"The brief we got [to create the Batmobile Tumbler] was for a vehicle that could do 60mph; we thought we'd give them a little bit more than that so we boosted it to 100mph, as we obviously wanted it to do some amazing things."
There's very little that doesn't sound incredible when talking to John Holmes, senior special effects technician on the team involved in creating the most recent iteration of the Batmobile. The Tumbler is one of the most iconic designs in cinematic history – no mean feat when it was replacing the original 'kitsch' Batmobile.
But what you don't know is that while you were seeing the Tumbler being thrown around Gotham City on the big screen, it was actually designed, built and mostly used in Britain, thanks to the 20-strong team working on the project.
It was conceived by Nathan Crowley and his team originally, but the difficulty in the project came from taking the Styrofoam model from a concept to actual reality – and required a lot of ingenuity when it came to the actual mechanics of making the Batmobile, according to Holmes:
"It's actually a bespoke vehicle, there's nothing on this that's already been seen [on another car] – people say 'oh, it's based on a Hummer, it's based on a Mercedes', but no, it's all bespoke. It is a Batmobile, there's no other made vehicle part on it."
That's true of most of the unit – although the tyres were off-the-shelf to a degree… if you can call super swamp tyres on the rear and racing boots on the front such a thing.
Even these were customised, with Holmes telling us that the team had to shave down the tyres to make sure the handling of the Tumbler was exact.
In terms of raw grunt, it's no surprise that the engine was a 5.7-litre Chevrolet unit, 350 cubic inches pumping out 400bhp to allow the Batmobile to roar around. Although there wasn't just the one car – there were multiple versions to allow for various scene set-ups.
That's not to say that each didn't drive, but each had a purpose. For instance, the interior of the 'race ready' Tumblers was just a steel frame with very little visibility; for filming a static, more luxurious interior was created to allow for cameras.
In fact, there were a number of versions that came together to create the cinematic effect of the new Batmobile. A smaller, 20 per cent size Tumbler was used to accurately film the flying scenes, but the jumps and speeds were all possible with the full-size version.
As Holmes tells us, the request was for "a car that could jump off a six foot ramp, travel 60 feet, land and drive off without cutting; [Director Christopher] Nolan didn't want another car needed, he wanted to use the one that does the jump."
The jet-engined version of the Tumbler was also real: multiple propane tanks were bolted into the vehicle to give the real jet effect, rather than adding it in post-processing.
Making the insane real
But how hard was it to take the Batmobile concept through to reality?
"[The Tumbler] has a very odd suspension," admitted Holmes. "It's a tubular space frame chassis, with a 15mm section, with the front suspension being the trickiest part.
"The wheels actually go inward, where normally they would go outwards; in the same way the stub axles, instead of going outwards, they go inwards.
"That was a little bit tricky to create, so we had to make it all very beefy. If you think that the anti-roll bar on your car is very thin, the one on [the Tumbler] is like a girder."
But it wasn't just the bespoke suspension that caused problems: the braking of such a vehicle needed to allow it to turn around the tight corners of the city scene, something most stunt cars aren't great at doing.
Holmes said the Batmobile team needed to come up with some ingenious ways to make this happen:
"The brakes were somewhat… reluctant… to work, shall we say. The brief was for the Tumbler to be able to do handbrake turns and stuff like that, so we rigged up a separate hydraulic brake so you could lock the rears up."
Given that five full-size Tumblers were made, the speed with which they were created was impressive.
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"The feeling was one of 'let's go" when making these things," said Holmes. "We made a working prototype in six weeks, and a further six months to build five cars.
"We had a bodywork department, working on the glass fibre stuff, but our first prototype was a shell, with no bodywork on it.
"We made five cars in total, although we've only got four left. We blew one up, there's one left in the States and the other three are in Britain. We made one black car, and the rest are all camouflage."
"One of our guys, Jim, designed the chassis, but the rest of the team took other elements: one guy worked on the suspension, one on the axle. We actually broke it several times during production to make sure it didn't break on the day… but then again we had five cars so there was always a backup!"
Although Holmes proudly states that none of the cars failed, broke or even refused to start, he did say they pushed it a little harder in testing to find the limits in other ways.
"We had to test the Tumblers to destruction, so we did blow an engine up; while doing a jump we broke the handling, so we beefed that up until finally we got a machine that would do what Nolan wanted it to do."
The great thing about the Batmobile project is that the finished products are actually driveable – although visibility is poor. The cars have even been used as pace cars in US NASCAR racing – and Holmes admitted that he and his team still try out the vehicles when they get the chance.
"You can't see much out of it when you're driving at speed, but when we're going to events with these cars I normally drive and Jim directs me.
"But on the track [the Tumbler] is very predictable, allowing you to oversteer in the wet for instance, so you can get the back to step out and it comes back in just fine. It's really good fun to test - I managed 90mph down the straight, but it will do over 100mph if you have the space."
Given that each of these Batmobiles costs nearly £200,000 to produce, and the whole project cost millions overall, it's impressive that the desire to create real, working cars was maintained through undoubted pressure to save money and use CGI.
But once you've heard the ear-splitting roar of the Tumbler engine, you can't help but feel more than a little glad that the Batmobile made it into real life… just make sure you're not standing too close to the back of it.