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Boeing 747SP x 2

19 October 2016

Nick Veronico is familiar to readers for his authorship, wreckchasing and—especially—NASA’s SOFIA. The exploratory SOFIA is the immense IR observatory within a highly modified Boeing 747SP (SP for Special Performance). SPs are 747s which are 50 feet shorter with length taken from ahead as well as aft of the wing to increase range, had specialty parts made, and an enlarged empennage—making it more of a sportster. A few were made but a following was created all the same due to their uniqueness—and there is a website for them at the B747SP Website.


Boeing 747SP paired, NASA’s SOFIA (L) and Pratt & Whitney Canada’s (R)—courtesy and copyright Nick Veronico

But Pratt & Whitney Canada has a 747SP, as well, which has been modified to test jet engines while in flight. The test engine is suspended from a wing stub located just aft of the cockpit on the right side of the fuselage. The upper cabin has been heavily reinforced for the stress of a powerful engine’s thrust. Additionally, the stub is angled slightly downward to better keep trim and pitch authority on the aircraft. Recently, Nick Veronico graciously shared these photos of these two aircraft as they were parked next to each another recently while at a recent meeting of both operators.


Boeing 747SP of Pratt & Whitney Canada up closer—courtesy and copyright Nick Veronico


Boeing 747SP wing stub attachment for in-flight jet engine testing by Pratt & Whitney Canada (during testing a small wing with the test engine suspended on a pylon is attached to the stub)—courtesy and copyright Nick Veronico

Boeing 747SP flown by P&W Canada engine testing wing stub mount—courtesy and copyright Nick Veronico

A closer view of the Boeing 747SP flown by P&W Canada engine testing wing stub mount—courtesy and copyright Nick Veronico


Boeing 747SP flown by Pratt & Whitney Canada has a glass cockpit as does SOFIA—courtesy and copyright Nick Veronico

But what about SOFIA?

NASA operates a Boeing B-747SP (see the previous post for a description of this unique 747 variant) so that a big eye can be carried aloft for SOFIA (Stratospheric Observatory for Infrared Astronomy)—the big eye is, as you likely infer, a telescope which senses within the infrared portion of the light spectrum. This telescope is quite large and more capable than those based on land or in orbit. SOFIA is a cooperative mission between the USA’s NASA and Germany’s Deutsches Zentrum für Luft- und Raumfahrt (DLR, or the German Aerospace Center). DLR built the quite large IR telescope which has a diameter of 2.5m (100 inches) and weighs 20,000kg (44,100 lbs)—operating within the range of  0.3–1600 μm (microns). It is a Bent Cassegrain/Nasmyth design and serves to gather information from nebular gas clouds which is fed to instruments aboard the NASA’s 747SP. One of these instruments is known as GREAT, an acronym for German Receiver for Astronomy at Terahertz (frequencies), though there are many other instruments, as well. Recently the frequency was nearly doubled from ~2 THz to 4.1 THz vastly increasing the richness sensed by the telescope.

The aircraft (N747NA) was originally built for Pan American Airways in 1977 and christened Clipper Lindbergh. Later it was sold to United Airlines and retired thereafter. Later acquired by NASA it was fitted for flight and modified to carry the large telescope aloft in a fuselage bay located between the wing and the tail. A large hatch can be rotated upward to expose the telescope to observe the heavens as well as to expose what is known as “the cavity” to the harsh conditions of the stratosphere. The aircraft is designed to fly 900 mission per year at an altitude range of 39,000–45,000 feet (~11,800–~13,600 meters) with as many as 25 persons on board for eight hours of observation at a time — all at -60º C (-76º F) and 800kph (500 mph). Clipper Lindbergh was refitted after 2011 with most of the science system wiring replaced (15,000 connections were rewired), three times more power made available to the scientific instruments, the telescope mirror cleaned, the cavity door improved as well as the cavity’s environmental control (better keeping water as well as water vapor out) and the cockpit was transformed from analog based to digitally based (i.e., a glass cockpit).


(Author’s notes)

Nicholas Veronico works for NASA on the SOFIA project as a writer as well as a photographer and we have seen his work before, as he is a prolific author. Read the book reviews for Hidden Warbirds and for Hidden Warbirds II—you’ll be pleased by the stories he has written of the recovery/restoration of WW II aviation wrecks with his particular skill at going beyond the easy and the obvious. His newest book will be out soon and is about the attack on Pearl Harbor—Nick does not fail to bring new and salient detail to a story as well as a huge dose of common senses so we are excited to see this new title.

Also, thanks again to Nick for the use of his photos in this post 🙂

4 Comments leave one →
  1. 787cape permalink
    19 October 2016 12:59

    “SP” stands for “Special Performance,” not “Special Purpose.”

    • travelforaircraft permalink
      19 October 2016 13:37

      Thanks. I’ll change that.

  2. 19 October 2016 15:49

    I once flew in a 747SP…of Iran Air, from JFK to LHR. It was at the height of the ‘DC-10 grounding crisis’, and capacity on the Transatlantic routes was very very sparse (we had flown into Newark on a World Airways DC-10, just before the DC-10 was grounded). We were extremely lucky to get seats back to the UK, but the flight was a very rough one (the crew were eager to get back to Tehran to participate in the Revolution, it seemed!) I, on the other hand, was eager to get out at Heathrow – as the next stop was Tehran, in the throes of the Revolution!!

    • travelforaircraft permalink
      20 October 2016 06:49

      Now that is an experience!

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