Come Back, SR-71 Blackbird

Belatedly, the US discovers it again needs (something like) the world’s greatest-ever aeroplane
by Gordon Campbell

Once upon a time, the age of surveillance could produce things of great beauty. Beautiful and iconic things for instance, like the SR-71 Blackbird reconnaissance plane. True facts…routinely, the Blackbird would fly faster than a speeding bullet shot from a high powered rifle and could out-run and out climb any missile sent up to knock it down. Not only would it cruise most efficiently at over three times the speed of sound, it could fly sky-high to the edge of space, while leaving behind an almost invisible cross-section radar signature.

Its engines were more powerful than those that drove the Queen Mary passenger liner. Because it went so fast and so high, 85% of its airframe had to be constructed of titanium – sourced by the CIA via a string of fake companies – from the same Soviet Union that the Blackbird was expected to monitor during the Cold War. Even though its earliest variants were designed over 50 years ago, nothing since has been able to match the plane’s range of abilities. Since 1976, it has held the world speed record for air-breathing aircraft.

And, newsflash : the US has finally concluded that it may need to replace the Blackbird, which was prematurely (and controversially) retired in fits and starts, around 20 years ago. As Foreign Policy magazine reports:

In the two decades since the Cold War ended and the SR-71 was retired, the United States has largely relied on satellites to provide overhead spy imagery of the world’s most heavily defended airspace. Now, however, new threats to satellites — think of China’s anti-satellite missiles and cyberweapons — mean that the United States may need to back them up with an air-breathing spy jet. What’s old is new again….Twenty years after the United States retired its fleet of super-sexy spy planes in favor of satellites, it has decided that there is once again a need for such aircraft….

What we’re talking about here – in the face of US Defence Budget constraints and the option of resorting to a new breed of surveillance super-drones – is something called the Joint Aerial Layer Network, a system that (hopefully) would enable the US communications, command and control network to survive a massive cyber attack. Incredibly, the US backup system currently deployed in Afghanistan still uses ancient Canberra jet bombers as one of its core ingredients. The details are here:

The Joint Aerial Layer Network….will consist of aircraft, manned and unmanned (drones can stay aloft much longer than manned aircraft), that provide a backup communications system allowing U.S. forces to pass data in real time should their radio, satellite, or Internet communications be taken out. These aircraft will contain a variety of transmission and relay devices known as “smart nodes,” allowing U.S. forces to pass data to one another. An existing example of the type of system is the Battlefield Airborne Communications Node (BACN} being used now in Afghanistan — it is sometimes hoisted aloft by ancient WB-57 Canberras, one of the world’s first jet bombers, designed just after World War II — where it translates and passes data that troops, aircraft and command centers send from a variety of communications devices that weren’t originally designed to communicate with one another….

But enough about that. We came to praise the SR-71, and its legendary designer Clarence “Kelly” Johnson, head of the almost-as-legendary ‘Skunk Works’ facility at Lockheed. (Besides the Blackbird and the its predecessor, the U-2, Johnson and his team designed the P-38 Lightning, the F-104 Starfighter and the C-130 Hercules.) In 2003, Aviation Week and Space Technology magazine rated Kelly Johnson as the 8th most important individual in the first century of aerospace, just ahead of Neil Armstrong.

Fortunately, the Blackbird’s legion of admirers mean that Youtube offers a lot of excellent documentart footage of the plane. This short 7 minute one is pretty good, and includes a useful explanation of why the Blackbird needed to be re-fuelled in mid air. The plane’s fuel tanks would only seal properly when the plane was airborne and operating at speed – at which point the titanium skin would become heated, stretch and cover the fuel tanks mid-flight. (On the ground, the Blackbird leaked its fuel straight out again, onto the tarmac. It therefore took off while its fuel tanks were nearly dry and would then have to quickly liaise with a flying tanker. ) The corrugated external skin also enabled the plane’s surface to expand vertically and horizontally, at speed-induced heat that would have caused a smooth skin to curl and shred. Most of the plane’s design features were intentional, but some were the serendipitous outcome of trial and error. For example:

The SR-71 featured chines, a pair of sharp edges leading aft from either side of the nose along the fuselage. These were not a feature on the early A-3 design; Dr. Frank Rodgers of the Scientific Engineering Institute, a CIA front organization, had discovered that a cross-section of a sphere had a greatly reduced radar reflection….Aerodynamicists discovered that the chines generated powerful vortices and created additional lift, leading to unexpected aerodynamic performance improvements. The angle of incidence of the delta wings could then be reduced for greater stability and less drag at high speeds; more weight, such as fuel, could be carried to increase range. Landing speeds were also reduced, since the chines’ vortices created turbulent flow over the wings at high angles of attack, making it harder for the wings to stall….

A more extensive documentary, with some great in-air footage can be found here. Of the many books that deal with the Blackbird, Kelly Johnson’s autobiography is pretty hard to beat. The several books by former SR-71 pilot Richard Graham are also chockfull of detail about the plane’s capabilities and handling peculiarities, while also being informative about the political lobbying between 1986 and 1989 ( and later, during the Clinton era) that caused the Blackbird’s early retirement.

Unfortunately, Graham is not a very interesting prose stylist. On that score, the best-written account of test pilotry and the most evocative account of the Right Stuff era of Chuck Yeager and Co. would still have to be Bill Bridgeman’s ghost-written memoir The Lonely Sky, which largely deals with Bridgeman’s experiences of flying the Douglas D558-II Skyrocket (pictured left) which was another beautiful design, and the first plane to exceed Mach 2. But that’s another story.