Boat tail project based on a single wheel trailer...

[aerohead]

First,consumer level,completely gap-filled trailer in world history?
"You better cut that pizza into four pieces because I'm not hungry enough to eat six." Yogi Berra

[BamZipPow]

The trailer loaded at 120lbs with the air bag at 95psi and the air shocks at 105lbs seemed kinda bouncy. I really liked how the trailer felt at 180lbs with the air bag at 95psi and the air shocks at 100psi. Depending on the trailer load, I'll probably have to add some sand ballast to make sure the ride is smooth. Since I'm headed up towards ice/snow country, if I need some sand...I'll already have it on hand.

[freebeard]

Maybe you could zip-tie a bunch of inner tubes together and stick a stack on either side of the hitch. Or two big beach balls.

[BamZipPow]

I'll keep that in mind...

Gonna use 180lbs of sand ballast. I can always lose some if I need to along the way.

[slowmover]

I'd try weight in the truck ahead of the rear axle. Mass dampening. The more weight in the trailer (distance behind the drive axle) the more potential for trouble. Polar moment of inertia. The truck has a lot of miles on it. Were I to attach a lever to either frame rail at the rear I would be able to obtain more movement per one rail versus the other compared to when the truck was new. Put some sort of "paint" on the trailer hitch connection points to see if "wear" is pronounced in some fashion. Reload the sand bags in truck side/side to see that can be "offset".

I realize this trailer is short so that this seems counterintuitive. But the trailer wheel is at the end of the "lever". Experiment in more than one direction to try and see relationships is the recommendation. Studies in N-V-H show some oddities like this. A quiet but rough-riding vehicle is considered "better" by most than a smoother-riding but noisy vehicle. In the same vein, actions on the truck at the steer axle are less annoying/alarming than those which cannot be "seen" as they are from the rear.

Same for tire pressure on the truck. More than what is required (load versus pressure) amplifies. Let aero resistance be more the goal than worrying over last bit of rolling resistance (which is counter to best braking/handling at any rate). Find the lowest tire pressure recommended and then test 5-lbs upward at a time. Set tire pressure according to the highest load per wheel if loading sand more to one side than another seems beneficial (CAT Scale is your friend) and use that for each axle.

There is going to be a sweet spot in re perceived best ride, braking and transition steering. FE will be fine, IMO. Delaying driver fatigue trumps the stunt of tenths of mpg per overly high tire pressure. Degadation of fine motor skills through the day is what matters for FE purposes. As fatigue climbs, attention strays.

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[freebeard]

slowmover -- I always appreciate your posts, they're always dense with information and you have an informed opinion. So I'm not trying to start a flame war.

The truck has a lot of miles on it. Were I to attach a lever to either frame rail at the rear I would be able to obtain more movement per one rail versus the other compared to when the truck was new. Put some sort of "paint" on the trailer hitch connection points to see if "wear" is pronounced in some fashion. Reload the sand bags in truck side/side to see that can be "offset".

If I get what your saying, would it not apply to a single-wheel with two pivot points? OP's setup has a cross-bar on a hitch receiver. Tell-tales might show torsion around the centerline.

[aerohead]

The BamZipPow family came through Denton today on their way north for the holiday.
We got to spend some time together over a late lunch.
The one-wheeler has really evolved over the course of a year and it cannot be fully appreciated until you watch it pull away.It's like some phantom apparition which screams efficiency and performance as it floats away into the distance.Maneuvering is effortless.
I'll let Bam' fill us in on the numbers.And whatever they are,they'll have to be taken within the context of this time of year and black swan weather events we're encountering.
Kudos to the King of Gap-fillers!

[BamZipPow]

This is my first run with the new hitch setup so as I git more seat time, I'll be able to make more changes and adjustments based in the feedback I git.

Got an indicated 25.8mpg at 65mph from College Station to Denton. From Denton to Ardmore I got an indicated 26.6mpg at 65mph. From Ardmore to Wichita, I got an indicated 27.5mpg at 65mph. No issues with the ride at all. Passengers were happy it didn't feel like a jackhammer.

Passing just outside of Ft Worth, the crosswinds did lift up the outer edge of the upper gap cover to the point where it was sticking up in the airflow. I had to find a safe place to pull over and fix the cover. I need to install a hold down setup before I head further up North as the winds will be very active.

As I understand how my new hitch setup with the air shocks work, the air pressure in the shocks will push down on the tail end of my truck. This force counteracts against the force of the tail end of the trailer from pushing up when it encounters a bump in the road. Adding the sand bags in the rear increases the amount of force required to bump the trailer end up and also keeps the air bag "active". I will have to find the proper weight to pressure loads on the air bag and air shocks based on trailer load and placement on future runs. I am also looking at increasing the tension of my Roadmaster Active Suspension or/and installing some air bags on the rear of the truck to offset some of the rear end drop and push the nose rise back down.

The potential to hit over 29mpg from Ardmore to Wichita was there until I hit the late evening stop and go traffic in Oklahoma City. Maybe next time my timing will better.

As always, it was great to share lunch and time with Aerohead. He finally got to meet my wife and my wife finally got to see Aerohead's T-100 truck which inspired me on this journey. She said as soon as she saw his truck, she knew it had to be Aerohead.

[slowmover]

Originally Posted by freebeard

slowmover -- I always appreciate your posts, they're always dense with information and you have an informed opinion. So I'm not trying to start a flame war.
If I get what your saying, would it not apply to a single-wheel with two pivot points? OP's setup has a cross-bar on a hitch receiver. Tell-tales might show torsion around the centerline.

If I am reading you correctly (expand what was said) my concern would be how much the truck frame is flexing (due to age and miles. All frames flex, even on the 18k empty Peterbilt I drive). One way to "eliminate" that concern -- which is more about uneven or unequal flex -- is to see whether it can be seen via trailer attachment points.

A rough ride isn't always easy to fix much less diagnose.

Second, and easier, is that the trailer frame can in no way accommodate as much applied force as the truck. The OP has this in mind. It is a balancing act. The forces onto the trailer from the truck are significant. One can damage (separate) the A-frame on some highly expensive travel trailers with a too rough riding truck.

[aerohead]

Numbers look good.
Air has been kinda dense (we've had negative density altitudes quite a bit recently) and you were doing some climbing,especially the Arbuckles.
There won't be much grades into and out of Iowa,so if the winds are mild and traffic doesn't eat your lunch,you've got a shot at some interesting numbers.
Fun!