At 15:35 23 December 2019, Eric Greenwell wrote:
Don Johnstone wrote on 12/23/2019 1:36 AM:

What is worth remembering is that the cause of the sway is
aerodynamic. Loading, tyre pressure, fiction dampers can only
ensure that the sway is damped out and does not increase.
Trailers
with less vertical surface area aft of the wheels suffer less from
snaking than those with equal or greater vertical surface area
behind
the wheels. You may not be able to change the aerodynamics of
the
trailer but a good friction damper and proper loading will
normally
ensure that the snaking is damped.
I have been a passenger in a car towing a Cobra trailer at over
100mph, scared the crap out of me but it was completely stable,
but
only when loaded with the glider. Empty it was a different story.

How did you decide aerodynamics was the important factor, and
not other
factors
like tongue length, tires, etc? That's counterintuitive and, for
example,
it's at
significant variance with Nelson Funston's paper on towing glider
trailers,
which
does not include aerodynamic factors.

http://journals.sfu.ca/ts/index.php/...wnload/779/737

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us"
to email
me)
- "A Guide to Self-Launching Sailplane Operation"

https://sites.google.com/site/motorg...ions/download-
the-guide-1

From observation of driving trailers over many years. Aerodynamic
forces are almost always the initial cause of the onset of snaking,
the other factors take over in damping out, or increasing the initial
disturbance. I can be towing at say 60mph in clear air. If I am
overtaken, especially by a large vehicle I fist notice that as the
vehicle is alongside the trailer is drawn towards the other vehicle,
when the vehicle has passed the trailer moves away and this is
where the snake starts. From that point on the other mentioned
factors take over, which, almost without exception, we all use
stabilisers, mostly ALKO type