Stability Studies Research
The Department of Mechanical Engineering at the University of
Bath has been studying caravan stability and towing dynamics for
nearly twenty years and is now regarded by many within the industry
as the foremost independent authority in this field. The following
examples explain some of the findings from this valuable research.
The joint sponsorship by Bailey Caravans and The Caravan Club
has enabled the design and development of a sophisticated reconfigurable
test trailer which has been used extensively to investigate how
aspects of a caravan affect the stability of the system.
The trailer is wired to instruments that measure the motion of
the car and trailer for later analysis. The results of this analysis
showed that, in transit, the towcar is constantly aligning the
trailer and damping out small oscillations before they become
serious. The trailer's willingness to be controlled by the towcar
is greatly increased by minimising what is known as the trailer's
Yaw inertia.
Yaw inertia is a measure of how far weight is from the centre
of gravity, which in this case is across the caravan axle. Reducing
the overall weight of the trailer will reduce Yaw inertia and
concentrating that weight near the mid-axle point will greatly
reduce Yaw inertia.
Good caravan design, in producing a well balanced trailer, will
go a long way towards minimising Yaw inertia. That is why, for
example, in the majority of layouts, the heavy items such as kitchen
appliances are located in the centre of the caravan and where
for example a spare wheel is specified as standard specification
it is located on a carrier behind the axle.
However it is not all down to caravan design and the caravan
owner too can play their part in reducing Yaw inertia when he
or she loads the caravan by positioning items, particularly heavy
ones near the axle mid point. Remember load for safety and not
for convenience!
It is also recommended that there is enough weight in front
of the axle to achieve a nose weight that is as high as allowed
by the vehicle manufacturer (7% of the caravan weight)
As a final point the research concluded that speed remains the
dominant factor in stability performance and caravan owners are
advised to drive within the speed limits regardless of their caravan
outfit setup.
The research carried out by the University of Bath covers all
aspects of towing stability. Recently the Department tested the
Electronic Stability Programmes (ESP) found on higher specification
cars and the new AL-KO ATC Trailer Control System for caravans.
In both cases they found that the fitting of these items improved
caravan snaking performance and trailer stability in an emergency
swerve manoeuvre.
For more information on the AL-KO ATC Trailer Control System,
as fitted as standard on the new Senator Series 6 range, please
visit www.al-ko.co.uk/alko-Trailer.htm
<PAGE TOP>
|
