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Mythbusters - "Motorcycle Water Ski" 6/5/13

Discussion in 'Now Playing - TV Show Talk' started by DancnDude, Jun 7, 2013.

  1. Jun 7, 2013 #1 of 46

    DancnDude Thrice as nice TCF Club

    Feb 7, 2001
    Madison, WI
    I was not all that excited about this one when the episode started because it just seems like a variation of ones of the myths they've tried before with a car and actually running on water which were both busted easily. But I was pretty shocked that it actually worked :eek:

    It was impressive seeing the stunt driver go over even the shorter parts of the lake but I'm really surprised they let Jamie go for the whole thing...and he went a long ways. That was crazy!
  2. Jun 7, 2013 #2 of 46

    GAViewer Member

    Oct 18, 2007
    But to me Jamie didn't get the answer to his own question. That is was the motorcycle staying on top of the water due to momentum or was the power from the wheel actually extending the time and distance the motorcycle could go?
  3. Jun 7, 2013 #3 of 46

    Hank AC•FTW

    May 31, 2000
    Boston, MA
    So glad you started this thread.

    I was also blown away by the results. I was *sure* that the bike would sink is a few feet, and they would have to go to plan b to find some way to make the myth true (like a plank underneath the water). But wow -- that was an amazing result.

    I'm surprised they didn't go slightly more into the science of it. It looked like on the water, the bike couldn't keep up the same speed, and as it started to slow, the front wheel started to dip causing more drag, and eventually stopping(sinking). If they had more time, I would have like to see them attach a pair of front "skis" to support the front wheel to see how much further they could go on just the rear wheel powering through. Either way, still a surprising result.
  4. Jun 7, 2013 #4 of 46

    Donbadabon Geocacher

    Mar 5, 2002
    Franklin, TN
    I agree.

    I was thinking it was so obvious it would be busted, why would they waste our time with it.

    Couldn't believe it actually worked.

    So it did seem to be the 'skipping rock' effect, since he finally sank. Unless he loses so much speed on the water that his speed isn't fast enough to keep him above water.

    That is something they should've addressed - What was his speed when he hit the water and then what was his speed as he crossed it.
  5. Jun 7, 2013 #5 of 46

    heySkippy oldweakandpathetic

    Jul 2, 2001
    Sarasota, FL
    I also was surprised it worked. The motorcycle clearly can run on the water given sufficient speed, but the rear tire wasn't getting enough traction to maintain that speed, so on the longer run he eventually sank. I'll bet with some mods it could be made to run on the water indefinitely.
  6. Jun 7, 2013 #6 of 46

    phox_mulder I get paid 2watch TV

    Feb 23, 2006
    Salt Lake...
    My first thoughts were:
    The myth was a motorcyclist was on a freeway, doing freeway speeds, when he couldn't make a turn and stayed straight onto the lake.

    A: You wouldn't be riding a dirt bike with knobby tires on a freeway, you'd be on a cruiser or sport bike with road tires, nice and smooth.

    B: I can't believe there are any freeways with a straight shot into a lake, there would have to be barriers, guardrails, something to prevent cars from sliding off.
    Except maybe in a 3rd world country somewhere.

    Then it was no way brand new knobby would tires be able to stay on top of the water.

    Then I was :eek: when it actually did.

    I wanted them to try with a lightweight sport bike with fatter/smoother tires and see what happened.
    You'd have zero traction to keep up speed, but you'd probably get a farther "rock skip" than the knobbies.

  7. Jun 7, 2013 #7 of 46

    john4200 Active Member

    Oct 31, 2009
    For the second question (whether the motorcycle could travel indefinitely over the water), it is merely a question of thrust. Traveling over the water is not greatly different than an airplane traveling through the air. You have thrust to propel the craft forward, and the craft itself needs to use that thrust to deflect enough air (water) downwards to support its weight.

    The motorcycle cannot generate much thrust on the water since it lacks a propeller and the knobs on the wheels are small. Perhaps if something like fins were added to the rear wheel it could obtain enough thrust to keep going. But probably not. Maybe with rear wheel fins plus replacing the front wheel with a ski (so it does not need as much thrust to support its weight) it would be possible for the motorcycle to "fly" the surface of the water indefinitely. Even then I am not sure because the rear wheel would tend to sink unless the fins were somehow shaped and angled to push more water down on the downward stroke than they push up on the upward stroke (which I am not sure is possible). Maybe it would also need an outboard ski attached near the back wheel.

    Jamie and Adam always do a much better job than the other three mythbusters. But even so, I was surprised at how badly the other three did this episode. I would have expected them to at least consult a parachuting expert. A skilled person can survive a faster fall than a "lump" by taking the landing properly, using their legs and body to absorb and deflect some of the landing force. Of course, the criminal might not know how to do that, but they should have at least mentioned the possibility. It also means that the parachute needs to be somewhat stable so that the person has a chance to use their legs to cushion the fall. A parachuting expert could have probably told them what was necessary to survive a faster fall, and could look at the high speed cameras and speed of impact and tell them whether someone could survive that. Just having Buster drop like a lump and hit the ground was a poor substitute for a skilled person landing.
  8. Jun 7, 2013 #8 of 46

    LoadStar LOAD"*",8,1

    Jul 24, 2001
    Milwaukee, WI
    I think they really, really need to finally let Buster go. It's in pieces, half of it doesn't stay together anymore, and looks like hell. I know Buster is iconic to the show, but I think people will get over it. The show has plenty of money, they can afford a new modern crash test dummy.
  9. Jun 7, 2013 #9 of 46

    jeff92k7 Annoyed with trolls

    Jan 18, 2006
    on planet earth
    Aren't they on their third or fourth Buster now? I recall past episodes where they retired one and showed that they just got a new one.
  10. ferrumpneuma

    ferrumpneuma fading fast

    Jun 1, 2006
    I knew it was confirmed. The Nitro Circus guys have done it many times. It is a bike powered ride and not just the momentum/skipping rock effect.
  11. john4200

    john4200 Active Member

    Oct 31, 2009
    If you mean this:


    at about 18 minutes, then it is clearly not working as a powered ride. He has a front ski surrounding the wheel, and the rear wheel looks like it has some small fins, and yet you can clearly see that as he loses his initial momentum he begins to sink and finally cannot continue traveling. He went a long way, but clearly could not continue going indefinitely.
  12. LoadStar

    LoadStar LOAD"*",8,1

    Jul 24, 2001
    Milwaukee, WI
    They've intermittently added in other dummies, but the one that the three were using for the drop test was AFAIK the original Buster.

    A while back, Jaime and Adam made a big production out of making a new Buster that had breakable "bones" made of balsa wood, but very shortly after stopped using it without much fanfare. My guess is that the process to un-do all of the ties to keep replacing "bones" was taking too much production time. More recently, Jaime and Adam have started to use the sim-cadaver for the same purpose. The problem with both is that they didn't have room for instrumentation, like the accelerometer.

    I don't think the show has ever actually gone and gotten a new crash test dummy, at least not that I've ever seen.
  13. ferrumpneuma

    ferrumpneuma fading fast

    Jun 1, 2006
    My mistake. It was a few years ago when I watched that. But I did believe it would be confirmed at the beginning of the Mythbusters episode.:D
  14. DancnDude

    DancnDude Thrice as nice TCF Club

    Feb 7, 2001
    Madison, WI
    Don't forget "Baby Buster" from a few weeks ago ;)
  15. Jonathan_S

    Jonathan_S Active Member

    Oct 23, 2001
    Having seen that trick done on Top Gear with a high powered 4x4 I was guessing that it wouldn't work for a bike unless it was a very rare one with a powered front wheel.

    Without power to the front wheel it can't 'climb' out of the water as well, if it ever sinks enough to slow its rotation it'll just plow in. I'm really surprised how well a rear wheel powered bike did.
  16. john4200

    john4200 Active Member

    Oct 31, 2009
    Do you have a link to that?

    I do not see how a wheel could "climb" out of the water, since a wheel is, you know, round. Whatever water it pushes down on the front of the wheel, it will push up on the rear of the wheel. You don't see a paddlewheel starting to climb out of the water on a paddleboat.

    For no particular reason (it is not relevant to this discussion but it is funny to look at):

  17. Waldorf

    Waldorf Super Duper Member

    Oct 4, 2002
    Phoenix, AZ

    4x4 at 3m20s
    4x4 vs snowmobile at 4m50s
  18. john4200

    john4200 Active Member

    Oct 31, 2009
    Thanks for the link.

    That run looked impressive. But I'm not sure what to make of it. It seemed like he was maintaining at or near his initial speed even near the end of the run, so the 4 wheels with special treads seem to produce a decent amount of thrust. As long as it can keep going fast enough, it can utilize the skimming / skipping effect that the motorcycle in Mythbusters used (but could not maintain sufficient speed).

    But I still wonder how long that 4x4 could have kept going. Maybe it would slow down and sink if it tried to do, say, twice the distance we saw. Too bad they did not discuss how far it could go beyond the 500m they demonstrated (or did they and I missed it?).
  19. MarkofT

    MarkofT ****

    Jul 27, 2001
    The Tall City
    Wheels stay on top of water for 2 reasons. Horizontal momentum that keeps the wheel skipping on the surface, and a powered wheel can climb vertically whenever it starts to get too deep.

    Thus that 4x4 zips along the water as well as it zips along the gravel bank. The motorcycle with the unpowered front wheel can only go as far as a skipping wheels can travel.

    Having already seen those hydrophobic 4x4s before, I knew the bike would be able to run on the water quite a ways.

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