5th Gear - Ultimate Crash Test
Discussion
Anyone else see this?.... Volvo and a 5 series BMW in a off-set head on smash at 60mph (normall NCAP tests for this are at 35-40mph) the damage to these cars was 
Both cars were 10 years old, but even a modern car would have sufered huge damage. The front wheel on the drivers side was level with the rear of the front door !! the sterring wheel nearly touching the back of the drivers seat - the verdict anyone in the cars would have died..... kinda makes you think when you seen it !!
Both cars were 10 years old, but even a modern car would have sufered huge damage. The front wheel on the drivers side was level with the rear of the front door !! the sterring wheel nearly touching the back of the drivers seat - the verdict anyone in the cars would have died..... kinda makes you think when you seen it !!It's the sort of thing the "speek kills" lobby would gleefully jump on to. However these two cars hit each other at about 120mph closing speed yet they would not have been driving above the limit on a single carriageway A road.
All the more reason why our concentration should not be diverted by speed cameras and talivans!
Ken
All the more reason why our concentration should not be diverted by speed cameras and talivans!
Ken
Why are you surprised? I assume the crash was with both cars running at 60mph? With a terminal velocity of 120mph, the kinetic energy of the impact is huge. Try visualising dropping a beamer out of an aeroplane at several thousand feet and letting it impact on a solid surface. The terminal velocity in air of an unstreamlined free falling object is approx. 120mph - it wouldn't really matter which corner hit first, you are stopping a ton and a half of car from 120 to 0 in say 5 feet or less. You wouldn't walk away from it!
Cheers
Graham
Cheers
Graham
Kinetic energy doubles as you double the mass, but quadruples as you double the speed.
So one car at 120mph has more than two doing 60.
Edit -
cos I'm bored I've done the calculations;
2 cars weighing 1000kg both doing 60mph = 729,000 J
1 car weighing 1000kg doing 120mph = 1,458,000 J
>> Edited by FunkyNige on Thursday 13th March 00:50
So one car at 120mph has more than two doing 60.
Edit -
cos I'm bored I've done the calculations;
2 cars weighing 1000kg both doing 60mph = 729,000 J
1 car weighing 1000kg doing 120mph = 1,458,000 J
>> Edited by FunkyNige on Thursday 13th March 00:50
This is true, but to a large extent, irrelevant IMHO - remember momentum is still conserved, so to the occupants of our notional cars, there would be no difference from 1 car travelling 120MPH & hitting a stationary car, and 2 cars travelling at 60MPH & having a head on collision.
FunkyNige said: Kinetic energy doubles as you double the mass, but quadruples as you double the speed.
So one car at 120mph has more than two doing 60.
Edited to say it's all relative - e.g. if we use a notional point in space as our origin, we all have loads of Kinetic Energy due to both the Earth's rotation about it's axis, around the Sun, and the Solar system's movement through space. Which is why it's kinda irrelevant in this case.
>> Edited by CraigAlsop on Thursday 13th March 01:14
an advert for running up the back of a car going the same direction or hitting a stationary object rather than swerve and take a head on hit.
yet people still swerve to miss a dog and go headlong into the mum with 3 kids in a school run panzer tank(any of the current crop of 4x4 never offroaders)
and then the ecilop name the road as an accident black spot,even though its dead straight with no junctions in no crests or dips.out come the gatso's and for the death of mabey only one person the chief constable gets to go to barbados.(on a fact finding tour to find out why a sleepy tourist island has less crashes per year than inner city london)
yet people still swerve to miss a dog and go headlong into the mum with 3 kids in a school run panzer tank(any of the current crop of 4x4 never offroaders)
and then the ecilop name the road as an accident black spot,even though its dead straight with no junctions in no crests or dips.out come the gatso's and for the death of mabey only one person the chief constable gets to go to barbados.(on a fact finding tour to find out why a sleepy tourist island has less crashes per year than inner city london)
This is the link to the program info:
www.channel5.co.uk/fifthgear/programmeinfo.php
not any pics of the Volvo and BMW though....
www.channel5.co.uk/fifthgear/programmeinfo.php
not any pics of the Volvo and BMW though....
It affected me just watching it on the telly (and think about the 'normal' stuff on the news etc. that just washes over us) but what brought it home even more was the usually shallow and chatty Tiff looking at the volvo and staring at it deeply and not really being able to say anything, just muttering about the crashes he'd seen on the race track not being anything like as bad as this.
I saw a low speed Saxo vs 5 series picture in some magazine a few months ago. It seems that a car has to support its own weight in the crash tests, so is built to stop itself against an imovable object. The light car changes momentum much more in a collision with a heavy car making the accident seem much more severe. The cars had only been doing ~20mph (IIRC) in that test, but the Saxo occupants would all have been killed. If the lighter is half the weight of the heavier, it would be similar to hitting the imovable object at, umm, 1 1/3 of the actual, and the heavier at 2/3.
Momentum kills?
Momentum kills?
The momentum will be the same with both 2 * 60 mph cars as it would be with one 120mph hour, but the engery dissapated in the latter would be much greater (crumpling, noise, heat etc). That's why is takes dis-proportionately longer to brake from a higher speed than a lower speed down to zero. There are of course many other factors at work that will effect the result (two crumple zones, side on collisions etc, different weight cars).
Either way it's messy!
I've always thought Peter Wheeler might have had a point about monocoque construction and crashes. What would the result be like if two TVRs or racecars collided head on? Would the occupant cell be more likely to be intact afterwards ? Indy racing has proven that people can survive much higher temporary g forces than currently thought and designed into current car assembly. Is one of the reasons we were shocked because the F1 cars crash at high speeds at the driver gets out ? That's a different construction technique than most cars.
Is this a useful area of research for production cars ?
Either way it's messy!
I've always thought Peter Wheeler might have had a point about monocoque construction and crashes. What would the result be like if two TVRs or racecars collided head on? Would the occupant cell be more likely to be intact afterwards ? Indy racing has proven that people can survive much higher temporary g forces than currently thought and designed into current car assembly. Is one of the reasons we were shocked because the F1 cars crash at high speeds at the driver gets out ? That's a different construction technique than most cars.
Is this a useful area of research for production cars ?
andyvdg said:Indy racing has proven that people can survive much higher temporary g forces than currently thought and designed into current car assembly. Is one of the reasons we were shocked because the F1 cars crash at high speeds at the driver gets out ? That's a different construction technique than most cars.
Is this a useful area of research for production cars ?
This is what my son now does for a living. One of the problems with inflicting higher g-forces on the occupants is that it would be necessary to have 6 point harnesses and fixed race shell type seats to avoid the stresses inflicted by the seatbelt being unsurvivable and the seat collapsing under the forces involved. In a 2 seater 4 point harnesses will increase accident survival rates, but obviously are incompatible with 4 seater cars. Worryingly I've seen a couple of cars where the shoulder straps were connected to the floor behind the front seats. Declination of more than 15degrees in the shoulder straps could cause fatal spinal compression in a low speed crash that would otherwise be survived.
Its worth pointing out that if two cars of equal mass hit each other at 60mph head on then the effect is exactly the same as one car hitting an immovable concrete wall at 60mph.
The reason is that if the two cars have the same mass and speed then when they hit each other they will come to a dead stop instantly. Which is exactly the same as hitting a brick wall at that speed.
Its amazing the number of people who don't believe this and insist that its the same as one car hitting a wall at 120mph. It isn't.
However when two cars hit each other at a slight angle (like Fifth Gear's test) then you'll notice they didn't come to a dead stop they crunch and then move sideways before stopping. This would be diferent to hitting a wall at a slight angle cos you CANNOT go through the wall as these two cars passed through their initial impact point. (if that makes any sense to anyone)
So the moral of the story is; if you're faced with a loony who pulls out RIGHT in front of you then swerve for all you're worth. Better a glancing impact than a head on.
Oh and if at all possible drive a TVR racing Tuscan.
Andy
(engineering student)
The reason is that if the two cars have the same mass and speed then when they hit each other they will come to a dead stop instantly. Which is exactly the same as hitting a brick wall at that speed.
Its amazing the number of people who don't believe this and insist that its the same as one car hitting a wall at 120mph. It isn't.
However when two cars hit each other at a slight angle (like Fifth Gear's test) then you'll notice they didn't come to a dead stop they crunch and then move sideways before stopping. This would be diferent to hitting a wall at a slight angle cos you CANNOT go through the wall as these two cars passed through their initial impact point. (if that makes any sense to anyone)
So the moral of the story is; if you're faced with a loony who pulls out RIGHT in front of you then swerve for all you're worth. Better a glancing impact than a head on.
Oh and if at all possible drive a TVR racing Tuscan.
Andy
(engineering student)
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