When German engineers were developing the Tiger II in the 1940s, they probably never thought that a miniature remote control version of their tank would be used to help develop a space craft for the United States 50 years later.
In the 1990s, NASA was stress-testing tires for their Space Shuttle, a very dangerous job that could end with a tire exploding with the force of a few sticks of dynamite. This was too hazardous for staff to approach, so they custom-made an RC drilling vehicle from a Tamiya remote control Tiger tank.
Looking like it was pulled straight out of Small Soldiers, the tank, named the Tire Assault Vehicle, or TAV, would drive up to Space Shuttle tires and drill holes in them to release the pressure inside.
Creating the Tire Assault Vehicle
NASA’s engineering prowess is the stuff of legend. They are famous for extremely tight tolerances, redundancies, and intensely scrutinising and testing systems over and over again. After all, sending anything into space is dangerous and mind-bogglingly expensive affair.
Unlike a tank, which will drive along quite happily with a few wheels missing or some holes in it, spacecraft are very delicate, and even a single error can result in a catastrophe.
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This makes how NASA approached testing the tires for the Space Shuttle orbiter even more hilarious.
The Space Shuttle was a radical departure from previous space vehicles as it was reusable. The orbiter was able to glide back down to Earth, deploy three landing gear legs and land on rubber tires. However as this one was hefty machine designed for extremely high-speed travel, it had a high landing speed and required a long runway.
These high landing speeds meant the Shuttle’s landing gear was subjected to tremendous forces. The tires had to be extremely strong to cope with such forces, and so, like everything else on the Space Shuttle, they were engineering marvels.
The tires were constructed from a bias-ply structure, which is capable of withstanding greater loads and offers better puncture resistance than the radial-ply tyres we have in our cars. They were filled with nitrogen, and pressurised to between 300 psi (21 bar) and 360 psi, (25 bar) depending on the tire.
Of course, these tyres had to be thoroughly tested before being used on an actual Shuttle, and for this NASA employed their CV-990 Landing Systems Research Aircraft (LSRA).
The LSRA was an ex-passenger aircraft converted into a test bed and used at NASA’s Dryden Flight Research Center, Edwards AFB, California.
It was fitted with an additional landing gear strut between the main gear that held a Space Shuttle wheel for testing. The unit would be extended during landings to monitor the performance of these systems.
These tests also aimed to find the failure point of these tires. In typical NASA fashion, they not only like to know how well their systems worked, they also like to know exactly how and when they will fail.
This is where the little Tire Assault Vehicle comes in.
When a tire pressurised to over 300 psi explodes, it releases the equivalent energy of around two and a half sticks of dynamite. These rubber bombs could injure people up to 50 feet away, and damage hearing at up to 100 feet.
During failure tests, some tires would be worn down so much that just one or two plies remained to contain the pressure.
These unpredictable bombs could explode any second and were too dangerous for staff to approach. Edwards AFB had access to a bomb disposal robot, but it was too large to fit under the CV-990, and at $100,000 (in the 1990s!) was a little too expensive to loose to an exploding tire.
So NASA commissioned physicist Dr. David Carrot to create a much cheaper remote method of approaching, inspecting, and drilling into damaged Space Shuttle tires.
Did David develop a super-advanced, futuristic robot assistant made from carbon fibre and titanium? No, he bought a remote control Tiger II, and strapped a drill and camera to it.
David’s vehicle of choice was Tamiya’s 1/16-scale production turret Tiger II – product number 56004, for those who perhaps wanted to recreate this Frankenstein’s monster.
The kit was released in 1981, and today fetches quite a premium second hand. However it was, for the time and size, quite a faithful rendition of a Tiger II. Its lower hull was made of metal, as was its suspension swing arms and some of the running gear.
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Inside, real torsion bars criss-cross the hull floor, electric motors powered a gearbox that drove the tracks, and the whole thing was remotely controlled. It was completed with miniature metal Tiger II track links
David discarded the kit’s plastic upper hull and turret, leaving only the running gear and rear “armor plate” on the lower hull.
He also removed the kit’s original motors and replaced them with Black and Decker drill motors powered by a single 12V battery. The motors sent their power through separate gearboxes so each track could be independently controlled.
Above this, a metal sheet covered the upper hull. There appears to have been some effort made to retain the Tiger’s original shape – whether for practical reasons or simply for fun – as the hull was clearly bent to resemble the real thing. It was even fitted with side skirts that closely match the original.
It received an metal upper glacis too, which, again, replicated the real thing.
The very top of the Tire Assault Vehicle was outfitted with a 3/8-inch DeWalt Drill and a small camera. Initially a hollow drill bit was used to allow the air inside the tire to vent out, but this was later discarded as it wasn’t necessary.
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The transmitter/receiver was supplied from the RC aircraft world, and allowed for control over each track and the drill. The camera relayed its signal wirelessly onto a black and white screen.
In the end, David had created an awesome little machine 18 inches (46 cm) long, 8 inches (20 cm) wide and 12 inches (30 cm) tall that weighed only 20 lbs (9 kg). Perhaps most importantly though, it had cost less than $3,000.
It was named the Tire Assault Vehicle, likely in homage to its tank chassis, and used on 32 missions. When the CV-990 landed, an operator, positioned at a safe distance, would remotely drive the TAV up to the damaged Shuttle wheel and carry out an inspection.
It would then position its drill against the wheel and drill through the tire, releasing the air and turning the tire from a bomb into a very expensive piece of rubber.
Over its career, it drilled into and relieved the pressure out of nine Shuttle tires, four of which where explosion was imminent.
Thanks to its live video feed and strong mobility, the TAV could have been used in other missions where safety is a concern.
Luckily no blast occurred on the TAV’s watch, and it ended its career in one piece.
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Today, it resides at the NASA Armstrong Flight Research Center (FRC).