Like a lot of these types of videos, I want them to be true.
However, my brain immediately starts screaming the there is something wrong here. And yes, the first thought I had was how precise those pieces of cardboard needed to be, mainly because of weight. also how hitting the center for the axle had to be absolutely precise to guarantee balance. (Precision I don't think you can get from cardboard.)

As far as the wight of lifting each of those flaps back up, I wouldn't think that the swinging flap would have enough energy to keep it going. Visually I see it happening in the video but I immediately question it. Again I want it to be true - think of the possibilities - but the skeptic in me tells me something else is at play here, even if I can't see it.

In reply to this comment by dannym3141:
Hi, don't know if you're satisfied about this video yet but;

If you accept purely gravitational motion, then the kinetic energy gained from lowering any individual card segment must be paid back in full when you raise it back up on the other side. Now factor in resistances (the pen cartridge axle, air resistance, and it's making noise which is a form of energy) and you quickly realise that for the whole thing to spin there must be an external application of energy.

Even consider how accurately he would have had to cut all those cardboard pieces to make them the exact same weight so that heavier ones didn't cause the contraption to slow. I can attest that i've made these types of things as a kid, as soon as you start building one you start to feel why it can't work; you can kinda feel the principle of conservation of energy yourself.

I have references if you need :
In reply to this comment by Sagemind:
Comments on YouTube claim that this is somehow fake - that there is a fan somehow blowing on it.

I see no fan in the one direction they show and his body blocks it from any wind on the other side while he is filming so..

Any takers...?

Hi, don't know if you're satisfied about this video yet but;

If you accept purely gravitational motion, then the kinetic energy gained from lowering any individual card segment must be paid back in full when you raise it back up on the other side. Now factor in resistances (the pen cartridge axle, air resistance, and it's making noise which is a form of energy) and you quickly realise that for the whole thing to spin there must be an external application of energy.

Even consider how accurately he would have had to cut all those cardboard pieces to make them the exact same weight so that heavier ones didn't cause the contraption to slow. I can attest that i've made these types of things as a kid, as soon as you start building one you start to feel why it can't work; you can kinda feel the principle of conservation of energy yourself.

I have references if you need
In reply to this comment by Sagemind:
Comments on YouTube claim that this is somehow fake - that there is a fan somehow blowing on it.

I see no fan in the one direction they show and his body blocks it from any wind on the other side while he is filming so..

Any takers...?

>> ^FishBulb:

Even if it can spin under it's own power (without fans or string, etc) try hooking it up to something else to extract work out of it. I think you'll find it slowing to a halt fairly quickly.


If it can work under it's own power then it's perpetual motion. You don't need to be able to extract power from it (although in a system like this power is being extracted all the time, heat from the axle, sound energy from the whole thing).

As for where the cheat is, if there's a ceiling fan in the room that would keep it going. To everyone trying to work out if it's fake, it is. There's no debate there. There's a hundred different ways this could be faked.

ETA: Just watch the lower hanging card strips when it's getting started.

That was a pretty forgiving shot of Axl.

nah, man. he was always fairly articulate...>> ^Payback:

Remarkably well spoken for someone I've always thought was mute.

>> ^maestro156:

So maths ...
according to this website: http://www.csgnetwork.com/stopdistinfo.html, a vehicle slows at roughly 15 feet per second per second, which means in the 0.2 seconds that it takes the bike rider to discover that the truck is braking, the speed of the 90km/h truck would have reduced to about 86-87km/h
which means while the bike will travel 5m in those 0.2 seconds, the truck will travel about 4.8m, putting him 20cm closer to the truck.
Once again, too close for my comfort, but I don't think I'd call it stupid. Just risky, like base jumping and wingsuits.


Adding to the maths frivolities there are some factors that need to be considered....

1) It is a 5 axle truck (they usually have 18 wheels)
2) We don't know if the truck is loaded or not
3) The friction coefficient of bicycle tyres is about 0.75
4) The friction coefficient of truck tyres is about 0.8

If the truck is fully loaded the stopping distance is going to be very far - probably well farther than the bicycle.
If the truck is empty the stopping distance will be a lot less than the bicycle (18 wheels at a higher friction coefficient = stopping on a figurative dime).
So unless we know more information, the calculations are guess work with a very wide margin of error.

I tried this out on some local speed bumps once when the company gave me a hire car for the weekend so I wasn't bothered about ruining my own suspension. It works. I got the car up to about 30mph and the suspension compressed while the chassis stayed level. It's definitely the smoothest way across them.>> ^sadicious:

An ambulance driver once told me "They are called 'speed bumps', not 'slow bumps'. Go fast over them." I tried it out with my normal-ish car and it went smoother then if I was going slow. The axle isn't elevated long enough for the shocks to push the frame up. Since the frame isn't up, it doesn't go crashing down. This only really goes bad if range of shock compression or the bottom of the frame to the ground is less then the height of the speed bump.
I'm not sure how that would apply to having 5-6 of them all in a row like that. Maybe most people in this area figured out the above technique and this is the way around it.

*edit* Oooops. I meant to reply in the thread rather than on your profile. Clicked the wrong link. *edit*

I tried this out on some local speed bumps once when the company gave me a hire car for the weekend so I wasn't bothered about ruining my own suspension. It works. I got the car up to about 30mph and the suspension compressed while the chassis stayed level. It's definitely the smoothest way across them.
In reply to this comment by sadicious:
An ambulance driver once told me "They are called 'speed bumps', not 'slow bumps'. Go fast over them." I tried it out with my normal-ish car and it went smoother then if I was going slow. The axle isn't elevated long enough for the shocks to push the frame up. Since the frame isn't up, it doesn't go crashing down. This only really goes bad if range of shock compression or the bottom of the frame to the ground is less then the height of the speed bump.

I'm not sure how that would apply to having 5-6 of them all in a row like that. Maybe most people in this area figured out the above technique and this is the way around it.

An ambulance driver once told me "They are called 'speed bumps', not 'slow bumps'. Go fast over them." I tried it out with my normal-ish car and it went smoother then if I was going slow. The axle isn't elevated long enough for the shocks to push the frame up. Since the frame isn't up, it doesn't go crashing down. This only really goes bad if range of shock compression or the bottom of the frame to the ground is less then the height of the speed bump.

I'm not sure how that would apply to having 5-6 of them all in a row like that. Maybe most people in this area figured out the above technique and this is the way around it.

>> ^cosmovitelli:

Looks like it has a turning circle of about half a mile.
Also what is Margaret Thatcher going on about with 'you are not relying on rotating the wheel to drive forward'?


What she's saying is that with a car, the wheels are turned via the axle, and to push the car forwards they must grip on the road and push the car, otherwise they just spin on the spot.

With these, the internal part is effectively turning the cabin bit against the inside of the wheel, and the wheel then moves forward or backwards just based on the weight of the internal portion pulling it around.

This contraption, while cool, is entirely impractical:

* How do you stop it? As in, how would you park this on a hill such that it wouldn't roll away?
* How do you see straight ahead?
* How do you make sure no-one inside it puts their hands into the spinning wheel of death?
* It's got waaay more size (especially height, good luck with multi-storey car parks) for less cabin space than a normal car
* The afore-mentioned poor turning circle.

Trying to sell this as actually being a practical vehicle is disingenuous.

>> ^dag:

Nothing like a little axle grease and burlap to give popcorn flavour.


Well you know the old saying: "That which doesn't kill you give you cancer"

Comment hidden because you are ignoring dag. (show it anyway)

Nothing like a little axle grease and burlap to give popcorn flavour.

>> ^Crosswords:

Its always sad to see an aged rock start trying to sing their hits well past their prime. Just as their body gets old and worn out so do their larynx. They tend to lose much of their range and vocal precision/endurance. I always cringe when I see some 80's 70s 60s rock start on the stage belting out their classics, it just doesn't work, you can't fight aging.


there are exceptions though, Sting still sings quite well, as well as Bruce Dickinson, but I don't think either of them ever smoked for example (which I'm sure is probably the #1 reason why a lot of singers lose their voice)

>> ^Lann:

sad


We really need a *sad channel.

Even in a straight line, I think the hollow wheels are what seriously limit its speed because the inability to drive at the axle produces a critical mechanical disadvantage. There is no room for any gears that are larger than the wheels, so the engine must always run many RPMs faster than the outer edge of the tires. It's why, on a bicycle, the gears mounted to the peddles are always larger than the gears mounted on the axle of the back tire. So, yeah, it's basically a kinetic sculpture--but still a really cool one!

>> ^robbersdog49:

What's limiting it's speed is a complete inability to lean more than a few degrees. Great piece of art, but it looks completely un-useable.