Class a motorhomes aerodynamics

[freebeard]

If you follow Permalink #174, according to Betterflow, the solution is hub motors and a catamaran design below the load deck.

[j-c-c]

So we agree, this stretched very partial undercarriage stretched fabric solution is stillborn?

If your last solution above is sought to be effective, the front very robust tractor steering beam axle will need a design that would not likely severely obstruct air flow, but doable, and all power to the drive wheels could no longer be by conventional large differentials, and hub electrics are the only viable solution currently for that task that meets proper airflows underneath. Trailer axles will of course need same consideration with their axles and all related brake actuation and suspension hardware.

All meaning a complete design evolution of existing transport vehicles?
Boxing the entire trailer undercarriage seems a lot simpler.

[freebeard]

Ultimately it's the constraint of loading dock heights. Edison2 showed an inwheel suspension and steering.

https://www.wired.com/images_blogs/a...n2-vlc-4-0.jpg

[j-c-c]

I don't see clearly any steering articulation, unless that is covered wagon straight axle steering set-up. It looks interesting. The bellows ended shaft is for drive or maybe steering inputs?

[freebeard]

All I know is it went around corners.

Edison2 failed trying to make the whole car. I wished that they'd sold the suspension on a 1937 Ford tube axle to street rodders.

[j-c-c]

Maybe with proportional torque application by individual wheel for vector corrections?

[freebeard]

Maybe ask DuckDuckGo? It points to https://www.autoweek.com: Driving The Edison 2 Very Light Car 4.0 BY ERIC TEGLER PUBLISHED: APR 18, 2013

It rides on Edison 2's patented “in-wheel” suspension, the most innovative (and likely most commercially attractive) aspect of the project. The arrangement consists of front and rear crossbeams attached to each bulkhead. The beams carry the in-wheel suspension and absorb its loads.

Entirely within 17-inch wheels are small, specially fabricated control arms, coil-over shocks/springs and a hub/spindle assembly.

Up front, the in-wheel suspension mounts to the beam through a carrier that anchors both the upper shock mount and a bearing that allows a large carrier to swivel. Out back, in-wheel components mount to the beam via short trailing arms. Driveshafts couple to a cogged-belt system within the hub assembly. Eliminating conventional strut towers confers packaging benefits. Kuttner has launched a new company, Edison 4, specifically to market the unique suspension.
...
We were the first to drive the VLC 4.0 outside the company. The feel is something between a traditionally suspended full chassis and a go-kart. Watching the beam move vertically in relation to the in-wheel suspension is fascinating. There's little body roll, but in hard cornering on rough pavement the chassis tended to understeer mildly then skip with noticeable bump steer. Narrower tires and revised springs will increase compliance for the street. Inside, basic controls are no problem, but the narrow rear seat and high floor are.

This author agrees about the commercial opportunity.

[aerohead]

Originally Posted by j-c-c

So we agree, this stretched very partial undercarriage stretched fabric solution is stillborn?

If your last solution above is sought to be effective, the front very robust tractor steering beam axle will need a design that would not likely severely obstruct air flow, but doable, and all power to the drive wheels could no longer be by conventional large differentials, and hub electrics are the only viable solution currently for that task that meets proper airflows underneath. Trailer axles will of course need same consideration with their axles and all related brake actuation and suspension hardware.

All meaning a complete design evolution of existing transport vehicles?
Boxing the entire trailer undercarriage seems a lot simpler.

I'll go on record as one who's not in agreement. The air is agnostic as to 'impermeable' membranes, whether fabric, composite, or metal.
I believe that presently, Porsche has 'fabric'-roofed' 911's running the Autobahn at 170+ mph.

[j-c-c]

This the first I am in hearing in this discussion that the 'impermeable' aspect of the material utilized is a or is not a concern, and for the record, I never questioned that on any Porsche or on any undercarriage semi-trailer additive aero device, I of course cannot speak for others.

[Piotrsko]

+170 needs lots of attachment or really robust fabric. Fuselage fabric at those speeds needs rib lacing every 3 inches