See also

www.20six.co.uk/roadtrafficaccidents

www.caravanaccidents.wordpress.com

 

www.caravanaccidents2.wordpress.com 

 

Paragraph 33 

 

Air Speed Indicators

.

Peter W Jones MInstP

.

.In drawing attention to the need for the above I am suggesting a change that has not, as far as I know, been proposed elsewhere.The Caravan Industry and the Caravan Clubs have regrettably resisted the use of safer technology for some years and have left the EU/UK very much in a technological backwater, whilst the air craft industry (Air Bus) are now amongst the world leaders.As Standen’s 1999 Bath University Phd thesis (Towed Vehicle Aerodynamics) still only resides in the British Library on microfiche, few people are aware of the fact that he proved in wind tunnel tests (with scale models) that an HGV could destabilise a car/caravan combination and aerofoils improved the stability of a caravan.In 2003 when I was using the Road Traffic Accident Investigators private Yahoo e mail system and circulated the above and other details of the Bath University research I discovered that the aerodynamic research mentioned above was quite unique far beyond the EU, and the fact that it must also at least apply to some HGV trailers ( the need for aerofoils) was also not known.

However, it may well be that research has been done that has not been published.

Even with aerofoils and electronic brakes there will still be an upper speed limit for all vehicles, particularly trailers, which must be decided on the basis of the Laws of Physics and then enshrined in Government regulations as is already done in a similar manner for the air craft industry.

I do not think it will ever be necessary to take as many precautions for solo vehicles as if you cannot sense yourself the effect of the wind on the vehicle you are driving, you should not be in charge on the road. When towing a trailer there is another vehicle to be considered with very different characteristics, and an electronic system is needed to give information about the forces on the trailer as well as an air speed indicator.

Designing a suitable air speed indicator for use by road and rail vehicles will be comparatively easy once the need for same has been accepted. All that is required is a “weather vane” (to sense direction) and rotating parts ( to sense speed) .   

 

 

 

 

 

 

 

 

 

The direction that the “weather vane” would point is determined by the wind produced by the forward motion of the vehicle and the wind ( if any) resulting from natural weather fluctuations. The software would then convert this into a “Head wind” component (in mph) and a “side wind” component. The two speeds would be displayed for the driver to read.

The maximum safe air speed ( road speed plus head wind component) must be established for each vehicle, but this as with aircraft will vary depending on the load being carried.

Similarly the side wind component will vary, but for the driver (as with the pilot) this only has to be looked up once in a set of tables for each journey. There would have to be anemometers in exposed places at the side of major roads to send out details of side wind speeds by radio ( information is currently transmitted by the RAC that determines “congestion points” by measuring traffic speed at many points on all major roads in the UK).

For minor roads drivers would still have to depend on the wind speed forecasts given by the met office, as we shall still have to do for some time in all cases.

Even if there are no fatalities or serious injuries every time an HGV trailer over turns or otherwise gets out of control we have a major problem as it takes some hours to get a crane to the site which is capable of lifting up the wreckage. A caravan is easily pushed out of the way by a Police Land Rover.

When considering the costs of my proposals the lost productive hours of the many thousands of people caught up in resulting traffic jams should be taken into account.

Currently I do not think the DfT have any records concerning HGV or caravan accidents resulting from the effects of the wind, as this in the past has not been properly recognised as a serious problem.  

 

.

Addendum 5-11-08.

It seems that I was seeking information concerning currently available anemometers for road and rail vehicles in the wrong place. I should have used Google !

There are suitable appliances on the market that will only need a comparatively minor modification ( to the software only in some cases) to meet the requirements of locomotives and road trailers.

It is most probable that suitable hardware already exists and the only remaining task is to programme same so that the “air speed” and “side wind component” can be displayed.

I have also recently realised that I have failed to draw attention to another aspect of this matter. Formula 1 racing cars and HGV’s with trailers frequently travel at about 100mph air speed, but only the former have the benefit of aerofoils to help keep them in good contact with the road and more able to resist any side forces from the wind. Racing cars are viewed by thousands of spectators and officials are prompt in their control of the situation when extreme weather conditions apply. On the motorways little can currently be done by traffic police in the same situation as critical air speeds and side wind components need to be known for each type of vehicle, as is the case for air craft.

However as I feel certain that the anemometers/air speed indicators that I have outlined above could be produced at a reasonable price and even if they were only half as popular as GPS navigation ( and I feel certain they would cost much less), a considerable contribution could be made towards reducing accidents because drivers would use their own judgement. Governments would then eventually legislate to ensure that ( as with the air craft industry) the critical speeds for each type of vehicle were stated in the manufacturers’ manuals for drivers.

 

ADDENDUM  22-11-08

I have now written to several manufacturers of anemometers and had one positive reply.

www.biral.com    of Portishead, Bristol, UK  sell a suitable anemometer which only needs extra software to be written to convert to my above mentioned specifications.

edit 30-09-09

I received a quote from biral.com of around 1500 pounds sterling (UK) for the above during the Summer.

This type of cost will be considered reasonable when more people become aware of the reduction in accidents that would result. However, Governments would have to legislate before the HGV industry would install these devices.

For recreational trailer towers like myself  the cost would be unacceptable at present and I shall continue pestering our Met Office to make more widely available their internet wind speed forecasts. I can always use the internet beore I leave home, but this Summer found myself having to restrict my speed considerably on one journey because I failed to get to an internet cafe before setting out. In another instance I made a detour to avoid the M5 bridge over the river Avon when it may not have been necessary. However, I have lived to start my 34th year of receational towing if the cancer clinic eventually discharge me tomorrow after 5 years of “monitoring.”

 

Lobbying Parliament

Para 34

Lobbying Parliament

Peter W Jones MInstP

..

I have several times attended at Westminster for the purpose of “Lobbying,” but I was always accompanied by many other affiliated members of the TUC.I have recently come to realise that lobbying by persons who are employed by the “Corporate Sector” is far more effective and I am endeavouring to draw attention to one particular item where the Corporate Sector have made a Scientific Error on the same scale as King Canute. He was reputed to have sat on his throne on a beach with the object of preventing the incoming tide covering the beach. Corporate Sector Lobbyists have clearly managed to convince parliament that however strongly the wind blows, it cannot possibly be of danger to road traffic (even high aspect HGV’s and Caravans.)Accordingly I wrote to Dr Tony Wright MP on this subject and I have printed his reply below... 

(see www.20six.co.uk/roadtrafficaccidents  Section 18b, for details concerning the effect of the wind on road vehicles)

********************************************************

 

 

 

 

 

Para 35   Letter from Dr Tony Wright MP 

Dear Mr Jones,

Thanks for your letter.

The subject matter of your letter is of course not within the remit of the Public Administration Select Committee, but it does offer an interesting insight into the role of lobbying. I shall bring it to the attention of the Committee.

Yours sincerely,

Tony Wright

Dr Tony Wright MP (Cannock Chase)
www.tonywright.org

—–Original Message—–
From: peterw****************************
Sent: 07 March 2008 19:18
To: Public Admin Committee
Subject: Committee on lobbying

Peter W Jones MInstP
Consultant for Towed Vehicle Accidents
HGV Trailers, Caravans and Small Trailers Charitable Status to be Applied for

www.caravanaccidents.wordpress.com

Tony Wright MP
Chair of the Committee on Lobbying

Dear Sir,

Although I have been in receipt of e mails from the HoC on all committees I had over looked the relevance of your work to mine until John Humpreys enlightened me at about 0745 today on Radio 4 News.

I wrote to the Hon Mrs Dunwoody MP in late 2005 concerning the lobbying by the Caravan club ( via two MP’s whose names were at that time listed in “members’ interests” as being paid to lobby by the Caravan club).

The Caravan Club sponsored a considerable amount of research that was carried out by the Department of Mechanical Engineering at Bath University; some of this gave rise to two Phd theses and an Mphil thesis. On the basis of this research Caravan Club officials assured myself and about 120 other CC members present at a meeting at the Thistle Hotel, East Midlands Airport in March 2003 that matters I had reported on concerning caravan instability were quite irrelevant as they had had everything researched at Bath university.
Their long held policies on caravan safety had been proved to be correct.

When I eventually managed to obtain and read these theses I found that the CC were seriously misleading the membership (and possibly the HoC) and since March of 2007 I have had blogs on the web setting out in detail my reasons for this allegation.

Mrs Dunwoody wrote that she would be pleased to consider any report that I wished to make that was within the existing terms of reference of the House of Commons Select Committee on Transport. Accordingly you will find in Hansard for February 2006 a report I wrote concerning Caravan Accident Statistics and the lack of adequate monitoring for wind speed by the Highways Agency (NB It was revealed this last weekend that Network Rail also fail to monitor for wind speed).

I gathered from John Humphreys’ news item that the committee enquiring into lobbying were so alarmed by the fact that firms of lobbyists were specialising in misleading Parliament, (and that some MP’s were
involved,) that they would wish to sweep this item back under the carpet.

Accordingly I am directing this letter via your committee’s press secretary, to emphasise the fact that I shall also be attempting to publish this material.
However, do not be unduly alarmed as the BBC have three times spurned items I have sent them, two having been rejected by BBC Watchdog.

Yours faithfully,

Peter W Jones

__________________________________________________

Para 36 Stabilisers; Bath University

 

 

Para 36

Peter W Jones MInstP

The above graph and the photograph below have been copied from the Bath University Report (see further below).

The electronically produced graph above shows the effect of an ALKO stabiliser on a snaking caravan (blue graph).  The red part of the graph shows the oscillations without the stabiliser in place. This graph should have appeared in the space in the account below.

The photograph below shows the ALKO stabiliser tested by Bath University.

Stabilisers; Bath University

Peter W Jones MInstP

.

Copied from the internet

 

 

 

University of Bath 

 

 

School of Mechanical Engineering 

 

 

THE DYNAMICS OF TOWEDVEHICLES

 

 

 

An experimental study into caravan snakingFinal year project

submitted by Christopher J Killer

for the degree of MEng

of the University of Bath

23 May 2003

Assessor RFN

Supervisor JD

Technician PC

 

 

 

*******************************************************************11 Conclusion

 

 

 

********************************************************************************************The performance of the Alko 2004 tow ball friction damper has been shown to be

very effective at smoothing down snaking oscillations and reducing settling time. But this does not necessarily mean that it makes the coupled combination any safer, i.e. increase the snaking speed. Theory states that this type of damping has little effect on the snaking speed, and tests have shown no evidence to suggest otherwise.

********************************************************************************************

 

 

 

11.1 Practical advice for caravan owners & designers 

 

 

Nothing fundamentally new was discovered in this study, but theoretical factorssuggested in the past have been substantiated by road-tested evidence. The

theoretical advice that is now known to be significant in increasing stability includes

the following points.

For owners:

 

 

 

• Make sure car is suitable for the size of caravan 

 

 

• Load heaviest items in the car if possible 

 

 

• Locate other heavy items in the centre of the caravan, just forward of its axle 

 

 

• Make sure tow ball load is adequately high 

 

 

• Avoid sharp steer inputs at high speed 

 

 

• Never exceed 60mph

for designers: 

 

 

• Put the heaviest parts of the caravan, e.g. kitchen, in the centre 

 

 

• Consider the distance h between the C.G. and the axle, and its significance in

terms of stability 

 

 

• Calculate the new stability coefficient (incorporating h) for each design

and although not tested in this study, other recommendations from mathematicalanalysis include:

 

 

 

• Make distance from tow hook to axle as long as possible 

 

 

• Move back the C.G. so as not to induce excessive tow ball load 

 

 

• Maintain a high tyre pressure to keep lateral stiffness high 

 

 

Bath University Report (cont)

.

(extracts)

.

9.5 The effect of using the stabiliser………….., small amplitude oscillations are attenuated considerably more than large ones. Theory also predicted that the frequency of oscillation would decrease when the damper was present, the graph does show this to a very small degree, though frequency was essentially unaffected.

.

………………………….), therefore if the initial one is too large for the friction damper to have any significant effect, thensubsequent oscillations will not decrease in amplitude and the system will become Unstable

Figure 23: Effect of stabiliser shown in blue

.

THE ABOVE  GRAPH HAS NOT APPEARED. IT CAN BE SEEN ON THE BATH UNIVERSITY WEB SITE AND IS NOW ALSO SHOWN AT THE START OF THIS BLOG.

..

Peter W Jones MInstP

.

I have selected the above items from Mr Killers’ work, but as this is displayed on the web it is very easy for interested parties to view the whole document. Mr Killer has made it clear in another section of his report that excessive load on the tow ball can lead to steering deficiencies in the tow car; this is not quite clear from the conclusions.In my view Mr Killer should not, on the basis of his results, suggest never exceeding 60mph. All his results were in the range 30 to 50 mph so it is only justifiable to say that the ALKO stabiliser does not necessarily make the car/caravan combination safer within the speed range 30 to 50 mph.

Standen (Towed Vehicle Aerodynamics 1999) showed in his wind tunnel tests that aerofoils increased caravan stability; my extensive experience towing on the road leads me to believe that aerodynamic lift is a factor over about 50 mph (air speed) and any future studies should investigate this matter in particular. I only have one vote in the caravan club, but I hope that other members will   ensure that the research at Bath University continues and that the results appear on the internet without editing.

I do not agree that sharp steering inputs ( when towing) should only be avoided at high speed. Such in puts are potentially dangerous from about 40mph. However, sharp steering inputs only have a minor effect on caravan/trailer snaking compared with the effect of side winds or the effects of Large High Aspect Vehicles (Standen 1999). When concluding that the ALKO Stabiliser did not necessarily improve safety Mr Killer did not consider the last two factors. The condemnation should have been much stronger.

My conclusion is that on the basis of Fratilla 1994, Killer 2003 and my further analysis of the ALKO stabiliser below, any friction based stabiliser failing the simple test I have outlined also below should only be sold in the UK with a clear “large type” summary of the Fratilla and Killer conclusions.

This action would encourage the caravan/trailer industries to seriously consider using the electric brakes which have been in use elsewhere for over thirty years and are cheaper than over run brakes plus stabiliser. Pneumatic and hydraulic brakes are also feasible; an example of the former was successfully tested for over 12 months by a journalist from Practical Caravan Magazine. Furthermore enterprising companies would develop aerofoils following the public attention given to friction based stabilisers, and HGV trailer manufacturers would also have to consider aerofoils as well as electronic brakes to improve safety.

 

Para 37

 

Peter W Jones MInstP.

Photograph of Stabiliser and Tow Ball …

Below is a photograph of the  same stabiliser that I published on >

.. 

March 9^th.

.. 

This time I have removed the tow ball cover so that the size of the

.. 

 tow ball relative to the circular part of the stabiliser can be

. 

.seen.The tow ball is a standard 50mm in diameter.

Inside the circular part of the stabiliser are TWO friction pads of

100mm diameter, with a circular space in the centre of 50mm

diameter where there is no friction material.

Readers who have remembered their GCSE Maths will be able to calculate the area of the friction material available in my now obsolete Scott stabiliser ( but similar stabilisers are still on sale) and compare that with the area of friction material available inside the ALKO stabiliser which is still on sale as a “retro fit” and as a standard item on most of the used caravans in dealers’ show spaces.

However, do not give up if you lack a GCSE Maths textbook because the difference in size between the area of friction available with the Scott Stabiliser and the ALKO stabiliser is so great that it is apparent from my photograph below and it is hardly worth doing the calculations.

For readers who are not familiar with ALKO stabilisers I must point out that this device uses friction between a tow ball free from grease and a “cup like” device which fits over the tow ball.

The force of friction generated by your cars’ brakes is not only in direct proportion to the area of your discs (on the brakes), but in direct proportion to the force applied to the brake pedal (this is of course not quite true if you have abs or a similar electronic system.)

My Scott stabiliser has a nut which can clearly be seen in the photograph and this is used to take up wear and keep the correct force on the friction plates. To the best of my knowledge the only way that owners of the ALKO friction based stabiliser can allow for wear on the friction pads is to replace them.

If ALKO engineers had viewed the matter in the above light they would not have made this type of stabiliser as it is clearly inferior to the type it has now managed to almost completely replace. I would give the ALKO device full marks for smartness of design and appearance, but very low marks for effectiveness in reducing snaking of trailers/caravans with over run brakes.

Details of my test for friction based stabilisers are in

www.20six.co.uk/roadtrafficaccidents Section 18a.They are also further on in this blog (or in the archives). The duplication is due to the fact that 20six.co.uk seems to be “off line” a great deal of late.

 

 

Letter to the Hon Mrs Dunwoody MP

Para 38

 

Dear Mrs Dunwoody,

Thank you for your prompt reply to my e mail.

I am publishing your reply in www.caravanaccidents3.wordpress.com
together with my e mail to Tony Wright MP
and my reply to yourself.

_________________________________________________________________________________________

The following is a reply to my e mail concerning the recent closure of
the West Coast Main Railway line due to Containers weighing up to 4
tonnes being blown off a freight train.
This reveals the fact that Network Rail, like the Highways Agency, do
not accurately monitor wind speeds.
Railways have always had strict regulations concerning the max safe
speed for particular stretches of track, but they seem to think that
all their tracks are safe at any wind speed.

I also mentioned in my e mail that I wished to complain about the conduct of a Senior Engineer at the DfT (Trading Standards) who did not adequately advise Birmingham Trading Standards when they asked for advice in 2006 concerning my test for caravan stabilisers.

——————————————————————————————————————————————

I HAVE DELETED MY HOME ADDRESS FROM THE FOLLOWING LETTER, BUT
OTHERWISE IT IS AS I RECEIVED IT.
THE ERRORS IN THE LETTER ARE DISTORTIONS PRODUCED BY MY SCANNER,
PARTICULARLY THE FACT THAT MRS DUNWOODY’S SIGNATURE HAS BEEN
ERRADICATED.

I NOTE THAT AS ANDREW MARR’S “HISTORY OF MODERN BRITAIN” DOES NOT
MENTION AN EMBARASSING DEFEAT OF (IN MY OPINION) ONE OF THE MOST OUT
STANDING PRIME MINISTERS OF MY LIFE TIME, I SHOULD
REMIND READERS THAT THIS DEFEAT BY MP’s WAS
PRECIPITATED WHEN TONY BLAIR TRIED TO REPLACE MRS DUNWOODY AS CHAIR OF THE SELECT COMMITTEE ON TRANSPORT.

———————————————————————————————————————————————–

MRS GWYNETH DUNWOODY MP.

HOUSE OF COMMONS
LONDON SW1A OAA
Tel: 020 7219 3490 Fax: 020 7219 6046

Peter Jones, Esq
4th March 2008
Dear Mr Jones
Thank you for your email of 3rd March 2008. I am grateful to you for
keeping me up to date, but as I was caught up in the problems over
the
weekend, I am only too aware of the
situation.
I understand your worries about the evidence that was presented and
we
do, of course, try to get as broad a cross section as possible to
give
us accurate information.
At the moment, we are not looking at the caravan/trailer points that
you raise and I am afraid that we do not have sufficient trained
staff
which would enable us to undertake the sort of inquiries that would
be
of interest to you.
I have, however, noted your views and will make sure that we keep
them
on file for the next time we meet the Secretary of State and the
Permanent Secretary to discuss them.

Yours sincere!

hon. mrs GwVNETH dunwoody MP
www.gwyneMi dunwoody.co.uk
Constituency Office: Tel. 01270 589132 Fax. 01270 589135

——————————————————————————————————————————————-

From Peter W Jones
Retired Head of Science in a Birmingham Comprehensive School.

I hope that Mrs Dunwoody means that she will not only be pressing for
monitoring of wind speeds on our main roads and railways, but will be
seeking an investigation in to the conduct of the Senior Engineer at
the DfT that I drew attention to.

I thought that civil servants at the DfT had a duty to provide
advice
and support when asked for same by colleagues in Birmingham.
I retired before OFSTED came into being, but if any one senior to
myself thought that I was not performing my duties satisfactorily I
would expect to see an HMI at the back of my laboratory observing how
I conducted myself when teaching a class of 16 year olds ( for
instance). I think some thing similar should apply at the DfT to
Professional Engineers.

My stabiliser test
( see www.20six.co.uk/roadtrafficaccidents Section 18a and
www.caravanaccidents3.wordpress.com)
is quite simple (in the Physics world), and it only
supports the results on caravan stabilisers produced by Bath
University
Department of Mechanical Engineering in 1994. (see a small section
of
Fratilla’s Phd Thesis ).
Exact quotes in section 2e of www.caravanaccidents2.wordpress.com

When the Caravan Club received this thesis in 1994 I think they
should have pressed for the banning of these stabilisers. In other parts of
the world electric brakes were in use and they are far more effective
as caravan/trailer stabilisers. If the Caravan Industry felt that
EU/UK
regulations on caravan/trailer brakes were unduly restrictive they
should have urged the authoriites to change the wording of the
regulations.

__________________________________________________

Para 39 PHOTOGRAPH OF A STABILISER

Information Concerning Stabilisers for those reading this blog

with no experience of caravanning or trailer towing. 

This stabiliser is several years old, but it still meets the specifications prescribed for a new item.

Similar items of the same type are still on sale in large caravan dealer’s show rooms, but under a different brand name.

The rather grubby spherical item of maroon colour is the cover over the tow ball. I keep the latter well greased.

The approximately circular item to the right of the tow ball contains the friction pads held between plates of metal.

The nut in the centre of the circular item can be tightened or slackened in order to obtain the prescribed amount of friction.

To measure the friction  place a set of accurate bathroom scales against the right hand end of the lever and apply pressure. The reading should be taken just as the stabiliser arm begins to move.

The amount of frictional force is laid down by the manufacturers, but according to the caravan club’s advice section for members it is almost exactly the same for all types. In my view the limiting factor is the amount of torque the towing bracket of the tow car will stand.

The caravan club did not give the specified torque for the ALKO stabiliser, presumably because it can not be adjusted

In use on the road the right hand end of the  stabiliser arm ( as shown in the photograph above) fits into a plastic mounting on the front of the caravan chassis, so that if the caravan oscillates from side to side  ( snakes) when being towed the friction between the sections of the circular part of the stabiliser should dampen down the oscillations.

For details of how to test whether the stabiliser is likely to be of any use on the road go to  section  18a by scrolling to the end of this blog and then clicking on “Older Entries,”  and scrolling further.

To read the 1994 Bath University result on Stabilisers

 go to section 2e

www.caravanaccidents2.wordpress.com

The 2003 Bath University report on stabilisers supports the 1994 result.

I shall add further comments on this within the next few days.