Nobody wrote:I THINK there's been waaay too much 'thinking' going on here . The dynamics/principles of trailer towing have been 'studied' to death by various agencies, individual, corporate, & government, for longer than I've been alive (I'll be 70 in a few days). They've all ended up coming to basically the same conclusion - design the trailer essentially as Andrew shows, 'balance' the load so there's more weight in front of the axle than behind, match the trailer to the TV (weight & power wise), remain alert & aware of your 'tow' even when the TV 'doesn't even know it's there', & mainly use a little uncommon 'common' sense. Trailers have been towed behind motorized vehicles for a hundred years, & with other 'power' sources long before that; the principles were learned early on, & they STILL apply! No need to reinvent the wheel.
Abstract
Previous work on car–trailer stability has been largely limited to theoretical studies with some reference to practical experience or accident statistics. In this study, extensive and systematic experimental investigations were carried out on a combined car–adjustable-trailer system. The influence of different trailer parameters on the system high-speed stability was examined by changing the mass, dimensions, and inertial characteristics of a fully adjustable trailer. It was found that the dominant factors affecting stability were the trailer yaw inertia, nose mass (mass distribution), and trailer axle position. The tyre pressure also affects the stability, although this effect is less significant. It is interesting to see that the trailer mass alone does not dramatically affect the high-speed stability, as this runs contrary to current guidelines relating to limits on the relative mass of the car and trailer. Experimental tests on a friction stabilizer and on car electronic stability programs demonstrate that both of these improve the high-speed stability and help to delay the onset of ‘snaking’.
TD Beej wrote:I am trying to understand the dynamics of trailer handling so I can make the best choices.
The point is to make informed choices and to do that one needs to be informed.
Now a multilink suspension is attractive for a number of reasons but it also has drawbacks and when the choice is made it will be done knowing why and not because anyone may think it is "overkill".
madjack wrote:...does anyone have a link to "Zyamfers" Mini running the "Tail Of the Dragon" while towing his torsion axled tear????
madjack
TD Beej wrote:And as to my swaying driver, the problem is that the suspension can store energies (even with correct dampening) and if the sway is at the correct rhythm the sway will amplify just like pumping your legs on a swing. Same thing can be setup up by the road, or wind, or turning inputs (Hollywood stunt drivers claim they can get any car to roll by the right turn inputs).
Designing suspension for cars is quite a different matter... So I don't see how to work out what geometry you actually want.
However I can believe an improvement on typical trailer suspension wouldn't be hard to achieve. My personal favourite would be to get the spring rate down (and travel up) from its current Model-T values so that the trailer would stick to a bumpy road, rather than pogo across it.
One thing to look at on this subject is what the (very thorough) German authorities require for travel trailers before they can increase their maximum speed from 80 or 90 km/hr (50 or 56 mph) to 100 km/hr (62mph). I know that hydraulic dampers is one of the requirements, but it would be good to find out all the others.
Another consideration with complex suspension systems is the typical width taken up by the various links and/or the typical spring/damper assembly.
Question, though... Would that help with stability in an obstacle avoidance situation? Is there any practical way to design a trailer suspension to maintain or regain control faster than what the typical trailer can do now?
That is the big question I have. I wonder if someone spending lots of time, effort and money to find the perfect suspension would find that it does very little to improve the actual performance of the trailer.
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