What’s the best way to know what happens when an F-4 Phantom jet hits a concrete wall at 800 km/h?
Of course, get an F-4 Phantom Jet and smash it against a concrete wall!
Crashing a jet into a nuclear reactor
While it seems like a bizarre waste of a good plane, the 1988 experiment had a clear purpose. The government was concerned about the strength of the material, as it was used to construct nuclear reactor facilities. Checking whether a plane would survive crashing into the sides could help protect against a nuclear meltdown — the Soviet Union’s Chernobyl disaster was only two years prior.
Sandia National Laboratories did just that, as they struck an F-4 Phantom aircraft to impact test an essentially rigid, reinforced concrete wall. The aircraft was accelerated using a 600m (2000ft) long rocket sled until it reached a constant velocity of 215 m/sec (480mph).
And just in case you were wondering, the F-4 Phantom was fully operational, only the main gears and wings were partially removed. Instead, transport mechanisms and sleds are used to guide the aircraft during thrust without allowing it to take off.
The target was a reinforced concrete block 7m (23ft) in length and breath while having a thickness of 3.66m (12ft). The concrete block weighed about 470 tons (42 (1000kips), which was approximately 25 times the weight of the incoming F4 Phantom aircraft.
Miraculously, the concrete block survived almost completely unscathed. The test aimed to investigate the impact of a jet onto a piece of reinforced concrete measuring 12 feet (3.66 meters) thick. The aircraft of choice is a fully functional F-4 Phantom. It was loaded onto a rocket sled track and was accelerated up to 480 mph, or about 770 km/h where it slammed directly into a slab of reinforced concrete. The jet did not contain jet fuel but was rather filled with water. The test did not look to examine the damage of an ensuing fire.
The jet was traveling so fast upon impact; it shatterd into millions of tiny pieces. The only section which remained intact was the small section of the wing which missed the target entirely. While the video is mesmerizing in its magnificent deconstruction, the resulting damage to the concrete block is surprisingly minuscule.
The damage left behind the nuclear reactor was merely a scratch
The maximum scar depth was 2.36 inches (60 mm) at a maximum. The structural damage sustained was merely a scratch. However, the force launched the block back nearl 6 ft (1.82 m). Nevertheless, behind the impact remained an incredibly high-energy impact. As the engine exploded into tiny fragments, it experienced an acceleration force of more than 700 times the force of Earth’s gravity.
Although the experiment looks incredibly brutal, it demonstrates that reinforced concrete can easily prevent a jet from causing serious damage to a nuclear reactor. While not all factors are considered during testing, it is important to note that government officials take many other safety precautions to ensure reactor safety and people in the country.