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#1
08-08-2005, 10:47 AM
 CC Charter Member Join Date: Apr 2000 Location: not elsewhere Posts: 4,293
How much does an empty space shuttle weigh compared to a full 747 load of passengers?

When the shuttle lands at Edwards, it has to be ferried back to Florida on the back of a specially fitted 747. That's a pretty heavy load, I imagine. But maybe not, compared to the weight of 200 (300?) some passengers and their luggage. I can't find anything that would allow me to compare the weight of the shuttle with the weight that a loaded 747 carries. What would be a good estimate? xo, C.
#2
08-08-2005, 11:07 AM
 engineer_comp_geek Robot Mod in Beta Testing Moderator Join Date: Mar 2001 Location: Pennsylvania Posts: 20,273
I found a site that lists the weight of Enterprise as 144,000 lbs when it was on the back of a 747 for tests back in 1977.

http://www.edwards.af.mil/archive/20...milestone.html

Various sites list the 747 maximum payload as somewhere between 200,000 and 250,000 lbs depending on which model 747 they are talking about.

Different models of 747 can carry somewhere in the neighborhood of 400 passengers (I found one site that listed 374 passengers for a 747-200 and 420 passengers for a 737-400). If you figure about 400 passengers, each weighing about 200 lbs total (person plus luggage), you only end up with about 80,000 lbs.
#3
08-08-2005, 11:09 AM
 engineer_comp_geek Robot Mod in Beta Testing Moderator Join Date: Mar 2001 Location: Pennsylvania Posts: 20,273
Oops. That 737-400 should say 747-400.
#4
08-08-2005, 11:21 AM
 Ravenman Charter Member Join Date: Jan 2003 Location: Washington, DC Posts: 22,282
I'm no engineer, but I would imagine that the Space Shuttle would create a significant amount of lift, so it wouldn't be like loading up the interior of a 747 with 144,000 pounds of luggage.
#5
08-08-2005, 11:40 AM
 Xema Guest Join Date: Mar 2002 Posts: 11,627
Of course, the Shuttle also represents a considerable amount of drag as compared to passengers and baggage carried within the fuselage.
#6
08-08-2005, 12:02 PM
 Raguleader Guest Join Date: Mar 2003 Location: Kansas Posts: 8,159
It's also worth noting that some 747 models are designed for carrying cargo (they're cool, they have a door in the nose that opens up kinda like the one on a C-5). I'd imagine a 747 loaded up with freight tends to be a good bit heavier than one loaded up with passengers (and of course, there are certain liberties you can take with payload, carrying more in exchange for less fuel, etc.).

The 747 that carries the shuttle almost certainly has structural reinforcements and maybe even uprated engines for the extra payload. Civilian cargo haulers and airliner airframes converted for military use recieve various structural reinforcements to support the weight of military vehicles and cargo (which includes trucks, armored vehicles, etc.) You'd be amazed how rugged you can make those airliner airframes. The Air Force has a cargo/refueler version of the DC-10 that, when unencumbered by extra fuel or cargo, can fly straight up (90 degrees from the ground) into the air after takeoff.

It's also worth noting that the piggyback 747 also has an unusual tail assembly, probably designed to compensate for the disruption of airflow past the rudder and stabilizers that the shuttle would cause.
#7
08-08-2005, 12:07 PM
 CC Charter Member Join Date: Apr 2000 Location: not elsewhere Posts: 4,293
SDMB - ya gotta love this place
#8
08-08-2005, 12:12 PM
 Tapioca Dextrin Guest Join Date: Dec 1999 Location: Staring blankly at my GPS Posts: 11,874
More than you wanted to know about the NASA747.
#9
08-08-2005, 12:14 PM
 Tapioca Dextrin Guest Join Date: Dec 1999 Location: Staring blankly at my GPS Posts: 11,874
Quote:
 Weight: Basic weight, NASA 905, 318,053 lbs- NASA 911, 323,034 lbs; Maximum gross taxi weight, 713,000 lbs; maximum gross brake release weight, 710,000 lbs; maximum gross landing weight, 600,000 lbs
#10
08-08-2005, 12:30 PM
 Raguleader Guest Join Date: Mar 2003 Location: Kansas Posts: 8,159
Quote:
 Originally Posted by Tapioca Dextrin (insert NASA 747 stats here)
Heh, that reminds me of a random, kinda off-topic thing I just remembered. Teacher I had who flew B-52s in the Air Force said that it was fairly common to load a plane up with fuel past the maximum takeoff weight, because by the time a B-52, with it's 8 turbofan engines, rolled on it's way from the ramp to the end of the runway, it would burn more than enough fuel to get under the takeoff weight limit again. Then, once they took off, they'd immediately refuel to top off the tanks (seems the wings can support a lot more weight than the wheels)

(back to the topic at hand) looking at the numbers posted for NASA's 747, it looks like they did indeed uprate the engines and airframe.
#11
08-08-2005, 01:36 PM
 Stranger On A Train Guest Join Date: May 2003 Location: Manor Farm Posts: 16,783
Quote:
 Originally Posted by Raguleader Then, once they took off, they'd immediately refuel to top off the tanks (seems the wings can support a lot more weight than the wheels)
Once the aircraft is airborne, the wings only need support the fuselage rather than vice versa. And while I'm not familiar with the -52, on most large planes the main tankage is inside the wing structure, so the weight of the fuel is supported (more or less) directly by lift rather than structure.

Stranger
#12
08-08-2005, 03:42 PM
 Padeye Member Join Date: Nov 1999 Location: Phoenix, AZ, US Posts: 7,672
Quote:
 Originally Posted by Raguleader The Air Force has a cargo/refueler version of the DC-10 that, when unencumbered by extra fuel or cargo, can fly straight up (90 degrees from the ground) into the air after takeoff.
I have to ask for a cite on this. Few fighter planes can be configured for a greater than 1:1 thrus to weight ratio. I do not believe any cargo plane is capble of that even with a light load.

Gross takeoff weight is almost never a matter of structural limits and certainly not limits of BUF's landing gear. It's a matter of aerodynamics and power. A too heavy plane may be within strutrual limits but less able to safely maneuver at normal takoff speeds. In some cases a plane may be capable of flying with more weight than it is able to take off with.

It's worth noting that many large planes can't land with as much weight as they take off with as the weight of fuel in the tanks can cause structural damage as it sloshes.
#13
08-08-2005, 04:33 PM
 pilot141 Guest Join Date: Mar 2002 Location: Mostly Texas Posts: 1,540
Quote:
 Originally Posted by Raguleader The Air Force has a cargo/refueler version of the DC-10 that, when unencumbered by extra fuel or cargo, can fly straight up (90 degrees from the ground) into the air after takeoff.
Ummm......no. No way, no how can a KC-10 get to 90 degrees nose up.

Back on topic - I once flew a "pathfinder" mission for the NASA 747 with the shuttle on top. They were flying the shuttle west, from the KSC out to Edwards for some work.

They needed a pathfinder - us in our trusty C-141 - to fly ahead of the 747 (with a NASA guy in the jumpseat) to make sure there wasn't any unexpected turbulence along the route. The 747 with the shuttle attached can only climb into the mid-teens (ie 13-16,000 feet), and it takes almost full power to maintain that altitude. Needless to say a 747 at 15,000 ft and full power burns a LOT more gas than usual, so their range is severely limited. They would typically fly 400-mile legs and then stop, refuel, check the weather, etc. I was only the pathfinder for two legs, but it was definitely one of my more memorable missions!
#14
08-08-2005, 10:30 PM
 postcards Guest Join Date: Aug 2001 Location: The other Long Beach. Posts: 3,061
Quote:
 Originally Posted by pilot141 The 747 with the shuttle attached can only climb into the mid-teens (ie 13-16,000 feet), and it takes almost full power to maintain that altitude. Needless to say a 747 at 15,000 ft and full power burns a LOT more gas than usual, so their range is severely limited. They would typically fly 400-mile legs and then stop, refuel, check the weather, etc.

Very interesting. All theses years I envisioned it done as a straight run. This also explains why NASA hates to land the shuttle anywhere but Florida.
#15
08-08-2005, 11:01 PM
 pilot141 Guest Join Date: Mar 2002 Location: Mostly Texas Posts: 1,540
Yeah, I never would have thought it was such a logistical nightmare until I was involved in it.

Talking to the pilots of the 747 I found out that NASA would do almost anything to avoid having to piggy-back a shuttle on the 747. Between the short legs, refueling, changing plans, weather avoidance and crew rest it can take almost a week to move a shuttle across the country.

Of course being NASA, they take full advantage of every possible angle: we were welcomed in Salt Lake City by a full contingent of the local press corps. Tours were given to key city officials, and the 747/Shuttle led the news stories that night.

But even if NASA did nothing, I think they'd still have a ton of people show up at the airport. It's just such a cool thing to see flying!
#16
08-08-2005, 11:37 PM
 drewbert Guest Join Date: Dec 1999 Posts: 2,181
http://www.msfc.nasa.gov/news/news/r...98/98-189.html

I wasn't in Nashville at the time, but people at work tell me they saw the shuttle on the 747 fly right between their building and downtown.
#17
08-09-2005, 02:55 AM
 Richard Pearse Member Join Date: Aug 2001 Location: On the outside looking in Posts: 10,019
Quote:
 Originally Posted by Raguleader Heh, that reminds me of a random, kinda off-topic thing I just remembered. Teacher I had who flew B-52s in the Air Force said that it was fairly common to load a plane up with fuel past the maximum takeoff weight, because by the time a B-52, with it's 8 turbofan engines, rolled on it's way from the ramp to the end of the runway, it would burn more than enough fuel to get under the takeoff weight limit again.
It is fairly standard to have a maximum ramp weight that is higher than the take-off weight. The take-off weight is generally limited by performance, specifically the aircraft's performance in the case of an engine failure on take-off.
#18
08-09-2005, 07:37 AM
 Raguleader Guest Join Date: Mar 2003 Location: Kansas Posts: 8,159
Quote:
 Originally Posted by Padeye I have to ask for a cite on this. Few fighter planes can be configured for a greater than 1:1 thrus to weight ratio. I do not believe any cargo plane is capble of that even with a light load.
Hrm... now that I think about it, my dad told me about it after he had been to an air show. Just now occurs to me that he mighta been pulling my leg.

I DO know for a fact that a C-130 can do acrobatic maneuvers. If you strap about 20 rocket pods to it.
#19
08-09-2005, 12:44 PM
 slinkydink Guest Join Date: May 2002 Location: Hell's Kitchen, NYC Posts: 19
The Blue Angels have a Hercules fitted with RATO (Rocket Assisted Take-Off) that can go nearly straight up after take-off. That's probably what he was thinking of.

#20
08-09-2005, 12:47 PM
 CC Charter Member Join Date: Apr 2000 Location: not elsewhere Posts: 4,293
Well, it must be possible for some fighter planes to do that, because every year at the Chicago Air and Water show, planes do that for the folks - or at least they sure seem to. xo, C.
#21
08-09-2005, 11:06 PM
 Rick Charter Member Join Date: Aug 1999 Posts: 16,451
Straight up? Just go watch an F-15 Eagle
Quote:
 . This gives the Eagle a total of 50,000 pounds of thrust. In other words, a nominally loaded F-15 Eagle of 48,000 pounds has a thrust-to-weight ratio of 1.04 pounds of thrust to each pound of aircraft weight. Thrust of this caliber allows an F-15 to accelerate while going straight up! A specially modified F-15A Eagle known as the "Streak Eagle" was able to outclimb a Saturn V Moon Rocket to almost 60,000 feet. This same aircraft flew to 98,430 feet (30,000 meters) in 207.80 seconds (less than 3 minutes and 30 seconds).
I used to have an office just off the south runway at PDX. The home town Air Force (Oregon ANG) flies F-15s. Every once and a while they would take off then go straight up on burner. Where they pulled vertical was right over my office. The concrete walls in the building would shake. Man what a sound!
I was told once that they did one of these take-offs anytime the engine had been out of the airframe. Don't know if it was true, but I do miss the sound of those engines.
#22
08-09-2005, 11:33 PM
 engineer_comp_geek Robot Mod in Beta Testing Moderator Join Date: Mar 2001 Location: Pennsylvania Posts: 20,273
Quote:
 Originally Posted by Rick Straight up? Just go watch an F-15 Eagle
I used to live near Martin State airport in Baltimore. Every year they have an airshow. One year, two F-15's went roaring across the runway at some ungodly speed, then when they got to the end of the runway they went straight up. It was way cool. Of course they went straight up so damn fast they strayed into commerical airspace and got themselves in big trouble, but still, it was way cool to watch.

The next year, during the air show I heard this loud boom and thought there go those damn F-15's showing off again. Then I heard a bunch of sirens come through my neighborhood. It turned out it wasn't F-15's showing off, it was a stealth fighter who lost his wing (due to one lousy bolt, IIRC) and came crashing down in our neighborhood. It literally flattened a house.
#23
08-10-2005, 08:33 PM
 EnderWay Guest Join Date: Jun 2005 Location: somewhere out there Posts: 140
Quote:
 Originally Posted by CC When the shuttle lands at Edwards, it has to be ferried back to Florida on the back of a specially fitted 747. That's a pretty heavy load, I imagine. But maybe not, compared to the weight of 200 (300?) some passengers and their luggage. I can't find anything that would allow me to compare the weight of the shuttle with the weight that a loaded 747 carries. What would be a good estimate? xo, C.
Yes, I remeberd correctly .. they did it in 1983 to Paris!

The SCAs are used to ferry space shuttle orbiters from landing sites back to the launch complex at the Kennedy Space Center

NASA 905 was the only SCA used by the space shuttle program until Nov. 1990, when NASA 911 was delivered as an SCA. Along with ferrying Enterprise and the flight rated orbiters between the launch and landing sites and other locations, NASA 905 also ferried Enterprise to Europe for display in England and at the Paris Air Show.

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