Emergency Stop

[Kevin]

Hmmmm . . .

I've seen old cowboy films where the wheels on the stagecoach seem to be rotating backwards

It wasn't the same effect as the film was taken with a very high speed camera and the other wheels were all rotating in the 'correct' direction. The film was specifically taken to demonstrate the effect of failing to de-clutch when braking with the assistance of ABS.

[TripleS]

I was told not to delay depressing the clutch pedal when braking, it being thought that engine braking on modern vehicles was not necessary given the efficiency of the brakes, but the main reason was that, when ABS was active, it is possible for one of the driven wheels to actually rotate backwards. Knowing that those of us on the course would find that hard to believe, we were shown a slow-motion video of an LGV braking hard with ABS fitted and the clutch not disengaged and, sure enough, one of the driven wheels began to rotate backwards.

. When the ABS slightly released braking on one of the wheels which had begun to lock up, the differential allowed the half-shaft to rotate backwards to dissipate the energy from the, still engaged, engine.

Hmmmm . . .

I've seen old cowboy films where the wheels on the stagecoach seem to be rotating backwards

As I understand it old cinema films were shown at 24 frames per second, but when TV came along they adopted 25 fps. If they ever devise a way of showing us a continuous moving picture I suppose the effect will disappear, but in the meantime wheels still appear to rotate backwards when viewed on TV, even with recently made programmes. I saw it on a recent showing of a 'Midsomer Murders' programme.

Best wishes all,
Dave.

[Horse]

I've seen old cowboy films where the wheels on the stagecoach seem to be rotating backwards

As I understand it old cinema films were shown at 24 frames per second, but when TV came along they adopted 25 fps.

A few days ago I was boring for England on my current employment, talking about conspicuity issues.

In previous life I worked in the TV industry

UK (and others) use PAL which is, as you say 25fps. In the US it's NTSC, at roughly 30fps (actually 29.97) for very complicated reasons you wouldn't understand

But if you're willing to waste a few minutes, have a read of this:
http://www.zerocut.com/tech/pulldown.html
http://www.projectorpeople.com/resources/pulldown.asp
and subsequent pages

Then start looking at other formats, such as the 'standard' of HD

[TripleS]

I've seen old cowboy films where the wheels on the stagecoach seem to be rotating backwards

As I understand it old cinema films were shown at 24 frames per second, but when TV came along they adopted 25 fps.

A few days ago I was boring for England on my current employment, talking about conspicuity issues.

In previous life I worked in the TV industry

UK (and others) use PAL which is, as you say 25fps. In the US it's NTSC, at roughly 30fps (actually 29.97) for very complicated reasons you wouldn't understand

But if you're willing to waste a few minutes, have a read of this:
http://www.zerocut.com/tech/pulldown.html
http://www.projectorpeople.com/resources/pulldown.asp
and subsequent pages

Then start looking at other formats, such as the 'standard' of HD

Yes, well, thanks for that.

I have so little useful information to impart I tend to let fly with what I have, or think I have, hence the tendency to be extremely boring. When it comes to understanding things, again I often find myself in trouble....e.g. the sudden and mysterious loss of refinement in motor vehicles following the fitting of new exhausts systems.

Best wishes all,
Dave.

[Horse]

Yes, well, thanks for that.

You're welcome

[Horse]

e.g. the sudden and mysterious loss of refinement in motor vehicles following the fitting of new exhausts systems.

Well, more qualified people than me posted on that thread, but it struck me that there were two ways of looking at the problem:

1. Change something and problem starts = 'changed item' is the problem
2. Changes item could 'enhance' a pre-existing problem, but your description seemed to show an awareness of the car which would have identified any earlier fault

Therefore, exhaust system = problem

[Porker]

The logic is good, but we also need to apply a "cost to experiment" factor in. If the engine mount is a cheap-ish item to swap out, it would likely be worth doing that before committing to a new Peugeot exhaust.

P.

[Horse]

The logic is good, but we also need to apply a "cost to experiment" factor in. If the engine mount is a cheap-ish item to swap out, it would likely be worth doing that before committing to a new Peugeot exhaust.

P.

How old's the driver? Replacing him with one who doesn't winge - and getting the original driver new car might be less cost-effective but a more fun answer

[TripleS]

The logic is good, but we also need to apply a "cost to experiment" factor in. If the engine mount is a cheap-ish item to swap out, it would likely be worth doing that before committing to a new Peugeot exhaust.

P.

How old's the driver? Replacing him with one who doesn't winge - and getting the original driver new car might be less cost-effective but a more fun answer

70 - but I don't want to clutter this topic up with yet more agonising over tiresome mechanical problems.

Best wishes all,
Dave.

[Kevin]

If they ever devise a way of showing us a continuous moving picture I suppose the effect will disappear, but in the meantime wheels still appear to rotate backwards when viewed on TV, even with recently made programmes. I saw it on a recent showing of a 'Midsomer Murders' programme.

You seem to have conveniently overlooked the fact that I said the other wheels were rotating in the 'correct' direction.

[redrobo]

Sorry I didn't put that very well did I.

Why spoil the advantage by being hit by following traffic because you have stalled.

I may be being a bit thick here, but why should de-clutching cause the engine to stall?

it's me. Get the clutch down as soon as possible to prevent stalling. As I said, why spoil the good work of avoiding an accident, by use of ABS, only to be hit by following traffic.

[Wolfy]

interestingly too....

my son (17 yr old) has just been told by his instructor that during emergancy stop, although you should press the brake pedal HARD,,,you must not press it hard enough to engage the cars ABS system !!!!!!

as far as im concerend anyway to stop the car quickly must be done...to say you shouldnt activate ABS is wrong surely ??

comments appreciated please ?

Paul.

[ROG]

EMERGENCY stop means just that so HAMMER that pedal to the floor and keep it here until the car stops (that will engage the ABS if fitted)

A CONTROLLED stop is different - that means controlled squeezing harder and harder and harder until the car stops - I never get the ABS to engage when doing that

[fungus]

interestingly too....

my son (17 yr old) has just been told by his instructor that during emergancy stop, although you should press the brake pedal HARD,,,you must not press it hard enough to engage the cars ABS system !!!!!!

as far as im concerend anyway to stop the car quickly must be done...to say you shouldnt activate ABS is wrong surely ??

comments appreciated please ?

Paul.

That is what I was told twelve years ago when I was training to bacome an ADI.

This is out of date thinking. If you read the section in the DSAs Driving the Essential Skills on stopping the car in an emergency, it states that whilst you shouln't drive in a manner that you are braking near the threshhold, emergencies do happen, and ABS is there to help. It is there to enhance your skills, not replace them. This is not quoted word for word, but in essence, what I have said is basicaly what is written in the book. Telling a pupil that you must not activate the ABS will result in the braking being too light.

I will leave the rest to Astraist.

[daz6215]

That's why we have ABS so use it, I have always taught people to 'stop' the car as if as in an emergency, in other words use the brakes and stop as quickly as possible, if ABS comes in then that's another teaching point that shouldn't be missed. For fleet client I teach emergency brake avoidance and lane changes implementing full use of ABS, its amazing how many experienced drivers still don't know what to do or are simply scared to use it!