Wind Deflector tested for towing range improvement

[pae1andonly]

There are no aero covers on the trailer wheels, so we have not yet reached "ALL in" status. Does it have 6 wheel steering?

I parked and went to a customer service window w/in view of the parking spot. The custsupp rep asked if that was 'my doorstop' out there. lol

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[pae1andonly]

I may tape on a bunch of yarn tufts to try visualizing air flow.

Would make for some entertaining video!

 

[TickTock]

After getting the Urander enclosed bed cover installed as a base, I assembled this monstrosity we call (chesse) Wedgie.

Used OSB because Menards had 4x9 sheets and the final dimensions are 4.5'x9'x3' so only needed 3 sheets. Doing it in a more durable material will take six or so.

Seems to reduce Wh/mile by around 10% at 65MPH (1075 vs 1200), but that was only one test run. And I found out afterward that Teslamate had stopped logging (fixed that this morning).
Drafting (following distance of 7 in TACC) a semi at ~62MPH we were at 750Wh/mile .

You may be focusing on the wrong end. Most of the drag from a box trailer comes from the vacuum behind it.

 

[mongo]

You may be focusing on the wrong end. Most of the drag from a box trailer comes from the vacuum behind it.

You're not wrong, but it's easier to put mods on the truck versus the trailer and I was trying to achieve similar numbers to a Lightning owner on X with a nearly identical trailer.

 

[Eka]

I'd use epoxy for coating and waterproofing it, then paint it orange. As said it also can be used to smooth when filled epoxy layers are used. I'd use standard epoxy, not polyester epoxy. Fiberglass could be used on the seams, but I don't think it is needed.

Ages ago me and my brother made large 200+ gallon fish tanks using epoxy coated plywood. They lasted well over a decade, and the only reason they were taken out of service was a move. We didn't use any fiberglass.

 

[pae1andonly]

https://interestingengineering.com/transportation/tesla-patents-inflatable-cybertruck-spoiler

Looks familiar ...

 

[pae1andonly]

https://interestingengineering.com/transportation/tesla-patents-inflatable-cybertruck-spoiler

Looks familiar ...

The complementary piece would be an inflatable fairing or tail on the back of the trailer to finesse the vacuum suckage.

 

[HaulingAss]

Cybertruck tapers to reduce frontal area and minimize material. Since the trailer is taller and wider than the truck, I don't think reducing the ramp would help.

The wedge angle does end up pointing over the front edge of the trailer, but I think the air stream tends to converge so I'm not sure that lowering it would help. Overall frontal area stays the same anyway. If the unit didn't fold, a shorter ramp would definitely help non-towing efficiency.

I may tape on a bunch of yarn tufts to try visualizing air flow.

I think it's pretty obvious that what you have will yield a small but significant efficiency gain. I think the biggest weakness of the shape is that it seems to focus on the aero as envisioned from the side view. In operation the top view is just as important. The trailer is significantly wider than the cybertruck, especially up high. That means significant gains could be made by accommodating the trailers width in the airflow.

If you don't want your fairing to be wider and more unwieldy, maybe adding an element to the middle of the ramp, splitting the airflow in the center of the wedge to flow left and right of the air conditioner would fill in the low pressure zones that will naturally form on the upper side of the trailer due to the air that pushes around the front of the upper trailer.

When you don't have an aerodynamic shape to begin with (the trailer), addressing the sore spots can help a lot. I mean, you said this was an experiment, testing only one idea yields limited data. Of course, you could just sell the brick of a trailer and get one that has a rounded roof so the narrowness of your fairing is not such a mismatch with the trailer.

 

[CyberGus]

After you paint, don’t forget the ceramic coating

Wrap is acceptable also

 

[mongo]

I think it's pretty obvious that what you have will yield a small but significant efficiency gain. I think the biggest weakness of the shape is that it seems to focus on the aero as envisioned from the side view. In operation the top view is just as important. The trailer is significantly wider than the cybertruck, especially up high. That means significant gains could be made by accommodating the trailers width in the airflow.

If you don't want your fairing to be wider and more unwieldy, maybe adding an element to the middle of the ramp, splitting the airflow in the center of the wedge to flow left and right of the air conditioner would fill in the low pressure zones that will naturally form on the upper side of the trailer due to the air that pushes around the front of the upper trailer.

When you don't have an aerodynamic shape to begin with (the trailer), addressing the sore spots can help a lot. I mean, you said this was an experiment, testing only one idea yields limited data. Of course, you could just sell the brick of a trailer and get one that has a rounded roof so the narrowness of your fairing is not such a mismatch with the trailer.

Yeah, design was constrained to the rack width of 54" versus the 96 inch width of the trailer, so about a foot [and a half] on each side. The trailer nose is curved though which helps.
Base Cybertruck profile appeared to dump the air right into the nose. Bed rack had to similar Wh/mile. Test wedge cut energy 10% which makes further interation worth attemping. Maybe add some flares to the wedge tail?

All the rounded roof trailers I have found in two years of searching lacked key features on our must have list such as interior ceiling height. So we have to work with a trailer that is 2 feet taller .

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