Aero Team Online QuestChat

December 6, 2001

Featuring: Tom Benson

[ Lori/NASAChatHost - 3 - 13:03:31 ]
You may go ahead and place questions in the chat room now to be answered during the webchat Please don't post test messages or repeats -- though you may not see your question, it is in the chat room. Again, PLEASE do not repeat your questions.

[ Lori/NASAChatHost - 4 - 13:03:47 ]
Remember, if for some reason you cannot join us for the live webchat, you can input your question ahead of time, and then read the archive later to see if your question was answered during the webchat. It's not near as cool as being there live, but it is very helpful when there are scheduling conflicts. Enjoy the webchat :-)

[ Lori/NASAChatHost - 8 - 09:49:57 ]
Welcome early arriving chatters!! We will begin our chat with Tom Benson from the Glenn Research Center in about 10 minutes. I hope you have had the opportunity to view the kite webcast. If you haven't read Tom's bio, there's still time.

[ Lori/NASAChatHost - 9 - 09:51:14 ]
Great questions coming in!! Once the chat has started, I will begin placing your questions in the chat room a few at a time.

[ Lori/NASAChatHost - 11 - 10:04:19 ]
Welcome Tom Benson from Glenn Research Center!!

[ TomBenson/GRC - 12 - 10:05:10 ]
RE: [Lori/NASAChatHost] Welcome Tom Benson from Glenn Research Center!!
Hi Lori ..Ready to answer some questions ...

[ TomBenson/GRC - 17 - 10:07:25 ]
RE: [Sarah] how is flying kites like airplanes.
Hey Sarah .. Flying a kite is just like flying an airplane, except that instead of using an engine to push you through the sky .. you let the wind pick up the kite.

[ TomBenson/GRC - 20 - 10:09:38 ]
RE: [Eric] How do kites fly?
Good question Eric .. kites fly because they deflect the wind down .. and since the wind gets pushed down .. it pushes the kite up .. if the wind isn't blowing, you can't fly a kite .. and you always fly a kite with the wind at your back .. so that it hits the kite.

[ TomBenson/GRC - 21 - 10:10:44 ]
RE: [Don] Does wind create drag?
Hi Don, yes the wind creates a drag force on the kite as well as a lift force. You can feel the force as a tension in the string ... good question.

[ TomBenson/GRC - 23 - 10:13:29 ]
RE: [Georgia] How come sometimes when you fly a kite it goes up but then crashes down?
Hi Georgia .. you sound like a kite flyer!! Making lift is only part of the problem of flying, you also have to control, or balance, the flying object. That's why airplanes have a tail -- sometimes on kites we hook a long tail to help control things. Kites are actually a little harder to control than airplanes, because they fly in such low speeds and there can be swirls in the wind, which can cause a loss of control.

[ TomBenson/GRC - 24 - 10:15:27 ]
RE: [Sylvie] did the Wright brothers think of their glider as a kite?
Hi Sylvie .. yes, the Wright brothers had flown kites in Dayton and they knew that their early gliders from 1900 - 1901 and 1902 could be flown (safely) as an unmanned kite or as a piloted glider. They usually flew them as kites to check out problems.

[ TomBenson/GRC - 26 - 10:17:25 ]
RE: [Frank] does the shape of the kite make it fly better?
Hey Frank ... yes, like any aircraft, the shape really effects how well a kite flies. You have to build them light so that they WILL fly, but you also have to build them strong to hold together. Then the shape affects how the air flows around the kite (the aerodynamics), and that determines how much lift and drag you get ... good question.

[ TomBenson/GRC - 28 - 10:20:05 ]
RE: [Maria] Doe you think the Wright brothers were heros?
Hi Maria .. yes, the Wright brothers were heroes. They risked their lives every day, and on every flight, to try to make the world a little better. There were many other people like the Wright brothers who tried to fly, but were killed doing it. The brothers knew the risks, and were clever enough to avoid a fatal crash. They also overcame a lot of obstacles, to finalize realize their dream.

[ TomBenson/GRC - 30 - 10:22:36 ]
RE: [Jose] does a kite have to have one string on it?
Hi Jose .. an interesting question ... they have to have at least one string on them, otherwise they just blow away like a piece of paper and come back to the earth. There always has to be a difference between the speed of the kite (usually zero) and the speed of the wind. Now there are some maneuvering kites which have 2. 3 or 4 lines on them. On our Wright brothers kite, we'll use at least 3.

[ TomBenson/GRC - 31 - 10:25:00 ]
RE: [Laura] What is a research engineer?
Hey Laura .. a research engineer is a person who studies a problem, which we don't yet have an answer for. Humans know a lot about aerodynamics, but there is also a lot we don't know. In my job, I like to study about those problems, and try to come up with an answer, so that we can have better, faster, cheaper airplanes.

[ TomBenson/GRC - 35 - 10:28:17 ]
RE: [Lisa] How does wind effect airplanes?
Hi Lisa .. wind can have both good and bad effects on airplanes. When you get ready to take off, the wind helps you because you don't have to go as fast (or as far down the runway) if you take off into the wind. If you are traveling from coast to coast, and you have a strong wind at your back, you can get there faster. BUT, the wind can also be unpredictable, and there have been cases where airplanes (and passengers) get really shook up by unsteady winds -- things called wind shears and ground bursts, like the blustery wind during a thunderstorm. That makes for difficult flying.

[ TomBenson/GRC - 36 - 10:30:53 ]
RE: [Tenisha] What kind of paper is the best for making kites?
Hi Tenisha .. good question ... you want the paper to be very light (since you have to make it fly), but also very strong (so that it doesn't rip). That's why you see a lot of store-bought kites made out of very thin mylar or plastic. When I make a kite, I usually use tissue paper -- but make sure that it is supported on the edges by thread or strings.

[ TomBenson/GRC - 38 - 10:34:29 ]
RE: [juliettegonnycaramailcom] How many hours do you work per week? Do you travel a lot for your job?
Hey Juliette .. I'm required to work 40 hours a week -- 8 hours a day, for 5 days. BUT, I really like what I do and so I'm usually here a little early in the morning and stay a little later at night (I don't get paid extra .. but it's just fun to do) I probably average 50 hours a week. During my career, I have traveled a lot, but I like that too -- been to Europe a few times, mostly presenting technical papers or meeting with other research engineers on some common problem.

[ TomBenson/GRC - 41 - 10:38:29 ]
RE: [Andre] How do you get a job at NASA?
Hey Andre .. that's a good question with a very long answer :-) It probably started when I was in grade school. I liked airplanes and rockets; I built kites and planes. I was good in math and science, and in high school I did science projects and went to lots of sci-fi movies and read sci-fi books. I went to college and studied engineering. It was hard -- lots of math and science. When I graduated, I went in the Air Force and worked on testing airplanes. When I got out of the Air Force, I went back to college for some work, then applied and came up here to work at NASA.

[ TomBenson/GRC - 43 - 10:42:24 ]
RE: [MrsWilson] What is the best way to describe/explain lift & drag to my first graders?
Mrs. Wilson, I would start with an explanation of forces, since lift and drag are just forces. Start with weight, which they understand. Then move on to the fact that things that move through the air also experience forces. They're probably aware of the wind pushing them on their bicycles, or the push on a windy day. Now lift and drag are exactly the same thing -- drag pushes you back (with the wind) and lift picks you up (against weight.) Though NASA doesn't recommend it :-) -- kids know lift (and drag) from sticking their hands out of the windows of a moving car.

[ TomBenson/GRC - 46 - 10:45:31 ]
RE: [Ryan] How does a box kite fly differently than a diamond shaped kite?
Hey Ryan .. a box kite is a little stronger than a diamond kite, owing to its structure. So you can fly them on very windy days, when you would probably snap a diamond kite. They are very stable. A diamond kite sometimes dances around the sky, but a box will just sit there. They have a lot of lift as well, because of the multiple panels, so they fly high and can support a lot of line.

[ TomBenson/GRC - 47 - 10:48:24 ]
RE: [juliettegonnycaramailcom] I am french and I study in Rennes' university .I have to lead a project about ingeneers in aeronautics.Please could you answer my questions? What kind of activities do you have in your work? What do you partcularlly like in your job?
Hey Juliette .. I almost missed this question ... sorry ... I'm an aero engineer who works in computational fluid dynamics. That just means I use computers to study how air flows around or through objects. I write and use computer programs. I really like my job because it challenges me. There are lots of problems to solve, and it keeps me busy.

[ Lori/NASAChatHost - 48 - 10:49:47 ]
We have about 10 minutes remaining for our chat. Once the chat is over, we would appreciate it if you would share your comments with us about NASA Quest. We have a SHORT online survey at: http://quest.nasa.gov/survey/. Thanks!!

[ TomBenson/GRC - 50 - 10:51:27 ]
RE: [Leon] How is math used for kite flying? What types of math?
Hey Leon .. good questions ... actually we can use some very simple math (algebraic equations), which describe how big to make a kite we are designing -- or we can use very sophisticated math (like calculus), which would actually describe how a given design would fly. This same procedure is used with big airplanes as well. We design with pretty simple equation and simple ideas, then we check out the details (which are very important) using more sophisticated math models.

[ TomBenson/GRC - 52 - 10:54:40 ]
RE: [Candie] Who came up with the lift equation (I watched your kite webcast)?
Hey Candie .. pieces of the lift equation were first discovered around the time of the Wright brothers (a hundred years ago). They knew of it as "Squire's" equation, and it described the relation of area and speed and a coefficient. I learned it as part of the Buckingham Pi theorem, a neat math theorem for analyzing systems.

[ TomBenson/GRC - 53 - 10:55:41 ]
RE: [Jesse] Hi Mr. Benson. I watched your kite webcast. It was really cool. I have been flying kites since I was little. I've built a few too. I never realized what I was doing & liking was aerodynamics. Thanks for helping me realize a hobby of mineis useful to my future. My mom was impressed, too.
Hey Jesse.. glad you enjoyed it. Maybe I'll see you out here in a few years, as an aero engineer, or scientist ... or astronaut!

[ Lori/NASAChatHost - 56 - 10:57:11 ]
We have about four minutes left to chat . . .

[ TomBenson/GRC - 57 - 10:57:53 ]
RE: [Ryan] To become an areospace engineer what are the most important courses to concentrate on?
Hi Ryan ... everything counts!!! Math and science for sure, but also English, art, even drama (I have to get up in front of people and give talks on my research). A lot of scientists and engineers have music backgrounds. I play bass in a rock band (composed of all NASA engineers), and sing at church.

[ TomBenson/GRC - 58 - 10:59:30 ]
RE: [Phil] What is the Beaufort scale?
Hey Phil .. I never use it :-) I believe it's a graph relating wind speeds and dynamic pressures, but the terminology escapes me.

[ TomBenson/GRC - 59 - 11:00:46 ]
RE: [Heather] What do planes, rockets & kites have in common.
Hey Heather .. rockets, planes and kites all move through the air, so they all depend on aerodynamics. They all have to be built light and strong.

[ Lori/NASAChatHost - 60 - 11:01:49 ]
That's all the time we have for today. I want to thank our participants today for such great questions! I would also like to thank Tom for sharing his time and expertise with us today!!

[ TomBenson/GRC - 61 - 11:02:32 ]
RE: [Lori/NASAChatHost] We have about 4 minutes left to chat . . .
Lori says it's about time to go. I want to thank all you students for GREAT questions -- keep up your studies and I hope to see you here at NASA some day in the future ... or maybe on Mars :-)

[ Lori/NASAChatHost - 72 - 11:28:45 ]
Tom has agreed to answer the questions left in the chat room when time permits, before I archive the chat. The archive for this chat will be available within 24 hours.

[ TomBenson/GRC - 73 - 04:54:55 ]
RE: [Jesus] Is drag, lift & weight the only forces?
Hi Jesus .. on a kite, we have one additional force which is the tension in the string. On a glider, we only have lift, drag and weight .. and on a powered aircraft we also have thrust ... good question.

[ TomBenson/GRC - 74 - 05:01:15 ]
RE: [Ryan] What are the hypergolic fuels that the shuttle uses to takeoff,hoy many pounds of thrust do the engines produce, and how large are the engines?
Hey Ryan ..hypergolic fuels are special because they spontaneously react with their oxidizers. You don't need an igniter to get them to burn, so they are much simpler engines to build and maintain. They fire every time, and you can control them very closely by stopping the flow of oxidizer (or fuel). The main liquid engines on the Shuttle (SSME) are rated at about 500,000 pounds thrust each (I believe), the solids at roughly 1.5 million each. The liquid engines (with exhaust nozzle) are about 10 feet high, the solids nearly 200 feet long!

[ TomBenson/GRC - 75 - 05:04:59 ]
RE: [yan] What are the hypergolic fuels used in the space shuttle engine
Hi Yan .. hypergolic fuels react with their oxidizers whenever they come in contact. Unlike standard burning materials, you don't need an external source of heat to initiate the burn. When these two materials come into contact, they burn. I'm not sure the exact combination used on the shuttle -- on the old Titans, it used to be unsymmetrical dimethyl hydrazine (UDMH) and red fuming nitric acid (RFNA).

[ TomBenson/GRC - 76 - 05:12:19 ]
RE: [juliettegonnycaramailcom] What studies did you do to become ingeneer in aeronautics? Do you manage teams or do you allwork in a group without any hierarchy?
Hi Juliette .. when I went to college, I first took a lot of general math and science for all engineers (two years of calculus, differential equations, systems of equations, one year of physics with calculus, a year of chemistry, a year of engineering mechanics and computer programming). Then I specialized in aero engineering and studied propulsion, structures, flight, stability and control. Now within aero, I'm a fluid dynamics guy, so I had more boundary layer theory, compressible and incompressible aero, thermodynamics, and hypersonic flows. I work in a team (all engineers do!) with a leader. I've chosen not to be the leader. I did a year of management and didn't like it because they have to do all the paper work, get the money, set milestones and schedules and stuff like that. I prefer programming and solving technical problems. (The pay is the same in NASA -- at other places managers receive more pay, but have less fun, in my opinion.)

[ TomBenson/GRC - 77 - 05:19:02 ]
RE: [Natalie] Who did the Wright Brothres get there ideas from?
Hi Natalie.. excellent question! When you think about it, they had no role models for inventing the airplane! There were other people trying to fly at the time, and the brothers read about them and studied their work. In their writings they often mention Otto Lilienthal, Samuel Langley, and Octave Chanute, but it appears that most of their breakthrough ideas -- like wing warping, coupling the rudder to the wing warping, their thin, high-speed propellers, and their extremely light weight-high performance engine -- were the result of their own trial and error, deep thinking and discussion. I think it's important that there were two of them working on the problems. They had a lot of discussions (arguments) about what was happening and what to try next.

[ TomBenson/GRC - 78 - 05:22:33 ]
RE: [Jodie] How is it possible to control a kite?
Hey Jodie ..to control the kite (or to control a big airplane) you have to be able to control the amount of force that parts of the kite (or airplane) produce. The amount of lift depends on the angle which a surface presents to the wind. If you can change the angle, you can change the force and make the kite move in the direction of the larger force. That's why maneuvering kites have several lines going to the kite -- pulling on a line makes the shape of the kite change, which changes the force and makes the kite move in a desired direction.

[ TomBenson/GRC - 79 - 05:27:54 ]
RE: [juliettegonnycaramailcom] Do economic crisis affect your job? What are your responsabilities if their is an accident?
Hey Juliette ..I personally haven't been affected much by economic crisis over the last thirty years as an engineer, but many of my friends in aerospace have been ... big time ... it's very confusing! When times are tough, a lot of production work is cut back because people are having trouble selling things; but sometimes, and in some areas, research is increased because people want to get new ideas to help get out of the economic crisis.

[ TomBenson/GRC - 80 - 05:33:20 ]
RE: [juliettegonnycaramailcom] Do economic crisis affect your job? What are your responsabilities if their is an accident?
Hi again, Juliette .. I missed the second part of your question :-( .. if there is an accident, what I do depends on the nature of the accident. If it's immediate and life-threatening, I do anything I can (when I was in the Air Force, I learned CPR and how to put out fires, stuff like that). If it's a job I don't know how to do, like handling a chemical spill, I get out of the building and let the professionals handle it. If it's something that I have a responsibility for, like computer security, then I do whatever it takes to solve the problem.

[ TomBenson/GRC - 81 - 05:37:20 ]
RE: [Lori/NASAChatHost] Tom has agreed to answer the questions left in the chat room when time permits, before I archive the chat. The archive for this chat will be available within 24 hours.
One last message .. I want to thank Lori (and the rest of NASA Quest at Ames) for the excellent job they did during this chat. There were a lot of questions coming in yesterday and they really helped me out ... teamwork, once again!

[ Lori/NASAChatHost - 62 - 11:03:39 ]
 Thanks Tom! I certainly enjoyed it!!

[ Lori/NASAChatHost - 63 - 11:03:39 ]
Hope you enjoyed the webchat today with Tom. Please join us next week for the continuing Centennial of Flight Celebration activities.

[ Lori/NASAChatHost - 64 - 11:04:08 ]
Have a great day in cyberspace!! :-)