UPDATE #6 - January 9, 1998
TALK TO NASA ENGINEERS!
One of the ways that Aerospace Team Online project is interactive is that it gives classrooms and interested individuals the opportunity to talk to NASA experts through Web chats. Luckily Aerospace Team members are happy to take a hour out of their busy schedules to be available to chat with children. We hope your students will join us. For more information visit: http://quest.arc.nasa.gov/aero/chats/index.html#chatting Another opportunity to interact with Aerospace Team members is through email Q & A. Imagine the fun for your class to check the email and find a reply from a NASA expert. For more information visit: http://quest.arc.nasa.gov/aero/question/ask.html
[Editor's Note: Fanny is I'm the Project Manager for an upcoming test of a future supersonic airliner.]
Three Weeks to Go
December 29, 1997 Preparations for my Supersonic Transport Wind Tunnel Test are alive and well. You'd think things might slow down a bit with the holidays coming. No way! We just found out that our internal balance doesn't work the way we thought it did! The internal balance fits inside the model and is held in place by struts that mount to the wind tunnel floor. This balance, in turn, holds on to the model and measures all of the forces acting on it, like Lift and Drag. By the way, these forces, like Lift and Drag, are what I will sometimes call "loads." This is a brand new balance that was built to handle the high loads this model will generate in our tunnel. It turns out that the electrical signals coming out of the balance are arranged differently than we thought, so we have to redo the wiring that takes the signals to the computer where they are recorded. We also have to change the way the computer software interprets those signals once they arrive at the computer. Late-breaking changes like this always add a lot of excitement and stress to test preparations. We have electronics and software experts on our team that are going to work over parts of the holiday to fix this problem. We had planned to move our model and new balance next week into a special preparation area where we have plans to check out the health of the balance. Hopefully, our team will have the balance ready so we can stay on schedule! Late-breaking changes like this always add a lot of excitement and stress to test preparations. We have electronics and software experts on our team that are going to work over parts of the holiday to fix this problem. We had planned to move our model and new balance next week into a special preparation area where we have plans to check out the health of the balance. Hopefully, our team will have the balance ready so we can stay on schedule! That's not all! In my weekly telephone conferences with Boeing, Lockheed, and Langley Research Center, we all decided to add some stuff to this test. On a test like this, we usually want to get a picture of the airflow on the model. We do this with a number of methods which I'll introduce to you later. But this week we decided to add another method, called oil flow pictures, to this test, which means we added some more runs to our run schedule. Oil flow is where we put drops of colorful oil on the wing, run the tunnel, and then take a picture of where all the drops flowed to. We get really neat pictures which show us how the air goes around the model. But then we have to stop the tunnel and clean off the model before we can get the next picture. This is slow work and really has a big impact on the run schedule. On another front, some members of the team wanted to add more instruments to our model. We already measure pressures and aerodynamic loads, but they wanted to add a device which actually measures the wing tip. We would have to add special devices to the model, run wires to get the signal from them to the computer, and modify our software to interpret the signals. We decided ... No! Sometimes we have to decide we cannot accommodate something new this late in the game. We also found out we were missing some accelerometers. These go in the model and measure the movement of the model since it shakes around a bit in the tunnel when the wind is turned on. It seems everyone thought everyone else was going to provide these. So now we are scrambling to find some and install them in the model. >From the above stories, you can get the idea that preparing for a test like this takes a lot of communication, debate, and decision making. When a miscommunication happens (and they always do) the test team has to really work hard to make things work, like with the balance. The goal is to have good communications, and that's why we have so many meetings to talk about how things are going. Sometimes this is the hard part of testing, and sometimes the fun part!
[Editor's Note: Larry Young is an aerospace engineer at NASA Ames Research Center. He specializes in rotorcraft aeromechanics research. Aeromechanics research is the study of the aerodynamics, dynamics, and mechanical aspects of helicopters and tiltrotor aircraft.]
WHY ROTORCRAFT ARE USEFUL
December 12,1997 In terms of dollar value, rotorcraft represents only a very small fraction of the total overall aerospace industry. Nonetheless, rotorcraft (helicopters and tiltrotor aircraft) perform all sorts of useful and important functions within our society. Many of these functions can only be performed by rotorcraft. Alternatively, even when other aircraft or equipment can perform a given job, oftentimes there are clear advantages for using rotorcraft. The ability to hover and perform low-speed maneuvers is an extremely valuable capability. The functions that rotorcraft can perform can be broken into three general categories: military, civilian, and public service. Rotorcraft are an essential part of U.S. national defense. Rotorcraft perform anti-armor, special operations, scout/surveillance, utility/transport, and search and rescue (SAR) military functions. Rotorcraft are used by all four U.S. military services -- although the principal users are the Marines and the Army. Among the current military rotorcraft used by the U.S. are the UH-60 Blackhawk (made by Sikorsky Aircraft), the CH-47 Chinook (made by Boeing Helicopter), the AH-64 Apache (made by McDonnell Douglas Helicopter and now owned by Boeing ), the OH-58 Kiowa Warrior and the AH-1 Cobra (made by Bell Helicopter Textron Inc.), and the V-22 Osprey tiltrotor aircraft (Made by Bell-Boeing). For civilian purposes, rotorcraft have many applications: news service information gathering, cinematography, oil-rig and other remote site utility and transport support, corporate personnel transport, remote site logging, tourism/site-seeing, heavy-lift applications for installation/retrieval of equipment from tall building sites, and many others. In the public service sector, helicopters perform exceptional service. Helicopters in public service roles include: Coast Guard search and rescue/drug-interdiction, police support, fire-fighting, emergency medical response, disaster relief. Many inspiring stories can be told about the use of helicopters for humanitarian purposes. Every year a "Heroism" award is awarded to a rotorcraft flight crew/operator that performs the most exemplary "heroic." This is often reported in industry publications such as "Rotor & Wing." Every day helicopter flight crews are out flying somewhere saving lives. Whether it is a Coast Guard crew pulling stranded seamen out of stormy waters or National Guardsmen rescuing flood, earthquake, or hurricane victims, or an emergency medical service helicopter taking a car crash victim to a distant hospital -- lives are being saved through the use of rotorcraft. It is because rotorcraft provide so much value to the public service and the U.S. national defense that NASA performs rotorcraft research. Even small incremental improvements in aircraft performance can sometimes have a tremendous impact on the overall mission capability. Also, NASA researchers hope that the next generation of rotorcraft such as tiltrotor aircraft can find their way into the public transportation mainstream. One day tiltrotor aircraft may become an essential part of the aviation transport network -- just as jet/turbo-fan and turbo-prop aircraft currently are. NASA technology will hopefully help make that possible. For more information readers can contact the American Helicopter Society, Alexandria, VA.
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