Caravan Snake Control
ฝัง
- เผยแพร่เมื่อ 21 ก.ค. 2017
- Reproduced courtesy of BBC TV from "So You Think You Are a Good Driver?" I do wonder if the test driver added to the problem when apparently attempting to correct the sway by steering. I believe that the brain delay factor may mean that, even with an experienced skid control trained driver, steering with a caravan sway may be impossible to co-ordinate, so will make it worse. I have read elsewhere that it's best to just let the car steering wheel move in your hands a little.
Pretty dramatic! Thanks for sacrificing two caravans to very effectively prove a point.
David - you have restored my faith in the human species - my only concern is that we all pull together to solve life threatening events that still plague our highways, I for one have tirelessly strived to accomplished this but alas upon deaf ears so far.
Thank you.
Thanks John and agreed. As you will have gathered, I wasn't previously aware that there was a facility allowing me to approve posts before publishing so will now try to change that. I believe the roads would be far safer that if everyone had regular refresher driving assessments and or tests, which are economically available in the UK from www.iamroadsmart.com/
I am surprized that no one knows what to do if a caravan or large trailer starts to sway, A swaying caravan or trailer will start steering the car in either direction, Do not try to fight this as you will only make things worse, Lock your arms and steer straight ahead take your foot of the accelerator, do not apply the brakes or accelerate the vehicle, You can apply the trailer brakes if you are able. I have used this method and it does work.
Only one thing stands out here . Badly loaded caravans cause accidents.
In all the tests the driver should have kept the wheel straight and avoid trying to counter the sway especially in the runs with the load unbalanced this is known as resonance or added force at a specific point. In all events uncontrolled sway is created when the ball loading is insufficient to meet the requirements of the tow vehicle rear axle loadings and tyre pressures because this causes the slip angles to increase on the rear tyres if pressure is to low. Easing off the gas is undoubtedly the best action to take. The problem with this is that you will be keeping the combination in the slipstream of the vehicle you are passing which may accentuate the yaw , however, if you could accelerate passed the bow wave of the other vehicle you may have a better result. However, there is NO substitute to having a PROACTIVE control system to stop yaw from starting in the first place whatever the cause - road rutting, wind and poor loading etc. This is the inherent flaw with caravan towing and there is only one proven method of prevention and that is the revolutionary "Differential Stability" The comment made "If all else fails slow down" will never occur with a PROACTIVE device.
Current electronic applications (Are not proactive) where the trailer is braked automatically can also prevent the combination from passing so beware they also brake both wheels of the trailer that in fact only aims to slow the combination down albeit at a predetermined slow rate to reduce the period and that also prevents the trailer from returning to equilibrium ( Try rotating your caravan with the hand brake on) - they do not offer any control of the induced inertia.
So how does Differential Stability work - It has a powerful hydraulic damper that integrates with a series of levers to apply a braking force to an individual brake via a very ingenious arrangement that applies a damped force to react if the applied inertia exceeds a specific rate on the upward slope of the sine wave thereby reducing the amplitude, then as the wave returns towards the centre of equilibrium a damped correcting equal and opposite force to the yaw is applied at or near the C of E if the rate is not further reduced. The result in practice is imperceptible sway by the driver. If you have ESP on your tow vehicle then this adds to the effectiveness of the whole combination since individual wheel braking of the tow car works in harmony. Ask about the revolutionary Differential Stability system at your local dealer.
Leave foot on throttle while gently braking and if anything, apply gradually throttle I was told. So, a combination of throttle and brake.
I have unsuccessfully tried to "reply" to John W that I don't recall his comment or removing it, but have now found it the "awaiting review" section and have now read and accepted it.
Hi David, it is now seven years on and yet no one has discovered how my differential stability works. The first company or person that does I will compliment the concept with my exact solution with no charge for doing so. To reiterate what it does I will explain. Leaving any maths out and just a simple explanation. There are no electronics involved just the energy and forces produced by the combination. When a force is exerted on the caravan it starts to sway by pivoting on the ball. Many have tried to stop this using a friction device on the ball hitch - a total nonsense to expect a 7m long trailer to be held by a 50mm ball.
So moving on - as the sway can be reduced by damping I use a suitable hydraulic damper that can be adjusted but does have a significant power ratio to make a difference. However, this is not enough to prevent a snake since it can also affect the tow vehicle adversely. Ok so what will control a sway - it is an equal and opposite force applied when the initial sway has pushed the vehicle out of line. The return swing will gain increasing momentum as it swings back and need to be checked just before or at the centre of equilibrium. This is the key to full control and is so easy to do it completely baffles the finest brains in the industry.
I say to those who advise on loading and speed control to continue doing so but it will not stem the problem until my differential control concept is adopted. I have covered 30,000 miles with my single axle combination around the French alps and some of the busiest roads in Europe with two electric bikes strapped to the rear of the van at any legal speed allowed. The silence is deafening.
@@Cruner62 How does your system differ from those which can now be fitted to cars and / or caravans?
Trailer brakes is the best way.
Install a weight equalizing hitch pulled a trailer in Canada with this type of hitch and no problems
This is bullshit, they usually start swaying on their own over 60mph, he's not even doing 50,and he's making it sway, my advice is keep below 60mph especially on hills and if you do feel even a slight sway coming on just take your foot off the gas and slow down until it disappears
Absolutely right. We can all do a 'snake' if we want to even at 20mph! I have been a caravanner for more years than I care to remember. Yours is the top tip, KEEP YOUR SPEED DOWN, and especially stay below 60. Number 2 is, don't let the van outweigh the towing ability of the car otherwise the tail will start wagging the dog.
Good advice William if you do not have a control system otherwise you are at the mercy of the elements - Differential stability is a control system that does what it says without the need for years of towing experience, it is proactive and constantly monitors the caravan for any sway and controls the return to centre if pushed by wind forces all this without any driver intervention - speed and relatively poor loading is covered - NB if there is negative ball loading it will let you know without going out of control. I cruise at 70 mph with two electric mountain bikes on the back of the van on France Autoroutes in heavy truck traffic.
Mr Warnham - I am saddened that you have chosen to remove my comment, it seems that you chose to do this rather than respond with a reason. Nothing I wrote could be interpreted as spam or malicious - it was only a truth. It seems that this is the fashion amongst the establishment that truth should be shut down rather than discussed. - Peace.
Apologies, John W, as I don't recall your comment or removing it. Please re-add it, and I will consider an appropriate reply.
Ah - I now see your comment is shown as "awaiting review" so I will now read it!
One lousy comment on here, two including mine
By "lousy" do you mean the quality of the comments or the lack of others alphadog158? If the latter, I admit I am also surprised, with 4,989 views.
Flexbase I mean the quantity as I thought there would have been a lot more but the film clip was very educational but if people actually had common sense you would know not to load the caravan unevenly as heavy one side means it will want to tip...
Also should maybe favour driver's side a tad more weight with the chamfer of the road
I drive my car at 80mph with my caravan and never had a problem 20 years on
Never had an accident but seen loads , all behind me lol.
The Captain of the Titanic had a perfect safety record too.
Don't feel too bad and good luck with that. There are many university professors cannot understand the physics involved let alone find a solution.