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  #1  
Old 09-21-2006, 10:11 PM
Paul Thomas Paul Thomas is offline
 
Join Date: Jun 2005
Location: Fort Myers, FL
Posts: 483
Default [Ironflight] Shuttle Arrival?

Paul,

Just a few question about the shuttle arrival that I?ve wondered about.
It?s my understanding that the shuttle came in from the west for a landing on 33, yet reporters mentioned a right turn?
Why the 270? How far out do you line up for final and when and how do you get on glidescope?
Why do you have to cool the ship with that big fan after it lands? I know the outside is cleaned after each mission and that it?s pretty toxic, but what are you cleaning?

I?ve often glossed over those small details but it?s all so interesting. Great job on another mission accomplished.

Paul
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  #2  
Old 09-22-2006, 04:33 AM
admin admin is offline
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Default

Morning Paul (T),

I'm sure Paul D will chime in, but until then....the fan is to keep the toxic gasses venting out of the orbiter away from the ground crew safing the vehicle. The orbital manuevering jets use chemicals that are very toxic.

The right 270 is to bleed off energy - the vehicle is doing something like 370mph as little as 30 seconds before touchdown. I'm sure Ironflight (if not others) will add more.

b,
d


Quote:
Originally Posted by Paul Thomas
Paul,

Just a few question about the shuttle arrival that I?ve wondered about.
It?s my understanding that the shuttle came in from the west for a landing on 33, yet reporters mentioned a right turn?
Why the 270? How far out do you line up for final and when and how do you get on glidescope?
Why do you have to cool the ship with that big fan after it lands? I know the outside is cleaned after each mission and that it?s pretty toxic, but what are you cleaning?

I?ve often glossed over those small details but it?s all so interesting. Great job on another mission accomplished.

Paul
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  #3  
Old 09-22-2006, 07:14 AM
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Ironflight Ironflight is offline
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Location: Dayton, NV
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Default TAEM 101

Morning Guys....is it really morning? My last few days have been so mixed up I really have no idea.....

TAEM = Terminal Area Energy Management. This is a fancy term for making sure that you always have a positive margin of energy to make the runway. Since the shuttle is a glider, you can only take away excess total energy, you can't add any. TAEM is a software module in the Shuttle that kicks in about 2.5 Mach. It is designed to guide the shuttle to the runway environment with excess energy, so that we are absolutely sure that we won't land short. to do this with a safety margin, you will always get there with an excess.

The result is an approach with a built in "circle to land". When you come into the airport environment, you are aiming not for the start of the final approach, but at a "Heading Alignment Cylinder" (OK, it's actually a cone, but the acronym has been used both ways...), or HAC. The HAC is a circle of decreasing radius off the end of the runway which lines you up on centerline, and you use it to modulate your energy so that you always arrive on final at the same energy state (distance and altitude from the runway at 295 knots IAS).

If you are approaching from the west for a landing on 33, and you have plenty of energy, you fly OVER the field, and turn right onto the hack that is southeast of the threshold, turning 270 degrees to get rid of the energy. That would be Plan A. But let's say that the winds weren't as expected, and as you are approaching the field from out over the gulf, the TAEM software says you are running low on energy. In that case, you can downmode to the HAC on the southwest side of the threshold, which means you make a LEFT turn, and only turn 90 degrees. See how it works?

(RV Content - you can do this same kind of planning in your head for a dead-stick emergency landing to make sure you make your field!)

Once the HAC dumps you out on final, you are doing 295 knots, on a 19 degree glideslope for the runway, passing through about 14,000'. At this point, you still have some excess energy, and the speed brake is used to dump that. Usually, you leave it in auto, letting it maintain speed and fly to the glideslope using pitch. The aim-point at this time is actually short of the runway. You say on this glideslope until about 2,000', where you fly a constant-G pull-out that we call the "Preflare" to attain a 0.5 degree glideslope, changing your aim point to a spot about 2500 feet down the runway. You hold that shallow glideslope until touchdown at about 195 knots (205 heavy). Piece of cake....except the Orbiter, being a delta wing, has negative glideslope response, so if you increase pitch, the instantaneous response is an increase in sink, not a decrease.....but that is a whole 'nuther article. The bottom line is that you bets be set up for touchdown at the end of the pre-flare, because if you work too hard to sweeten the landing, you just make things worse....

And Doug is pretty much right on the big fan on the runway - it is used IN CASE there are any toxic gasses escaping form the vehicle. They deploy that first, then send out guys in suits with sniffers to make sure the jets aren't leaking (rocket fuel is REALLY nasty stuff!). Once they have cleared the vehicle, then it is safe to approach in regular clothes - but they keep the fan running anyways - I think maybe they think it keeps the 'skeeters away?

OK, that qualifies as my work for today....gotta run out to Ellington to welcome the crew back to Houston at noon - if you're in the area, come join us! But first, I'm headed to the airport to give the Valkyrie a Dynamic Prop Balancing I've been promising her all along.....just now getting around to it.

Paul
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  #4  
Old 09-22-2006, 09:10 AM
Paul Thomas Paul Thomas is offline
 
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Thank you very much for the education. My first thought was that the fan would be for heat management but I quickly realized that it didn't make much sense.
I pretty much had the reason for the 270 figured out though. I also thought that it was part of the instrument approach that the shuttle makes. Have you ever had to make the 90 in?

Thanks again,

Paul
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  #5  
Old 09-22-2006, 11:31 AM
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bumblebee bumblebee is offline
 
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Quote:
Originally Posted by Ironflight
Once the HAC dumps you out on final, you are doing 295 knots, on a 19 degree glideslope for the runway, passing through about 14,000'.
Think about that for a second.....Entering FINAL at 14000 feet @ 295kts with a 19* slope, no engine and virtually no wing.

Sounds like your average RV engine-out landing sequence.....
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  #6  
Old 09-22-2006, 03:10 PM
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Kevin Horton Kevin Horton is offline
 
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I flew a couple of simulated low L/D approaches in an T-38 years ago when we were down to Edwards to provide famil flights for some of the Test Pilot School students in Canadair Tutors. They have special approval to exceed the published max speed with landing gear down, as long as they do special inspections of the gear doors every few flights. The profile they used was idle, gear down, speed brakes out and 280 kts (if I recall correctly). You started the pattern on base leg at 25,000 ft, and rolled out on final about 7 miles back at 14,000 ft. It was quite a rush.
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  #7  
Old 09-22-2006, 04:06 PM
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Ironflight Ironflight is offline
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Quote:
Originally Posted by Paul Thomas
Have you ever had to make the 90 in?


Paul
We might have had one low-energy case back in the early flights, but to tell you the truth, I can't really remember the details that far back. Part of the problem is that we sim so frequently, and so realistically, that it sometimes is hard to separate the sims from the real thing when you try to dig that far back.....They say the memory is the second thing to go...and I forget what the first is....

And yes Kevin, we still use the T-38 for low L/D's, along with the G-II based Shuttle Training Aircraft. A Shuttle Commander will have about 1,000 hours of STA time before he gets to land the Shuttle for the first time.

Paul
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Editor at Large - KITPLANES Magazine
RV-8 - N188PD - "Valkyrie"
RV-6 (By Marriage) - N164MS - "Mikey"
RV-3B - N13PL - "Tsamsiyu"
A&P, EAA Tech Counselor/Flight Advisor
Dayton Valley Airpark (A34)
http://Ironflight.com
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  #8  
Old 09-22-2006, 08:11 PM
Fallguy Fallguy is offline
 
Join Date: Jul 2005
Location: Hillsboro Oregon
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Default Did anyone else hear Ironflight interviewed?

While tooling along at work the other night, I caught Paul on my XM radio. He was interviewed by (or they picked it up) by USA Network News about the debris (garbage bag?).

Neat. Probably no big deal for Paul, but interesting.
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