Archive for January, 2009

Bath University Research on Caravans

January 23, 2009

Paragraph 31a

Peter W Jones MInstP

I am pleased to note that people are reading the Bath University Research to such an extent that Google have now placed this item almost as high as 
The above is my brother’s attempt to run an internet newspaper.
He has only been working on this since he eventually gave up part time work at City University about 12 months ago.  He retired from his full time post as Senior Lecturer in Journalism some considerable time ago.

University of Bath

School of Mechanical EngineeringTHE DYNAMICS OF TOWED

An experimental study into caravan snaking

Final 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


Peter W Jones.

The following are a few items of importance that I have pasted in. 



. This is manifested in the fact that nearly all snaking accidents involve caravans.



Caravans are the most numerous of the high aspect vehicles in this class


Extensive studies into articulated lorry dynamics have been done, but due to the hobby nature

of caravanning there has been little money or academic interest in this field until

relatively recently.


Friction yaw dampers were found to increase stability; they reduced the amplitude

of oscillation and hence reduced the settling time. However, it was shown that the

stabiliser could not contain unstable oscillations if the situation would otherwise

become unstable without dampers. This was due to limitations of the moments

generated by the stabilisers.


It was discovered that stability reduced with both speed and stability and towing

coefficients. Thus a fast moving caravan with a large mass distributed around the

perimeter would be highly unstable. It was also confirmed that a heavy tow ball load

was more stable than a light tow ball load, and that it is beneficial for the caravan

mass to be low in comparison to the car

2.2.6. This theory is backed up by the fact that snaking does not occur

when the trailer is light and the car is heavy. a powerful yaw damper was found to

increase the snaking speed only a little, so generally it was considered an
unsatisfactory solution to the snaking problem
. Part 2: active caravan braking
A virtual braking system was developed in light of the results in Part 1. It consisted

of a control system that applied a brake to the caravan wheels in phase with the roll
oscillations, providing the greatest force when the tyre load was at a maximum.
Very effective stabilisation of the snaking vibrations was demonstrated in a variety
of circumstances, many of them much too challenging for friction dampers to deal
with. The power consumption requirements were easily manageable and the

technology is much closer to a prototype as a result of the work


See also paragraph 36 below