Self-balancing bicycle concept

[Tim McNamara]

In article <[email protected]>, "Tim Cain"
<tim_no1@you_know_what_to_cut_timcain.co.uk> wrote:

> "Tim McNamara" <[email protected]> wrote in message
> news:[email protected]...
> > In article <[email protected]>, "Tim Cain"
> > <tim_no1@you_know_what_to_cut_timcain.co.uk> wrote:
> >
> > > Bikes are stable and self-correcting already.
> >
> > If that was the case, your bike could ride without you. It would coast, riderless, without
> > falling over.
>
> They do.

No, actually, they don't except for a few feet. Wilson's URB is the exception as it can travel
indefinitely on its own, given a long slope. It won't fall over until it is virtually at a stop.

> Try it sometime - a sloping parking lot is your best bet. Point the bike downhill, give it a good
> shove, and off she goes. (Obviously, don't use your Sunday-best Bianchi for this kind of stunt).

Why not use your Sunday-best Bianchi? It's going to fall over, which your post acknowledges
implicitly, because it's *not* stable and self-correcting. If it was capable of coasting long
distances without you on it, it would be so stable that it would be unrideable for any practical
purpose. You woldn't be able to turn a corner.

 

[Jasper Janssen]

On Wed, 18 Jun 2003 11:25:11 -0400, Ron Hardin <[email protected]> wrote:

>There is not the slightest difficulty in minutely and accurately changing the angle of a helicopter
>rotor blade, in spite of its being huge and fast. You may

When you say changing the angle of a rotor blade, do youa ctually mean changing the angle of a rotor
blade (which has absolutely zero to do with gyroscopic effects plus which you do by moving it into
the direction you want it to go), or do you mean changing the angle of the entire rotor?

Jasper

 

[Ron Hardin]

Jasper Janssen wrote:
> >There is not the slightest difficulty in minutely and accurately changing the angle of a
> >helicopter rotor blade, in spite of its being huge and fast. You may
>
> When you say changing the angle of a rotor blade, do youa ctually mean changing the angle of a
> rotor blade (which has absolutely zero to do with gyroscopic effects plus which you do by moving
> it into the direction you want it to go), or do you mean changing the angle of the entire rotor?
>
> Jasper

The entire rotor. You orient it by changing lift 90 degrees away from where you want the effect. If
you want the front blade higher, you add lift 90 degrees away at the forward-going position, and
take away lift 90 degrees past at the backward-going position.
--
Ron Hardin [email protected]

On the internet, nobody knows you're a jerk.

 

[Peter]

Tim McNamara wrote:
> In article <[email protected]>, "Tim Cain"
> <tim_no1@you_know_what_to_cut_timcain.co.uk> wrote:
>
>
>>"Tim McNamara" <[email protected]> wrote in message
>>news:[email protected]...
>>
>>>In article <[email protected]>, "Tim Cain"
>>><tim_no1@you_know_what_to_cut_timcain.co.uk> wrote:
>>>
>>>
>>>>Bikes are stable and self-correcting already.
>>>
>>>If that was the case, your bike could ride without you. It would coast, riderless, without
>>>falling over.
>>
>>They do.
>
>
> No, actually, they don't except for a few feet.

I remember when we performed this experiment as kids. We would ride down the street (one without
parked cars or traffic) and then jump off our bikes. It wasn't uncommon for them to go most of a
city block before finally crashing upon hitting the curb or a tree (if done in an alley).

> Wilson's URB is the exception as it can travel indefinitely on its own, given a long slope. It
> won't fall over until it is virtually at a stop.

The difference with the super-stable URB was that it would over-correct when starting to fall. So it
would start falling one way, turn, and then fall the other way - going back and forth many times. In
contrast our normal bikes would turn in one direction and eventually spiral into a crash as they
slowed down if they didn't hit something first. But they could stay upright for hundreds of feet
even on a level surface.

>>Try it sometime - a sloping parking lot is your best bet. Point the bike downhill, give it a good
>>shove, and off she goes. (Obviously, don't use your Sunday-best Bianchi for this kind of stunt).
>
>
> Why not use your Sunday-best Bianchi? It's going to fall over, which your post acknowledges
> implicitly, because it's *not* stable and self-correcting.

Eventually it'll either hit something or slow down so much that it crashes - that's true of both
normal bikes and the stable URB. In neither case would I want to use one that I didn't want
scratched.

 

[Tim Cain]

"Tim McNamara" <[email protected]> wrote in message
news:[email protected]...
> In article <[email protected]>, "Tim Cain"
> <tim_no1@you_know_what_to_cut_timcain.co.uk> wrote:
>
> > "Tim McNamara" <[email protected]> wrote in message
> > news:[email protected]...
> > > In article <[email protected]>, "Tim Cain"
> > > <tim_no1@you_know_what_to_cut_timcain.co.uk> wrote:
> > >
> > > > Bikes are stable and self-correcting already.
> > >
> > > If that was the case, your bike could ride without you. It would coast, riderless, without
> > > falling over.
> >
> > They do.
>
> No, actually, they don't except for a few feet.

Yes it will. Done it, seen it. Raleigh Grifter, Morrison's car park circa 1978.

> Wilson's URB is the exception as it can travel indefinitely on its own, given a long slope. It
> won't fall over until it is virtually at a stop.
>
> > Try it sometime - a sloping parking lot is your best bet. Point the bike downhill, give it a
> > good shove, and off she goes. (Obviously, don't use your Sunday-best Bianchi for this kind of
> > stunt).
>
> Why not use your Sunday-best Bianchi?

Because:

a) It cost so much that you wouldn't be able to bring yourself to chuck it down a slope with
sufficient abandon.
b) It's likely to have a low trail, hence very little margin for error correction.
c) It's very light, so won't gain or maintain speed very well.
d) It *will* hit a stray shopping trolley (cart to our US cousins), kerb or other obstacle.

>It's going to fall over, which your post acknowledges implicitly, because it's *not* stable and
>self-correcting. If it was capable of coasting long distances without you on it, it would be so
>stable that it would be unrideable for any practical purpose. You woldn't be able to turn a corner.

Get your hands on a clunker - the heavier the better - and try it. Be prepared to give chase as it
trundles towards a BMW. Or just turn your back and look nonchalant.

Tim.

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[Sam Huffman]

"Tim Cain" <tim_no1@you_know_what_to_cut_timcain.co.uk> writes:

> > Wilson's URB is the exception as it can travel indefinitely on its own, given a long slope. It
> > won't fall over until it is virtually at a stop.
> >
> > > Try it sometime - a sloping parking lot is your best bet. Point the bike downhill, give it a
> > > good shove, and off she goes. (Obviously, don't use your Sunday-best Bianchi for this kind of
> > > stunt).
> >
> > Why not use your Sunday-best Bianchi?
>
> Because:
>
> a) It cost so much that you wouldn't be able to bring yourself to chuck it down a slope with
> sufficient abandon.
> b) It's likely to have a low trail, hence very little margin for error correction.
> c) It's very light, so won't gain or maintain speed very well.
> d) It *will* hit a stray shopping trolley (cart to our US cousins), kerb or other obstacle.

My brother's Mag Scrambler (kids BMX bike) stayed upright for about 25 yards down a reasonably steep
(let's say 15% - it was a long time ago) wooded slope. This included at least one short stint in the
air and a lot of ruts and roots.

Needless to say we were both impressed.

Sam

 

[Tim Cain]

"Sam Huffman" <[email protected]> wrote in message
news[email protected]...
> "Tim Cain" <tim_no1@you_know_what_to_cut_timcain.co.uk> writes:
>
> > > Wilson's URB is the exception as it can travel indefinitely on its own, given a long slope. It
> > > won't fall over until it is virtually at a stop.
> > >
> > > > Try it sometime - a sloping parking lot is your best bet. Point the bike downhill, give it a
> > > > good shove, and off she goes. (Obviously, don't use your Sunday-best Bianchi for this kind
> > > > of stunt).
> > >
> > > Why not use your Sunday-best Bianchi?
> >
> > Because:
> >
> > a) It cost so much that you wouldn't be able to bring yourself to chuck it down a slope with
> > sufficient abandon.
> > b) It's likely to have a low trail, hence very little margin for error correction.
> > c) It's very light, so won't gain or maintain speed very well.
> > d) It *will* hit a stray shopping trolley (cart to our US cousins), kerb or other obstacle.
>
> My brother's Mag Scrambler (kids BMX bike) stayed upright for about 25
yards
> down a reasonably steep (let's say 15% - it was a long time ago) wooded
slope.
> This included at least one short stint in the air and a lot of ruts and roots.

Hmmm. could be that I got away with this stunt because my bike forks which were crash-damaged in the
customary fashion of the day (bent back into a slight S-curve). This would have increased the trail,
and so made it more stable. The geometry was already very lazy and stable before this - very easy to
move off the pedals, put one foot on the saddle, stand up on it, and coast along. I should have sold
it to the circus when I outgrew it.

Tim.

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