The Blackbird reconnaissance plane, formerly known as SR-71, has performed over 3,550 reconnaissance missions during its entire service period. It has visited important facilities in many countries, such as missile silos, radar positions, nuclear submarine bases. It can be said that the SR-71 has flown almost all countries considered hostile by the United States since it was commissioned, but has never been shot down. For that alone, a thumbs up must be given, that’s awesome. So about the question of this article title, I will divide it into two parts to explain. The first one talks about how SR-71 was created, and the second one talks about why SR-71 is so powerful.

It is said that in December 1954, the United States officially approved the production of U-2 reconnaissance aircraft.
There are thirty reconnaissance planes in the batch, which are controlled and deployed by the CIA.

The U-2 was really powerful, and the altitude ceiling of 20,000 meters was definitely a huge challenge for the air defense systems of many countries at that time.
U-2 reconnaissance planes all flew to Moscow’s Red Square at that time, and took big photos of the Red Square with high definition.

This is equivalent to a provocation, and the Soviet Union will definitely find a way to knock down the U-2.

As a result, the Soviet Union really used the SA-2 missile to knock down the U-2.

So the President of the United States at the time was asked the military industries to develop a reconnaissance plane that was more powerful than the U-2, not only faster but also flying at a higher altitude.
Since it was an order issued by the president, the plan was quickly arranged. This is the scientific research project code-named “Sunset Project”.

At that time, the project was undertaken by Kelly Johnson of Lockheed Martin.

In the end, according to the requirements, specific mission objectives were formulated. The developed high-altitude reconnaissance aircraft is required to be able to fly at an altitude of 30,000 meters.

And this new reconnaissance aircraft can be refueled in the air, so that it can get the ability to fly around the earth.

In addition to stealth, it should have the ability to travel up to three times the speed of sound.

This requirement was unprecedented at the time, so once the aircraft was to be developed, it meant that from the design of the shape, to the aerodynamic layout, and even the materials and electronic engineering, it would need to be pushed back to the previous experience but still the challenge is not too big.

So it took a year and a half to demonstrate this new type of aircraft, and finally Kelly Johnson submitted a new plan to the US Air Force.

According to the plan given at the time, once this new aircraft came out, it would maintain its technological leadership for at least 30 years, and could not be intercepted or hit by missiles or fighter jets of any country.

Not to mention anything else, the proposed concept of triple the speed of sound means that at that time, the cruising speed of this new aircraft was 60% higher than the limit speed of the best jet fighter in the world. The flight altitude was eight kilometers higher than that of any aircraft at that time, and the overall technical level was a whole generation much more advanced than most advanced Soviet aircrafts.

As soon as the U.S. Air Force got the plan, it immediately agreed to the plan, and at the same time, it also thoughtfully assigned a number A-11 for the verification machine of this new aircraft, nicknamed “ox cart”.

According to the old rules, this plan was finalized, and the American media began to report, saying that the US military developed a new generation of high-altitude reconnaissance aircraft to replace the U-2.

This news was continued for four or five years. When the time came to 1964, the US military unveiled this new high-altitude reconnaissance aircraft.

At this time, this new aircraft has the official model SR-71. At that time, the President of the United States confirmed the incident to reporters at the White House meeting at the White House, and also showed some A-11 models of the verification model.

At that time, what people saw were only photos, and it was also a photo of the verification machine, and the real thing could not be seen at all.

After ten years of secretiveness, it was not until September 1974 that the U.S. military drove a real SR-71 reconnaissance plane to the Farnborough International Khan Expo opened in the United Kingdom, and people saw it. The true face of this legendary aircraft.

In fact, as early as 1952, the A-11 as a verification machine had already come out. At that time, the speed of the A-11 was close to three times the speed of sound.

Then from this verification machine A-11, two models were derived. The first model was an interceptor called YF-12A. The speed of this interceptor exceeded three times the speed of sound.

However, the U.S. military did not produce this YF-12 interceptor. There are two reasons for this. One is that the price is too expensive, and the second is that the biggest enemy of the United States was the Soviet Union at that time, and the U.S. military judged that the Soviet Union could not produce these kinds of interceptors.

So at that time, the US military threw the interceptor aircraft with a speed of more than three times the sound into the trash can without looking at it.

The second type is the SR-17 reconnaissance aircraft, which is very similar to the YF-12.

As for the SR-71 reconnaissance plane, its first flight was in December 1964. After two years of running-in, it began to be equipped with the U.S. Air Force in 1966. At that time, more than 30 were produced in one breath.

There are actually three variants of the SR-71 reconnaissance aircraft. The A-type is commonly referred to as the SR-71 high-altitude reconnaissance aircraft. The B-type is a trainer aircraft, so two were produced. The last C-type was modified from the A-type.

The power of the SR-71 reconnaissance aircraft

The first is the aircraft aerodynamic layout. It can be said that the aerodynamic layout of the SR-71 reconnaissance aircraft is an excellent thing. It is much more complex and advanced than ordinary aircraft.

To know 3 times the speed of sound, this is not to say, it has many difficulties to overcome, the biggest problem is the air resistance problem.

Because the faster the speed, the greater the resistance the air will give.

In order to solve this problem, the Americans made major changes to the aerodynamic layout of the SR-71, designing a large aspect ratio delta wing without tail strips, and a wing-body fusion double vertical tail layout.

These names sound vague and incomprehensible. Simply put, the biggest feature of this layout is that the engine is installed at half the half-wingspan.

Then triple the speed of sound brings not only the air resistance problem, but also the impact of a continuous strong shock wave to the aircraft. If the SR-71 cannot withstand this strong shock wave, it may disintegrate, so at that time, the Americans also carried out special engineering on the nose and fuselage.

It’s really hard to explain how to deal with it. In short, this extremely bad trouble was turned into an advantage, and the strong shock wave was transformed into the extra lift of the SR-71.

In this series of designs, there is also the largest design, that is, the vertical tail above the engine compartment of the SR-71 is a full-motion type, and the vertical tail is inclined fifteen degrees inward.

So what’s the benefit of doing this? First, it can effectively reduce the cross-sectional area of ​​the radar and improve the stealth ability of the aircraft. Second, it is very good to reduce the resistance of the air to the aircraft from the side, so that the SR-71 even encounters bad weather with a side wind speed of up to 65 kilometers per hour, can easily complete the take-off and landing work.

The next great thing is that it is known to be fast and fly high.

The speed of the SR-71 has reached 3.2 times the speed of sound. How fast is this speed?

In other words, the initial speed of a rifle bullet is only eight or nine hundred meters per second, while the SR-71 can fly one thousand and one hundred meters in one second, which means that in the blink of an eye, more than one kilometer will pass.

Then there is the famous missile Sidewinder missile at that time. The speed of this missile can only be 2.5 times the speed of sound. In fact, the flight speed of all air-to-air missiles is two to three times the speed.

This means that when the SR-71 is seen, the missile is launched at the same time to attack, even if the aiming accuracy reaches 100%, the missile will not catch up with the SR-71.

Speaking of this, it is estimated that some military fans will think of the MiG-25. The flight speed of this fighter is more than three times the speed of sound, and it is likely to catch up with the SR-71.

If you just look at the data, this statement is really possible, but in fact, the MiG-25 cannot maintain three times the speed of sound for a long time. Even if the fuel in the tank is completely exhausted, the speed of three times the speed of sound is only for five minutes.

After these five minutes, the engine of the MiG-25 is basically scrapped, and it must be overhauled before it can continue to be used.

What kind of realm is the 30,000-meter flying height of the SR-71?

Let’s put it this way, at this altitude, even the most advanced aircrafts such as F-22, Su-57, F-35, etc, can’t reach this altitude.

And more importantly, there is no surface-to-air missile on the ground that can hit the SR-71 flying at an altitude of 30,000 meters.

How to say? During the entire service period of SR-71, many world firsts have been set, and many of these world firsts have not been broken until now.

For example, from London to New York, the average passenger plane takes about four hours to fly, and the SR-17 can complete it in only two hours.

According to the information, as long as anything happens, SR-17 can fly to any place on earth within six hours.

So the SR-17 can achieve such a fast and high flight height, which is inseparable from its engine.

What about the SR-17’s engine?

The engine used by SR-17 is called J-58, which is specially used by Hewlett-Packard for 2.5 to 3 times the speed of sound.

At that time, when the US military developed the SR-71, it used the J-58 and found that it could not meet the requirements of the SR-71 at all, so an improvement was made to the J-58 later.

The improved J-58 is quite powerful, and the power of a single unit has reached nearly 150,000 kilowatts.

The SR-71 uses two J-58 engines, which is the fundamental reason why the SR-71 can fly more than one kilometer in the blink of an eye.

In other words, once the speed of any object reaches a certain level, it will generate huge heat by friction with the air.

Then the speed of the SR-71 exceeds three times the speed of sound, and after friction with the air, the temperature of the aircraft’s casing can reach 650 degrees Celsius.

What is the concept of this temperature?

The SR-71 is black. Once the plane reaches three times the speed of sound, the body will turn red like a red-hot iron block due to the constant accumulation of heat.

The SR-71 is called the black bird, but it is also correct to call it the red bird.

Okay, let’s go on.

At that time, the materials used in ordinary aircraft were aviation aluminum alloys. Once the temperature of this material reached 150 degrees celsius, the strength of aviation alloy aluminum began to gradually weaken, so once the temperature reached 650 degrees celsius at that time, aviation alloy aluminum basically turned into slag.

To this end, the Americans developed a new type of titanium alloy for SR-71, called B120.

This material can not only withstand the high temperature of 650 degrees, but also can reduce the overall weight by half.

Finally, I have to say about the SR-71’s fuel tank problem.

One of the biggest features of the SR-71 is that if it is parked on the ground, its fuel tank will continue to leak oil, and the fuel will flow out from the gaps in the fuel tank.

Many people don’t understand when they see this. How can such an advanced aircraft still leak oil and can’t be repaired?

Really can’t make it up, because many objects have a characteristic of thermal expansion and contraction, and SR-71 can’t escape this fate.

When the plane reaches three times the speed of sound, the temperature of the casing rises, and the fuselage actually begins to expand.

Then the heat can be conducted, and the fuel tank of the SR-71 will also expand.

At this time, these gaps are of great use. As soon as the fuel tank expands, it occupies the space of the gap, so that the whole of the aircraft has reached a level of tight fitting, and the fuel tank will not leak oil.

And if there are no gaps, this expansion is estimated that the fuel tank will explode, and the consequences will be unimaginable.

In the world, that is, the fuel tank of the SR-71 is like this.

Furthermore, the fuel used by SR-71 is also unusual. This is a fuel called JP-7. Its characteristic is that it is basically solid when the temperature is below 30 degrees celsius, so when it does not enter the combustion chamber of the engine, it can be used as a coolant.

And this kind of fuel occupies two-thirds of the capacity of the SR-71 fuselage and half of the space in the wing, which also allows the SR-71 to carry 3.8 tons of fuel.

Although the SR-71 carries a lot of fuel, it will perform some missions that need to fly tens of thousands of kilometers, and it still needs three to five tankers to deliver fuel to it more than ten times.

So every time the SR-71 flies, the fuel consumption is a terrifying figure.

It is said that every time the SR-71 completes a mission, the various costs add up to 20 million US dollars.

In other words, the SR-71 is definitely a very expensive machine.

After the SR-71 is finished flying, don’t think it’s all right, it still needs maintenance. It is said that it needs 400 hours of maintenance and 650 inspections for one hour of flight.

If the flight time reaches 200 hours, I’m sorry, it will need to remove the engine for an overhaul, and this overhaul will take a month.

In fact, even the day before the flight, there were still a lot of people on the ground circling an SR-71.

Of course, SR-71 flight accidents are also frequent.

So by 1989, the U.S. military had deployed more than 80 reconnaissance satellites in space and retired the SR-71.

However, it was later found that the flexibility of SR-71 is much better than that of satellites. After all, satellites revolve around the earth and are not necessarily in the position of the mission when needed.

So after the SR-71 retired in 1989, when the Gulf ധąɾ broke out, the US military thought of the SR-71 again, and let this guy out again.

At that time, $100 million was allocated and three were restored, but fifty-four KC-135T tankers were used to support the work of these three SR-71s.

Source: https://www.defenceview.in/