Boeing Nut
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Joined: Fri Feb 23, 2001 2:42 am

How Much More Lift Does Shuttle Make On The 747?

Sat Jul 16, 2005 10:50 pm

I'm sure this has been talked about before. I tried the search but I'm one of "those people" who has issues with the A.net search.  embarrassed 

Anyway, how much more lift does the Shuttle make while being ferried on the 747? I know the drag is substantial but I am curious if there is actually more lift during flight.
I'm not a real aeronautical engineer, I just play one on Airliners.net.
 
TedTAce
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Joined: Sun Mar 27, 2005 12:31 am

RE: How Much More Lift Does Shuttle Make On The 747?

Sat Jul 16, 2005 11:17 pm

This was the best I could do:
http://www.edwards.af.mil/moments/docs_html/77-02-18.html
"When NASA pilots Fitzhugh "Fitz" Fulton and Thomas McMurtry first flew the 747 with Enterprise attached, they discovered the shuttle had little adverse effect on the handling of the 747. In part, this was due to the large tail-cone fitted to Enterprise for the five captive-inert flights. The wings of the shuttle also provided useful lift, leading some to maintain that the combined aircraft created the world's largest biplane."

http://www.edwards.af.mil/archive/20...002-archive-shuttle_milestone.html
"When NASA pilots Fitzhugh "Fitz" Fulton and Thomas McMurtry took the SCA/Enterprise combination into the air for the first time, they discovered that the Shuttle had little adverse effect upon the 747's handling qualities.

In part, this was due to the large tail cone that was fitted to the Enterprise for the five captive-inert flights.

The Shuttle's wings also provided useful lift, leading some wags to maintain that the combination was unquestionably the world's largest biplane. "

[Edited 2005-07-16 16:22:59]
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SATL382G
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Joined: Sat Aug 14, 2004 12:02 am

RE: How Much More Lift Does Shuttle Make On The 747?

Sun Jul 17, 2005 12:44 am

Not trying to be a smartass but how do you know it's generating lift?

It depends too on what configuration you're talking about. For the ALT tests the orbiter is decidly much more nose up than on a ferry flight. This additional angle of attack was used to ensure the orbiter had sufficient lift at separation to clear the 747s vertical stabilizer.

regards

edit: SCA figures from Jenkins, 3rd edition

Shuttle attached:
Max airspeed: Mach .6
Cruise Alt: 13,000 - 15,000 ft
Max Range: 1,150 miles

No shuttle:
Cruise Alt: 24,000 - 26,000 ft
Max Range: 6,300 miles

[Edited 2005-07-16 17:52:03]
"There’s nothing quite as exhilarating as being shot at and missed" --Winston Churchill
 
Boeing Nut
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RE: How Much More Lift Does Shuttle Make On The 747?

Sun Jul 17, 2005 2:20 am

No worries sir. I'm was wondering because there is still a positive angle of attack in cruise and the Shuttle still has a slightly higher angle of attack than the 747.

Regards

Also, why is the cruise altitude so low during ferry flights?
I'm not a real aeronautical engineer, I just play one on Airliners.net.
 
SATL382G
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Joined: Sat Aug 14, 2004 12:02 am

RE: How Much More Lift Does Shuttle Make On The 747?

Sun Jul 17, 2005 4:23 am

Quoting Boeing Nut (Reply 3):
I'm was wondering because there is still a positive angle of attack in cruise and the Shuttle still has a slightly higher angle of attack than the 747

I thought of that too. Trouble is I don't know how far away from the 747 wing you have to be before you're out of the wings local airflow. The local airflow over the top of a 747 goes up at the front and then curves around and heads down aft of the wing (checkout the rain gutters above 747 pax doors to see what I mean). My point here is that the shuttle wing may well be sitting in the 747s local flow at a zero angle of attack, even though it looks to the MKI eyeball like it is sitting a bit nose up. I'm not an aerodynamics guy but I think a zero angle of attack would also minimize handling and drag problems for the 747, that's a WAG.

Quoting Boeing Nut (Reply 3):
Also, why is the cruise altitude so low during ferry flights?

I don't know and Jenkins doesn't say in his book. I'd guess and say they can go higher but if they do the range starts to drop.
"There’s nothing quite as exhilarating as being shot at and missed" --Winston Churchill
 
TedTAce
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Joined: Sun Mar 27, 2005 12:31 am

RE: How Much More Lift Does Shuttle Make On The 747?

Sun Jul 17, 2005 4:33 am

Quoting SATL382G (Reply 2):
Not trying to be a smartass but how do you know it's generating lift?

(tongue in checck) I will NOT BE IGNORED!!
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HaveBlue
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RE: How Much More Lift Does Shuttle Make On The 747?

Sun Jul 17, 2005 6:32 am

Quoting SATL382G (Reply 2):
No shuttle:
Cruise Alt: 24,000 - 26,000 ft
Max Range: 6,300 miles

Why is the NO shuttle altitude so low and why would it be any different than a normal 747? Without the shuttle it still has the attachment struts on the dorsal side of the plane and the vertical fins on the end of the horizontal stabs, but I don't see that knocking the ceiling down by 20,000'. I may have read that the interior is no longer pressurized on the NASA 747 during the conversion, but I can't remember that for sure.


And I know on the E-3 Sentry the radar dish lift and drag pretty much cancel each other out completely. Again its fuzzy but that may be the same with the 747/Shuttle combo, though thinking about it that doesn't seem to make sense.

[Edited 2005-07-16 23:34:24]
Here Here for Severe Clear!
 
A350
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RE: How Much More Lift Does Shuttle Make On The 747?

Tue Aug 09, 2005 9:41 am

Quoting SATL382G (Reply 2):

Shuttle attached:
Max airspeed: Mach .6
Cruise Alt: 13,000 - 15,000 ft
Max Range: 1,150 miles

There are emergency landing sites for the Shuttle in Europe. In the case one of them will be used one day, it will be a long way with many refueling stops to bring the Shuttle back home! Or am I missing something?

A350
 
SATL382G
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RE: How Much More Lift Does Shuttle Make On The 747?

Tue Aug 09, 2005 10:01 am

Quoting A350 (Reply 7):
There are emergency landing sites for the Shuttle in Europe. In the case one of them will be used one day, it will be a long way with many refueling stops to bring the Shuttle back home! Or am I missing something?

You're not missing anything. When the 747 & shuttle went to Paris Airshow in 1983 they made a lot of stops. NASA thought about making the 747 air refuel capable but decided the spilled fuel could damage the tiles...
"There’s nothing quite as exhilarating as being shot at and missed" --Winston Churchill
 
HaveBlue
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RE: How Much More Lift Does Shuttle Make On The 747?

Tue Aug 09, 2005 12:27 pm

Quoting SATL382G (Reply 8):
You're not missing anything. When the 747 & shuttle went to Paris Airshow in 1983 they made a lot of stops. NASA thought about making the 747 air refuel capable but decided the spilled fuel could damage the tiles...

That would have to be the oddest sight of connected airplanes if that had actually went thru and happened... and boy would I have loved to seen it.  Smile

SATL382G when you can please respond to my July question in my previous post (reply 6 above). I have no doubt that you know the answer and I'm very curious as to why the 'no shuttle' cruise altitude is so low.

Thanks!
Here Here for Severe Clear!
 
SATL382G
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RE: How Much More Lift Does Shuttle Make On The 747?

Tue Aug 09, 2005 5:09 pm

Quoting HaveBlue (Reply 6):
Why is the NO shuttle altitude so low and why would it be any different than a normal 747?

I have no idea & I don't care to speculate.
"There’s nothing quite as exhilarating as being shot at and missed" --Winston Churchill

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