Accordion Kammback for big rigs ?

[Cd]

I fully agree Demian. I was just presenting an idea.
I have no intention of even trying to ask anyone to produce this thing.

However, if this thing could be made of nylon tent material it would be really light and
it wouldn't absorb water and mildew / get heavy like canvas /would be lighter and more durable than rubber )

(Just think of how lightweight that a nylon tent is. I'd bet I could lift even a large tent easily with one arm.)

The nylon fabric could be bought at any large cloth store. To make things less complex, it could be designed like a curtain that simply pulls back to meet the trailer.

( Minding the hot exaust stacks and any other such things of course.)

One more thing that I thought of : The middle section of the top portion of the Kammback could be pulled downward and secured when there is a cooling unit on the trailer. This would actually direct air right into the unit and it might even operate better than within the open section of a conventional setup.

I'll have to do some illustrations when I get back home.

[Demian]

When I spoke of discussing existing designs, I was really commenting on the picture posted by gascort (no offense intended!). It is basically a redesign that would have to be done by a manufacturer, not a "mod" that we could apply to current designs.

I know I was critical at first, but I have come to see some good use for an accordion style kammbak for flatbeds. It would be much easier to use with a flatbed than my design (which is intended for vans). To load overlength rebar on this design all you have to do is collapse the accordion down so that the rebar's overhang clears the accordion. To do the same with my design would require removing at least the side panels, which is certain to be a chore for the driver (and would require the liability of them using a ladder in the rain), and likely the top piece as I am uncertain that it would be very useful without the sides in place.

Nylon is certainly light, but will it fray when it flaps in the wind (while the accordion is in the contracted position?)

[Cd]

Originally Posted by Demian

Nylon is certainly light, but will it fray when it flaps in the wind (while the accordion is in the contracted position?)

Hopefully it would last long enough to 'defray' the costs.

[SmallFry]

I would like to try something like this, but I don't bobtail enough to matter. The "closing the gap part would need alot of work. because of when the trailer is at 90 degrees in relation to the truck when in a hard turn. Maybe there could be a work up of snaps up and down each side of the rear of the truck, and on the front of the trailer, then stretch an elastic/spandex material between the two so it flexes with flex and moderate turning. It still doesn't deal with hard turning.

A simple test boattail could be a large conduit rod starting at one side of the bottom of the cab, following the curvature of the sleeper up and over and back down the other side. Make serveral just like it, except taper them in each one. on the truck frame, make some type of flag pole holder to set them in while bobtailing. Just a driver's simpleminded perspective.

[Cd]

Thanks for posting SmallFry. I thought this thread was long dead.
I sort of gave up on it when I saw what NASA did decades ago.
They did some aero studies on big rigs and simply used this ingenious ( but common sense ) idea : hinged gap fillers.



I do wonder how that this sort of setup would work in a jacknife type turn though.
Would it flex enough ?

I like your idea, but can't really visualize it. Can you do a quick sketch ?

( And P.S. - nice sleek looking rig you drive )

[oldpecan]

SmallFry, demian, and everyone, I'm wondering what type of truckers DO end up driving the most bobtail miles?

Congratulations on your over 10 MPG's there, SF, btw. do much bragging? j/k

Cd, If you picture some rectangle outlines made of narrow white plastic pipe, and each rectangle is a little smaller than the last, and they nest together flat when pushed together...maybe that describes SmallFry's concept. The biggest recatangle is just behind the cab and the smallest is the tail of the Kamm-back.

just blue-sky-ing it >>> what about venetian blind-like material?... keep the nesting rectangles that provide the strong, collapsible frame, but put venetian blinds plastic in-between instead of fabric?...it's more of a telescoping idea. I have no idea how the "blinds" attach or how much they haff to rotate for turning corners.

Or maybe just line camping tent nylon fabric with something friction resistant where it touches the frame elements.

[edit: the venetian-blind material would probably just end up being a new kind of road-side debris, come to think of it. I'll just leave it in this post there in case someone can take maybe the "telescoping" idea to a good place]

[Demian]

I would say that the most bobtailing is probably done by Mobile Home trucks. After delivering they are almost always bobtailing back. The second most I see is Lowboy trucks. Not often, but sometimes they deliver their tractors and dozers on the trailer and just drop the trailer rather than pulling it back. I don't see a ton of van or flatbeds bobtailing, and especially not long distances. Keep in mind I see a very narrow spectrum of the entire industry.

[SmallFry]

I wonder if something like this would work for a bobtailing truck?

[SmallFry]

While searching for Truck aero stuffs, I found this: freightwing.com.

They also have products for "bridging the gap" between the cab and trailer. Freight Wing Incorporated - AeroFlex Fairing product info page

[Blue Bomber Man]

Why not make it simple. Have two vertical rollers with a sheet that attaches to the trailer and has a tension coil to keep it taut. A similar roller could be mounted on the top