August 15, 2005

Science Takes the Summer Box Office by ‘Stealth’

Ah, the summer blockbuster, a time-honored tradition of deafening explosions, eye-popping special effects… and science?

Yes, you read that right; this summer, studio execs have been hedging their bets on action flicks with a healthy dose of sci-fi thrown in. First, we were given War of the Worlds, whose alien invaders were made ultimately susceptible to humble Earth bacteria; then came The Island, a surprisingly thought-provoking look at cloning humans as spare parts. Now, we can add Stealth, the latest from director Rob Cohen (XXX, The Fast and the Furious), to the mix.

The true star of Stealth is not any of its human actors, but rather the futuristic plane its plot centers around. EDI (“Eddie”) is a prototype Uninhabited Combat Aerial Vehicle, or UCAV, being piloted by the US Navy — in other words, he’s to be a replacement for human fighter pilots in particularly risky missions. Although he sounds (both literally and figuratively) eeriely similar to 2001′s HAL, his technical specifications are actually quite grounded in reality.

In fact, the real-life Navy has been looking into the construction and deployment of UAVs for both combat and surveillance since the 1960s. 11 different models have been developed over the course of various programs, and 3 have entered actual production. And in the decade between 1985 and 1994, UAVs logged over 10,000 operational flight hours.

In particular, the Pioneer UAV highlights the effectiveness of such vehicles, with its great contributions to the success of Operation Desert Storm. Six of these planes flew in over 300 combat missions, their AI systems aiding in target selection, detection of enemy gunfire, and damage assessment. There was even one incident where Iraqi soldiers surrendered to a lone UAV; they knew that despite the lack of weaponry on the plane itself, they were surely being targeted by far-off battleships that had just been tipped off to their location.

Currently, you’ll be more likely to see UAVs like the Pioneer silently gathering intelligence instead of kicking ass and taking names like on the silver screen, but a squadron of machines like EDI is not out of the realm of possibility.

EDI’s brain isn’t the only thing of note about him, though. He’s also equipped with a Supersonic Combustion Ramjet, or “scramjet,” that can propel him to speeds up to 15 times that of sound. The basic premise for these propulsion systems is to eliminate the liquid oxygen used in typical rockets, which allows crafts to be either smaller or carry more cargo. Replacing the liquid oxygen is air taken in from the surrounding atmosphere; the air is passed through a constricted tube where it is compressed, used to combust liquid fuel, and vented at a higher speed than it entered at. There are few or no moving parts involved in this process; however, since the scramjet requires supersonic speeds to operate, some other propulsion system is also needed to accelerate to such speeds. Options include a booster rocket or a combination with a traditional jet engine; the SR-71 Blackbird, which incorporates basic ramjet that takes in air at subsonic instead of supersonic speeds, is a prime example of the latter.

The operational requirements limit the scramjet’s use in low-altitude aircraft, so it likely won’t replace our current jumbo jets. However, it remains an extremely viable option for high-altitude travel and space exploration. A scramjet-powered plane, be it for passengers, cargo, or combat, could potentionally traverse the Earth via its upper atmosphere in 90 minutes, once issues such as the safety of high-g loads are addressed. And though much work on it is classifed, we do know that NASA has looking into building practical spacecraft based on this design for the past decade. Incorporating a scramjet stage into launch procedures would decrease fuel requirements and make space travel cheaper; one prototype design, the X-43A, is currently undergoing ground testing.

As a movie, Stealth is is nothing particularly spectacular. It’s a decent two hours worth of summer entertainment, free of gaping plot holes and complete with fetching eye candy and fiery explosions, though not one that the Academy would pay mind to. A few moments are devoted to talk of the implications of a military comprised totally of machines, though not nearly enough to satisfy policy buffs. However, what’s remarkable about this movie is the degree of accuracy in its science fiction; though it’s not perfect, Stealth comes the closest of any movie this season to depicting technology that we may see in the skies both now and in the very near future. Here’s hoping for more stars like EDI in the future.

Comments (4) | 5:25 pm |


  1. [...] LJ’s got the skinny on scramjets, space travel, and the technology that we’ve got today, and how long it might be before we see a real-world EDI. Funny, though, there doesn’t seem to be much in the way of actual stealth in Stealth. Go figure. [...]

    Pingback by » The science of Stealth — September 19, 2005 @ 6:55 pm

  2. I somehow think the US has already got an EDI or something like it. Their last stealth fighter was not known by the world until it was shot down in Yugoslavia, 10 years after it began serving.

    Comment by Matt — January 30, 2006 @ 6:49 am

  3. I couldn’t understand why the planes like the F-37 have to be fast. If it is engaged in a dogfight, then it only needs mach 2.

    Comment by Ben — September 25, 2007 @ 8:48 am

  4. I do not see how this page can claim Stealth is “free of gaping plot holes”. Plot holes and technical errors abound.

    The aircraft supposed accelerates from mach 1 to mach 2 in 2 seconds and from mach 1 to mach 4 in 7 seconds. A peak acceleration of 165 m/s/s (16.8 g) requiring over 23000 kN thrust, being a mere 2100 times more powerful than an F-15 powerplant and using somewhere in the order of 11 GW, or 4 times as much power as produced by all the hydroelectric dams in Greece or about 2/5 of all the power produced by Canada’s second largest power company. All this from one little plane.

    The planes fly from wherever they are launched to Tajikistan. Jessica Biel’s plane then flies over 2400 nautical miles to North Korea in only a few minutes without refuelling . This is despite having already flown into combat and not carrying any external fuel tanks. Combat radius is more likely to be around 600 NM for a total range of 1200 NM. Let’s ignore that she flies at least 2100 NM over hostile Chinese airspace.

    The other guy’s plane flies over 3000 NM from Russia to Alaska. Aside from refuelling issues, most of this is over Russian airspace and it is only challenged once by 3 Su-27 fighters. A big deal is made out of it approaching Russian airspace from Tajikistan, not mentioning that he had to fly over Kyrgyzstan and/or Uzbekistan then Kazakhstan for at least 700 NM before reaching Russia.

    That the plane does refuel from a flying airship says that a giant USA gasbag is stationed over one of these afore mentioned countries former USSR countries.

    The EDI refuels itself by blowing the nozzle off a hose, yet the pump valve is located at the other end of the hose closest to the fuel tank so fuel would not have escaped. Tankers refuel aircraft when flying in a straight line, not constant matching of rate of turn when circling so no ring of fire would have existed.

    In the opening scene of the film, two ground launched sidewinder missiles are fired at Biel’s plane. They travel at mach 2.5. Given that they barely caught up to her over their 17 second flight time (travelling 14 km which is, thank God, inside their 18 km range) she must have been travelling only slightly slower than mach 2.5 or somewhere around 800 m/s all the while performing combat manoeuvres for a ground attack while engaged in nap of the earth flying.

    The EDI plane also spends it’s time flying in the troposphere so any claims that it could traverse the earth in 90 minutes are spurious in relation to the film, especially as a substantial amount of time is spent at a height of 15 feet.

    Somehow, the EDI plane, having flown from Tajikistan to Russia to Alaska then flies a further at least 2700 NM from Alaska to North Korea without having refuelled since the airship. At least 5700 NM and it had the intent to travel back to friendly airspace. An insanely huge distance. All these flights take inordinately short times.

    An apparently burgeoning romantic relationship between the two main lieutenants is wrongly claimed to be inappropriate. Fraternisation occurs between officers and enlisted, not between officers and other officers.

    Comment by Stealth plot holes — January 13, 2008 @ 10:01 pm

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