Picture videos you've seen of a line of explosives being used to cut open large areas of ground for mining etc. Now picture a slower version of those explosions and using a specially constructed "surf board" to ride the wave of dirt as the explosives kick it up.
The trick would be to slow down those explosions so you could ride them in one piece but if you could figure that out it would be quite a rush. The example shown in the link looks like it's pretty close to rideable as is assuming they're not slowing the video down.
I would pay real cash money to see somebody do this and I'd want their autograph if they survived.-- doctorremulac3, Dec 28 2010 Surf's up! http://www.youtube....watch?v=ukPyhbWbnSI [doctorremulac3, Dec 28 2010] //I would pay real cash money to see somebody do this //
Sp. [21Quest]
I suggest good ol' composition 4... Or Ammonium nitrate, depending on how much you want that autograph.-- MikeD, Dec 28 2010 ANFO slurry or a LOX-based Sprengel explosive, maybe even good old BP, would deliver a controlable rate of propagation given a suitable ripple-initiation system.
If you can find a volunteer, [doc], ourselves and [MikeD] will be most gratified if you assign us to the duty of setting this up.
You may need several volunteers, as there will - despite the most careful back-of-a-beermat calculations carried out just before closing time - be an unavoidable amount of triall and error before success is (possibly) (eventually) achieved.
Don't worry about the financing - "Jackass" will buy the rights to this one in a microsecond.-- 8th of 7, Dec 28 2010 I'd want to see it work with Buster from mythbusters first. Maybe that surfing squirrel.
The mass of the stuff you're moving also has to be calculated in pretty carefully since it's velocity is what you need to get just right. Like I said, the explosions in the first part of the video look pretty close though.
Wonder if I could submit this as a myth to Mythbusters.-- doctorremulac3, Dec 28 2010 No, let us have a go first. Please. Pretty please ...-- 8th of 7, Dec 28 2010 I like ya 8, I'd hate to have to call The Borg and tell them you've accidentally been de-assimilated.
Or at least blown to bits.-- doctorremulac3, Dec 28 2010 20 or so cratering charges, each initiated by progressively shorter shock tube branched off a det-cord line main is how I see this working. What say you, by cymergetically enhanced friend? (friends?)-- MikeD, Dec 29 2010 Some of the shots in the linked video look as though they could have used a bit more stemming.
Anyway, picture the volunteer crouched on his board as the first charge is detonated. There's going to be a shock wave which kicks the board upward, together with a thick cloud of dirt.
Is our surfer supposed still to be airborne when the next charge is detonated? If he's not, then what we've invented is not so much surfing as extreme tiddlywinks. If he is, then what force is supposed to be carrying him forwards? Is he simply being blown forwards, on the assumption that each explosion is a little way behind his current position, or is he supposed to be riding his board down the advancing face of the dirt wave? If the latter, then we must imagine a board which is somehow buoyant in a cloud of dirt, and a cloud of dirt which somehow exerts a continuous push on the back end of the board.
The thing is, a wave can be propagated in a medium, whether it's water, dirt, air or luminiferous ether*, without that medium itself moving much in the direction in which the wave is propagated. So, it's not enough for the surf board to behave in the same way as the dirt. It's not enough for the surf board to be jolted up and down. It has to be carried forward. In water surfing, as I understand it (IANASD**), you have gravity pushing straight downward and you have the buoyancy of the board pushing, not straight upward (because the surface of the wave is not horizontal) but at an angle, and you get a resultant force vector pointing roughly towards the beach.
In this proposed dirt-surfing, the board is never really buoyant in the dirt, is it? Board and dirt together get kicked into the air, but thereafter, they are both just falling back under gravity. The next charge gives you a second kick as the shock wave passes through the air under the board, but it is just a discontinuous kick, not a continuous push, right?
So, we're playing tiddlywinks again. Unless I've missed something here.
*just kidding **I am not a surfer dude.-- pertinax, Dec 29 2010 // shock tube branched off a det-cord line main //
A valid approach, certainly. An alternative would be computer sequencing of instantaneous electric dets, which would be less reliable but have greater timing flexibility.
Given the necessity for close proximity of the charges, the issue of sympathetic detonation needs to be considered too, even with highly insensetive secondaries, due to ground conduction of the shock wave.-- 8th of 7, Dec 29 2010 {tugs at [8th]'s sleeve} Still tiddlywinks!-- pertinax, Dec 29 2010 So, no need to reference people skiing down dune faces in the sixties as potential prior art?-- normzone, Dec 30 2010 A one-man Atro-boy Orion project. Cool.If instant acceleration is the problem, perhaps you could sling-shot to a velocity that will not send your boots through your torso when they detonate.-- 2 fries shy of a happy meal, May 06 2012 I put some off-road skateboard wheels on my land luge and rode it down some Arizona back country dirt roads once - Ouch, is my primary memory of that day. You're going to want some tough young test pilots for this experiment.-- normzone, May 06 2012 In my youth I was known to engage in a particularly inadvisable activity known as 'dirt skiing'. It's exactly what it sounds like: downhill skiing without snow. Every now and then a hard turn would trigger a minor rockfall, and then we'd be skiing on a _moving_ hillside without snow, which I think is pretty close to this idea.
I've also skied in the midst of an avalanche. Given the option, I'd take the avalanche--just as terrifying, but softer.-- Alterother, May 06 2012 It's amazing you are still alive. This idea is too dirty for me.-- blissmiss, May 06 2012 All the evidence collected thus far seems to indicate that I am indestructible (though not immune to injury). And there's _a lot_ of evidence. As soon as I finish my physical therapy I'll be out collecting more.-- Alterother, May 06 2012 random, halfbakery