LIST OF CONTENTS

December 16, 2011

(1)     ALKO   CONVERSION    KIT  FOR  OVER RUN  BRAKES

(2)    GCSE  PHYSICS  LABORATORY   SIMULATION   OF   TRAILER   ELECTRIC   BRAKES

(3)    EXTRACTS   FROM  THE  CARAVAN  AND  CAMPING  CLUB’S   2008   TOW

           CAR   AWARDS    SUPPLEMENT.

(1) ALKO OVER RUN TO ELECTRIC BRAKE CONVERSION KIT

February 18, 2011

Peter W Jones MInstP

18-02-11

The ALKO ad that I wrote about below seems to have been removed from the web.

For the record I have pasted the script of their removed ad in to my blog:-

www.hgvaccidentstatistics.wordpress.com

ALKO ELECTRIC BRAKES

January 28, 2011

Peter Jones MInstP
Consultant for Towed Vehicle Accidents
(Voluntary Status to be Applied for)

Alko Electric Brakes

I noticed on 28-01-11 that the brief summary on Google concerning Alko that appears when one enters “Caravan and HGV Trailer Snaking Accidents” in to Google contained a reference to Turbulence, snaking and HGV’s .

I had not read anything technical on the web originating from the caravan/trailer industry since my clash with them via TouringandTenting.com which I wrote about some time ago in www.caravanaccidents.wordpress.com

From the short reference above it is clear that the caravan/trailer industry think that turbulence from HGV’s may cause high sided trailers to snake. This is quite impossible. When any fixed wing aircraft takes off it is because the streamlined air flow over the wings produces “aerodynamic lift.” Whenever, on very rare occasions, an aircraft encounters an area of turbulence it immediately looses all aerodynamic lift and drops like a stone until calmer air is encountered.

It follows therefore that if HGV’s and similar large vehicles produced turbulence we would have far fewer caravan snaking accidents caused by HGV’s. There is still of course what cruiser and dingy sailors call the “Ventrui Effect.” This happens when an HGV passes very close to a caravan when overtaking, and the effect is even stronger when the caravan overtakes the HGV when they are very close together. There could even be a disastrous snake in this instance even though the caravan was moving below the critical air speed which I have explained previously. This is because ( in my opinion) the force exerted on the caravan is so much greater than when the “bow wave” of the HGV influences the caravan.

Standen of Bath University, showed in his 1999 Phd thesis “Towed Vehicle Aerodynamics,” that suitably sized caravan aerofoils (similar to those on the front and back of F1 racing cars) could reduce snaking by creating extra down force on caravans and high aspect trailers. Standen verified this important item of Physics by extensive experiments with models in the university wind tunnel.

If any Scientific Academics do wish to take an interest the exact parts of Standen’s results that I am using will be found in “quotes” in my unpublished report (apart from blogs) sent to the Institute of Traffic Accident Investigators (www.itai.org) in 2005.
See “Archives for April 2007” in www.caravanaccidents2.wordpress.com

Edit 14-02-11
I have now copied parts of my 20six.co.uk blog in to
www.itai2005reportpart2.wordpress.com 

Caravan/trailer brakes:-  5f,6b,6e&f,7b,8a,9d,10c[1,10 & 14]

Selby Rail/Road disaster:- (Did the over run brake contribute to this disaster?)

see www.caravanaccidents3.wordpress.com  Scroll to  Para 31i and  for stabilisers scroll to para 36 for Bath University results and to para 43 for the Peter Jones  stabiliser test which is suitable to carry out in schools.

I think I showed ( using Standen’s results) that the “air disturbance” produced by a HGV was a bow wave and not turbulence. ( Assuming air acts in a similar way to water the bow wave effect is confirmed every time a boat is observed moving through calm water).
Similarly the Ventrui/suction effect is confirmed if one notes that a boat never moves close to and parallel with a harbour wall. The crew man/woman holding the rope in the bow always jumps on to the wall as the boat gets close when approaching at an angle of about 30 degrees. (It will cost sailors a great deal of money if they overlook this when taking a 2 million pound sterling GRP boat alongside a harbour wall built for ancient sailing ships.)

It is possible that if turbulence could be created using many simple and small wind deflectors on the top of HGV trailers, the aerodynamic lift would be eliminated and jack knifing would be much reduced.

See also www.aerodynamicsoftrailers.wordpress.com

____________________________________________

COPIED FROM ALKO’S ON LINE ADVERTISING BLOG ON 28-01-2011

AL-KO has created an automatic system which detects signs of Caravan Instability, to take preventative action at the earliest stage, before disaster takes place. It was also vitally important that the existing caravan braking systems was used to quickly control the problem.

Thus taking the Car and Caravan combination down below the “critical speed, and prevent a disaster situation”

AL-KO ATC is the emergency braking system for caravans and works in a similar way to ESP systems for cars. The sophisticated, but simple electronic system monitors the lateral movement of a caravan during travel. When difficult driving conditions are experienced, such as evasive manoeuvring, high side winds and turbulence encountered while overtaking HGV’s, AL-KO ATC takes control to regain stability and prevent dangerous snaking accidents.

____________________________________________________

PWJ

The caravan clubs/industry (to the best of my knowledge) have never tried to explain what the “critical speed” for a caravan is, or how it varies. In fact, I have not before noticed that they now agree there is such a thing as a “critical speed.”
( see my explanation near the start of
www.caravanaccidents4.wordpress.com
and entitled “Paragraph 103; Caravan Club Technical Advice.”)

Concerning the rest of the material I have quoted above I suggest that readers look at my blog
www.caravanaccidents4.wordpress.com
and scroll down to “Caravan and Camping Club 2008 Tow Car Awards Tests.”
In addition if one scrolls further down this blog some rather poor copies of the CCC 2008 Tow Car Awards Tests can be seen, plus a link to www.caravanaccidents4.wordpress.com

December 10, 2009

Peter W Jones MInstP

see also

www.caravanaccidents.wordpress.com  (to learn of my experiences when I communicated with a web site sponsored by the Caravan Club.)

www.20six.co.uk/roadtrafficaccidents  ( to read about  the good relationship I built up with some of the members of the Institute of Traffic Accident Investigators and other related topics.)

 

);

Edit 04/02/11

The ALKO electric adaptation of the over run brake must be either “on” or “off.” It is most probably held in the “on” position by a strong spring and when the car engine is switched on electric current flows to the electromagnet and this holds the brake in the “off” position. The system must switch off this current when the tow car brakes are applied thus applying maximum braking force and probably locking the caravan wheels.
The CCC testers must have sensed this state of affairs and this is why they disconnected the ALKO system when doing the emergency lane change.

Some small mobility scooters ( max speed 4 mph) do exactly the same thing ( I know because I some times ride my wife’s mobility scooter). When the lever is activated to start the scooter for a few seconds nothing happens. This must be because the electric current is being used by the electromagnet to switch off the brakes. When the battery recovers from this operation the scooter starts. In an emergency the reduced mobility person justs lets go of the steering tiller. The electric motor looses all power and the spring applies the brakes and at even 4 mph one is pitched slightly forward.

The USA electric brakes are not the same as students can check for themselves. If the coil shown in the diagram is connected to a rheostat the current can be varied and this will alter the pull of the magnet as shown by the force meter reading. In other words the brakes could be gradually applied by an electro magnet.

All this is hypothetical as I have not tested the new alko electric brakes or the USA electric brakes. However, I have tested a friction based stabiliser and found this to be of no use whatsoever in reducing caravan snaking because the amount of frictional force produced by the stabiliser is neglible. This ALKO friction based stabiliser is an integral part of the latest ALKO electric system.
The Consumer’s Association (” Which” Magazine)said some years ago that they could not use my test as they did not understand my Physics.

Since I have produced rough notes for Physics teachers in my blogs ( see above address) the Consumers’ Association could now run these tests in conjunction with a school. In addition they could also test the USA electric brakes and compare them with over run brakes as this does not require a knowledge of Physics.
When the two types of brakes are tested on the road with the caravan in line with the trailer, I doubt that there would be much difference between the two types.

When a caravan is snaking (with over run brakes the Highway Code virtually says do not use the brakes) the testers will very likely refuse to test the over run brakes. The USA electric brakes should not only stop the car/caravan combination when it is snaking, but should also illiminate the snaking.

(2)   GCSE PHYSICS LABORATORY SIMULATION OF TRAILER ELECTRIC BRAKES

December 10, 2009

 

(3)    EXTRACTS FOM THE CARAVAN AND CAMPING CLUB’S  TOW CAR AWARDS

           SUPPLEMENT OF 2008

December 8, 2009

CCC   TOW  CAR  AWARDS  2008   PAGE  45

See www.caravanaccidents4.wordpress.com   for the  explanation of the items the testers overlooked when running these trials on the caravan industry electric adaptaion of the over run brake.SCROLL RIGHT DOWN TO   ‘CARAVAN AND CAMPING CLUB 2008 TOW CAR AWARDS”

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December 8, 2009

CCC  TOW  CAR  AWARDS 2008  Page  51

December 7, 2009

CCC  TOW  CAR  AWARDS  2008    PAGE 5

December 7, 2009

CCC  TOW  CAR  AWARDS  2008    Page  4