Lockheed SR-71 Blackbird

 

Lockheed SR-71 Blackbird – a strategic reconnaissance aircraft is one of the fastest plane ever built. This is definitely worth including in your list of aircraft models. But before we start building it, let’s get to know this important plane a little closer.

Some sources may have different reports about the SR-71 Blackbird’s top speed, but it’s clear that it is 3x faster (Mach number 3 – we will discuss it later) than the speed of sound and can reach 2193 mph (3529.2 km/h), and some sources even show speeds above 2485 mph (4000 km/h). In terms of speed, the SR-71 Blackbird concedes only to the North American X-15, which was able to reach a speed of 4520 mph (7,274 km/h), but its biggest disadvantage is the ability to fly only 280 miles (450,6km). The Blackbird, while slightly slower, is specially designed for long distances and can fly up to 3250 miles or 5230.3 km, making it the world’s fastest long-range reconnaissance aircraft.

 

Mach number

A Mach number is basically a value that denotes the ratio of the speed of an object to the speed of sound. When aircraft flies in the air, the air molecules close to the plane are disturbed and move around the plane. The density of the air remains constant if the aircraft flies through the air at relatively low speed (less than 250 mph or 402 km/h). 

If aircraft speed is higher, a portion of the energy generated by the plane goes into compressing the air around it and locally changing the density of the air.

This compressibility effect alters the amount of resulting force on the aircraft. The fact becomes more important as speed increases.

Near and beyond the speed of sound, about 330 m/s or 760 mph, small disturbances in the flow are transmitted to other locations isentropically or with constant entropy. But a sharp disorder generates a shock wave that affects both the lift and drag of an aircraft.

This speed ratio is significant in avionics, so the aerodynamicists and physicists introduced the parameter Mach number named after Ernst Mach  (1838–1916), an Austrian physicist and philosopher. Mach number M gives us the opportunity to define the flight regime in which compressibility effects vary. 

The table shows 6 flight regimes according to Mach number:

(Picture source: wikipedia.org)

Road to the fastest reconnaissance aircraft in the world

During WW I the first reconnaissance aircraft were developed to photography the enemy in an attempt to gain a tactical advantage. After then WW II saw more sophisticated aircraft and camera technology that played a vital role in the Allied victory. After WW II, the world was left with two ideologically opposed superpowers, the Cold War had begun, and the United States wanted to keep a watchful eye on events behind the Iron Curtain. America was desperate for information about Soviet nuclear stockpiling fighter capability and bomber threat.

In early December 1954, the task of creating the next generation of reconnaissance aircraft was assigned to visionary design at Kelly Johnsons and his elite team from Lockheed’s advanced development program known as the Skunk Works. They produced their first spy plane in 1955 the U2, which was good at their work, but Soviet Union radars were one step further and could recognize these aircraft flying over their territory.  

But the mission was to build a plane that never would be seen to the other sides radars or at least at the lowest possible presence on enemy radar screens. So the idea to build a supersonic aircraft that could fly faster and higher than the U2 was born.

Picture source: National Air and Space Museum

Challenges to building the Lockheed SR-71

One of the biggest problems to make this plane the fastest and highest-flying aircraft in the world was the temperature. At speed where the plane was planned to operate, it encounters the temperature level, which will not be suitable for the traditional aluminum airframe, and the frame would not withstand these extreme conditions. Friction caused by aerodynamic processes and continuously working engines during high-speed flight subjected some parts of the airplane to reach temperatures as high as 565 °C (1,050 °F).  Average surface temperatures ranged from 238 to 327 °C (462 to 622 °F).

In the end, they decided to build the airframe from titanium, which was still light enough for the plane to reach altitudes in excess of 80 000 feet and strong enough to withstand the enormous temperatures made at a speed of Mach 3.

The second challenge was to combine such a plane performance with the new science of stealth. To avoid features that would create strong radar reflections, the plane had taken on a revolutionary shape:

1. The wings were blended into the body 
2. The long surfaces on the forward fuselage were designed to deflect incoming radar waves
3. As with the inward angled twin fins, pointed engine cones, and the nearly flat lower fuselage
4. Also, a special radar-absorbent “plastic” laminates or a composite of phenyl silane, silicone-asbestos, and fiberglass was developed to be incorporated into all the leading edges.

Structural assemblies of SR-71. / Source: NASA Dryden Flight Research Center

The Launch

On December 22, 1964, coated in black radar-absorbent ferrite paint the first SR-71 or the Blackbird as it became known was ready to be tested by test pilot Robert Gilliland. And in 1966, the first SR-71 spy plane was delivered to Beale Air Force Base in California.  By the end of 1967, a total amount of 31 airframes had been delivered to the Air Force,  but on March 21, 1968, the first SR-71 operational sortie flown out of Kadena Air Force Base in Okinawa Japan.

During Blackbird family service lives, 12 were lost in accidents with none lost to enemy action. In 1990 the operational fleet was retired the first time. Then a few aircraft were returned into service but were retired again in 1997. After the Blackbird operational life, NASA also used some of the planes for their research purposes and, in the end, became the last agency that flew the SR-71. Last Blackbird flight was on 9th of the October in the year of 1999.

Some of the airframes were displayed in various museums around the U.S., and one exemplar in the United Kingdom.

Each plane needed two crew members: the pilot and the RSO – the reconnaissance systems officer. The potential crew had to pass a rigorous physical examination, the same as experienced by the astronaut corps. In SR-71 missions, there was no place for error, even the smallest ones you could imagine, so the crew had to be the best of the bests.

Here is a full highlight of the Blackbird family according to information available on Wikipedia:

 

• • • • • • • 3,551 mission sorties flown

• • • • • • • 17,300 total sorties flown

• • • • • • • 11,008 mission flight hours

• • • • • • • 53,490 total flight hours

• • • • • • • 2,752 hours (Mach 3 time) in missions

• • • • • • • 11,675 hours (Mach 3 time) total flown

 

 

Speed and Altitude

The Blackbirds are best known for their speed and altitude performance. The airplanes set numerous records, both official and unofficial. Some of the latter remained unknown to the public for many years. 

According to “Design and Development of the Blackbird: Challenges and Lessons Learned” by Peter W. Merlin:

The maximum design cruise speed for all Blackbird variants was Mach 3.2. According to the SR-71 pilot’s handbook (flight manual), Mach 3.17 was the maximum recommended cruise speed for normal operations. The pilot, however, could increase speed to Mach 3.3 as long as the engine CIT did not exceed 427 °C. Speeds exceeding Mach 3.3 were occasionally recorded during test flights, but these operations put excessive thermal stress on the airframe. Maximum speed was limited by structural temperature restrictions, a part of the flight envelope known as the

“heat barrier.” In July 1976, relatively cool outside air temperatures allowed an Air Force crew to set an official speed record in the SR-71A, accelerating to Mach 3.32  – 3529.2 km/h (2,193 mph). This record stood even after the airplane’s official retirement flight, in March 1990, set a 1,998-mile straight-course speed record between Los Angeles and Washington, D.C., of just over 64 minutes at an average speed of 3450 km/h (2,144 mph). 

The Role

To gather photographic and electronic data of their enemies, flying daily over territories where one mistake could cost the lives of the crew and provoke an international incident.

The SR-71 was a multi-sensor platform, capable of carrying a variety of cameras, radar, and other mission equipment simultaneously in the nose and fuselage bays. Mission equipment for the reconnaissance role included Signals Intelligence sensors,  Capability Reconnaissance (CAPRE) side-looking radar, Optical Bar Camera (OBC), and Advanced Synthetic Aperture Radar System (ASARS).

Why “BlackBird”?

As written on the “Design and Development of the Blackbird: Challenges and Lessons Learned” by Peter W. Merlin. 

“The Blackbirds earned their nickname because they were coated with a high-emissivity black paint for improved heat radiation, thus reducing thermal stresses on the airframe. The first A-12 (the first variant of Blackbird family) flew unpainted. Early models in the A-12 and YF-12A series were subsequently painted black only on the periphery of the airframe where heating was highest: on chines, leading and trailing edges, and rudders. Engineers soon realized it would be advantageous to take advantage of Kirchoff’s law of Radiation that describes how a good heat absorber, such as a black body any extremely dark object), is also an efficient heat emitter. Although convective heating decreases with increasing altitude, heat radiation occurs independently of altitude. 

Therefore, in late 1963, Skunk Works engineers decided to take advantage of the black-body radiation phenomenon by painting the A-12 fleet and subsequent variants entirely black.

A fact sheet about SR-71 Blackbird

1. The SR-71 was a hundred times smaller radar return than an F-14 which is only half as big and developed 10 years later

2. The SR-71 Blackbird did not carry any conventional weapons for self-defense. It relied only on its stealth capabilities and signal jamming sensors

3. The requirements for piloting an SR-71 was the same as the requirements for being an astronaut

4. During its service, a total of 3551 mission sorties were flown and it has more than 1000 surface to air (SAM) missiles fired at it but not none of the SR-71 was shot down during its long service life

5. The Blackbird is most fuel-efficient at speeds higher than Mach 3

6. The SR-71 engines could push the aircraft faster than Mach 3.3 but it was limited to cruising speed of Mach 3.2 to prevent the plane from overheating

7. Its service ceiling height was up to 85 000 feet (26km) 

8. The SR-71 fuel tank was designed with gaps that would expand when in flight, sealing the leaking fuel tanks. 

9. The aircraft was constructed approximately 85% out of titanium which was mainly delivered by the Soviet Union, which in fact was the main target of the spy plane’s missions

10. The Lockheed SR-71 Blackbird made its first flight on December 22, 1964, and still, it holds the official speed record for fastest jet-powered aircraft

 

SR-71 Blackbird scale model 1:72

Every model builder will definitely want to put together such a historical masterpiece. It will certainly be a real pleasure to include it in your scale model arsenal.

So what we are waiting for – let’s look for a 1:72 scale SR-71 Blackbird model manufactured by Revell, which we can buy here on the Amazon website for only $ 23.34. It is plastic, and the completed model is approximately 18 “X10” in size.

Building this model is suitable for ages 12+. You should also take into account that some beginners could have some hard time to build the model because it is described as a Level 4 model which could not be that easy to assemble for someone who doesn’t have such an experience. However, we still encourage you to take this challenge, and step by step put up a hard work on it because it will definitely be worth that.

Features:

• Highly detailed reproduction
• 66 parts in black and clear plastic with raised panel lines
• One-piece cockpit tub with separate instrument panels, seats, and seated pilot and observer figures
• Optional position canopies.
• Waterslide decals with markings for USAF
• Detailed landing gear and wheel wells, exhaust nozzles, and intake cones
• Illustrated assembly instructions
• Includes D-21 reconnaissance drone with ground trolley

 

Quality:

The overall quality of the aircraft model is pretty good. The cockpit interior is nice, but hardly visible when the canopies are closed. Also, the crew member are good; they have correct suits and equipment for this aircraft. The fit of fuselage/wings is reasonably good, but some filling is needed for the small gap. Generally, you have to be aware that almost on any model you are building, there will be smaller or bigger fitting problems that can be resolved with filling putty. It just can’t be manufactured 100% perfect. Some batches of any manufacturer will be better, some not so.

 

! Keep in mind – that according to some other builders’ experience, there could be some production batches with even quite big fitting problems and pretty low overall quality, but it happens very rarely!

 

Don’t forget about the tools! 

The kit has only the model details as itself – there are no tools to build it. So be sure to collect all necessary basic equipment for the building process, for example:

• • Glue
  • Sanding sticks
  • Sprue cutter
  • Budget brushes
  • Hobby knife
  • Tweezers
  • Model cement
  • Filler putty
  • Paint set
  • Masking tape
  • Thinner
  • Scissors
  • and other stuff you are used to

Sometimes questions arise about the glue which to use for getting parts together.

One of the ways you can go for is the Testors cement for plastic models. Some builders use this one, especially those who are new to modeling but also experienced sticks to this one as works very well. On the other hand, some suggestions come from Tamiya lovers, and they use extra thin glue. They say that Tamiya glue dries quickly, is almost odorless, is incredibly strong, and it won’t over-soften the adjacent plastic as sometimes it could happen with Testors cement. But here is another point: some professionals this material softening when gluing, count as an advantage, other as a disadvantage. So there is no correct/incorrect answer.

What about color?

All parts of this model with the exception of the transparent windscreens are made of black plastic. So you can choose to leave the model in that color, or you can repaint it to get a more perfect, finished, and original look for the fuselage. Also, you would want to paint small exterior features like the wheels, wells, and interior.

The complete list of paint colors listed in the directions for this model are: aluminum, flat black, gray, gunmetal, olive drab, orange, red, white, and yellow. For the summary, there is only one thing to add – The SR-71 Blackbird is truly an engineering masterpiece, and it will be a pleasure to have it in your collection, and it will be a great time spent on building such a beautiful aircraft!

Enjoy! 

And take a look at this comprehensive video about this masterpiece of engineering:

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