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[ Katy/FairfaxR3HighSchool - 1 - 14:40:22 ]
Hi I'm Katy!

[ Conrad - 3 - 08:49:36 ]
Hi I'm here Kathy

[ Brent/Ames - 5 - 09:49:23 ]
RE: [Katy/FairfaxR3HighSchool] Hi I'm Katy!
Hi, Katy; what is your question?

[ Susan/NASAChatHost - 6 - 09:52:09 ]
Good Morning Everyone, Brent is here do you have questions for him?

[ Conrad/Netherlands - 8 - 09:52:59 ]
Hi Brent... I've a question about earth's gravity.. Yesterday Wednesday Feb 4 at 10:35 UTC the Mir Crew declared an Emergency when the complex lost attitude-control and went into free drift.. NASA had put tracking stations in Virginia, New Mexico, and California on alert to help support communications with Mir. Question to you or Nasa-officals: Can you explain the attitude control systems on board MIR and why they fall in free drift? Thanks! Conrad - University Groningen-Netherlands

[ Conrad/Netherlands - 9 - 09:54:03 ]
06:53 local PM Susan

[ Brent/Ames - 10 - 09:54:19 ]
RE: [Conrad/Netherlands] Hi Brent... I've a question about earth's gravity.. Yesterday Wednesday Feb 4 at 10:35 UTC the Mir Crew declared an Emergency when the complex lost attitude-control and went into free drift.. NASA had put tracking stations in Virginia, New Mexico, and California on alert to help support communications with Mir. Question to you or Nasa-officals: Can you explain the attitude control systems on board MIR and why they fall in free drift? Thanks! Conrad - University Groningen-Netherlands
I'm not really involved with Mir or ISS. These guys have control systems to keep them pointed in a particular direction, either for stability or science requirements. When these break down, the station is at the mercy of aero drag (small, but enough to erode an orbit), and differential gravitational forces (part of the station is farther from the earth than others, and therefore has less gravitational pull, and orbital velocity -- the result is a "gravitational torque").

[ Conrad/Netherlands - 11 - 09:55:58 ]
Thanks Brent & Susan..

[ Susan/NASAChatHost - 13 - 09:57:59 ]
RE: [Conrad/Netherlands] Thanks Brent & Susan..
Conrad have you been studying aerodynamics?

[ Conrad/Netherlands - 14 - 10:01:13 ]
No Susan...I'm Coordinator of Medical Assistance Radio NL [like Doctors without Borders}...but I've many contacts with NASA in case of Medicine in Space, like the Upcoming Neurolab-Missing in April..

[ Brent/Ames - 15 - 10:02:11 ]
RE: [Susan/NASAChatHost] Brent, in your work designing helicopters are your using andy of the ideas of lift we talked about today?
Actually, not at present. There *was* a helicopter experiment that used an airfoil shaped like an egg (an ellipsiod). It generated lift (circulation) by blowing compressed air over the top trailing edge. It hovered OK, but wasn't really a "pilot's aircraft." Lessons learned there were translated to the X-Wing project, where there were TWO slots for blown air, because it was supposed to fly spinning or backwards not spinning. Really imaginative stuff.

[ Susan/NASAChatHost - 16 - 10:03:09 ]
RE: [Conrad/Netherlands] No Susan...I'm Coordinator of Medical Assistance Radio NL [like Doctors without Borders}...but I've many contacts with NASA in case of Medicine in Space, like the Upcoming Neurolab-Missing in April..
Do you know about project Nueron? http://quest.arc.nasa.gov/neuron It is following the Neurolab project?

[ Brent/Ames - 18 - 10:06:43 ]
RE: [Susan/NASAChatHost] Will your computer program for designing helicopters have different airfoil shapes built in?
No. The program uses user-generated airfoil tables so they can run any airfoil they can dream up. There is NO WAY our program can keep up with people's imaginations!

[ Conrad/Netherlands - 20 - 10:08:43 ]
Right Susan..I know all about it..I've subscribed to the bulletins of Linda Conrad.. I've also contact with a German member of the Neurolab-tam -Dr. Baisch of DLR in Germany about one of the experiments.named micro-neurography.. At the moment I'am looking NASA-TV Ch 2..Prevous Mission to Mir with Shannon Lucid

[ Brent/Ames - 21 - 10:09:09 ]
RE: [Susan/NASAChatHost] Brent, How many times should people wrap the button thread around the coat hanger?
Depends. Enough times so that it doesn'tslip off the tube and gives it a good spinn. Not so many times that it drags the tube as it passes by...

[ John/ParkSchool - 22 - 10:11:41 ]
Is anyone still here? - our computer crashed.

[ Bill - 23 - 10:12:05 ]
yes I am still here

[ Susan/NASAChatHost - 25 - 10:13:56 ]
Welcome do you have questions for Brent?

[ Susan/NASAChatHost - 28 - 10:15:26 ]
RE: [John/ParkSchool] We have to go now - we enjoyed the show.
Thanks John I hope you try the experiments

[ Brent/Ames - 29 - 10:15:53 ]
RE: [John/ParkSchool] For the egg experiment, we want to know how much water needs to be in the tub before you try it.
Cover the egg. The point is to see the egg center itself in the flow. It also helps to have a tap that gives a nice cylinder of water coming down. (Remember, falling water accelerates, and if you let it fall too far, the stream will contract and break up. Do you think the experiment might work with a marble in a wash basin? A golf ball?

[ Susan/NASAChatHost - 31 - 10:16:55 ]
RE: [Conrad/Netherlands] Susan...Is this the only chat-channal with NASA?
I think we are the only one although some people use cu-seeme

[ Brent/Ames - 32 - 10:17:04 ]
RE: [Susan/NASAChatHost] Thanks John I hope you try the experiments
Too bad, John, I hope you read the transcript when it is up on the web.Sorry, but I don't touch-type.

[ Brent/Ames - 34 - 10:22:35 ]
RE: [Christin/homeschooled] Hi Brent. I had heard about forward swept wings on jets and their many advantages. I was wondering with all these advantages, why aren't more aircraft made with this type of wing?
One was.The X-29. Actually, there was an earlier experiment, too, but not as successful. The problem is that such wings are statically unstable when they flex. When a swept wing bends generating lift, it tends to twist to decrease its angle of attack, which lowers the lift. This is the idea of static stability (the swept wing MAY also be dynamically unstable and "flutter" at some speed). A forward swept wing tends to twist so as to INCREASE the lift without limit, and the wing shears off. The X-29 gets around this through the use of very fast control computers that keep this effect in check. Certain other aircraft have swept-forward wings, namely every tiltrotor I am aware of...

[ Brent/Ames - 35 - 10:24:31 ]
RE: [Conrad/Netherlands] Brent..which is the max attitude of a Nasa-Test-plane, before they entry in orbit..hi
Hi.I am not familiar with the attitude schedule for shuttle atmospheric entry. I *think* you mean the shuttle...

[ Brent/Ames - 37 - 10:27:19 ]
RE: [Susan/NASAChatHost] Brent does it matter if you use heat on the Ping pong ball hair dryer experiment?
Good question. You should try it!!!

[ Brent/Ames - 39 - 10:28:33 ]
RE: [Brent/Ames] Good question. You should try it!!!
FYI, I used heat in the video clip. Do you think it would make a difference if I had turned it off?

[ Susan/NASAChatHost - 41 - 10:29:19 ]
RE: [Brent/Ames] FYI, I used heat in the video clip. Do you think it would make a difference if I had turned it off?
I think it would fly better with the heat On!

[ Susan/NASAChatHost - 43 - 10:31:23 ]
RE: [Conrad/Netherlands] Rgr Susan & Brent, thanks for chat and info..Bye for now and till next time..
Thanks Conrad, be seeing you!

[ Brent/Ames - 44 - 10:31:23 ]
RE: [Conrad/Netherlands] No Brent..I does not mean the shuttle..On Discovery Channel I saw a clip about Nasa Test planes, which was so high and nearly in the entry-level..
We have LOTS of test planes, from the high-flying ER-2 to the high-alpha F/A-18, to the high and HOT SR-71. I really can't comment. You might find out more at www.discovery.com

[ Brent/Ames - 47 - 10:37:56 ]
RE: [Christin/homeschooled] Thanks, Brent! I have another question about wings and lift. I know that the curve of the airfoil affects the pressure that creates the lift. What about the thickness of the wing? Does it affect the lift?
In some important ways, yes. The air must part to accomodate the wing passing through it. In so doing, the speed of its parting is added to the speed of the airplane and an area of relative low pressure is created (by Bernoulli), on BOTH surfaces. The trick is to get more of that low pressure on the top or high pressure on the bottom, or both. Air must part wider and rush to come together more for a thick wing than a thin one,and they tend to have more "profile drag". Yet they also tend to generate more lift at low speeds (THAT all depends, of course).So yoiu usually see thick wings on low speed airplanes, thin ones on fast airplanes.

[ Christin/homeschooled - 49 - 10:41:08 ]
Thanks for the answers Brent!

[ Brent/Ames - 50 - 10:42:39 ]
RE: [Susan/NASAChatHost] I think it would fly better with the heat On!
So put it to the test!! That is what science is about. Do you think that the width of the nozzle matters? The power rating of the dryer? Low speed/high speed? I'm not going to answer those things, because that's what science is about!!!

[ Brent/Ames - 51 - 10:43:31 ]
RE: [Susan/NASAChatHost] Thanks everyone good questions and great answers Brent. Our next chat for Aerospace Team Online will be on Feb. 12 at 9 AM Pacific with wind tunnel test engineer Ross Shaw. Hope to see you there!! Thanks again Brent for a very instructive demonstration!!!
You're welcome! Thanks everyone!

 
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