Episode 157: President’s Challenge

Air Date: December 8, 2010

President Obama appeared in this episode and challenged the MythBusters to revisit this controversial myth. (It was previously tested in Ancient Death Ray and Archimedes’ Death Ray and was busted both times.)

An army of 500 people holding mirrors can focus enough of the sun’s light to set a wooden ship on fire.

busted

Recalling their experience with previous experiments, Adam and Jamie knew that it would be extremely difficult to coordinate 500 people in focusing their mirrors on to a single spot. They set about trying to construct aiming systems to assist the shield bearers. While Jamie’s efforts with a gunsight system proved unsuccessful, Adam found that stretching a net across the front of the mirrors provided a usable visual guide for aiming the beams. After a test in the workshop with 12 pepole holding mirrors proved the feasibility of this method, 500 double-sided mirrors were delivered and the crew covered one side of each with bronze Mylar film to represent the Greek mirrors, leaving the other side a modern mirror finish.

In the full-scale test, 500 high school students stood in for the Greek soldiers trying to set a boat’s sails on fire, using first the bronze and then the modern mirrors. Both of these efforts failed, as did a third trial in which the boat was pulled close enough to the shore for Jamie (representing an invading captain on the boat) to throw tennis balls and hit the students. Though Adam and Jamie declared the myth busted, Jamie noted that the reflections from the mirrors were extremely distracting and had blinded him temporarily, and that this may have been Archimedes’ true intent in recommending their use in warfare.

A strong enough punch, directed down onto the hood of a moving SUV, can cause it to somersault into the air. (Based on a scene from the film Hellboy)

busted

The Build Team first did some tests to determine the amount of force needed on the hood in order to get the SUV’s front end to touch the ground. They found that a total of 5,000 pounds was required, so Tory built a giant fist from a steel cylinder, to be dropped from a crane to give that much force on impact. The first few tests revealed problems with positioning and timing of the drop to hit the hood; after they fine-tuned the system, they scored a solid hit but failed to flip the SUV.

Reverting to small-scale testing with a toy SUV, the team experimented with combinations of fist weight, vehicle speed, and center of gravity, but still could not get a flip. They declared the myth busted at this point, then attached a long lever to a full-sized SUV’s roof in order to move the impact force away from the front axle, which served as the fulcrum for the car after impact. Even with this modification, the rear end only lifted 45 degrees into the air and the car did not somersault forward.

34 Comments

  1. faiz says:

    Dear Mythbusters,
    I think that Mr Savage and Mr Hyneman should conduct the experiment in a bigger scale or maybe use the real archimedes death ray size mirror.
    Regards,faiz(12 yrs old)From Singapore

  2. Dilshod says:

    Hello! Here you can see Big Solar Furnace Tashkent, Uzbekistan).
    http://www.pr.uz/nashe-vse/5596?print

    And Odeillo-Font-Romeau Solar Furnace in France (t= 3,500 °C (6,330 °F))
    http://en.wikipedia.org/wiki/Solar_furnace

    I think their energy enough to conflagrate ship.

  3. Danny McMullan says:

    I think that the testing is flawed in that shields are curved, not flat. A curved mirror would provide greater magnifacation of the sun and greater heat. I have looked at greek and roman sheilds and they are all curved like a (. Also it is hotter in the mediteranian than in the bay area.

  4. Sleepy E says:

    you’re assuming that the curve would provide a focal point at the correct distance which is unlikely to be the case

  5. Ben says:

    The hammered bronze mylar was a good touch but I like the idea of curved surfaces also.
    Great focus over a measured distance like the length of a spear or staff or something readily available seems a likely variable for plausibility.
    Imagine if every one of the thousands of soldiers on a beach were to focus his shield at his platoon leader who in turn directed his at a point above so that only the general is aiming any kind of laser.
    Also How “period” would a pirate style colapsable spyglass be?
    Could we incorporate that into the last bit as a general to have been carrying?

  6. nicholas says:

    will you pleas pleas poot thies on air .tack a bag and put sealeam and tie it and tack some oal and poor it away frome the bag and light the end of the oil and light it and see what hapends ok by.

  7. Dennis Barneveld says:

    They should have drilled a smal hole trough the double mirrors. Aim the mirror like described in “The SAS survival guide”. It warns you not to use such mirror to signal an SOS to a plain because you wil be sussesful and resque missions might be started. If this would have been done aiming at the black circle the result would have been “busted” I really really , read my lips, think.

  8. john says:

    Why so complicated. Jamie himself said he believes that the simple answer was to blind the enemy. Imagine a wooden ship caulked with tar, tarred ropes, dry sails, the crew blinded by reflected sunlight and a hundred or more flaming arrows. Survivors if any blame the light and the Greeks play mind games about secret weapons.

  9. Joe says:

    I have watched all of these with frustration. Everyone is so struck with tunnel vision, why hasn’t anyone used a Fresnel Lens? These deliver 2000 degrees and wood instantly bursts into flame copper melts in a few seconds and steel in around a minute is red hot. If you have the sun to your back it is easy, if the sun is to the front you might have to use a mirror to redirect the light but the lens is what is doing the work.

    • Mia says:

      Probably because the myth is the mirrors reflecting the light directly. Not the light into a lense.

  10. mylene says:

    hey! guys sorry for my english,but i’m from quebec!! i really enjoy youre show but i juste want to let you know then i watch your show all the time ,and i thing, i found a another way to try the myth about the veil of the ship… i don’tknow if you call it like that but i thing then you should try the parabolic glass… i’m pretty sure then you could have better results with this kind of glass to make this ship on fire with the sun. i know this is a better way to concentrate the sun in 1 place!! i don’t know if you can understand what i mean… but i hope so!! if not just give me some news and i’ll be right there for you guys!! tank you for you’re patient!! i love you guys!!

  11. peter heiss says:

    Glad to see I’m not the only one who has picked up on the basic flaw in the mythbusters sheild assumption! i.e. when did you ever see a shield from any age that was flat. Most shields were iether a curved ‘u’ type shape, which would focus into a line, or a parabolic shape which would focus into a point. Now I’ve personally seen a parabolic mirror light up a piece of timber in under about 15 seconds on a clowdy day. the only thing you would need as ‘sleepy E’ says is a focal point that is the right distance. get one that is about 100 meters or so, (easy in the days of slave labor) and multiply that by even 100 shields and I guarantee that you would have ignition.

  12. Jeff Schulte says:

    Hi Guys, this is about the Hell boy super punch. Unfortunately, the experiment was flawed in that both the steel fist and the 5000lb concrete block got in the way preventing the car from flipping. Have a look at the slow motion videos and you’ll see what I mean. Hellboy didn’t have that problem as the car somersaulted over the top of him. I believe you should revisit this test with a different approach where there is nothing in the way to prevent the flip! I have a test in mind which may help so please don’t hesitate to contact me if you’re interested.

    Cheers
    Jeff

  13. ZeninWolf says:

    Scale is not the issue. At a certain point the number of ‘soldiers’ or ‘shields’ used in the experiment becomes ridiculous. But the myth has yet to be properly tested. Ancient ships, being made of wood, were not completely waterproof because it was impossible to lock the wood together and make a perfect seal. Sailors would repeatedly tar the decks of their ship in order to fill these imperfections in the ship’s hull. A proper test of this myth would consist simply of a number of planks of wood treated coated with a variety of historically accurate sealants to see which, if any, are flammable enough to ignite by means of a reasonably sized mirror.

  14. Tom says:

    I’m curious about the actual text where the original “Death Ray” is described. Could you post either it or a link to it?

  15. Sanek says:

    Hi! I think that you do not take into account the fact that the mirrors were concave

  16. Thorbjørn Holst says:

    Hi folks, nice show.
    Just saw episode 157 her in Norway.
    …about HellBoys super punch…. seriously,
    you can not make a fool of HellBoy like that.
    The punch you guys performed is missing the fact that you can not let the fist move along togther with the car. Like HellBoy you have to stay stil. The fist punching down is flipping the cars trunk up, but also has to act as a pivot point that the car can spinn around up in the air.
    Like my son sugested: guide the fist on a wire fixed to the ground, blocking it to move along with the car. That will take to wieres, one on each side and the fist attached to a beam running from wire to wire guided down like a quliotine. Or a trap-like devise bolted to the ground, punching the front down on impact (make it look like HellBoy….)

    It is this hinge effect redirecting the cars velosity that your attempt is missing. The cructial point then, is to avoie car to get stuck in the qiliotine-/fist-/hinge-device.

    We just wait for the next attempt – dont let us or HellBoy down. Meanwhile we look forward to the next episode, what ever it brings.

    Thanks for the show.

  17. David Freitas says:

    This myth buster myth busting was wrong. It can be done.
    See the proof by this team:
    http://www.youtube.com/watch?v=a9qk1l0LjEs

  18. Dave Hayward says:

    Hi Guy’s
    Here in New Zealand my son and I love your show. In episode 157 about the Hellboy car flip, I wounder if a fixed angled post would flip the car as Hellboy just stand still and drives the car down.
    kind regards
    Dave.

  19. Blaine says:

    Regarding the Hellboy experiment: A downward punch on the radiator cap of a vehicle sufficient to cause it to flip surely would provide enough opposite-reaction force to propel Hellboy into orbit (if he doesn’t collide with the flying vehicle).

  20. Asela de Silva says:

    Hi Guys,

    I’m a big fan of your show.
    I agree with Dave Heyward on Hellboy car flip, The punch has a force of slowing down the car from front as well as pushing it to the ground.
    It definitely cannot be 90 degrees.
    You’ve already got an close angle from your last attempt. Hope you guys get to re-visit this again.

    MythBusters rock!
    Thank you guys, keep up the nice work :)
    Cheers!
    Asel.

    • Asela de Silva says:

      One more thing guys, Hellboy punch the car and and let go his hand. In your test, the weight is still on the car.

      Cheers!
      Asel.

  21. barry says:

    Archimedes Death Ray:
    could atmospheric temperature and moisture content hamper the test … maybe the team should go to an area which is higher in temperature and very less moisture content or dry air …

  22. Mac says:

    Joe, fresnel lenses were invented in the late 1700s-early 1800s… a tad late for the ancient greeks to have been using them to set ships on fire.

    • Jennifer says:

      Exactly what I’m trying to say! Jesus!

  23. Leighton says:

    I believe the Hellboy experiment was done incorrectly if you watch Hellboys punch it hits the car on the top lip of the car, at the front, in a forward and down direction not straight down on the bonnet, also in the last part of the experiment the 5000 pound weight hit straight over the bonnet. I think you need to do it again guys.

  24. Mike says:

    The important issue is aiming the mirrors! If the mirrors had a small hole and the rear surface was reflective, the mirrors are easily aimed. There are WWII movies showing how this is done. The mirrors used on the show would have been perfect for this, as the rear side actually was reflective. BTW, use flat mirrors. The focal length is an issue, and at much of a distance the parabola would look flat!

  25. Joshua A. Weber says:

    If it were to be moving fast enough it would flip at the right moment of impact, but it would take a lot of force to do it.

  26. Dave says:

    First I want to say that i love the show and would never say these guys did anything wrong, but this one brought a question to my mind that has got me curious. I work in wood refinishing and repair, and for centuries back still to today pine pitch was used to fix all sorts of wooden projects. Boats were known to in some cases be lined both inside and out. It was used to repair holes or anything that needed caulking in general back then. With a melting temp of 77 degrees and an ignition temp far lower than the sail would this be a prefered target. If not set ablaze it should weaken the joints and holes. I am just curious and would like to know what the Mythbusters think.

  27. Pat reeves says:

    I totally agree with comments above re the Hellboy experiment. I think there were two elements to what caused the car to flip in the movie; the downwards motion of the punch on the bonnet PLUS the fact that the punch would have served as an immovable lever that might have allowed the vehicle to flip.

    So, in my view the experiment was totally flawed. You only need to see footage of rally cars hitting tree stumps or grounding the front of the car in dirt to see that if the front of a car is brought to halt by an immovable object it can flip over…

  28. Stephen says:

    I wonder why President Obama made the Mythbusters do Archimedes death ray again?

  29. Stefano Troncossi says:

    I agree with all the people who says that the Hellboy myth is wrong, you dont consider the axial opposed vector of force that is working trough friction between the foots of Hellboy and the floor. Put an articulation to the punch, otherway is like hellboy it was stand on rollers. (sorry my bad english)

  30. Mark says:

    Archimedes death ray works fine. In italy in the 90′s they made it right. heading towards a replica of a Roman ship (with the same materials that were used at the time) 24 polished metal panels in material similar to those used by sirausani as shields. After a few seconds the wood began to emit smoke and then burn.

  31. AMartin says:

    Calling for Archimedes Death ray 4.0 – I’ve never been able to find anything wrong with your mythbusting till now. I completely agree with those who say you need to use convex mirrors. Greek soldiers would have curved shields. If you started small scale and determined what curvature of shield has a focal point of about 200 yards (or however far away you think the Roman fleet would have been out in the bay), you could then take it back to large scale with the President-recommended 500 soldiers. You should also try the aiming strategy of making a hole in the middle of the shield to aim better. Maybe combined with Adam’s mesh aiming system it would make aiming easier. As you can see, there are lots of comments all saying the same thing. You still haven’t fully tested this myth. We await Archimedes Death Ray 4.0.

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