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PostPosted: Fri Mar 10, 2006 01:52 
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smeggy wrote:
Thumbs_Down wrote:
F1 cars have incredible braking power Why?

You missed the extra down-force due to the spoilers; this is a critical component of the traction system.

And some of it is down to chemistry... The tyres only last at a maximum 200 miles (last year) and about 60 this year because they're made from a very soft compound that becomes positively sticky when up to working temperature. Mind you, F1 tyres are hopeless compared to those used on "Formula A" karts - they pull better than 2.5G lateral, without the benefit of aerodynamics... :lol:

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 Post subject: Re: Super braking
PostPosted: Thu Jul 09, 2009 14:06 
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this thread's a blast from the past.....

http://www.emercedesbenz.com/Jun09/10_0 ... rview.html
Quote:
Braking Bag: This auxiliary brake accommodated in the vehicle floor is a new type of PRE-SAFE® component. If the sensor system concludes that an impact is unavoidable, the Braking Bag is deployed shortly before the crash and stabilises the car on the road surface by means of a friction coating. The vehicle's vertical acceleration increases the friction, and helps to decelerate the vehicle before the impact occurs.


this looks like a large high friction braking surface pressed against the road for emergency braking .... sounds familiar to what was discussed earlier on this thread.

aha... this being the key image:
http://www.emercedesbenz.com/Images/Jun ... 544_02.jpg


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 Post subject: Re: Super braking
PostPosted: Thu Jul 09, 2009 16:33 
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I initially thought this bag was an extension to the bumper, like an extended crumple zone (which may not be as daft as it sounds).
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and helps to decelerate the vehicle before the impact occurs

Would I be right to assume this bag has a significantly higher coefficient of friction than the tyres? If so, and it wears well, is it possible to make tyres out of this stuff?

This bag is taking up some of the vertical force that would otherwise be available to the tyres, hence reducing the level of traction from them; so what impact does this have on the ability to steer when the bag is deployed?

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 Post subject: Re: Super braking
PostPosted: Thu Jul 09, 2009 20:02 
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Steve wrote:
Would I be right to assume this bag has a significantly higher coefficient of friction than the tyres? If so, and it wears well, is it possible to make tyres out of this stuff?

This bag is taking up some of the vertical force that would otherwise be available to the tyres, hence reducing the level of traction from them; so what impact does this have on the ability to steer when the bag is deployed?


well i'm guessing .... but it seems like this is the last ditch attempt in automatic collision avoidance... and would rely on just having a massive surface area to do the braking.. so just a big anchor.

but yes it would reduce load on the tyres which are already braking.. making that and any steering input less effective. a similar brake based collision mitigation system i've worked with waited until it wasnt physically possible to for the driver to avoid the crash by steering before applying the brakes, i'd guess if last ditch this would be similar.. ie steering aint gonna help you now (buddy).

also interesting it helps to stop the nose dipping too.


also interesting to note the car has just potentially saved itself from a write off or £££££s worth of damage.... how much does the bag cost to replace ? .. in a merc !!! yikes. :wink:


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 Post subject: Re: Super braking
PostPosted: Thu Jul 09, 2009 20:04 
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Steve wrote:
I initially thought this bag was an extension to the bumper, like an extended crumple zone (which may not be as daft as it sounds).


one of the other features in this particular demo car is the side impact beams ..... which are metal profile.. but before a side impact are expanded by internal air pressure (10-20bar !) to a bigger, stronger profile.

also presumably helping self destruct the car :D


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