We HAVE the technology

I, Science is pleased to introduce our newest addition to the blog team: Rosemary Peters. Rosemary will be guiding us through the plausability of all those ‘that’s-so-cool-bit-it’s-obviously-impossible-or-is-it?’ Sci Fi film moments. We can’t wait…

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helicarrier

My mission: Stay awake as long as possible. My tool: A 9-inch TV screen. My team: The Avengers.

On my 10-hour flight back to the UK to start my second term at Imperial, The Avengers movie was my third in a trio of action films I watched to try to stay awake as part of my mission to avoid jet lag. I had seen the movie in theatres when it came out last May, but watching it a second time enabled me to move past the action and actually think about the technology in the film.

Before we begin, let me say the flick was an awesome one. It is full of some of my favourite comic book heroes and hilarious comments from the snarky Tony Stark. If you haven’t seen it yet, watch it.

But as much as I loved the movie, I just couldn’t buy into the feasibility of the S.H.I.E.L.D Helicarrier (pictured). Seeing the massive carrier lift out of the water and turn into an aircraft was entertaining, but there is no way it could ever fly…

Or is there?

Let’s individually look at the two devices that make up the Helicarrier: a helicopter and an aircraft carrier.

Warning: I am using some pretty heavy-handed estimations and simplifications, because unfortunately the Helicarrier does not exist and neither Marvel nor Walt Disney was kind enough to provide us with any dimensions for this beast.

First things first, we need to establish the weight of the Helicarrier. I compared a screenshot of the Helicarrier to aircraft carriers of various nations to see if I could estimate the weight of The Avengers’ kick-ass mode of transportation. I concluded that the Helicarrier’s runway is nearly equivalent to that of the USS Nimitz. Therefore, the Helicarrier would weigh about 100,000 tons (or 9.1 x 107 kg). It would also be about 77m wide and 333m long.

destroyer

USS Nimitz

I also needed to figure out the weight of those turbofans used to lift the Helicarrier from the ocean. This gets a little shakier estimation-wise, because there simply isn’t a device about the size of a Helicarrier that has turbofans that I can compare it to. Instead, I compared it to Rolls Royce Trent turbofan engines, which are found on many commercial planes. After some mathematical manipulation and taking into account that there are four turbofans on the Helicarrier, I would say that the Helicarrier is roughly 108 kg total.

That means this craft would have to have on board a power source powerful enough to lift the 108 kg Helicarrier off the ocean as well as the energy to fly it for extended periods of time!

Let’s go to the most simplistic case for the Helicarrier: hovering.

At a mass of 108 kg, the Helicarrier has a gravitational force of 9.8 x 108 N keeping it on the surface. It would need to at least match this force in order to hover, and it would do this by having the blades of the turbofans spinning ‘crazy fast’. In fact, the blades would be spinning so fast that they would thrust out air moving downward at a speed of about 640m/s – that’s faster than the speed of sound. If the Helicarrier were hovering above your home, you would literally be knocked down by the craft’s air thrust before you’d even hear it coming.

Taking the velocity of the air, the area of the turbofans and the density of the air into consideration, I roughly calculated that the power S.H.I.E.L.D. would need just to keep the Helicarrier hovering is approximately 3.2 x 108 kW.

So what? Well, the elite, most advanced, I-am-not-sure-they-have-already-been-built nuclear power stations at maximum are only able to produce about 1.5 x 106 kW. So if the Helicarrier is actually going to be able to hover, it would definitely need more than one nuclear power station on board. A lot more, in fact. Over 200 more.

All in all, we may have the technology to build the Helicarrier, but using the amount of power needed to make it fly would be ridiculous. At least until we figure out cold fusion.

2 thoughts on “We HAVE the technology

  1. If nuclear reactors require massive amounts of water for cooling, if the Helicarrier is in the air, how would it acquire the needed water?

  2. > If nuclear reactors require massive amounts of water for cooling, if the Helicarrier is in the air, how would it acquire the needed water?

    Actually, I think the estimate could be downgraded a bit, and I think cooling is probably irrelevant. Why?

    Our biggest single reactors are 1.5 x 10^6 kW, sure – but that’s kWe. The reactors actually generate more like 4.5 x 10^6 kW of heat. Assuming that these turbines are jet turbines – driven more by heat than motors – we only need around 71 of them to hover.

    I’d be surprised, though, if the efficiency was better than 33% at LWR temperatures, though (e.g., 300C). So we’re likely back up to that 200 reactors figure.

    Meanwhile, the reactor is, by definition, being cooled by the air it’s passing through the turbines. We normally don’t do this on the ground because the flow rate of air necessary to air-cool low temperature reactors like we have now is high enough to provide a significant thrust. You can see how that’s an issue on the ground. It’s not exactly what one would call a problem in this application, though.

    The Aircraft Reactor Experiment and subsequent Molten Salt Reactor Experiment operated at higher temperatures – between 600C and 900C. At these temperatures, you can get around 40% efficiency – bringing the need down to ~178 max-power reactors.

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