Reply
 
Thread Tools Search this Thread Display Modes
 
Old 05-17-2011, 08:16 PM   #15
3 Rivet Member
 
Lucky Dog's Avatar
 
2014 25' FB Flying Cloud
Down the Shore , New Jersey
Join Date: Jan 2010
Posts: 102
What you experienced was probably bow wave effect from air displacement when the truck approached and passed you. Check out this thread http://www.airforums.com/forums/f463...low-58771.html
for some good reading or do a search using key words for more info on the subject.

Rich
__________________

__________________
Rich
WBCCI #1512
2014 25FB Flying Cloud
2006 Chevy Silverado 2500 Duramax/Allison
Lucky Dog is offline   Reply With Quote
Old 05-26-2011, 08:17 PM   #16
Vintage Kin
 
slowmover's Avatar
 
Fort Worth , Texas
Join Date: Nov 2006
Posts: 7,582
Images: 1
Remember that the drive axle of the TV is the Steer Axle of the TT (in a manner of speaking). The driver has more movement to control with the TV Steer Axle, so any movement from elsewhere has a peculiar and unsettling feeling associated with it.

With body-on-frame vehicles with crude suspension (live axle, etc) the movement of the body against the suspension at the rear is the culprit. The Drive Axle also tends to feature stiffer springs, but this may do little against side-to-side movement. The wind forces -- especially abrupt ones as described above, and by Inland Andy elsewhere -- that reverse direction are more than unsettling, they become threatening.

Mr. Thomson is correct about TV tire sidewall stiffness. IMO, a rear anti-roll bar is also recommended (as are poly bushings for it and the front bar).

Power steering systems also tend to mask the beginning of this phenomenon, so see to it that any "dead center" is better than new. Older shock absorbers are also part of the problem, so an upgrade to BILSTEIN is recommended.

Is any of this "sway". Precursors, yes, but one needs a camera to say when these forces (and the reactions of the vehicle plus the actions of the driver) cause this sway (yaw) to become a problem.

A few suitable upgrades, some mechanical adjustments to the TV, and then hitch rigging as sorted by weight scale readings will take care of almost all of this (assuming a decent hitch system). A sway eliminating hitch system (such as Pro Pride) is a best idea. Beyond that, trailer disc brakes and finest controller.

In other words, do some homework (reading around here), ask questions and verify with numbers.

.
__________________

__________________
1990 35' Silver Streak Sterling; 9k GVWR.
2004 DODGE Cummins 305/555; 6-manual; 9k GVWR.
Hensley Arrow. 9-cpm solo, 15-cpm towing
Sold: Silver Streak Model 3411
slowmover is offline   Reply With Quote
Old 05-26-2011, 08:34 PM   #17
Rivet Master
 
MrUKToad's Avatar

 
2011 28' International
Chatham , Ontario
Join Date: Dec 2010
Posts: 1,372
Images: 17
Blog Entries: 13
Came along the I90 south of Rochester NY on Monday and experienced a lot of that sucking effect as the big trucks passed. There was a nasty side wind which was making it seem all the worse. However, the Airstream just followed what ever the TV did and showed no sign of sway, just leaving me to adjust my road position as the truck passed. We have friction anti-sway bars that won't prevent sway but will dampen it if it starts.

If you think it's bad when towing, though, you should try it on a motor cycle!
__________________
Steve; also known as Mr UK Toad

"You can't tow that with that!"

http://toadsoftowedhaul.com
MrUKToad is offline   Reply With Quote
Old 05-26-2011, 09:22 PM   #18
CLOUDSPLITTER "Tahawas"
 
ROBERT CROSS's Avatar

 
2003 25' Classic
Zanadude Nebula , WNY
Join Date: Jun 2007
Posts: 11,153
Images: 1
There is no such thing as swing.... without sway.

Get camping....
__________________
PFC.....

“After all these years the reason I continue to love Thanksgiving.....I still sit at the kids table.”
RLC

Sandra wanted to go to Cleveland on vacation,
but I’m the Husband, so we went to Cleveland.
RLC
ROBERT CROSS is offline   Reply With Quote
Old 05-26-2011, 09:35 PM   #19
Rivet Master
 
Lumatic's Avatar

 
1971 25' Tradewind
1993 34' Excella
Currently Looking...
Estancia , New Mexico
Join Date: Feb 2005
Posts: 6,642
Images: 16
Blog Entries: 1
Quote:
Originally Posted by Lucky Dog View Post
What you experienced was probably bow wave effect from air displacement when the truck approached and passed you.

Rich
There are 2 forces at work it seems. First the bow wave that pushes you away from the passing vehicle. This is immediately followed by a reduction in pressure which sucks you towards it. You get a double whammy when the trailer is hit by the same.

Keep a weather eye on your mirrors for large overtaking vehicles, pull to the right as far as possible, ease up the gas and cover the brake. There is a tendency to over correct steering setting up a dangerous reciprocating sway.

IMHO the worst vehicles seem to be car carriers.
__________________
Sail on silver girl. Sail on by. Your time has come to shine.
Lumatic is offline   Reply With Quote
Old 05-27-2011, 12:34 AM   #20
Vintage Kin
 
slowmover's Avatar
 
Fort Worth , Texas
Join Date: Nov 2006
Posts: 7,582
Images: 1
Quote:
Originally Posted by Lumatic View Post
There are 2 forces at work it seems. First the bow wave that pushes you away from the passing vehicle. This is immediately followed by a reduction in pressure which sucks you towards it. You get a double whammy when the trailer is hit by the same.

Keep a weather eye on your mirrors for large overtaking vehicles, pull to the right as far as possible, ease up the gas and cover the brake. There is a tendency to over correct steering setting up a dangerous reciprocating sway.

IMHO the worst vehicles seem to be car carriers.

I would like to modify parts of the above. Defensiveness is not timidity (that's how it is interpreted while on the road; and, as this is America, to be taken advantage of: "I'm driving faster so they should move over for me"), and the passing vehicle DOES NOT have right of way over the vehicle being passed. In fact ALL obligation is upon them, for practical purposes. (Speeders have no defense, here).

1] It is your lane (speaking here of the Interstate), so stay centered in it. Others have a tendency to move towards a vehicle that is in the right of it's own lane. Dumbo Americano. They nearly none of them know where the right side of their vehicle is, so they tend to ALWAYS maintain the same distance to that side. You move over and they follow. (Don't believe me, then try it out).

I tend to move the rig towards the left lane, and then move back just a bit past center towards the shoulder when the other vehicle is almost on top of me.

I give the other a psychological "push" in other words. This works well whether I'm solo, towing a trailer or driving a tractor-trailer. I maximize the distance at the right moment, but DO NOT give up the center of my lane to do so. These aren't big movements, but adjustments of lane position. They work. I am riding across the big truck rut trough from one wave top to the other wave top is about what it amounts to (for you water skiers). Just enough that the usual morons adjust their position in the passing lane.

We're dancing . . . and I'm taking the lead.

(If I'm worried about someone coming up I may in fact wander all over the lane and literally over into his before they're next to me . . sobers them up quickly I notice: get around that crazy driver!!).

One needs all of the room of his lane that he can have. And only from the center of his lane can he be sure of this space; sacred space in a manner of speaking as travel trailer rigs are so very limited in handling..

Do not let others intrude . . push 'em over (don't have the brainless anywhere near you, for any length of time).

The passing vehicle tends to have chosen a path past the slower vehicle a fair distance back, usually unconciously. I want him over in his lane as far as he'll go, relatively.

The decent ones out there will already be over a little and well above 5-mph more than my speed. Those who are barely passing or who are sorta passing (on cruise control), and those who travel in the cretin packs bumper-to-bumper with others are not the decent sort!


2] I would also NOT ease up on the throttle, but set the speed -- with positive forward momentum at all times -- to one that is lower; a bit. Come off the cruise, perhaps, but have NO slack in the rigging (no deceleration occurring) when any other vehicle is near. In fact, if I am worried over who or what is passing I may in fact be accelerating as they pass me. Not much, and not enough to cancel the speed difference between us, but enough that it is more difficult for the passing bow wave (or waves) to affect momentum.

(For the occasional speed limited big truck barely getting around me, I just drop off the cruise and let him get past then get back over, wait till there's proper distance and glide back up to my travel speed, re-setting the cruise. Never stay near a big truck no matter who is passing. And, big trucks never want to stay in the passing lane!! Do what you can to shorten that time for them).

Again, this is all rather gentle in effect. My passenger may not notice and my conversation may not flag, it's pretty well automatic. I am only re-setting my steady state to one slightly different (but I've also been doing these things for nearly forty years).

When it is not gentle then I will in fact be moving as far over as possible and down to below 50-mph -- and re-accelerating somewhat -- for the truly scary once-a-decade stuff (a trio of tractor trailers at above 100 mph; never forgot that one .. was all the way onto the shoulder for that).


3] The brake to cover is the brake controller, not the TV service brake. If the rig starts to sway then slam the trailer brake home and slam the TV throttle down at the same time. It's not easy to lock the trailer brakes so that the TT tires slide, but anything to slow the trailer back to the speed the TV is traveling is key. (And this is why one wants positive forward momentum: so that the steering slack is already taken up . . that trailer is going to jerk and jerk hard once the brakes hit.) This is where steering over-correction will occur.

A swaying trailer is trying to pass you. You might reconsider that cutesy name so many are fond of giving theirs as it tries to jerk the TV drive axle loose from it's grip to yank you both into the ditch while at a highway speed.

Do what you can to avoid getting to that point. As was drilled into me, "There's no such thing as an accident". Wherever the margin to improve your rig can be found, incorporate it. A few $$ will mean a lot in worsening situations of road, load, traffic and weather.

And a fair amount of this is moot for those with either crappy hitch rigging or no WDH. It'll be enough work to keep the danged thing straight in the same crosswind that day. Forget the forms of signaling to others as above.

The best hitched rigs can have more than just sway elimination going for them . . same for best brakes, best brake controller, best tires at best pressure, etc, etc, et. al. Those little movements of offense are the best defense, IMO. Get the maximum distance and the minimum times.


As to car carriers ("parking lots") the worst possible fuel mileage for any big truck is that type with a 3/4 bow wind off either side. Empty or loaded they are aero nightmares and in having one pass we experience in miniature the reversing wind phenomenon spoken of above and elsewhere usually associated with several trucks.

.
__________________
1990 35' Silver Streak Sterling; 9k GVWR.
2004 DODGE Cummins 305/555; 6-manual; 9k GVWR.
Hensley Arrow. 9-cpm solo, 15-cpm towing
Sold: Silver Streak Model 3411
slowmover is offline   Reply With Quote
Old 05-27-2011, 06:41 AM   #21
CLOUDSPLITTER "Tahawas"
 
ROBERT CROSS's Avatar

 
2003 25' Classic
Zanadude Nebula , WNY
Join Date: Jun 2007
Posts: 11,153
Images: 1
I would like to modify parts of the above.... Never Mind.
__________________
PFC.....

“After all these years the reason I continue to love Thanksgiving.....I still sit at the kids table.”
RLC

Sandra wanted to go to Cleveland on vacation,
but I’m the Husband, so we went to Cleveland.
RLC
ROBERT CROSS is offline   Reply With Quote
Old 05-27-2011, 08:46 AM   #22
Rivet Master
 
Lumatic's Avatar

 
1971 25' Tradewind
1993 34' Excella
Currently Looking...
Estancia , New Mexico
Join Date: Feb 2005
Posts: 6,642
Images: 16
Blog Entries: 1
Quote:
Originally Posted by Lumatic View Post
There are 2 forces at work it seems. First the bow wave that pushes you away from the passing vehicle. This is immediately followed by a reduction in pressure which sucks you towards it. You get a double whammy when the trailer is hit by the same.

Keep a weather eye on your mirrors for large overtaking vehicles, pull to the right as far as possible, ease up the gas and cover the brake. There is a tendency to over correct steering setting up a dangerous reciprocating sway.

IMHO the worst vehicles seem to be car carriers.
I would like to modify parts of the above. Defensiveness is not complacency.

As a ex New York City cabbie. I learned to drive rather aggressively and defined defensive driving as defending my little piece of road at all costs. I have considerably modified this road philosophy. I am assuming we are talking about highway driving and not downtown NYC, and we are talking about being passed by large vehicles. Let me modify my original post with 2 basic tenets of my philosophy of life:

1. Most commercial drivers are professional and appreciate the courtesy of giving them a little space for passing and will extend the same.
2. I want that big hunka hunka 18 wheeler away from me as soon as practically possible.

I do reserve my right to adjust my driving tactics to individual conditions rather than ridgidly adhering to any so called rule of the road.

I also realize that when I am passing a smaller and slower vehicle I am creating the same aerodynamic forces acting on the little guy..

And lastly the other driver is not always going to drive like you think he should and I expect the unexpected.
__________________
Sail on silver girl. Sail on by. Your time has come to shine.
Lumatic is offline   Reply With Quote
Old 05-27-2011, 09:45 AM   #23
Rivet Master
 
r carl's Avatar
 
Vintage Kin Owner
Lin , Ne
Join Date: Dec 2009
Posts: 2,056
Quote:
Originally Posted by RellikJM View Post
As I was towing the Airstream this weekend I noticed that when a large vehicle (pickup with horse trailer, 5th wheel, motorhome) passed me that there was a "sucking" sensation. When the "sucking" sensation occured I had to correct for lane position slightly as they passed. Was this sway?
No, you experienced being pushed by wind from annother vehicle.
__________________
r carl is offline   Reply With Quote
Old 05-27-2011, 09:56 AM   #24
CLOUDSPLITTER "Tahawas"
 
ROBERT CROSS's Avatar

 
2003 25' Classic
Zanadude Nebula , WNY
Join Date: Jun 2007
Posts: 11,153
Images: 1
My fingers hurt....
Hitching Up - Trailer - Sway
__________________
PFC.....

“After all these years the reason I continue to love Thanksgiving.....I still sit at the kids table.”
RLC

Sandra wanted to go to Cleveland on vacation,
but I’m the Husband, so we went to Cleveland.
RLC
ROBERT CROSS is offline   Reply With Quote
Old 05-27-2011, 10:12 AM   #25
Rivet Master
 
Lumatic's Avatar

 
1971 25' Tradewind
1993 34' Excella
Currently Looking...
Estancia , New Mexico
Join Date: Feb 2005
Posts: 6,642
Images: 16
Blog Entries: 1
Quote:
Originally Posted by ROBERT CROSS View Post
My fingers hurt....
Hitching Up - Trailer - Sway
I am hanging out at home dealing with the residual pain of the shingles, wishing I was camping, with nothing better to do than beating dead horses.
__________________
Sail on silver girl. Sail on by. Your time has come to shine.
Lumatic is offline   Reply With Quote
Old 05-27-2011, 10:38 AM   #26
Full Timers/Diesel power.
 
Mike Leary's Avatar
 
1983 31' Airstream310
Cactus Hug , Arizona
Join Date: Mar 2007
Posts: 2,540
Images: 11
Airstreams "sashay", other makes "sway". Many times, we've taken the next exit and waited a while rather than trying to pass an "accident waiting to happen".
__________________

__________________
"A settled wisdom, plus the itch to be elsewhere"
Mike Leary is offline   Reply With Quote
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Front sway bar, Part number for Bushing ? John H. Mechanics Corner - Engines, Transmission & More... 5 06-09-2011 12:27 PM
Sway control Stumpjumper Hitches, Couplers & Balls 27 05-24-2011 03:20 PM
Hitch sway or weight or both!!!! Luc_DK Hitches, Couplers & Balls 5 03-29-2011 09:22 AM
Experience Technician wanted - Airstream of Chicago AoC Commercial Listings 1 03-02-2011 02:46 PM
67 Caravel Help: to sway or not to sway vonzellen Hitches, Couplers & Balls 15 01-26-2011 06:07 PM


Virginia Campgrounds

Reviews provided by




Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -6. The time now is 04:06 PM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.

Airstream is a registered trademark of Airstream Inc. All rights reserved. Airstream trademark used under license to Social Knowledge LLC.