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PostPosted: Mon Oct 31, 2005 12:33 
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Oh oh oh, and another one. This one might be the answer...

A flywheel with a transverse axis. When you brake the vehicle you also brake the flywheel. Reaction to braking the flywheel drives the front of the car down.

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PostPosted: Mon Oct 31, 2005 12:36 
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JT wrote:
As an aside, the "FWD has more traction" thing shows itself up as a fallacy...


don't think i've ever heard anyone claim this!

the only time this would apply is relative to a rear engine - FWD setup which is the worst of both worlds!

packaging and cost is really the only reason front engine FWD became the norm.


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PostPosted: Mon Oct 31, 2005 12:42 
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SafeSpeed wrote:
Oh oh oh, and another one. This one might be the answer...

A flywheel with a transverse axis. When you brake the vehicle you also brake the flywheel. Reaction to braking the flywheel drives the front of the car down.

:lol:

But I thought we were trying to drive the rear of the car down?

Either way, all this can achieve is to alter the front rear balance - unlike a wing / thruster it doesn't actually add anything to overall traction (apart from the mass of the flywheel, which is cancelled out by it's overall forward momentum).

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PostPosted: Mon Oct 31, 2005 12:43 
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SafeSpeed wrote:
Oh oh oh, and another one. This one might be the answer...

A flywheel with a transverse axis. When you brake the vehicle you also brake the flywheel. Reaction to braking the flywheel drives the front of the car down.


or counteracts the weight transfer... not sure which would be more beneficial.

i quite like that one (aside from the scary amounts of inertia in a flywheel in close proximity to the passengers)... simple, doable with current technology, low energy requirement (spin it up at start up and just keep it going gently), controlable (you could control the amount of flywheel braking and hence amount of weight transfer it causes easily with current systems.. .could even be a dumb system linked straight to the master cylinder: flywheel deccel proportional to brake pressure).

flywheel weight would kill acceleration & 0-60 times.... which for some reason sells cars! i wonder if you'd improve the 0-60-0 times overall or not...


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PostPosted: Mon Oct 31, 2005 12:49 
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ed_m wrote:
JT wrote:
As an aside, the "FWD has more traction" thing shows itself up as a fallacy...


don't think i've ever heard anyone claim this!

the only time this would apply is relative to a rear engine - FWD setup which is the worst of both worlds!

packaging and cost is really the only reason front engine FWD became the norm.

I think if you ask Mr Average motorist you'll find they are convinced that FWD is better in snow because "the engine is over the driving wheels".

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PostPosted: Mon Oct 31, 2005 12:50 
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ed_m wrote:
JT wrote:
As an aside, the "FWD has more traction" thing shows itself up as a fallacy...


don't think i've ever heard anyone claim this!


Actually I believe that many FWD setups have more traction in low power / low grip situations. And that's because FWD packaging tends to put up to 70% of the weight over the front driving wheels.

FWD has another related advantage in snow conditions. If you need to steer to pull away in RWD (think parking place) the steering wheels waste available traction by tending to plough. FWD doesn't plough and provides its traction vectored appropriately.

Don't get me wrong. I'm a life-long confirmed FWD hater.

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PostPosted: Mon Oct 31, 2005 12:55 
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JT wrote:
SafeSpeed wrote:
Oh oh oh, and another one. This one might be the answer...

A flywheel with a transverse axis. When you brake the vehicle you also brake the flywheel. Reaction to braking the flywheel drives the front of the car down.

:lol:

But I thought we were trying to drive the rear of the car down?

Either way, all this can achieve is to alter the front rear balance - unlike a wing / thruster it doesn't actually add anything to overall traction (apart from the mass of the flywheel, which is cancelled out by it's overall forward momentum).


Having thought about it since posting, I suspect you're right. However, I'm having trouble convincing myself that it doesn't work if we apply the flywheel brakes progressively. It's sort of like a continuous down-bounce. Isn't it?

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PostPosted: Mon Oct 31, 2005 12:57 
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SafeSpeed wrote:
ed_m wrote:
JT wrote:
As an aside, the "FWD has more traction" thing shows itself up as a fallacy...


don't think i've ever heard anyone claim this!


Actually I believe that many FWD setups have more traction in low power / low grip situations. And that's because FWD packaging tends to put up to 70% of the weight over the front driving wheels.

Agreed. Under extreme low grip on a flat surface RWD won't get the dynamic weight transfer it needs for traction, so the FWD often gets away better.
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FWD has another related advantage in snow conditions. If you need to steer to pull away in RWD (think parking place) the steering wheels waste available traction by tending to plough. FWD doesn't plough and provides its traction vectored appropriately.

Yes, the RWD / snowy parking space / cambered road thing can be a bit of a conundrum, but at least once you do manage to extricate it you know you'll have a fighting chance of climbing the hill at the end of the street! :hehe:

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PostPosted: Mon Oct 31, 2005 12:58 
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ed_m wrote:
SafeSpeed wrote:
A flywheel with a transverse axis. When you brake the vehicle you also brake the flywheel. Reaction to braking the flywheel drives the front of the car down.


[...]

flywheel weight would kill acceleration & 0-60 times.... which for some reason sells cars! i wonder if you'd improve the 0-60-0 times overall or not...


With flywheel energy storage you can always trade mass for speed. Need more energy or a lighter flywheel? Spin it faster.

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PostPosted: Mon Oct 31, 2005 13:01 
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SafeSpeed wrote:
JT wrote:
SafeSpeed wrote:
Oh oh oh, and another one. This one might be the answer...

A flywheel with a transverse axis. When you brake the vehicle you also brake the flywheel. Reaction to braking the flywheel drives the front of the car down.

:lol:

But I thought we were trying to drive the rear of the car down?

Either way, all this can achieve is to alter the front rear balance - unlike a wing / thruster it doesn't actually add anything to overall traction (apart from the mass of the flywheel, which is cancelled out by it's overall forward momentum).


Having thought about it since posting, I suspect you're right. However, I'm having trouble convincing myself that it doesn't work if we apply the flywheel brakes progressively. It's sort of like a continuous down-bounce. Isn't it?

No. The bounce works because you are accelerating a mass away from the contact point. All a flywheel can do is provide a torsional acceleration, and it's fulcrum is entirely limited to being within the vehicle, therefore all it can do is alter the weight distribution. Ultimately it could make the car do a "wheelie" or even a "stoppie" depending on which way it's turning, but there would still be no more than the total car mass bearing down on the two wheels in contact with the road, would there?

Does a wheelie-ing motorcycle press down on the back tyre with more than the mass of the machine and rider? I don't think so...

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PostPosted: Mon Oct 31, 2005 13:06 
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SafeSpeed wrote:
ed_m wrote:
SafeSpeed wrote:
A flywheel with a transverse axis. When you brake the vehicle you also brake the flywheel. Reaction to braking the flywheel drives the front of the car down.


[...]

flywheel weight would kill acceleration & 0-60 times.... which for some reason sells cars! i wonder if you'd improve the 0-60-0 times overall or not...


With flywheel energy storage you can always trade mass for speed. Need more energy or a lighter flywheel? Spin it faster.

But the faster you turn it the more energy you need to keep pushing in to keep it up to speed, due to friction and windage losses.

Unless of course you are running it on non-contact bearings and in a vacuum, which you could then dump in an emergency to suck the car down to the road... :roll:

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PostPosted: Mon Oct 31, 2005 13:23 
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JT wrote:
No. The bounce works because you are accelerating a mass away from the contact point. All a flywheel can do is provide a torsional acceleration, and it's fulcrum is entirely limited to being within the vehicle, therefore all it can do is alter the weight distribution. Ultimately it could make the car do a "wheelie" or even a "stoppie" depending on which way it's turning, but there would still be no more than the total car mass bearing down on the two wheels in contact with the road, would there?


<sigh> :yesyes:

JT wrote:
Does a wheelie-ing motorcycle press down on the back tyre with more than the mass of the machine and rider? I don't think so...


fx: clutching at straws...

But the energy to lift the front wheel must come from somewhere so there is a little crumb for me isn't there?

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PostPosted: Mon Oct 31, 2005 13:31 
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JT wrote:
All a flywheel can do is provide a torsional acceleration, and it's fulcrum is entirely limited to being within the vehicle, therefore all it can do is alter the weight distribution. Ultimately it could make the car do a "wheelie" or even a "stoppie" depending on which way it's turning, but there would still be no more than the total car mass bearing down on the two wheels in contact with the road, would there?


This is a valuable jigsaw piece isn't it? Now we have a method to control weight transfer...

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PostPosted: Mon Oct 31, 2005 13:34 
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Why not just fit wider, (and larger diameter) tyres in the first place so the contact area is greater by default.

Or, this has just sprung in to mind as I typed... a dual compound tyre. The normal wearing surface, but with a high density foamy layer under it. (This is not for a braking surface - but like a secondary layer) Under braking (severe) the normal action of front tyres compressing under braking load could be added to - increasing the footprint / contact area, but only 'active' when under abnormal load. It would be like automatically dropping the tyre pressure a fraction under heavy braking - to return to normal as the load reduces.

No patents pending....yet! :D


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PostPosted: Mon Oct 31, 2005 14:00 
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Another thought on the flywheel issue - is it's going to have enough mass/energy to affect the vehicle under braking this certainly wouldn't be a great idea to have it always in motion - think gyroscopes!!. The last thing you need is a hefty flywheel to improve handling.

Ooo..another thought.

What if.... the flywheel(s) had stored energy so not permanently in motion - eg. a flippin' massive spring and it's held under tension (kinda seat belt pre-tensioner idea) and when braking forces required it is released - up to it's full potential and then damped to transfer it's energy back into the 'chassis' and provide a downward 'push' inceasing road/tyre friction. OK, we're talking 100's of Kg's to make a difference here, and supply a meaningful time duration.

Firing it off with a rocket or charge wouldn't work would it? - 'equal & opposite reaction' stuff?

I'm no physicist - this is just about 'Brainiac' level :lol:

Thoughts?


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PostPosted: Mon Oct 31, 2005 14:09 
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hobbes wrote:
Why not just fit wider, (and larger diameter) tyres in the first place so the contact area is greater by default.


The tyre / tarmac interface is a pretty strange non-linear sort of thing, but if we idealise it for a moment we'll find that a larger contact patch does little because the pressure per square inch reduces in direct proportion to the increase in footprint.

hobbes wrote:
Or, this has just sprung in to mind as I typed... a dual compound tyre. The normal wearing surface, but with a high density foamy layer under it. (This is not for a braking surface - but like a secondary layer) Under braking (severe) the normal action of front tyres compressing under braking load could be added to - increasing the footprint / contact area, but only 'active' when under abnormal load. It would be like automatically dropping the tyre pressure a fraction under heavy braking - to return to normal as the load reduces.

No patents pending....yet! :D


Tyres probably experience far bigger loads from bumps than they do from brakes. But there is one way that tyres know you're braking - and that's because they experience an axial twisting torque. I don't know if that could be used to raise hackles or something.

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PostPosted: Mon Oct 31, 2005 14:35 
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squeegee in front of the tyre method, if it has any great effect has some appeal, again from simplicity.

use the dive of the car under braking to apply them to the road, so they dont rub in normal driving, or have to be 'controlled' in any way.

punters may not like the noise tho' :roll:


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PostPosted: Mon Oct 31, 2005 18:27 
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tyre heaters. when braking you could divert the whole engine power to some kind of high power radiant heater that increases the avaliable grip of the tyre, especially if the tyre was designed with this in mind. this would also make the car very controllable when braking/cornering. I'm suprised this idea hasn't been toyed with in motorsport.

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PostPosted: Mon Oct 31, 2005 19:14 
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SafeSpeed wrote:
hobbes wrote:
Why not just fit wider, (and larger diameter) tyres in the first place so the contact area is greater by default.


The tyre / tarmac interface is a pretty strange non-linear sort of thing, but if we idealise it for a moment we'll find that a larger contact patch does little because the pressure per square inch reduces in direct proportion to the increase in footprint.

hobbes wrote:
Or, this has just sprung in to mind as I typed... a dual compound tyre. The normal wearing surface, but with a high density foamy layer under it. (This is not for a braking surface - but like a secondary layer) Under braking (severe) the normal action of front tyres compressing under braking load could be added to - increasing the footprint / contact area, but only 'active' when under abnormal load. It would be like automatically dropping the tyre pressure a fraction under heavy braking - to return to normal as the load reduces.

No patents pending....yet! :D


Tyres probably experience far bigger loads from bumps than they do from brakes. But there is one way that tyres know you're braking - and that's because they experience an axial twisting torque. I don't know if that could be used to raise hackles or something.


I overlooked that....bugger. :twisted:

Hairyben's tyre heaters - I had that idea this afternoon too. And brainstormed myself!. The hotter the tyres - the higher the tyre pressure - so an IR non-contact monitoring feedback loop would be required to keep it optimal - not rocket science. But how to get heat onto the tyres. Hot contact roller? - perhaps using the excess heat from the cats / manifold.

Squeegee (rubber roller - not a blade) idea fantastic for the wet - deployed in 'normal' operation to push most of the standing water out of the way before the tyre gets to that spot. Could be a disaster if it hits 'road debris' though! Would need something more advanced than a spring holding it down! Forward scanning radar or laser (put the guts of a few LTI 20-20's to good use...) to see sizable debris & take appropriate action.....imagine, a wet day, 1/2" of standing water in places & you can do 70 without fear of aquaplaning or your T/C freaking out, all you'll get is a little flicker on the dash to say the 'active roller' took action and lifted for 150ms to avoid that chunk of stone in it's path. Cooooool :D


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PostPosted: Mon Oct 31, 2005 19:14 
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What about Eddy currents instead of an attracting electromagnet? You could have a kevlar skid that drops down on an array of pistons, each with just enough vertical force (spring/air/whatever) to ensure the skid is in contact with the metalled road, and with sufficient sheer withstanding force to tolerate the skid being retarded by seriously high (but for short duration) DC currents in the coil above the skid.


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