tunnel at NASA Ames Research Center in 1998. Aerospace Team Online has a series of journals about this test at http://quest.arc.nasa.gov/aero/events/test.html The fourth test went back to NASA Langley Research Center. If you recall the TCA-3 test basic low speed performance test where they tested a number of leading edge flap configurations with some additional flow visibility tests including pressure sensitive paint. During the TCA-4 test at NASA Langley Research Center, they tested three different wing planforms. A planform is the shape of the airplane from above or below. See http://quest.arc.nasa.gov/aero/events/collaborative/help.html The way they changed the planform was to change the wing tips. On the TCA model the wing is in two parts, the wing spar and the wing tips. They tested three different wing tips. The baseline tip was used in the first three tests and they also tested two other wing tips that had different wing sweep angles. In that test they were looking at the effect of different planforms on the low speed characteristics, (landing and takeoff configurations) of the airplane. Another thing they tested was a canard on the forebody of the model. Canards are put on for stability and control in low speed flying. In this case the canard was placed at mid-mount, or at the mid-point of the height of the fuselage. They also tested different flap angles. TCA-5 Test Objectives One thing that is important to understand is that the 14'by 22' wind tunnel is an atmospheric tunnel, similar to the 40' by 80' wind tunnel at NASA Ames Research Center. This is to say the test was done at an atmospheric pressure of 14.7 pounds per square inch, psi, or in terms of dynamic pressure, 85 pounds per square foot, psf. The twelve-foot pressure tunnel can test up to 6 atmospheric pressures. In this test we will be looking at planform effects on the low speed characteristics of the airplane using higher Reynolds Numbers. We will use the baseline wing tip and one of the other wing tips tested in TCA-4. A second objective for this test is to look at some different and new leading edge devices on the aircraft. In this test we will test a mid and high mount canard. All of these objectives will be tested at one atmosphere and at 3.7 atmospheres, two different pressures. The type of data we will be collecting includes forces and pressures, and flow visualization. We are going to do two different types of flow visualization. One type is called a surface flow visualization using an oil. During the TCA-3 test they tried to do color oil flow visualization which didn't work very well. This time we will use a different method. The model is in the prep room now. They are painting the surface of the right side of model white. The oil mixture we plan to use is black so it should leave black streamlines on the wing. We will use a digital camera to capture this information. The technicians are painting the right side of the model black for an off body flow field survey. We will be using a technique called laser smoke screen. We will be injecting smoke into the tunnel and shoot a laser beam on to the model and with a video camera we will be able to track the vortex off the canard. In TCA-4 the vortex went inside engine producing and undesired effect. We hope the high mount canard will change this effect. This is my first High-Speed Research low speed test. I look forward to sharing the fun with you.
[Editors Note: Phil Luan is a mechanical engineer in the calibration lab. Read his bio at http://quest.arc.nasa.gov/aero/wright/team/luan.html ]
CHECKING IT TWICE
by Phillip Luan
July 23, 1999 We recently finished a balance check for the High Speed Civil Transport test in the 12-foot wind tunnel. This is the last in a series of tests for a high speed passenger concept plane. The balance used for this test is a newer single piece design from NASA Langley. Traditional Ames balances consist of multiple components that are assembled together, measuring three forces and three moments. Amazing improvements in machining technology allows this balance to be machined out of a single piece of metal. This balance was calibrated previously at NASA Langley. Therefore instead of calibrating the balance here again, we decided to check Langley's calibration with a series of check loads in the Cal Lab. The results from the check loads came out in agreement with the Langley calibration. The next step was to send the balance over to the Twelve-Foot and have them wire the balance up to their data system. Later we got a call from the Twelve-Foot saying they were getting different outputs from the balance then what we were getting. It turned out to be a wiring problem. The Twelve-Foot wired the balance up in a different configuration then what we did in the Cal Lab. Usually there's no problem with our Ames balances because it uses a four-wire setup. But because this Langley balance uses a six-wire setup the difference in wiring mattered. It was a miscommunication between the Cal Lab and the Twelve-Foot. Sometimes you get use to doing something the same way and when something different comes along you forget to think it out. We decided in the future to provide a wiring diagram to the wind tunnels about how the balance should be configured.
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