What is the harm in downshifting gears and braking during th

For discussion of topics relating to the Driving Standards Agency Learner Test (DSA L Test) and contribution by ADI's (Approved Driving Instructors)

Postby TripleS » Mon Sep 08, 2008 5:46 pm


Porker wrote:Dave

From my perspective, I think you might do well to reduce the level of sarcasm employed in some of your posts, specifically those where you're having a pop at what are generally advocated as "advanced" techniques.

In the final analysis, your way of doing things has been tested for 50 years and perhaps 500,000 to 1,000,000 miles. The approach outlined in Roadcraft has been in use for around 75 years and several tens of billions of miles, if not much more.

I don't care much whether you choose to adopt some of it, all of it or none of it. However, your desire to dismiss it out of hand seems somewhat arrogant to say the least. I would liken that approach to someone who's managed not to crash a light aircraft for a few years believing that they can teach the RAF a thing or two about flying.

Please remember that there are a lot of us out there doing our best to reduce the chances of those who come for advanced coaching having a crash which might be a life-changing event for them or someone else. Dismissing the approach we advocate in favour of one which suggests doing whatever they like because it hasn't failed *yet* is not especially constructive, not least because every big crash is preceded by many occasions where the flawed method employed didn't let the driver down.

regards
P.


Boiing!

OK, Nick, after re-reading what I said, I accept there is some justification for your criticism. On reflection there was too much of a sarcastic/clowning quality to it, and I apologise for that - but IMHO the essential points do have some validity, even if they're out of place in a forum of this type.

I won't re-ignite things by elaborating at this time, beyond gently suggesting that the methods I use might be regarded as different, rather than markedly inferior to those generally promoted by the advanced driving community.

Best wishes all,
Dave.
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Postby Porker » Mon Sep 08, 2008 9:09 pm


Dave

Your apology is accepted, even though we may have to differ, for the moment at least, on your second point :wink:

regards
Nick
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Postby Martin A » Sun Sep 28, 2008 12:37 pm


fungus wrote:
Remember a vehicle is at its most stable when traveling in a straight line under gentle power.

Nigel ADI
IAM car


Surely a vehicle is at its most stable when stationary or when travelling at a constant speed. I don't think that I would be alone in inferring that under gentle power means accelerating.

Definition of stable below.

3 a (1): placed so as to resist forces tending to cause motion or change of motion (2): designed so as to develop forces that restore the original condition when disturbed from a condition of equilibrium or steady motion

Just hoping to clarify things

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Postby vonhosen » Sun Sep 28, 2008 1:18 pm


Martin A wrote:
fungus wrote:
Remember a vehicle is at its most stable when traveling in a straight line under gentle power.

Nigel ADI
IAM car


Surely a vehicle is at its most stable when stationary or when travelling at a constant speed. I don't think that I would be alone in inferring that under gentle power means accelerating.


There are forces acting on the moving vehicle that would tend to slow it down, if you aren't negating them (usually by applying some power) then it won't be traveling at a constant speed.
Any views expressed are mine & mine alone.
I do not represent my employer or these forums.
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Postby Martin A » Tue Oct 14, 2008 4:00 pm


vonhosen wrote:
Martin A wrote:
fungus wrote:
Remember a vehicle is at its most stable when traveling in a straight line under gentle power.

Nigel ADI
IAM car


Surely a vehicle is at its most stable when stationary or when travelling at a constant speed. I don't think that I would be alone in inferring that under gentle power means accelerating.


There are forces acting on the moving vehicle that would tend to slow it down, if you aren't negating them (usually by applying some power) then it won't be traveling at a constant speed.


Very true. I was hoping for a reply from Nigel ADI to find out what he meant. I should have said what I meant rather than putting what I inferred. Perhaps he can clear up the confusion for us by saying whether he meant accelerating, maintaining a constant speed or, to be pedantic, decelerating.

HTH

Best regards

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Postby martine » Tue Oct 14, 2008 5:05 pm


In 'Nigel ADI's absence how about a reply from 'martine'!

I think :!: what he was getting at is:

If very gentle acceleration is used in a corner, the thinking is the suspension is compressed at the rear which tends to make the car feel firmer (less bouncy). The opposite (deceleration) esp. with a softly sprung car feels horrible and makes for a good impression of the QE2 in a force 10.
Last edited by martine on Tue Oct 14, 2008 5:09 pm, edited 1 time in total.
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Postby fungus » Tue Oct 14, 2008 5:07 pm


Martin A. To clarify what I meant by the statement "remember that a vehicle is at its most stable when traveling in a straight line under gentle power"is this. As Von said, "there are forces acting on the moving vehicle that would tend to slow it down, if you dont negate them (usually by applying some power) then it wont be travelling at a constant speed". ie resistance from the tyres, steering input etc.

In relation to cornering. When a driver applies steering, the vehicle will start to loose speed. In order to maintain stability, the driver must apply enough power to maintain speed, not accelerate. Any extra forces such as braking or decelerating would only serve to destabilise the vehicle further.

Most front wheel drive cars will have a tendency to understeer. However this can be transfered to dramatic oversteer by entering a bend too fast and lifting off the accelerator harshly as you start to steer in. The Peugeot 306 is an example of this. Applying too much power as you steer in will increase the amount of understeer. So my meaning was that you apply enough power to maintain a constant speed, not to accelerate or decelerate.

I hope this clears up the confusion.

Nigel ADI
IAM trainee observer.
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Postby 7db » Tue Oct 14, 2008 11:18 pm


fungus wrote:So my meaning was that you apply enough power to maintain a constant speed, not to accelerate or decelerate


You will find that a little more power than this will help further tighten the line and add cornering force (until it speed up the car and overcomes that force)
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