Potential mpg loss % with custom aero trailer.

[aerohead]

If this works, it'll be an overhead photo of the boat-derived trailer, before the gap-fillers. It allowed maximum interior space, while form-fit to the truck later on, when articulated panels went on.
https://ecomodder.com/forum/showthre...t-7839-23.html
It's down at # 228 (permalink)
-------------------------------------------------------------------------------------
On page-22, down at # 217 ( permalink ) there are some additional shots.
I'd left on the maiden run with loose lug nuts on the driver's side, and when that wheel left the trailer, it was the end of the wheel fairings on that side.
Poor old George Poteet and his crew had to look at for a day during Mike Cook's 'Shoot-out'. They were very polite.

[freebeard]

Arches are nuanced. Optimal might be a Tudor Arch of the Late Gothic style , a variation of the Islamic four-centered arch.


en.wikipedia.org/wiki/Four-centred_arch

And we haven't even touched on the
en.wikipedia.org/wiki/Superellipse.

[aerohead]

The task before us is, while maintaining jack-knife capability, we also minimize the total volume of the aerodynamic gap.

[freebeard]

The optimal case would be a fifth-wheel hitch. With a convex quarter-spherical nose on the trailer and a concave quarter-spherical tail* on the tow vehicle, centered in the hitch.

Polished stainless steel surfaces at a fraction of an inch gap. Blown gap. The exhausted air would constitute a Shauberger Trout Turbine and provide forward thrust through the Coanda effect.

* Two separated axes of rotation like a surveillance cam.

[Gschuld]

Originally Posted by freebeard

Arches are nuanced. Optimal might be a Tudor Arch of the Late Gothic style , a variation of the Islamic four-centered arch.


en.wikipedia.org/wiki/Four-centred_arch

]

This makes sense to me. I was thinking of using rounded outer edges like that but with a v shape to the hitch to maximize gap volume reduction while allowing turning clearance.

But I just couldn’t see the great benefit over a full round. And if you overlaid a full round over your shape above, they would be pretty similar on overall cornering clearance and gap volume reduction.

I love the pics of the boat trailer T-100 project BTW. That’s Jedi level experimenting right there. I certainly appreciate the craftsmanship and effort required to make all those mods.

George

[freebeard]

You could just free-hand the curve and bend things around a tree trunk. I was pointing to mathematically representable options.

[redneck]

Originally Posted by freebeard

The optimal case would be a fifth-wheel hitch. With a convex quarter-spherical nose on the trailer and a concave quarter-spherical tail* on the tow vehicle, centered in the hitch.

Polished stainless steel surfaces at a fraction of an inch gap. Blown gap. The exhausted air would constitute a Shauberger Trout Turbine and provide forward thrust through the Coanda effect.

* Two separated axes of rotation like a surveillance cam.

🤔

Victor would approve...





>

.

[Piotrsko]

How about when you're backing, stop and install a hitch extender? They are like 24" of harbor freight style cheap metal tube extension. Drop the landing gear, Pull the hitch pin, insert extender, re attach, jack up landing gear. Would get you all kinds of jacknife capability, annnnd if that isn't enough, add another.

[Gschuld]

It’s not just about backing up, but a bare minimum of 45 degrees per side is required for even basic maneuvering going forward. Like negotiating a gas station, making a tight turn, etc. Even if there was no specific law on the books requiring a certain minimum angle, and cop would rightly consider a trailer setup limiting reasonable cornering clearance a safety hazard.

Theoretically, and I briefly even considered the idea, a hydraulically actuated telescoping trailer tongue could be designed that would allow a driver to pull the trailer way fwd when on the highway, and extend again off highway. It would require an automatic activation speed, say 60mph. Once you hit 60mph on the highway, it tightens up to allow a minimal 10 degrees per side. When you get below 60mph, it retracts to a safe distance for 90 degree turning. It is mechanically doable. One would have to overcome the need to keep tolerances in the telescoping system to a minimum, and the mechanism of automated control worked out( a manual control system would be asking for trouble)

Though it’s a workable solution, it’s a rather complex thing to do correctly and reliably and if done wrong, it is a safety hazard. I’m going on the assumption that I could reach my efficiency goals without needing to resort to such things.

Freebeard, I do appreciate your drawings. I hope I didn’t come off as dismissive. It wasn’t my intention I assure you.

I like the aero 5th wheel thing. I recall a drawn image of one similar to what you described posted on this forum earlier.

I’ll stick with a bumper hitch though….

George

[Gschuld]

Originally Posted by aerohead

The task before us is, while maintaining jack-knife capability, we also minimize the total volume of the aerodynamic gap.

I totally agree. Leave as little room as possible for all the turbulence to get started