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Vertical thrust braking

Increase tyre friction to slow down quicker
  (+19, -3)(+19, -3)
(+19, -3)
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This is for emergency braking, with ABS system in action.

A set of chemical rocket engines fire from the roof, pressing the car onto the road. Just a few seconds should do it, to get better results from the normal brakes and steering.
Even if the car is stopped, a few seconds more burn won't do any harm.

I assume that the system is disposable, and must be replaced each time.

Ling, Apr 10 2006

(??) JATO-braked C-130 http://www.users.qw...ove1/fatalbert.html
See video link below [Ling, Apr 10 2006, last modified Apr 11 2006]

Darwin awards, for improvement of the gene pool. http://www.darwinaw.../darwin1995-04.html
Don't try this at home. Or anywhere. [Ling, Apr 10 2006]

The video of the JATO-braked C-130 http://www.theaviat..._credible_sport.mpg
Big direct video link. [Ling, Apr 10 2006, last modified Apr 11 2006]

Or the opposite ... http://www.ashcom.h...d.com/Elford2J.html
Jim Hall's Chaparral 2J [Letsbuildafort, Apr 11 2006]

Emergency Braking Friction Material Emergency_20braking_20friction_20material
[kneeslider, Jan 30 2010]

[link]






       (+) but with all those rockets involved ... why not horizontal in the opposite direction?
ixnaum, Apr 10 2006
  

       How strong are these rocket engines? I don't want to bring the ceiling of the tunnel down with them.   

       At high speeds, this could be done (much more safely) using shaping of the car as a reverse aerofoil, which would press it into the ground.   

       + anyway.
dbmag9, Apr 10 2006
  

       //Even if the car is stopped, a few seconds more burn won't do any harm.// Ever see the video of the JATO-braked C-130 modified to rescue the Iranian hostages?
coprocephalous, Apr 10 2006
  

       (+)make the rockets movable like the Sea Harrier..maybe you just wanna go fast .. ;)
Zen, Apr 10 2006
  

       Why not put the rockets pointing down and jump over whatever you were about to crash into? Turbo Boost - weeeeee! Might need a parachute to land safely though...
Texbinder, Apr 10 2006
  

       Thanks for the tip, [coprocephalous].
Ling, Apr 11 2006
  

       Maybe simply directing the rocket exhaust at the tyres would increase their stickiness, like F1 cars.
coprocephalous, Apr 11 2006
  

       The famed Chaparral 2J produced by Jim Hall would actually create a low-pressure area under the car by means of a snowmobile motor and two large fans. "The vaccum cleaner" they called it.   

       Thats not really pertinent to this idea, but I say its worth a mention. Bun for using rockets. [+]
Letsbuildafort, Apr 11 2006
  

       Traffic signals, overhead lighting, power lines, bridges, pedestrians on bridges, birds, trees, blah blah blah.
egbert, Apr 11 2006
  

       A device to squirt rubbery goo under the tires might be more effective, though it would be a bit messy.   

       A serious problem with any type of braking improvement, however, is that at highway speeds many people judge following distance based upon the perceived stopping ability of the vehicle in front (this is part of why stopping distances are longer behind motorcycles than behind cars). If some vehicles on the highway can stop too much more quickly than others, this creates a potential hazard (car in front with super brakes stops 20 feet before hazard; car behind with ordinary brakes stops 5 feet ahead of where the front car's rear bumper used to be).
supercat, Apr 12 2006
  

       Sticker on back of car:
"If you can read this - I've already stopped"
Ling, Apr 12 2006
  

       This would only increase stopping force by the force of the rockets reduced by the coefficient of friction (tires/road). Facing the rockets forward would not be reduced by friction coefficient. So, cool, but very half-baked.
sophocles, Apr 12 2006
  

       This would be a more effective in propelling the earth in the direction opposite heavily populated areas. Since rush hour is always in the morning and early evening, the net effect would be to distance earth from the sun, thus cooling the earth and solving global warming! Bonus.
Infinity88, Apr 13 2006
  

       [infinity88] that's quite an appropriate anno of half-understood physics to this half-understood physics idea. Unless, of course, your rockets are so powerful that they actually push mass outside the outer atmosphere.
sophocles, Apr 13 2006
  

       How about just jamming four replaceable steel rods into the road?
kinemojo, Jun 02 2006
  

       "The famed Chaparral 2J produced by Jim Hall would actually create a low-pressure area under the car by means of a snowmobile motor and two large fans. "The vaccum cleaner" they called it."   

       I was thinking the same thing. Look up the "Fan Car" from Formula 1 history. Active ground effects are easier and safer to achieve than such rocket power.
kevinthenerd, Jun 02 2006
  

       Would be fun to have little dragster parachutes pop out every time you touch the brakes, and retract ripcord style once released.
epicproblem, Jun 02 2006
  

       Having done the math for a later posted idea, I'll also drop it here:   

       For the tire/road interface the coefficient of friction is ~.7 .   

       Therefore, a 2000kg car has a maximum theoretical stopping force of 13.72kN.   

       An Estes model rocket E9-4 is 9 Newtons of thrust for 4 seconds. One of these would produce a .04% increase in braking power for that time period.   

       If you get into the engines available for "high powered rocketry" over a similar time period, thrusts of about 13kN are available, giving an extra 9100N of braking force. However I'm pretty sure that carrying several pounds of explosives around on the roof of your car doesn't add much to safety. The extra weight required to reinforce the roof, however, would add some braking force.
MechE, Jan 29 2010
  

       Well I think this is a brilliant idea and well worth a bun.
pocmloc, Jan 29 2010
  

       Did any of you guys ever built a rocket? Or look at the spec. sheets of an amateur rocket or even the ones that put things in space?   

       How come carrying a few pounds of some thing like silicon rubber sounds less feasible than carrying pounds of explosive rocket fuel on the roof of a car?   

       Do the math guys (just like it was done by [MechE]).   

       In the end, I suppose, putting a rubbery goo under the wheel does not grab the imagination of people as much as fires shooting at the skies right before a car going for a crash.   

       Well, I also offer a bun for the rocketry.. it would look awesome I can imagine.   

       A couple of fish bones for the engineering merit.
kneeslider, Jan 30 2010
  

       split the difference have the rockets melt the tires.
FlyingToaster, Jan 31 2010
  

       //split the difference have the rockets melt the tires//
Psst, I already did that one, up there ^^^.
coprocephalous, Feb 01 2010
  

       though it sounded familiar.
FlyingToaster, Feb 01 2010
  
      
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