h a l f b a k e r yGuitar Hero: 4'33"
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“Yo Dad, whazzup? You wouldn’t believe what I got to ride with Heather – promise not to tell anybody - a triple-barreled uhh yada yada hovermobile! … Oh Heather, she’s the daughter of that Segway guy. It’s his prototype we tested. … Yeah, I met her at a rave the other night. Anyway, her father, the Segway
dude, has made this personal hover transporter – he’s looking for a cool, you know, Latin name for it – and it floats on three parabolas that each pneumatically bounce and catch a ball. … Well, they do it really fast, you know dribble them, and the reaction force keeps the machine up. It’s kinda like the recoil of a gun or that the handles of a jackhammer never have direct contact with the ground. … Yeah, it only works on pretty even ground and was sorta noisy, though the balls did bounce in cadence. But the ride was AWE-some. You sit and lean or twist if you want to go faster or brake or turn, and one or more parabolas angle slightly and dribble balls in the opposite direction. … Oh, I almost forgot, Heather and I got married in Reno last night. … Dad? … Hello?”
(??) Yup - here's the idea I linked to Marcus before...
http://www.halfbake...lancan_20Basketball
[thumbwax, Oct 05 2004, last modified Oct 17 2004]
[link]
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You'd need BIG BALLS to drive that! |
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You could call it the "Marcus Mobile" - as in Marcus Haynes, world's fastest and greatest dribbler/ball handler. Saw him play when I was a kid. In fact, I linked before- |
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I have no idea what you're on about, Johnnie boy. + |
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Trirotalaris: "Three heeled"? |
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Never mind what I thought when I saw "ball dribbling"... |
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I wanna see a team game played with these. |
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Would be like riding a jackhammer. Which sounds fun for at least a few seconds until I pass out. + from me. |
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Just because you *can* submit an idea doesn't mean you should. Don't you think, FJ, that you could maybe lay off spamming your crappy ideas all over the halfbakery? |
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I'm kinda a sucker for new forms of
transportation. + |
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Avoid mud holes at all costs. |
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[TJ & BN] Hmm, criticized by someone who quotes a psychopath and another with a racist moniker. I seem to have inherited UB’s bane of collecting school’s-out-losers like persistent leeches. JEFF, if you can’t stand my almost daily contribution, don’t read it or filter me out or produce something better since you’ve obviously proven you can. |
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Balancing between cute and gross, often trying to be humorous and always attempting to present something original and thought-provoking, I do my best to and sometimes succeed in delivering well-received ideas. I dislike personal attacks on any baker and seldom participate myself. I find your comments unfair and disrespectful. |
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By the title I thought Tom Wolfe had joined the bakery. |
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[TJ] if this //crappy// then how come it has several
croissants? |
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getting back to the idea, i don't think it's physically possible. |
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also, how does it take off? |
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That's okay John. I'll be happy to take care of the dirty bit on your behalf. |
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BunNazi, crawl back under whatever rock you came out of, and take Jeff with you. |
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They're just jealous, jealous, jealous. |
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...and unwise enough to flame a .5B regular. TJ, BN, FarmerJohn didn't invite you to the bakery, show some respect - and have some decent ideas - before you tell him you've decided to change how the bakery works just to suit yourself. |
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[xclamp and maybe DrBob] I’m glad you asked. The three heavy balls sit at the top inside of the three parabolas pointing downwards like rocket nozzles. Thrust is produced when the balls are blown down by compressed air. The reaction force is complemented by the impact of each ball returning from the ground. The parabola shape is to better catch and center the ball for the next chuck. Halfbaked to be sure, but with enough power and high velocity dribble, I believe it could raise itself from the ground. |
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The polyorchid levitator? |
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Like the idea John but cannot picturee it - I don't understand what you mean by parabola (sure I know what a parabola is, in terms of it is a curve decribed by an f(x) = nx^2 which will always reflect vertical paralell waves (or streams of bouncing balls) to the same point, as in radio telescope), but do not understand exactly how this relates to the balls.
Are these parabola shaped nozzles we're talking about? can someone link to a picture? |
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P.S. The Jeff - it's got a lot of croissants for a crappy idea don't you think?
And by the way, what gave you the right to act is if the HB is your domain all of a sudden? I've never even heard of you..... |
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Nice idea. However, I think it is not parabolas that you want. As goff points out, the characteristic of a parabola is that it reflects to the focus all incident parallel rays, ie those rays originating at a point at range infinity. What your farmermobile needs is a curve that reflects to the focus all rays originating at a second focus, at range less than infinity. The first focus is your ball catcher/chucker; the second focus is the point where the ball impacts the ground. With this curve the machine will be able to compensate for bumps in the ground.
Does anyone know what this curve is called? I have a sneaking suspicion it may simply be an elliptical section. |
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[goff] Yes, think nozzles, but as [spacemoggy] points out, not paraboloidal. |
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Why stop at three bouncing balls? |
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Come to think of it, what you've got is really a macro-quantized hovercraft. |
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[goff], [swimr]: It's got a lot of buns because people are easily amused by junk (cf "Survivor", NASCAR, pro-wrestling, Bud Lite, Deepak Chopra). Apart from the first 100 or so "best" entries, it becomes clear that there's often little correlation between the number of buns and the quality of an idea. |
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Look at the "best" links: they're amazing. The coffee cup watermark, for example, is brilliant and is exactly the sort of thing that shows what's right about hb. |
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It's concise, straightforward, and well-written. It's plausible, yet at the same time highly improbable that it would ever be turned into a viable commercial product. It manages to be genius yet trivial. I defy you to read the idea and not laugh at its wonderful absurdity. |
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Contrast this with [FarmerJohn]'s idea. It's couched in a dopey dialogue that's poorly written. Is that supposed to be funny? The idea is bland; essentially it boils down to "weird levitating craft that make a dribbling noise." Yawn. It's not funny, it's not inspiring, it's just dumb. |
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Too much of hb is getting to be a lame contest to see how many ideas one can pump out. Focus on the quality, people, not the quantity. |
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And finally, [FarmerJohn] what psychopath was I quoting? There's only two sentences in my reply. As I think about it now, I seem to recall Tom Servo once remarking about a Roger Corman movie, "Just because you can edit something doesn't mean you should." Maybe that was my inspiration. Is Tom Servo a psychopath? |
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[TheJeff] - I believe FJ was referencing your Silence of the Lambs quote on your user page. As for me, I come to the HB to entertain my brain, which this idea does. I find it terribly creative, and could care less if it is plausible or not, as it is not presented in a serious manner. |
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If you do not find this site to your liking, you are free to leave. The HB is the kind of place that it is because of the people here. Regulars like FJ have had (and hopefully will continue to have) more of an effect on that than you or I. It is a bit disrespectful to have been around here for only a couple of months and start trying to impose your idea of what the HB should be upon those who have helped shape it. |
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I agree that there are probably too many crap ideas on here, but I certainly wouldn’t throw this one into that bag. |
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Hey I like this idea. No it will not make it to mass production, but it could work. The balls are basicly a projectile being used as thrust in the primary action with a second push after rebound. With my limited understanding of the laws of physics this seems possable. The limiting factor is the amount of force initially used to propel the ball(s) down.
If this became a reality you would have factors like balance and equalizing the thrust accross the surface of the device.
In answer to thejeff, it may not be plausible, but neither is the unicycle, pogo stick, hover craft, segway (a moped is much less expensive and practicle), or a number of other devices used every day. |
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(- on the thread for flaming, though. :P Can't we just ignore the trolls?) |
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[TheJeff] Yes, I referred to the words of ‘Buffalo Bill’ who kidnapped size fourteen women, kept them in a hole in his basement and then made a suit for himself out of their skin, because he wanted to be a woman. I should hope that you can relax, take the bakery half seriously and realize that most of us are doing our best, and that not everyone laughs at or is interested in or feels challenged by the same ideas. |
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[half] Yes in writing //to go faster or brake or turn, and one or more parabolas angle slightly and dribble balls in the opposite direction// I didn’t omit those details. I thought of the problems you mentioned and realized that the balls could only be shot at a *slight* angle to return to the same nozzles, and that when they did they would impart a horizontal force diminishing the original directional thrust. |
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[q2cannonfodder] Mr. Kamen did say something about pneumatic pixies. |
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[absterge] I plead self defense. |
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As [Gabe] Said, "avoid mudholes.." Also, when the balls hit, you would need to make sure it is Completely Level. No rocks in the way also, when a Ball hits a rock, the ball goes in a differnt direction. Neat Idea though. DC |
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I agree with [Loris] that this is a discretized hovercraft. Maybe if the balls formed a clock in some way... |
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This is neat...it's a rocket that recovers the mass it expells...anyways a few more thoughts: In order to move forward, you could send the balls back at an angle adding back spin so they return closer to the catcher.
Also, maybe the balls should be tethered? |
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[gabe] like those little rubber balls tethered to the
paddle? hehe, those are awesome |
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Just some thoughts:
to move it will need to spin the balls. If you just bounce them at an angle and then catch them, the impulse you gain from firing it will be cancelled completely by the impulse from reflecting it back to the firer. You need to put spin on the ball, so you can fire it backwards and it comes back along roughly the same path. This could be done with an arrangement like that used in sports training ball guns: two rotating cylinders fire the ball. If one is moving faster than the other, it will impart spin.
The point of the parabolas ([FJ] please correct me on this if I'm misrepresenting your invention) is to allow for the ball not returning exactly to the catching/firing mechanism. Just like a satellite dish reflects all the rays that hit it onto a single point (i.e. the focus), so [FJ]'s parabolic dishes will bounce the balls towards the catching mechanism even when they come back slightly off-target. I picture it as being like three upside down dishes on the base of the vehicle, with the catching mechanism being at the centre of each. |
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"//Can this be done?// What kind of a question is that to be asking in the HB?"
You might regret saying that when the "faster than light custard drive" gets posted... Any minute now! |
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mike you forgot the ninjas... |
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1400m/s/s that is 142g acceleration, having said that would your calculation work better treating the balls as springs? |
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"mike you forgot the ninjas..."
Well they pilot it of course! |
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[absterge] My goodness! Have you been away in a time machine or something? |
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the balls could be attached by elastic - rather lessening the purity of the idea but perhaps making it easier for them to return to the right position |
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How about instead of using pneumatic pumps for propelling the balls, use balls containing piezo-electric material? When they reach the craft, they get whacked full of electricity, causing them to expand and bounce back to earth again. |
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142Gs?! Hahahaha, that's insane, so I'm finally commiting my croissant. Well done, folks. |
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[goff], indeed, we share some similarities in longevity and shy intensity. And I am more or less back, I suppose. |
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[absterge], What was the name of your band? |
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Well, it was Evidence (at weareevidence.com; apparently someone with too much time on his hands has cracked the site now, that's just lovely. The password has gotta be simple, nobody's gonna hack our little site, this host is cheaper, blah, blah, blah. So now I get to say "I told you so!", and they *still* don't believe me! damn it!), but the band went on hiatus, the permanent kind. It was a peaceful split, due some other circumstances outside of our control, but it was on its way anyway. (That was the long answer) |
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Here is my analysis:
There are several factors affecting the performance of this device. Basically this is a momentum problem. |
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The craft is supports itself by the impulse of the ball firing down and the impulse of the ball returning. Obviously the rebound impulse will be somewhat less than the intial one.
Impulse= Force*Time or dM*dV
If you average the Impulse over the period of the bouncing ball you get average thrust, which must be equal to the craft's weight since it's not accelerating upward.
Now here's the fun part. I want my hover thingy to play an A (440 Hz). I also want it to hover at 0.5 meters. I'll assume a rebound ratio of 0.8. |
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The initial Velocity is then Frequency*HoverHeight*(1+ReboundRatio)/ReboundRatio= 440Hz*0.5m*1.8/0.8=495m/s |
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The impulse imparted to craft each cycle is Impulse=(1+ReboundRatio)*BallMass*InitialVelocity |
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The average force acting on the craft is
Force = Impulse*Frequency =(1+ReboundRatio)*BallMass*InitialVelocity*Frequency |
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Since the Force is equal to the weight of craft, which I'll call 100kgf, we can solver for BallMass:
BallMass=CraftWeight/{(1+ReboundRatio)*InitialVelocity*Frequency} |
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Plugging in numbers we get a BallMass of ~2.501gram. |
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So to hover 100kg at 0.5 meters in the key of A, you need only 2.5 grams of balls, shot at 495 m/s, which is only slightly supersonic...This idea is sounding better and better! Just imagine getting blasted by sonic booms at A440. You can adjust frequency by varying ball weight, craft weight or hover height. |
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More realistic numbers:
to hover 100kg at 0.5 meter and 60Hz with 0.8 rebound ratio requires ball velocity of 67.5m/s and total mass of 135 grams. This, I beleive is roughly equivalent to a very high speed paintball gun. This idea would work, and probably without too much effort with off the shelf components. |
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I'd like to see the military version - a
tank-like vehicle hovering 20 metres
above a battlefield with lasers scanning
the terrain below looking for the right
angle to bounce a ball off so that the
ball will be caught and a supply of spare
balls to replace those that explode on
hitting anti-personnel mines. |
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Is it somehow better to have the balls there than just resting the craft on the jets of air? Or are they just decoration? |
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I could understand the purpose of the balls if they were fired mechanically by a throwing arm, but if you have a jet of air bouncing the balls, won't the jet of air alone do it? |
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[gabe] Nice number crunching. |
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[GPL] I would think that you’d miss a lot of the ricochet effect with just the air, much of which disperses to the side - it reminds me of “wing-in-ground effect”. Of course energy will be lost powering the balls, but they make it more halfbaked. |
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My 'girl-friend' likes fuzzy balls,, she call's them
'gelato', she has a very limited verbal range - only this
within reach appears to her mind, AND she want's
balls that goes 'up and down', for some reason,,.. :-) |
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