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February 10, 2000
QuestChat with Kelly McEntire

Turbomachinery Branch Chief
NASA Glenn Research Center, Cleveland, OH

Thu Feb 10 11:21:11 2000

[ Oran/NASAChatHost - 2 - 09:32:40 ]
Hello to our early arriving chatters. Today's Aerospace Team Online chat with Kelly McEntire from NASA Glenn Research Center will begin in just under 30 minutes. Be sure you have read Kelly's profile at http://quest.nasa.gov/aero/team/mcentire.html to prepare your questions for today's chat.

[ Oran/NASAChatHost - 3 - 09:34:22 ]
Today's chat will be MODERATED to help Kelly keep up with our questions. This means we will post a few questions in the chat room at a time for Kelly to answer.

[ Oran/NASAChatHost - 4 - 09:35:10 ]
DON'T WORRY if you don't see your questions on your screen immediately. We will post new questions in the chat room periodically during today's chat.

[ Oran/NASAChatHost - 5 - 09:36:25 ]
At the conclusion of the chat, we ask that you take a few minutes to share your thoughts with us. Please visit our QuestChat Information Center and use our feedback feature to submit your comments to us. Our QIC is located at http://quest.nasa.gov/qchats. We look forward to hearing from you today!

[ Oran/NASAChatHost - 6 - 10:00:25 ]
Hello and welcome to today's Aerospace Team Online chat with Kelly McEntire from NASA Glenn Research Center. Kelly McEntire manages a small group of mechanical, aerospace and structural engineers. They are responsible for all mechanical engineering in their lab. Kelly's grroup must determine practical and efficient methods for turning their lab's aeropropulsion engineers' (or rocket scientists') ideas into reality.

[ Oran/NASAChatHost - 7 - 10:00:58 ]
And now, here is Kelly McEntire to answer your questions.

[ KellyMcEntire/GRC - 10 - 10:03:40 ]
RE: [Jack] How long did it take to get a both a bachelors degree and masters degree in structural engineering?
It took 5 years for me to complete both degrees.

[ KellyMcEntire/GRC - 12 - 10:05:05 ]
RE: [Roberto] Hi, I'm an aeronautic engineer from Bolivia, I want to ask you about some design of fuselage of airplanes, can you help me?
I probably can't help much, and certainly it would be difficult in this chat forum. I deal mainly with gas turbine engines and have dealt with spacecraft structures.

[ KellyMcEntire/GRC - 15 - 10:07:57 ]
RE: [Jack] Only 5 years, What kind of an IQ do you have ?
I really don't know. It took 4 years for a bachelor's and 1 year for a master's. I also went to school one summer, so that helped to shorten it. It would normally take 4 years for a BS and 1-1/2 for a master's.

[ Oran/NASAChatHost - 20 - 10:11:45 ]
Kelly, while we're waiting for more questions from our users, do you ever think about returning to work in an area devoted to space flight within NASA?

[ KellyMcEntire/GRC - 22 - 10:14:12 ]
I worked at Goddard Space Flight Center for 11 years and thoroughly enjoyed that career path. I however did not want to live and raise my children in the big city environment of Washington, D.C., so I moved to Ohio. Glenn does not do that kind of work. I am now enjoying a different area of mechanical engineering.

[ KellyMcEntire/GRC - 24 - 10:16:05 ]
RE: [Jack] What is the cost of one of these turbine engines ?
Turbine Engines range from very 1 ft in diameter to 12 ft in diameter and so the cost varies accordingly. Most jet engines that you see on commercial aircraft start at about $5 million each.

[ KellyMcEntire/GRC - 25 - 10:17:40 ]
RE: [Jack] Do you get to watch various launches, How often do launches occur?
Since most launches occur down in Florida at the Kennedy Space Center and I live and work in Ohio, no I don't get to see many launches close up. I see them just like you, on TV.

[ KellyMcEntire/GRC - 27 - 10:19:51 ]
We at Glenn Research Center do research in ways to improve jet engines. At least this is the part that we work on. Glenn also does work in Microgravity.

[ KellyMcEntire/GRC - 30 - 10:21:57 ]
RE: [Oran/NASAChatHost] Kelly, does your job involve any significant amount of travel during the year that takes you from your family?
In my current work assignment, I only travel 2 or 3 times a year. On past assignments, I would travel 7 or 8 times a year. Not now nor before have I ever traveled for more than a week. Since I was not gone for very long, it was never a large hardship on my family.

[ KellyMcEntire/GRC - 31 - 10:23:00 ]
RE: [Jack] How do the size of your engines compare to the recent Alaska air crisis?
We work on many different sized engines. Yes, some are of the size that was on the Alaska Airline Aircraft.

[ Oran/NASAChatHost - 34 - 10:24:38 ]
RE: [Jack] Oran, I think this chat is pretty cool.
Jack, we're glad you joined us today and are enjoying today's chat with Kelly McEntire. Thank you for your great questions!

[ KellyMcEntire/GRC - 37 - 10:26:17 ]
RE: [Jack] Kelly, Do you think the shuttle will be obsolete in a few years, If so what aircraft do you think will replace it?
The shuttle will be obsolete in a few years because it is too expensive to operate. Each launch costs almost a $1 billion. We are working on a jet engine that is referred to as a Rocket Based Combined Cycle Engine. It combines a rocket engine with a jet engine. This permits the engine to breathe oxygen from the atmosphere on its way to space. After it gets up into space, it switches over to rocket. The advantage of this kind of system, is that since it is breathing oxygen from the air, it does not have to carry the oxygen thus saving 1000's of pounds of fuel.

[ KellyMcEntire/GRC - 38 - 10:28:10 ]
RE: [Jack] What kind of hours do you put in a week? Over 40, 50?
We all work about 40 hours a week. We sometimes have to work longer hours if we are involved in testing. Many of the wind tunnels we have at Glenn are operated at night, because they use so much electricity. The power companies can't provide that much electricity when everyone is awake and it is also a lot cheaper.

[ KellyMcEntire/GRC - 40 - 10:30:37 ]
RE: [Sarah] How can you make jet engines quieter?
Part of our research is in making jet engines quieter. People who live near airports still complain about the noise to their congressman. This in turns gives us research money to continue the pursuit. We are looking at blowing air through the middle of a hollow fan blade to smooth out the air flow as it goes through the engine. This should help to quiet the engine.

[ KellyMcEntire/GRC - 42 - 10:33:09 ]
RE: [Sarah] how do you study propulsion do you use wind tunnels or Computer models?
We study propulsion both ways. We have about 4 large wind tunnels here at Glenn. They are always busy. We also have a lot of engineers that run computer models using Computational Fluid Dynamic computer programs to model the air flow. There is a saying that goes "One test is equal to a 1000 expert opinions". Computer modeling can go a long ways, but it still has to be verified by test before it can be adopted into real engines.

[ KellyMcEntire/GRC - 44 - 10:37:53 ]
RE: [Jack] On these turbine engines, what components wear out? What is the main metal making up this engine? What is the cost of this metal? Do these metals ever get melted and reused? What is the lifespan of one of the engines?
The rotating parts are the parts that wear out the fastest. There are many disks of blades in a turbine engine, sometimes up to 15 sets. They are often made from titanium or Incolnel. In hotter portions of the engine, other metals are used that are more tolerant to high temperatures. The cost of the material is not great, the greatest cost is the manufacture process. Yes, most metal is recycled. It may not be used in the same way but may end up in your toaster oven. The life span of these engine varies, but it is in the range of 15,000 hours of operation.

[ Oran/NASAChatHost - 46 - 10:38:53 ]
For those of you observing today's chat, be sure to visit our QuestChat Information Center to send your comments to us, and to learn about our upcoming chats with NASA experts, at http://quest.nasa.gov/qchats.

[ KellyMcEntire/GRC - 48 - 10:40:34 ]
RE: [Sarah] How does the position of the engine effect the design of the airplane and its performance?
Mostly the position of the engine effects the control surfaces of an aircraft. Engines must be placed symmetrically on an aircraft and there must be redundancy or more than one. If there is more than one, when one fails, the other one can still get the aircraft to the nearest airport without crashing.

[ KellyMcEntire/GRC - 49 - 10:42:28 ]
RE: [Jack] In regards to Computational Fluid Dynamics, how long does it take from a CFD to a wind tunnel test?
CFD is performed all the way along. It may take 2 to 8 years from the "first" CFD analysis to testing to verify the analysis. Since CFD is must less expensive than testing, a lot of time can be spend doing this.

[ KellyMcEntire/GRC - 51 - 10:43:18 ]
Can you tell me a little about yourselves. What state do you live in and what grades are you in?

[ Jack - 54 - 10:45:58 ]
I work on computers, just going through the school of life. I am married, wife and 2 girls.

[ KellyMcEntire/GRC - 53 - 10:44:57 ]
RE: [Jack] How often do engines fail on aircraft? I am not a fan of flying, the more engines the better!
Thank goodness not very often. See, we do a good job. Of course on a military jet, they fail every time an enemy missile hits it.

[ KellyMcEntire/GRC - 55 - 10:46:39 ]
RE: [KellyMcEntire/GRC] Thank goodness not very often. See, we do a good job. Of course on a military jet, they fail every time a enemy missile hits it.
The airlines are responsible for maintenance of their engines. They spend a lot of time tracking the number of hours the engines are run. Many engine parts are rated for a particular number of hours. When the engine reaches the rated hours, the engine is taken off the jet and the parts are replaced with new ones.

[ KellyMcEntire/GRC - 57 - 10:49:25 ]
RE: [Sarah] Wow thanks for the answers. Do different engines do better and worse at different speeds, I would like to know more about this.
Engines are designed to operate at different speeds. Commercial jet engines are designed to operate a speeds from 400 to 600 mph and so at these speeds they run their best. They are the most fuel efficient. Military jet fighter engines are designed to operate at similar speeds, but have the added requirement that they must also operate at supersonic for limited periods of time.

[ KellyMcEntire/GRC - 59 - 10:51:16 ]
RE: [Sarah] Does NASA share what it learns with pilots and mechanics?
Yes, NASA is in the business of sharing our information with businesses. We call it information transfer. That is the whole purpose of NASA. We do things that businesses can't do because they can't make a profit at it. We develop technologies that are then passed on to private enterprise.

[ KellyMcEntire/GRC - 62 - 10:55:35 ]
One of the best wind tunnels in the world is right in my building. It has a test section that is 10'x10' and can achieve speeds of 4000 mph. It is hard to say which is the best, because they are usually designed for a special purpose. Langley Research Center in Virginia studies airframes and so its tunnels are for that purpose. Ours are for studying engines. Ames Research Center in Silicon Valley, CA also has several. The Air Force's Wright Patterson Base in southern Ohio also has many. The one in my building can consume $10,000 worth of electricity in a single night.

[ KellyMcEntire/GRC - 63 - 10:56:45 ]
RE: [Roberto] What is the most common structural failure in the space crafts
Mechanisms are always the most troublesome. Whenever there is motion, there are many more unforeseen things that can go wrong.

[ KellyMcEntire/GRC - 66 - 10:57:43 ]
RE: [Jack] Where are the best wind tunnels? Is bigger necessarily better? How often are wind tunnels tested for stress? Have you lost any co-workers over the years through job related accidents.
I am not aware of any accident where a wind tunnel exploded hurting anyone. There are build with many safeguards in place.

[ Jack - 67 - 11:00:27 ]
Kelly, Thank you for your time and insights!!!! Jack

[ Sarah - 69 - 11:00:27 ]
Thanks mr, McEntire! Bye!!

[ KellyMcEntire/GRC - 70 - 11:01:15 ]
RE: [Sarah] What kind of engines do Military jet fighters have?
Military jets have gas turbine engines like commercial jets, except they are of the variety called High Bypass Engine. This means they have a big fan in the front that captures a lot of air that get propels right out the back and does not go through the combustion cycle of the engine.

[ KellyMcEntire/GRC - 71 - 11:02:29 ]
RE: [Roberto] Can you send me a some information about the structural design in modern aircrafts or contact me with a person who know more about this topic
Visit NASA Langley Research Center web sites.

[ KellyMcEntire/GRC - 72 - 11:03:00 ]
RE: [KellyMcEntire/GRC] Visit NASA Langley Research Center web sites.

[ Oran/NASAChatHost - 73 - 11:04:36 ]
At this time, we would like to thank all our chatters for joining us for today's chat with Kelly McEntire from NASA Glenn Researcher. Our very special thanks to Kelly for sharing his career experience with us today, and thoughtful responses to our questions today. THANK YOU, Kelly!

[ Oran/NASAChatHost - 74 - 11:05:29 ]
A final reminder to share your comments about today's chat with us at http://quest.arc.nasa.gov/qchats.

[ KellyMcEntire/GRC - 75 - 11:06:24 ]
RE: [Oran/NASAChatHost] At this time, we would like to thank all our chatters for joining us for today's chat with Kelly McEntire from NASA Glenn Researcher. Our very special thanks to Kelly for sharing his career experience with us today, and thoughtful responses to our questions today. THANK YOU, Kelly!
You are welcome

[ Oran/NASAChatHost - 76 - 11:06:35 ]
Be sure to check our Black History Month and National Engineers' Week chat schedules at http://quest.nasa.gov/qchats/special/mlk00 and http://quest.nasa.gov/qchats/special/eweek00.

[ Oran/NASAChatHost - 77 - 11:08:09 ]
Thank you again for joining us today, and have a good day!

[ Roberto - 78 - 11:11:06 ]
Thanks for all your answers Mr. Kelly, and i hope contact to you in another oportunity, bye.


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