Do trailers with coil springs and shock absorbers sway at higher speeds?

On Thursday, June 12, 2014 11:24:57 AM UTC-4, son_of_flubber wrote:
On Thursday, June 12, 2014 9:34:18 AM UTC-4, wrote:

I tow an Avionic behind a BMW 325 with a 2 inch ball- no problems.



Lots of good ideas shared here. Thanks.



My goal is to achieve 70 mph stable towing for East Coast towing and 80 mph for western states towing.



From comments made here, it appears to be possible to achieve these numbers with the Avionic torsion bar suspension with a moderate sized vehicle like Volvo XC70.



Things to try:



1)Increase tongue weight which is a measure of how much the CG is forward of the axle.



2)Increase cargo mass close to the tow ball in both the trailer and the tow vehicle.



3)Trailer tires- use trailer type tires, use max pressure to increase sidewall stiffness. Avionic specific, increase tire size to 175 from 165.



4)Tow vehicle- increase cargo mass near tow ball, verify/upgrade suspension stiffness, increase rear tire pressure for sidewall stiffness. Possibly upgrade rear tires for side movement stiffness.



5)Check that the axle is perpendicular with the longitudinal axis of the trailer. Correct misalignment if possible.



My glider is assembled in a hangar, so I'll experiment to get the best performance with the empty trailer and expect things to change a bit with the glider. I'll replicate the best tongue weight when I put the glider back in and go from there. The trailer CG is close to neutral with the glider and nothing else in the front of the trailer. One of the best trailer sales/maintenance meccas in the region is within an hour's drive of the airport and I will get their help if I still have problems.

1- Any tongue weight over about 100 lb is doing no good and possibly bad.
2 Is not correct. You want the mass in the vehicle between the axles, not behind the rear axle as this only adds to the extra load the rear suspension sees.

You may want to tow the trailer with a known good tow car to see how much is the trailer and how much is the car.
UB