Updated: Mar 15, 2021
This story begins during the Cold War. This was a very trying time for the world. The 2 most powerful nations in the world, the United States of America and the United Soviet Socialist Republic (or the Soviet Union) were locked in a deadly game of Nuclear Chess. Each side made a move that dared the other side to be more reckless, yet neither fell for the traps, because they were both subject to reality. One miscalculation, one false move, even the most minor, could mean mutual destruction. Because of this, the Cold War was mostly fought in the shadows, the American CIA vs the Soviet KGB. There was a silent arms race that most never knew about, with spy technology advancing faster than ever before.
Money was poured mostly into the spy and nuclear arms race, but one sector stood out. The Air Force of both received lots of money, with the Soviets very interested in surface-to-air missiles and the Americans focusing more on spy planes. Their most used model was the U2, a light and fragile thing. It wasn't a very fast thing, so Soviet surface-to-air missiles with a speed of Mach 2 could destroy them effortlessly. The CIA needed a plane that was able to outrun these, so they ordered Lockheed Martin to build a plane capable of cruising at Mach 3 at the very least at a height of above 60,000 feet. Amazingly, Lockheed Martin was able to meet all those requirements and the result was the single fastest plane ever made by man: The SR-71, A.K.A The Blackbird.
I feel this is the obvious starting point because in order to travel at Mach 3, they need to be ludicrously powerful. But there was a major problem: engines that powerful did not exist or have existed since. They could not invent an engine more powerful than the ones that were available to them. How did they get around this issue of power?
Pure genius. They changed the intakes so that the air was squeezed very tightly upon entering. This high pressure air increased the engines' power output by forcing the turbines to spin much faster, thereby increase power and thrust. Due to the high heat created from these engines, some of the parts were even made of gold, specifically to direct the heat away from those parts.
With the power taken care of, the engineers had to worry about the body, and ran into a major, major problem.
The problem was not the shaping of the wings, Lockheed Martin already knew how the wings should be shaped due to their many fighters up till that point. Their problem was heat. At the speeds the SR-71 was travelling at, the friction from the air at all altitudes was so great, the body panels actually expanded from the heat, potentially damaging the plane if to tightly fitted. So the plane's panels were purposely designed not to fit properly at ground level and temperature. There were specially designed gaps in the body of the plane for the panels to expand into, so there were gaps in the body on the ground. In fact, these gaps were so big that the plane actually leaked fuel when stationary on the ground. At high speeds however, the gaps were closed, and the plane was incredibly streamlined.
There's another interesting story surrounding the body. Titanium was decided as the best material for the plane's body but America had no titanium mines. Guess where they were all located. Yep, in the USSR, talk about irony. This was a major issue, as they had to order quite a bit of titanium for the plane and couldn't let the USSR guess what they were up to. So the CIA created a number of fake companies to buy the titanium for them and then had that secretly shipped to the factory where the SR-71 was being built. However, they had to order way more than initially thought. In order to build the plane, new production methods had to be made and certain tool types could not be used as they could cause corrosion. So over 80% of the titanium they ordered was rejected, as it contained impurities that could destroy the plane. That is how they built the body of the SR-71 Blackbird.
Many people also are a little confused by the colour of the paint. The Blackbird was, obviously black, which made no sense from a scientific perspective. This is because it was well known that black paint actually absorbs a lot of heat, which is not ideal for this sort of plane where excess heat can destroy the plane. The Concorde was even painted white because of this heat issue. But the thing is, black is a good heat absorber and a good heat emitter. It was actually the best colour the plane could have been painted due to the nature of mach speed flight. Plus, it looked cool.
What was its service record?
Very good. It was never shot out of the sky and ran over 17000 reconnaissance missions over enemy territory. Sadly, 1 pilot did die, but overall, the service history of the plane was amazing.
The SR-71 was retired 3 times, each time getting reactivated due to increasing tensions in areas. However, it was retired permanently in 1999, when the USAF decided it was too costly to run the plane constantly and it flew last on October 9th 1999, setting ANOTHER world record in the process. Speaking of which:
World Records held by the Blackbird
The most famous record held by the Blackbird is of course the record for fastest plane ever, at a top speed of Mach 3.5. It also holds many records for the shortest time taken to travel between two places just by travelling between those places for maintenance. Nothing has eclipsed the SR-71 in terms of pure speed. It was unbelievably fast and still is the fastest plane ever created. But why? With our technology today, and our improved understanding of physics, shouldn't we be able to design a plane faster than the Blackbird?
Why there is nothing faster than the SR-71
It was because there wasn't really a need for something like the SR-71. The main issue facing the U2, the most used reconnaissance craft before the Blackbird was its low speed that was insufficient to avoid surface to air missiles. It didn't help that the plane kept on getting spotted on enemy radar either. The SR-71 exists just because at the time, it was not possible to fly and go undetected on enemy radar. But that technology to fly invisibly through a radar zone began to develop and really become available. And this began to render the SR-71 somewhat obsolete as the speed of the craft and the altitude at which it flew meant that getting good information of enemy territory was a little difficult. By having a lower flying, slower plane, more detailed pictures could be taken. So to put it bluntly, the SR-71's greatest feature was also the feature that rendered it obsolete, ironically.
So to be honest, the SR-71 was just not needed with all the advancements in technology. Planes like the Northrop Grumman's B2 Spirit showed why the SR-71 was unnecessary, as it could get more detailed shots of enemy territory while costing less to run. It showed that the SR-71 was not without fault and that it needed to be replaced. Kinda ironically, the very thing that made the SR-71 so unique was also the thing that pushed it out of service if you think about it. I mean, it was flying so high and so fast the pictures of the surface must have been of a lower quality than the ones the B2 provided, so the military would obviously shift spending towards the B2. So really, the success of the B2 and the uniqueness of the SR-71 is really why there is no plane faster than the SR-71 Blackbird. Pretty ironic.
Why is it a legend?
Is it not obvious? I mean, this plane is the only thing humans invented that could go at Mach 3.2 in the atmosphere and unlike the Concorde, which was rather flawed, the SR-71's flaws could largely be ignored because it was a military plane, meaning that it received a lot of maintenance, so the design flaws were addressed quickly. This plane is the absolute peak of human engineering, and it really shows.
This plane is the zenith of human engineering, because after this plane, stealth planes stopped being speed focused and became more, well, stealth oriented. But this plane stood on a unique pedestal and has a well deserved seat in the Hall of Fame.