Talk:Shuttle Carrier Aircraft/Archive 1

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Archive 1

Weight

I'm not an aeronautical engineer, but it seems to me that the shuttle's weight would alone would counteract some of the lift generated by the SCA's flight, so that even if it added no drag, more of the plane's energy would have to go into keeping itself aloft instead of moving forward. The article I linked to (which isn't written by an aeronautical engineer, either) also says the weight is significant. Could you explain why you removed it? Thanks, Dave (talk) 16:20, August 10, 2005 (UTC)

I'd just had a quick discussion on sci.space.shuttle where I was told off for assuming it was weight not drag :-). Basically, the loaded weight of the Orbiter is about the same as the cargo+passengers weight on a normal 747, so the weight of the SCA plus Orbiter is about the same as the weight of a 747 taking off on a normal passenger flight. [1], which is written by an aeronautical engineer ;-)

As such, just lugging the Orbiter (and ignoring drag) would require no more fuel than flying normally, so in theory the SCA would have the same range... but it doesn't, and the difference is almost entirely due to drag (weight to a small degree, but also things like flying inefficiently). Shimgray 16:55, 10 August 2005 (UTC)

That makes sense, although it's hard to imagine the shuttle plus stabilizers etc. weighing less than three times as much as passengers, seats, and cargo. Maybe we should clarify in case it confuses someone else. Thanks for the quick response. Dave (talk) 16:57, August 10, 2005 (UTC)

Bear in mind that the SCAs have been gutted inside - they're missing all the seats, cabin furniture, and so forth. That weighs quite a bit. [2] quotes a quarter-million lbs of payload (presumably for a cargo variant), whereas the orbiter is about 240,000 lbs at takeoff (presumably similar or a little less on being ferried, as fuel and payload are missing, but tailcone &c added). So the numbers are pretty similar. Shimgray 17:06, 10 August 2005 (UTC)

I agree it's probably worth noting something about the payload issues ("weight no problem", basically), but I'm not best sure how to do it. Hmm. Shimgray 17:11, 10 August 2005 (UTC)

Fuel stats

Something looked odd with the fuel stats, so I looked up some of the info. There should be an infobox for this, but I didn't see it.

Range 1000 nautical miles [3], = 1152 mi = 1852 km
Fuel capacity of standard 747-100, 183,380 liters Boeing_747#Technical_data = 48,440 gal
Length of standard 747-100, 70.7 m Boeing_747#Technical_data, = 232 ft

This gives fuel stats of 99 L/km and .0238 mile/gal. However, .0238 mpg is 125 ft/gal, about than half the plane length. Thus, the "1.5 times the length of the plane" part is not consistent with the other units. [4] Gimmetrow 23:55, 4 July 2006 (UTC)

why a plane?

Why do they use a plane for this? Why not a barge, for example? Wouldn't that be cheaper, or are there other concerns that influenced deciding to refit an airplane? 71.102.132.76 05:20, 13 August 2007 (UTC)

Air lifting is quicker and simpler. Airlifting the Shuttle takes days vs weeks for other transport modes. Water is a corrosive environment. Not the best thing for expensive aerospace hardware, especially if not designed for it. Also, NASA has more control over things airlifting it themselves vs. getting a shipping company to ship it. Besides, it'd take some airlifting to get it to a seaport for water transport. -Fnlayson 05:37, 13 August 2007 (UTC)

Obliged. 10:08, 14 August 2007 (UTC)

(Very late answer) - because it is rather difficult to get a barge from Edwards Air Force Base, where the shuttle sometimes lands, and from Air Force Plant 42, where it was built, as these locations are in the Mojave Desert, far from any barge-able waterways. AKRadecki^Speaketh 22:37, 31 October 2007 (UTC)

Consider 2 new sections

consider 2 new sections, one for each aircraft. The joke wording, currently under trivia, is not so trivial and could be moved to the section about that aircraft. Archtrain 19:22, 9 September 2007 (UTC)

The carrier mods are basically the same on both aircraft. I don't see the need for 2 sections that. -Fnlayson 00:27, 10 September 2007 (UTC)

Video previews

Please note that the large and overpowering video previews in this and other articles is currently being discussed at Wikipedia talk:WikiProject Aircraft#Media content?. Input invited; if you don't participate, don't complain when consensus is achieved without you... AKRadecki^Speaketh 22:44, 31 October 2007 (UTC)

Piggy-back flying

An editor has questioned how the shuttle could be launched in flight from the SCA when it is on top. He/she has since added a source which confirms that this did indeed happen. However, I've not been able to find a sourced aerodynamic exclamation for how it is done. I think it would be good to have a brief summary of how this occured during the Approach and Landing Tests (ALT). Also, launching piggy-back aircraft is not unique, and dates back to the purpose-built Short Mayo Composite, and possibly to even before. - BillCJ (talk) 02:21, 13 February 2008 (UTC)

It's not a terribly crazy thing. I suspect the editor is thinking of a drop-type release, when in fact the 747 dove away from the shuttle after release. Quote: "Accompanied by five T-38 chase planes, the 747 flew a racetrack pattern above the lakebed. The release was scheduled for 8:30 a.m., but higher-than-normal air temperatures slowed the climb to the release altitude. At 8:48 a.m., Fulton nosed the 747 SCA into a shallow dive, and Haise radioed "The Enterprise is set; thanks for the lift." Haise then pushed the separation button, firing seven explosive bolts. The Enterprise seemed to pop off the back of the 747. Fulton then put the 747 into a descending left turn, while Haise pitched the Enterprise to the right." Source:[5].--ABQCat (talk) 10:42, 13 February 2008 (UTC)