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



 
 
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  #21  
Old June 12th 14, 06:23 PM posted to rec.aviation.soaring
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Default 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
  #22  
Old June 12th 14, 08:12 PM posted to rec.aviation.soaring
Six-Seven
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Default Do trailers with coil springs and shock absorbers sway at higher speeds?

On Thursday, June 12, 2014 7:39:03 AM UTC-5, Mark628CA wrote:

For a tongue without a surge brake, there are several designs that are inexpensive and very effective. Most will require some welding and proper alignment is necessary, so a pro should be consulted. Here is a link to sway control devices from etrailer.com: http://accessories.etrailer.com/search?w=sway%20control


I did install this item without welding.

- Basically the only think that you need to do is mount two small 1-1/4" diameter balls that come with the kit.
- The first 1-1/4" ball goes a few inches left or right of the main trailer ball. This looks exactly like a miniature "standard" ball. The easiest way to mount this is via an accessory plate that goes underneath the main trailer ball. http://www.etrailer.com/Accessories-...e/RP26003.html
- The second 1-1/4" ball is provided already welded to a plate which is intended to be bolted to the trailer tongue. I bought a second ball (like the first one) and put that into a drilled and tapped hole in the tongue. http://www.etrailer.com/Accessories-...rt/C40093.html
- The two 1-1/4" balls are mounted 24" apart and 90 degrees from one another.
  #23  
Old June 12th 14, 10:30 PM posted to rec.aviation.soaring
Bob Kuykendall
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Default Do trailers with coil springs and shock absorbers sway at higher speeds?

On Thursday, June 12, 2014 8:24:57 AM UTC-7, son_of_flubber wrote:

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


I'd advise a modicum of caution in this matter. In many states, the maximum speed for towing any trailer is lower than the normal speed limit.

Getting popped for towing a trailer above the applicable speed limit can be a pretty strong ticket in many states. The patrol officer will not care that your trailer is really light and tows like it isn't there. The presumption will be that the trailer substantially reduces maneuverability and increases braking distance (both technically true), and you are unlikely to make much headway convincing either the officer or the judge otherwise.

Thanks, Bob K.

  #24  
Old June 12th 14, 10:36 PM posted to rec.aviation.soaring
Karl Striedieck[_2_]
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Default Do trailers with coil springs and shock absorbers sway at higher speeds?

On Friday, June 6, 2014 6:44:32 PM UTC-4, son_of_flubber wrote:
My Avionic trailer has leaf springs and no shocks and the rhythmic ass end sway that develops at higher speeds encourages me to keep the top speed at 60-65 mph. That speed is just fine with me except when interstate traffic if flying by at 80 mph. In that case I feel that I'm something of a hazard, especially if I'm trying to merge or change lanes.



I'm thinking that shocks might dampen out the rhythmic sway that seems to be self-reinforcing. Tow vehicle is 2004 Volvo XC70. Single seat glass glider.


2nd try. The most important factor affecting trailer stability is the distance of the tow ball to the rear axle with zero being the theoretical optimum. Wil Schumann modified this 1966 Olds Tornado just that way.

So if there is a choice of vehicles go with the least "overhang." A VW Touareg is good, an extended van or pickup not so good. And the ratio of tow vehicle to trailer weight is important too. Heavier vehicle is better, as in RV's (which aren't affected by the relatively light trailer.
  #25  
Old June 13th 14, 02:05 AM posted to rec.aviation.soaring
Mike the Strike
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Default Do trailers with coil springs and shock absorbers sway at higher speeds?

No restriction on trailer towing speeds here out in Arizona and I believe most adjacent states are similar. Posted limits are generally 75 mph (except Utah and Texas which have some higher ones) and most of these states will give you 10 mph grace.

For those going to Region 9 in Moriarty, I can confirm that speeding fines in New Mexico are very affordable (I got $75 for a trailer-free 92 mph).

Mike
  #26  
Old June 13th 14, 02:51 AM posted to rec.aviation.soaring
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Default Do trailers with coil springs and shock absorbers sway at higher speeds?

California is 55mph with a trailer.
  #27  
Old June 13th 14, 03:20 AM posted to rec.aviation.soaring
son_of_flubber
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Default Do trailers with coil springs and shock absorbers sway at higher speeds?

Trailer towing speed limits by state:

http://drivinglaws.aaa.com/laws/trailer-speed-limits/

I was woefully ignorant of this law and I'd guess that others are too.

Inadvertantly omitted from my previously posted list of possible remedies would be the possibility of adding shocks to Avionic trailers that have torsion bar and leaf spring suspension.
  #28  
Old June 13th 14, 05:11 AM posted to rec.aviation.soaring
Frank Whiteley
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Default Do trailers with coil springs and shock absorbers sway at higher speeds?

On Thursday, June 12, 2014 3:30:00 PM UTC-6, Bob Kuykendall wrote:
On Thursday, June 12, 2014 8:24:57 AM UTC-7, son_of_flubber wrote:



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




I'd advise a modicum of caution in this matter. In many states, the maximum speed for towing any trailer is lower than the normal speed limit.



Getting popped for towing a trailer above the applicable speed limit can be a pretty strong ticket in many states. The patrol officer will not care that your trailer is really light and tows like it isn't there. The presumption will be that the trailer substantially reduces maneuverability and increases braking distance (both technically true), and you are unlikely to make much headway convincing either the officer or the judge otherwise.



Thanks, Bob K.


Especially Illinois.

Frank Whiteley
  #29  
Old June 13th 14, 05:23 AM posted to rec.aviation.soaring
Frank Whiteley
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Default Do trailers with coil springs and shock absorbers sway at higher speeds?

On Thursday, June 12, 2014 9:24:57 AM UTC-6, 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.


You're coming out west? Mountain passes in Colorado top 10,000 MSL. Snow recently on Berthoud pass for the Ride the Rockies Bicycle Tour. Wyoming and New Mexico not so bad. Montana's okay also. Arizona, Flagstaff to Tucson is interesting, both ways. Bring range, horsepower, and all or 4WD. Nevada and California are okay. Idaho, Washington, and Oregon are mostly easy. The Pendleton grade is fun, both ways, and interesting on ice. I'm presuming summer travel. Winter is a bit different when I'd recommend a big tow vehicle option.

Frank Whiteley
  #30  
Old June 13th 14, 03:57 PM posted to rec.aviation.soaring
son_of_flubber
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Posts: 1,550
Default Do trailers with coil springs and shock absorbers sway at higher speeds?

On Friday, June 13, 2014 12:23:47 AM UTC-4, Frank Whiteley wrote:

You're coming out west? Mountain passes in Colorado top 10,000 MSL. Snow recently on Berthoud pass for the Ride the Rockies Bicycle Tour. Wyoming and New Mexico not so bad. Montana's okay also. Arizona, Flagstaff to Tucson is interesting, both ways. Bring range, horsepower, and all or 4WD. Nevada and California are okay. Idaho, Washington, and Oregon are mostly easy. The Pendleton grade is fun, both ways, and interesting on ice. I'm presuming summer travel. Winter is a bit different when I'd recommend a big tow vehicle option.


Frank Whiteley


The earliest that I would tow my glider out west would be 2016. Getting ready now to tow from Vermont to Florida in Nov 2014 and back to Vermont in 2015.

Bring range, horsepower, and all or 4WD.


My 2004 Volvo XC70 has all of that, highish ground clearance, comfortable seats and a 'safety cockpit'. It is a light truck trapped in a station wagon body (with a low CG compared to most light trucks/SUVs). That said, a two-wheel drive full size van tempts me.
 




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