Stupendous and Special 747s

I’m a big fan of really big airplanes.  😉  And my favorite is, without question, the 747, though I’ve got a place in my heart for the other widebodies too.  My home airport of MSP no longer sees many 747s, though MD-10s (the old DC-10s after the McDonnell-Douglas merger) still run in and out for FedEx, with their distinctive purple tails.  But I do miss those 747s.

So today’s post is dedicated to the amazing versatility of these very large aircraft, particularly the Boeing 747s.

We’ll start off with what’s probably the most famous of all the modified 747s: a pair of customized 747-200Bs, designated VC-25 by the USAF: Air Force One.

vc25-liberty

In the distinctive livery of the White House, these two aircraft (SAM28000 and SAM29000, only taking the call sign “Air Force One” if the President is actually on board) are probably the most recognizable 747s in the world, with a range of special features both classified and otherwise.  They are equipped to be able to act as a mobile office and command post for the White House, so that even if the President is traveling, he still has all that he needs to carry out the functions of his post.  Funny story about the picture above: the USAF decided it would be nifty to get some great photo ops with the aircraft, and so flew it above a few major national monuments.  (They also photographed it over places like Mount Rushmore, the Grand Canyon, and of course Washington, DC.)  Downside: somebody forgot to tell the NYPD, as well as the general public, so a lot of people got needlessly alarmed at the sight of a widebody airliner flying low and slow over Manhattan, given what happened the *last* time someone did that.  Oops.  The VC-25s are aging, having been ordered in 1986, and are due to be replaced with 747-8s.

Of course, I’m more fond of this one:

sca-endeavour

Sometimes joking called “The World’s Most Sophisticated Biplane,” this is N905NA, the older of NASA’s two Shuttle Carrier Aircraft, a modified 747-100, carrying the space shuttle Endeavour during its final ferry flight to California.  (It’s landing for the night at Edwards AFB in this picture.).  It had originally served as an airliner for American Airlines (and the patriotic pinstriping of American Airlines was preserved for a long time before they fully repainted it in NASA’s standard livery) before NASA bought it and modified it to carry the Space Shuttle Orbiters from California to Florida.  Surprisingly, the 747 required few modifications, owing to the deliberate overdesign of its wing; the 747 had been designed from the start primarily as a cargo aircraft and as such is built to fly very heavily laden.  But this stretches even the most liberal definition of overburden.  To carry the 75 ton Orbiter, the 747 has had almost everything stripped out inside, save for a few seats at the front to carry support crews.  To account for the Orbiter’s bulk interfering with the function of the vertical stabilizer, additional stabilizers were welded on to the ends of the horizontal stabilizer.  (Of course, the Orbiter’s own stabilizer and wings do also function while in ferry, but as they’re locked in place, they aren’t entirely helpful and this thing steers very ponderously.)  It also must fly very low and slow, meaning that a cross-country flight even for the long-legged 747 still requires a refueling stop.  Both SCAs are of course retired now; NASA managed to get one extra customer for N905NA, which ferried a stealthy UCAV from Boeing’s Phantom Works faciltiy, but that was a one-shot deal.  N905NA is now parked permanently at Johnson Space Center, on static display with a high-fidelity mockup Shuttle Orbiter on its back.  NASA’s spare, N911NA, is parked at Edwards AFB to be cannibalized for parts for the SOFIA aircraft, to be discussed later on — though that aircraft’s fate is not clear any longer.  Like Air Force One, these birds got to have an awesome radio call sign when in operation; N905NA (which made the majority of the ferry flights) always went by Pluto 95 Heavy.  Oh, and when they did a close flyover of New York City (to deliver OV-101 Enterprise to the Intrepid Sea Air & Space Museum), they didn’t repeat Air Force One’s blunder; they not only announced it, they made an event out of it, treating the city to a meticulously documented flyover prior to landing at JFK International.

And speaking of NASA 747s….

sofia

Originally belonging to Pan Am as the Clipper Charles Lindbergh, this 747SP was sold to United Airlines in 1986, and then to NASA in 1997.  Ten years later, modifications were complete to transform it into a flying infrared observatory.  Ground-based infrared astronomy is possible, but only in very narrow wavelength bands; outside of those, emissions from the atmosphere itself swamp everything.  So typically you want your IR telescopes in space or at least very high in the atmosphere.  Building on Everest isn’t very practical, but an airliner can get high enough.  That’s where SOFIA, the Stratospheric Observatory for Infrared Astronomy, comes in.  A joint project with the German Aerospace Center (which furnished most of the telescope), SOFIA is a 2.5-meter reflector telescope of the Schmidtt-Cassegrain design, equipped with an infrared imager, mounted in the aft section of a 747.  The aircraft endured substantial modifications, including enlarging the aft section, adding a bulkhead to allow the telescope compartment to be cooled and then depressurized prior to opening the door, and of course, adding a really big door.  This was a major challenge, as the huge door is a structural nightmare.  But the engineers rose to it, and SOFIA has been a complete success.  Sadly, it’s continued operations are now in jeopardy, as NASA has diminishing funds available for it and has stated that the German Aerospace Center will need to start pitching in more funds if it is to remain operational.  Cross your fingers and write your Congressman, if you want this aircraft to stay in the air!

After all, the fate of this one is a little amusing….

kc747-flyover

Back in the 1970s, the USAF was looking for a new tanker, bigger than the 707-derived KC-135 Stratotanker.  They ultimately went with the KC-10 Extender from McDonnell Douglas, based on the DC-10, but Boeing had also submitted a contender based on the 747.  The USAF experimented with it, but ultimately declined, although they did carry out extensive inflight refueling tests with the test article Boeing provided.  (It was the actual original 747, in fact, with modifications.  It’s in a flight museum in Washington state today.)  But another country did go for it — and now the Republic of Iran is the sole user of this very large tanker, having purchased two of them back in the days of the Shah.  Only one remains in service.  It was most recently seen at a military parade in Iran, performing a flyover in formation with a MiG 29 UB, an F-4E (the Shah bought tons of those, so they still form the bulk of the Iranian airforce), and another interesting example of a remarkable aircraft no longer found flying outside Iran: the F-14 Tomcat.  We had a different relationship with Iran back in the day….

But that tanker is for fueling warbirds.  What about a tanker that puts fires out?

747supertanker

Founded in the 1960s, Evergreen Aviation was a venerable aviation company offering mostly cargo services but also some charter flights before it eventually got into firefighting as well.  It fell on hard times, and in 2013 they closed the doors on the aviation business and have been gradually selling off their fleet.  Unknown is the fate of this particular aircraft, the 747 Supertanker, with unique modifications that make it difficult to sell for any purpose other than dumping 20,000 gallons of liquid onto a target.  Its performance as a firefighter was somewhat mixed; it can deliver a massive amount of water, but it takes a long time to fill the tanks, and it can only operate out of large, well-developed airfields, which is not an asset when you’re talking about firefighting.  Still, it’s a very impressive vehicle, and I wish I knew what has become of it.  The FAA lists its certificate as having expired last year, and still shows Evergreen International Aviation as the owner.

That’s not the only 747 that Evergreen has helped modify into something unique:

dreamlifter

This one isn’t as unique, since there are actually four of them, but it certainly looks unique.  Born of the needs to transport 787 sections over very large distances, the Boeing 74 Dreamlifter (formerly the Large Cargo Freighter or simply the “Flying Pickle” due to the primer color of the first one, which made its test flights prior to receiving its livery) is inspired by the monstrous-looking Pregnant Guppy.  Its tail section swings open to accept large cargos, and rather than just a little bump over the front of the aircraft, this one’s whole fuselage is enlarged.  The enlargement designs were done by Rocketdyne (then a Boeing division) in conjunction with Boeing Moscow and Gamesa Aeronautica of Spain, while Evergreen performed the actual modifications.  The four Dreamlifters are working all the time shuttling parts two and fro in the Dreamliner production line.

And then there are the slightly scarier 747 mods….

b747

The B-747 was a paper-only proposal to turn it into a bomber, or more accurately, a cruise missile carrier.  With internal rotary carriers stretching the full length of the fuselage with an overhead handling system and a device to punch missiles out into the airstream through the aft of the aircraft, this would’ve created an aircraft that could fairly efficiently carry 72 cruise missiles to target — which could be quite a ways away, given the 747’s impressive unrefueled range.  As a bonus, the “hump” which on airliners was used for first-class accommodations could provide ample space for the aircraft to double as a command-and-control aircraft.

And then there’s this one.  Sometimes, ya just gotta have a BLOD.

yal-1

I remember playing video games with my then-fiancee back in the late 90s, when he introduced me to the concept of the Blue Laser Of Death.  In a real-time strategy game, those things would come very much in handy, so you wanted to get units that could field such weapons.  Well, the military has been attempting to build the real-world equivalent, but the main problem is that you need an enormous power source.  Ship-mounted lasers are starting to see operational testing, but the USAF toyed for a while with an aircraft-mounted one: the YAL-1.  This one-of-a-kind aircraft was a massive chemical laser built into a 747, the only aircraft that could easily accommodate its huge size.  The idea was to use it for ballistic missile defense, and it did successfully destroy two missiles in tests.  The downside is that it’s almost completely impossible to have it actually be in a position to fire its weapon except by total luck, plus it’s really only useful during a limited portion of a hostile missile’s flight.  The YAL-1 was moved to the boneyard at Davis-Monthan Air Base in Tuscon, AZ, but did not stay in storage for long; it has been broken up for scrap.  Alas.  Incidentally, that nose features the largest turret ever installed on any aircraft.  Like everything about the 747, it’s even bigger than it looks.

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