eStream hitch

[LNBright]

While most of the excitement over the concept eStream is regarding its driven axle via batteries, etc., one of the things I noticed was the mention of its hitch system.

https://youtu.be/rUvIpUygzaY?t=62

[Bobbo]

The Airstream in that video has no air conditioner and no roof vent fans. Also, no plumbing vent pipe. Hmmmm.

[jcl]

Originally Posted by Bobbo

The Airstream in that video has no air conditioner and no roof vent fans. Also, no plumbing vent pipe. Hmmmm.

Much better idea to mount the AC down low, with a split system. Others are doing it already. See Bolus. Less weight up high so more stable. Less wind drag so more efficient. And more room to mount solar panels.

[LNBright]

A: it IS a concept, not a production trailer

B: as Jeff said, there’s a move to put the a/c underneath for aerodynamics

C: plumbing vent can be adjusted to come up underneath a solar panel. I would miss the roof vents, but, maybe they’d keep those…

D: reason I posted this here, was the lack of need of a WD hitch with it. It would simplify things, instead of wondering if you should have a BlueOx or an EZLift or a ProPride or whatever…

[waninae39]

the video is for a euro model with a euro type hitch
it is NOT compatible with NA type hitches

the video is only a demo/prototype
it is likely many years away from production

[jcl]

Originally Posted by waninae39

the video is for a euro model with a euro type hitch
it is NOT compatible with NA type hitches

the video is only a demo/prototype
it is likely many years away from production

Why not? It has a North American tow coupler mounted. It is being shown in North America. I expect it will be sold in both markets when it goes to production.

No WD, likely due to a lower design tongue weight, and that would make it more suitable for the vehicles they are targeting to tow it.

If the coupler is load sensitive, and applies both electric assist and regen/braking based on that load sensing, WD could be a challenge.

[DCPAS]

Originally Posted by jcl

Why not? It has a North American tow coupler mounted. It is being shown in North America. I expect it will be sold in both markets when it goes to production.

No WD, likely due to a lower design tongue weight, and that would make it more suitable for the vehicles they are targeting to tow it.

If the coupler is load sensitive, and applies both electric assist and regen/braking based on that load sensing, WD could be a challenge.

If sway is controlled electronically with the driven trailer wheels, you could design the trailer to have very low tongue weight. That would make the trailer towable with a small vehicle. And no need for WD.

[jcl]

Originally Posted by DCPAS

If sway is controlled electronically with the driven trailer wheels, you could design the trailer to have very low tongue weight. That would make the trailer towable with a small vehicle. And no need for WD.

The partners in this product development are Thor, and ZF. Thor has two companies involved, Dethleffs, which started the idea and built prototypes, and Airstream, which has the current concept model.

Dethleffs is European, and designs their trailers for a minimum of 4% tongue weight, even before we get to the concept vehicle with electronic sway control. 5% would be a reasonable target. They put the weight low, and near the axle(s). The chassis design here is like that, but even more so.

I think they should have a 5% tongue weight target, to allow the greatest number of potential purchasers. Modern EVs do not have the payload of heavier trucks, even if they are EV trucks. The Hummer EV weighs over 9000 lbs, but has a payload of 1300. The Silverado EV has a payload of 1200 lbs. The Model Y has just moved to around 1200 lbs.

The torque vectoring to manage sway events could be a safety feature, not something that the vehicle would be using every km travelled.

[richard5933]

Originally Posted by jcl

The partners in this product development are Thor, and ZF. Thor has two companies involved, Dethleffs, which started the idea and built prototypes, and Airstream, which has the current concept model.

Dethleffs is European, and designs their trailers for a minimum of 4% tongue weight, even before we get to the concept vehicle with electronic sway control. 5% would be a reasonable target. They put the weight low, and near the axle(s). The chassis design here is like that, but even more so.

I think they should have a 5% tongue weight target, to allow the greatest number of potential purchasers. Modern EVs do not have the payload of heavier trucks, even if they are EV trucks. The Hummer EV weighs over 9000 lbs, but has a payload of 1300. The Silverado EV has a payload of 1200 lbs. The Model Y has just moved to around 1200 lbs.

The torque vectoring to manage sway events could be a safety feature, not something that the vehicle would be using every km travelled.

What speeds are those European trailers designed to be towed at? My understanding is that they don't pull trailers as fast as done in the US.

[DCPAS]

Originally Posted by richard5933

What speeds are those European trailers designed to be towed at? My understanding is that they don't pull trailers as fast as done in the US.

They tow at lower speeds because the low tongue weight will result in more sway at higher speeds. If sway is controlled by the trailer, you no longer need high tongue weight.

[jcl]

Originally Posted by richard5933

What speeds are those European trailers designed to be towed at? My understanding is that they don't pull trailers as fast as done in the US.

The maximum legal speed limit is 100 km/h (62 mph) when towing. 80 km/h in some situations. 50 km/h in urban areas. 100 km/h is as fast as I tow. Those who want to tow at 80 mph, or whatever, may need to evaluate whether this type of design would be suited for them.

I don't know what this particular trailer's design speed limit is.

[richard5933]

Originally Posted by DCPAS

They tow at lower speeds because the low tongue weight will result in more sway at higher speeds. If sway is controlled by the trailer, you no longer need high tongue weight.

True, but I'm not sure that they'll ignore the higher speeds and just let the tech do all the work. Kind of like planning for when the trailer brakes crap out, there will be times the eTrailer just has a hiccup. Would really suck if they designed the thing to work with a tongue weight otherwise suitable for towing at slower speeds and counted on the electronics to control the sway, only to have it decide to reboot while doing 75 mph or while being passed by a semi going the other way.

Some type of fail safe has to be built in, and a very easy one for towing at higher speeds will be to keep tongue weights up higher than in Europe. I'm not convinced they'll abandon the current tongue weight recommendation even with the added tech.

[jcl]

Originally Posted by richard5933

True, but I'm not sure that they'll ignore the higher speeds and just let the tech do all the work. Kind of like planning for when the trailer brakes crap out, there will be times the eTrailer just has a hiccup. Would really suck if they designed the thing to work with a tongue weight otherwise suitable for towing at slower speeds and counted on the electronics to control the sway, only to have it decide to reboot while doing 75 mph or while being passed by a semi going the other way.

Some type of fail safe has to be built in, and a very easy one for towing at higher speeds will be to keep tongue weights up higher than in Europe. I'm not convinced they'll abandon the current tongue weight recommendation even with the added tech.

Setting a high tongue weight is a poor fail safe. It results in the product having a smaller potential market, and relies on the customer loading practices, which we already know are a cause of crashes.

Thinking about it, that fancy coupler, which could sense longitudinal loads to activate propulsion or regen/braking, could also have a vertical sensor. That would tell the operator what the tongue weight was. No need to get out the bathroom scales and rig up a lever arm.

A reasonable failsafe would be to use individual trailer brakes for a backup for the torque vectoring. Brakes are already employed as a failsafe on trailers, in the event of breakaway, with the brakes being applied automatically. Add in an alert for the driver.

[DCPAS]

Originally Posted by richard5933

True, but I'm not sure that they'll ignore the higher speeds and just let the tech do all the work. Kind of like planning for when the trailer brakes crap out, there will be times the eTrailer just has a hiccup. Would really suck if they designed the thing to work with a tongue weight otherwise suitable for towing at slower speeds and counted on the electronics to control the sway, only to have it decide to reboot while doing 75 mph or while being passed by a semi going the other way.

Some type of fail safe has to be built in, and a very easy one for towing at higher speeds will be to keep tongue weights up higher than in Europe. I'm not convinced they'll abandon the current tongue weight recommendation even with the added tech.

You're absolutely right, of course. Depends on what you can live with. The sway control part really isn't new. It's been on cars for decades with few issues. Electric motors and brakes (not sure which it uses) are not new either. I agree with the trailer brakes crap out analogy, but I'm in the camp of "I only have to stop it once so I don't need a massive truck" on that. I really like the concept. It opens the door to towing with smaller and more comfortable vehicles.

[wulfraat]

This is a compression coupler on the front of the A-frame that sends signals back to the control unit in the trailer so it can determine if the TV is accelerating, decelerating, or staying steady so the trailer can adjust power output to its motors accordingly.

Most WD / sway control mechanisms would likely defeat this / would not be compatible with this design of coupler. More challenges to address although with vehicle dynamics control within the trailer body control unit traditional sway control may not be necessary as noted above.

[jcl]

The concern over new types of vehicle electronics failing is not new.

I recall, years ago, installing manual chokes (with a cable, a bracket, and a pull knob) on new vehicles purchased by owners who didn't trust automatic chokes. There was a kit available.

Those same owners were really put out when fuel injection came along.

I recall removing an electronic ignition system to install points and condenser for a customer who didn't want a system they couldn't set the gap with a feeler gauge with.

ABS had lots of detractors when it came out, and some argued that they were better at stopping the vehicle than some electronic system.

Traction control systems had similar detractors. People asked for the ability to defeat stability control systems so that they could control vehicle oversteer with the throttle instead of relying on the yaw sensor.

And so on.

We got through it.

If we can eliminate separate aftermarket WD systems, and sway control systems, it would be huge. Not just for the performance benefit of the new system over the old (when the old system was properly installed and set up) but because in many (some say most) cases, the old system wasn't set up correctly. That issue would be resolved.