The World’s Most Expensive Biplane

By Deane Barker on July 1, 2007


The space shuttle had to land at Edwards AFB in California last week due to weather, so they had to get it back to Florida via the piggy-back method. I watched it on CNN, and was struck by how cool it was. I’ve seen it before, of course, but you kind of take it for granted.

However, I found myself wondering if the 747 gets any extra lift from the wings on the shuttle. I know the drag and weight are a problem, but you do have two extra wing surfaces now, so do those help at all? With the shuttle on top, it’s like the world’s most expensive bi-plane.

The Wikipedia page for the Shuttle Carrier Aircraft had some interesting information:

Flying with the drag of the Orbiter imposes fuel and altitude penalties – the range is reduced to just over 1000 nautical miles (1900 km) compared to an unladen range of 5500 nautical miles (10,000 km), requiring a SCA to stop several times to refuel on a transcontinental flight

Wow, an 80% reduction in range and they can’t refuel in flight.

It takes a crew of about 170 a week to prepare the shuttle and SCA for flight, and each transcontinental trip costs about $1.7 million.

Yikes.

Still, I have no information on whether or not the wings of the shuttle provide the entire, two-vehicle apparatus with any net increase in lift. Opinions, anyone?

Gadgetopia

Comments

  1. Considering that in the atmosphere the shuttle is pretty much a flying brick, I have a feeling that the extra pair of wings is not helping out in the least bit.

  2. The shuttle’s glide slope on landing approach is approximately 1:1, meaning that it drops a foot for every foot it goes forward. Depending on the source, a 747’s glide ratio is somewhere in the 15:1 and 17:1 range.

    In other words, the orbiter can’t really be called a glider, since it’s more of a controlled fall. It’s wings can’t keep it up in the air too well, even under its own power. (On the plus side, they don’t snap off during reentry)

    It’s likely that the orbiter does provide the SCA some lift, but it also provides a lot more weight and drag. If you think of the two aircraft as separate bodies, the orbiter is still gliding at that 1:1 ratio, which means that it’s net velocity is still pushing down ( a lot ) on to the 747.

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