View Full Version : Take some pigeons and add a cat

7th Mar 2008, 18:04
There's a show on Nat Geographic now that's going to do an experiment involving a plane and a conveyer belt... :E

<runs while he can>

7th Mar 2008, 18:13
Is it one of those special treadmills that can match the "wheelspeed", whatever that is?

I don't get that channel here so please be sure and tell us how it ends. I have a fiver on the airplane taking off, just for starters.

7th Mar 2008, 18:15
It did, easily

7th Mar 2008, 20:08
Take some pigeons and add a cat

And I thought this may be a Hugh Fearnley-Whittingstall cookery tip.

Bugger. :hmm:

7th Mar 2008, 20:52
Was that Mythbusters? I'll see it on the Discovery Channel soon, so... no spoilers, please! :}

7th Mar 2008, 21:16
Funny things, wheels.

With the whole wheel moving forward at 100mph and rolling along the ground, the top of it is doing 200mph, whilst the bottom of it is stationary.


7th Mar 2008, 22:33
Not the Mythbusters, bnt, but another one they have on...

"What if" something-or-other, not that "How do they do that" one

7th Mar 2008, 22:53
With the whole wheel moving forward at 100mph and rolling along the ground, the top of it is doing 200mph, whilst the bottom of it is stationary.So no matter how fast the aircraft goes the conveyor belt always stands still?

7th Mar 2008, 22:56
Ah hells, is that the one with the Hamster on? I was hoping to watch that but the remote was snaffled and some rubbish put on instead, so I retired to my computer!

7th Mar 2008, 22:58
Going to be up for a while, so will see the repeat soon and get back to you.

7th Mar 2008, 23:03
HB sorry, possible misunderstanding there. By "the Hamster" I meant Richard Hammond from Top Gear.

7th Mar 2008, 23:20
I thought that at first Matt, but then beer kicked in and made me think sensibly...

No, they used a model plane

7th Mar 2008, 23:33
Again, possible misunderstanding, I didn't mean actually on the aircraft, I meant is the show being presented by Richard Hammond?

<note to self, write 100 times in best copper plate "I must strive for greater clarity in my online postings">

7th Mar 2008, 23:38
Ahhh... Sorry, suffering from Beer-fade

No, ain't brainiacs

7th Mar 2008, 23:44
Oh, Boris.

When you put it that way it sounds more like a standard UK Chinese Takeaway....

7th Mar 2008, 23:44
Does the Hamster 'rotate'?

7th Mar 2008, 23:46
Only when ya spin his ball

8th Mar 2008, 00:01

Why do they keep going back?

8th Mar 2008, 00:05
Oh, I thought you meant THE Hamster....

Well, he must have lost one in that crash

8th Mar 2008, 09:12
No no no no NOT Brainiacs Hells. Yesterday I saw a trailer for a programme, presented by Richard Hammond, that sounded similar to the one you were describing. :ugh::ugh::ugh:

8th Mar 2008, 11:29
I see... I missed that trailer. Programme is called "what would happen if" and the presenter is some scientist chappie called Dr. Marty Jopson

Seems that Nat Geo over here in Belg´e is different to the one in UK, so could explain why there hath been some confusion (especially since beer has now finally worn off)

8th Mar 2008, 13:18
Can somebody describe the escape tarjectory of the hamster when it gets thrown out of the hamster wheel?

I keep looking but it's too blurry. It looks like it is coming towards the camera in a spiral, but that doesn't make sense.

It should be slung outward in a straight line and out of the camera view.

Maybe somebody can run an experiment using a board with nails sticking out to capture the hamster and prove where it hits.

8th Mar 2008, 13:36
The hamster begins to 'go unstable' when it fails to run as fast as the peripheral speed of the wheel.
The hamster gets 'spun' backwards. If the hamster remained firmly within the confines of the wheel then it would continue to rotate restrained by the outer surface, but it either gets bounced off the back surface or steps out of the open front. At the instant of 'freedom' from the wheel the hamster will have a tangential velocity (if there was a trapdoor that suddenly opened the hamster would be ejected both radially and with a longitudinal (as far as the hamster is concerned) component. With the axial component (created either by bouncing off the back 'wall' or by the hamster moving to escape) will, indeed result in a helical and spiral motion.
The question is, why do hamsters return and repeat the experience?
This might help:- http://www.youtube.com/watch?v=YXRH50fvHWA

8th Mar 2008, 18:56
Well I still don't buy a true spiral theory for an unimpeded ejection. Can anything be done to remove the chance for a bounce or forced change in trajectory and then observe how the hamster behaves?

8th Mar 2008, 20:32
I guess that gravity plays a part in determining the trajectory, but the hamster has angular momentum which could persist until it reaches a solid object. Try swinging one on a string and then cut the string (easiest way is to set light to the string before swinging the hamster around, then when the string burns through . . .

8th Mar 2008, 21:55
I guess that gravity plays a part in determining the trajectory, but the hamster has angular momentum which could persist until it reaches a solid object. Try swinging one on a string and then cut the string (easiest way is to set light to the string before swinging the hamster around, then when the string burns through . . .

What causes the angular momentum to persist once all force except gravity is removed?

After you set fire to the string spinning a hamster, which way will the flame move. Will it run out the string under centrifugal force torwards the hamster or just sit still?

8th Mar 2008, 22:11
I think this should really be attempted in zero gravity, perhaps on the ISS.

Also, if there isn't one already, there needs to be a drink called "The Flaming Hamster". One suggests tequila, tabasco, that red stuff, and perhaps something fizzy. No ice.

Edited to say that by "that red stuff" I mean grenadine. Couldn't remember what it was called just before. And maybe a slice of orange. And another shot of tequila.

8th Mar 2008, 22:24
PSOI - grenadine is derived from the juice of pomegranate (so called because of its resemblance to a hand grenade - or is it otherwise that hand grenades are so-called because of their resemblance to pomegranates?).

According to the OED, the word grenade originated about 1532 from the French name for the pomegranate, la grenade. La grenade also gives us the word grenadine, the name of a kind of fruit syrup, originally made from pomegranates, which is widely used as a cordial and in cocktails.

8th Mar 2008, 22:29
This is excellent news. The drink should go off with quite an explosion.

On reflection, the fizzy stuff should probably be dry gingerale. Substitute cherry cola or even raspberry and lemonade to make a Flaming Gerbil instead, for obvious reasons. :suspect:

10th Mar 2008, 08:04
The hamster should depart the wheel in an arc that is the product of its straight-line path plus its drop due to gravity.

If it is spinning as it exits the wheel, slipping off the edge of the wheel, then it should also rotate around its C.G. I am no expert but hamsters look as if they have an aft C.G. so that I would guess the beast should rotate around its hindquarters to a certain extent, producing the spiral flight path noted in the video, a sort of "tumble".

If someone can come up with a weight and balance report for a hamster perhaps we can get that computer genius to do a simulation for us. Of course we shall need to put one in a tiny wind-tunnel to measure its Cx, not forgetting to specify whether this is the bog standard, smooth-coated Syrian Hamster or perhaps the more aerodynamic Long-tailed Siberian Hamster. Or we put tiny rollerskates on it and ask NeoDud for his opinion on its wheelspeed. Or is there someone here who speaks Hamster?

10th Mar 2008, 10:40
1. After enough flaming cocktails, we will all speak Hamster. And very little else.
2. I still prefer the zero-G scenario.
3. Your aforementioned fellow PPRuNer will alter the rules to suit him/herself anyway, so the rollerskates are probably immaterial. ;)
4. The apparent aft bias re. the hamster's C of G is possibly dependent on the hamster having a full bowel, rather than a full belly. Hamster spin may be dependent on whether the said creature is sh1ts-prioritised or chunder-prioritised. A chunder-prioritised hamster may have a forward bias instead. Hamsters should be psychologically evaluated prior to ejection from the treadmill.
5. If and when I ever make it to Africa with a case of Laphroaig under my arm, you still owe me a fly.

10th Mar 2008, 13:52
OK, I buy some of the theory above, but suggest that it does not all apply.

While I agree about the angular momentum bit about the CG, it really isn't all that important since the hamster is quite flattened against the circumference of the hamster wheel and thus not much difference in momentum.

I do agree that the acceleration due to gravity is probably significant here since the wheel is probably not turning fast enough to become the prime contributor to the trajectory path. Perhaps if we could add an electric motor here to spin the wheel up 10 times faster we could visualize results.

It did occur to me that the most contribution to the tumbling after leaving the wheel was the hamster not letting go all at once. The simple act of clinging with its front paws for only the briefest moment while it's ass is swinging outward would appear to be the cause of its tumbling in flight.

In short, I do believe that an entirely different appearance of flight would be had if we simply rolled the little bugger up into a nice ball, tied him with rubber bands and gave him a ride until he fell out of the wheel.

12th Mar 2008, 06:51
The Siberian Hamster called Basil?

12th Mar 2008, 07:42
To go further with the zero-G issue, shouldn't this experiment be carried out in a vacuum as we are ignoring the effect of air resistance on the hamster's lickle legs stretched out as he tries to stabilise himself in flight and that will obviously affect the trajectory and spin.....

12th Mar 2008, 08:45
Methinks the wee rodent will not be able to run for very long in a vaccuum, unless he has breathing apparatus.

A sodastream bottle, filled with oxygen, and suitable mask and respirator, should suffice.

I would also suggest that provision be made for a cocktail hatch. I wouldn't run on one of those damn things myself, and to expect a hamster to do so, in zero gravity, and a vaccuum, wearing a scuba rig, without a few double Flaming Gerbils on board, is asking a bit much.