February 12, 1998
QuestChat with Ross Shaw

[ Susan/NASAChatHost - 6 - 09:03:46 ]
Ross, what was the most interesting thing about being a wind tunnel test engineer?

[ Ross/Ames - 7 - 09:04:55 ]
I think the most interesting thing is seeing the next generation aircraft concepts.

[ Ross/Ames - 9 - 09:08:31 ]
RE: [Susan/NASAChatHost] Can you say something more about that?
Well, I have been on wind tunnel test projects for the F-22 Raptor, for upgrades to the F/A-18, for the Boeing 777, and even for the replacement for the Harrier.

[ Ross/Ames - 11 - 09:15:33 ]
RE: [Susan/NASAChatHost] What advice do you have for kids who want to be aeronautical engineers?
I would say take math and science classes, perhaps build model and/or remote control airplanes. Most importantly, if you like airplanes try to keep up with the what is happening in the field. I think if it is something you really enjoy, go for it!

[ Ross/Ames - 15 - 09:22:31 ]
RE: [Susan/NASAChatHost ] Which was your favorite test?
I think my favorite test was when we were testing an F/A-18, which is a Navy/Marine fighter. On this test we were using a new technology, pressure sensitive paint, to determine the pressure distribution across the entire airplane. This was fun because it was the first time this pressure sensitive paint was used to get real data for a fighter airplane; it also was fun because when the ultraviolet lights were shown on the plane, it made the plane look pink, but ominous.

[ Ross/Ames - 17 - 09:28:21 ]
RE: [Parker/HomesteadHigh] Is it the longer travel time of the air that goes over the wing or the lower pressure on the air rushing over the bottom of the wing that generates lift
Lift is generated by a pressure difference between the upper surface of the wing and the lower surface of the wing. The higher pressure is on the upper surface of the wing and lower pressure is on the lower surface of the wing. Therefore, it is the lower pressure on the lower surface of the wing that generates lift. The air on the upper surface goes faster because it has to follow the contour of the leading edge. The fundamental equation that best describes this is Bernoulli's equation: P + 1/2V^2 = const.

[ Ross/Ames - 19 - 09:33:03 ]
RE: [Susan/NASAChatHost] Have you ever been discriminated against?
When I was in college there was a counselor in the Minority Engineering Program who told me I should not be an engineer but a physical education major. This was based on the fact that my resume had jobs that were sports related and my gpa was not all that great. After talking with family who believed in me, I stuck it out knowing I would be successful. By the way, he did not return the next year as a counselor for the MEP. I did go on to graduate school and have done well since.

[ Ross/Ames - 21 - 09:37:50 ]
RE: [Parker/HomesteadHigh] Can you actually see the paint change colors under the different presures as the test is performed? And is the paint allowed to go through many different color changes or does it hit a max and stop?
You can't really see the colors change with the naked eye. There are special ultraviolet cameras that digitize the image and a computer program interprets the data. After a couple of minutes the computer will create a picture of the pressure distribution on the surface of the airplane. There will be different colors on the surface indicating where the low and high pressure regions are.

[ Ross/Ames - 23 - 09:43:22 ]
RE: [Susan/NASAChatHost] What was different about your job working on lunar prospector?
Now Lunar Prospector was a spacecraft that actually had some similarities and differences. The similarities involved coordination of tests needed to validate the spacecraft. The main difference is we were testing hardware that was not coming back for servicing. For this reason we had to be very careful. We also had to really understand any problems before we could continue to test. This was a new experience for me because it was a project that dealt with space, which has no atmosphere to work against. Things like lift and drag were not involved in the design and construction of the vehicle. Instead we had to worry about lack of gravity and solar winds and spacecraft power from the sun. Lunar Prospector was a lot of fun!

[ Ross/Ames - 26 - 09:48:35 ]
RE: [Christin/homeschool-Christin/homeschool] What exactly do you look for when you test jets in the wind tunnel?
There are a number of things depending on the objective of the test. For the most part we look at things like lift and drag characteristics because these are the most important parts of airplane design. For fighters, a lot of lift and a little drag is best. A lot of lift means we can get to the fight faster, a little drag means we can go farther on the same amount of fuel. We also look at performance characteristics: how will the airplane fly when we have the flaps drooped, or how will it fly when there are a lot of bombs underneath the fuselage, how will it fly if we make a hard left turn.

[ Ross/Ames - 28 - 09:51:51 ]
RE: [Patti/CJHS] Did you get to go watch the Lunar Prospector launch?
I was fortunate to not only watch the launch at Kennedy Space Center in Florida, but I even participated in launch preparations. I was able to sit in the Launch Control Room where they did the countdown. My family saw me on TV and my oldest son was really excited about it. It was an experience of a lifetime. If you ever get a chance to see a Shuttle launch or other rocket launch I would highly recommend it.

[ Ross/Ames - 31 - 09:54:55 ]
RE: [Parker/HomesteadHigh] What colors are the pressure sensitive paints?
Actually the pressure sensitive paint is white when applied in normal light. The system we use at Ames turns pink when we shine the ultraviolet lights. McDonnell Douglas had their own pressure sensitive paint that turned yellow when they shined their special lights on the paint. Now the pictures we received after the data was analyzed by the computers showed the colors of a rainbow: blue, green, red, yellow, purple, orange. Each color represented a pressure level on the surface.

[ Susan/NASAChatHost - 32 - 09:57:14 ]
Wow, some great questions today! Thanks kids! Send in your last ones the chat will end at 10 am.

[ Ross/Ames - 33 - 09:58:58 ]
RE: [Christin/homeschool] How can you see the affects of the lift and drag on the planes in the wind tunnel? Is it all measured by computer?
Actually you cannot physically see the effects of lift and drag in the wind tunnel. There is instrumentation on the airplane that measures the pressure as well as a balance in the model that can measure the forces placed in it when the air is blown across the plane. A computer then takes the data and computes the lift and drag. We also have a computer program that takes the data and creates plots. It is these plots that aerodynamics engineers use to assess the performance of the plane. The pressure data is used to compare the results of the force balance. Aerodynamicists use special equations to calculate lift and drag from the pressure readings.

[ Ross/Ames - 35 - 10:04:52 ]
RE: [Patti/CJHS] Do most planes begin as military and then get commercial application? or do commercial companies come to you for testing? and how does that work in a government facility?
They don't generally begin as military applications. Military and commercial airplanes have very different design requirements. On the other hand the fundamentals of the design are the same. An aeronautical engineer will use the same tools to design a military airplane as a commercial airplane. Military airplanes typically want to go faster and higher and carry fewer people. Both types of airplanes have wind tunnel testing as a verification test in the design process. Being a government facility we have the advantage of supporting to both military and commercial companies. Whoever wants to run a wind tunnel test need only have the money. Also, one of NASA's missions is to support the advancements of aircraft technologies.

[ Ross/Ames - 38 - 10:08:24 ]
RE: [Susan/NASAChatHost] Thank you very much Ross, I learned a lot! Your answers were wonderful, bye kids see you next time!
Thanx for the opportunity to talk to you all.