CRV Cross Country Trip Aero - Temporary Aero Just for the Trip

[winkosmosis]

I think that looks like a good design.

Is the rear going to be big enough for the bike to roll in? Or are you going to make the top removable by lifting it off the trailer?

[hypermiler01]

Speaking from experience, PVC pipe is an absolutely TERRIBLE material to be using for framing. I tried building a carport from it once.

It is flexible, so it will twist and sway and flap all over the place in any wind, such as the 60mph buffeting that you will give it.

PVC does not have good fatigue strength, and when it fails, it fails catastrophically. After it has been twisting and swaying in the wind for several hours, it will crack and then shatter, sending panels flying into the wind, and possibly causing a severe accident behind you.

You are spending more money building this trailer than you can possibly save on improved gas mileage from it, even if it miraculously doesn't break.

[Xringer]

My experience with PVC pipe is, it's just about impossible to break the larger diameter pipe.
I have some furniture made over 30 years ago, using 1.5" pipe and it still looks like it did on day-one.

I just built a small Snow Shed using 1.25" pipe and I figured it's going to last about 30 years.




It does flex, and move around in the wind, but a 2x2 wood frame would do the same.
A heavy wood (4x4) or steel frame would stop it from moving, if that was necessary.

As to suitability of PVC in building a frame-work for an aero-body, I think it would depend on the design.
The larger OD pipe has much less flex, and using rigid outer skin with plenty of fasteners could make it very stiff.
Notice the cross-beam I used in the little roof? That keeps it flat, from sagging under a heavy snow load.
If a structure is build using closely spaced support under a rigid outer skin, the skin will add a lot of stiffness to the structure.

That green PVC siding (skin) on my house still looks good after about 30 years.
It's strength today is the same as those spare pieces stored away, just the color has gotten lighter.
It's still tough stuff to cut. Need to use sharp tools to work with it.

The best thing about using the PVC Pipe, is the price. The second best
thing, is the ease of use. Since I have a cut-off saw, I can put together
a PVC pipe structure together very quickly..

It's also great for plumbing in experimental projects..

If the electrical power fails when the basement is getting flooded?
Just flip a valve and use the city water pressure to pump it out..
Liberty Pumps : Back Up Sump Pumps

PVC is great stuff to work with..

[Rokeby]

Originally Posted by walteraxe

I'm realizing this is going to be a difficult situation...
1. The trailer will have to be taller than the CRV at some point.
- CRV = 64" tall
- Trailer + Bike = 67" at tallest point of bike +/-...

You could decrease the height of the bike/trailer by making arrangements
to carry the bike with its wheels unmounted... could reduce height by,
maybe 10 inches. Folks carrying bicycles do this all the time.

It would make the loading/unloading slower/cumbersome. But you only do
that at either end of the trip. The trailer cover would have to be mounted
after the bike was attached to the trailer itself.

The hold down method for the wheelless bike would also hold it
securely and rigidly to the trailer.

[Xringer]

Since Walteraxe was planing to go on this trip in the summer of 2008, and it's now 2010,
I wonder how he made out on his trip..?.

Did he just tie the bike down on the trailer and head out, or did he make a nose-cone?

[hypermiler01]

Originally Posted by Xringer

My experience with PVC pipe is, it's just about impossible to break the larger diameter pipe.
I have some furniture made over 30 years ago, using 1.5" pipe and it still looks like it did on day-one.

I just built a small Snow Shed using 1.25" pipe and I figured it's going to last about 30 years.

The strength of the "beams" and joints increases exponentially with the diameter. 1.5" pipe is more than twice as strong as 1" pipe.

Also, your furniture may be subjected to high static loads, but it is the rapid dynamic loading which is the main concern that will make PVC fail when it is used for a vehicle frame.

Vehicles have been made out of wood for thousands of years. Wood does not weaken from dynamic loading the way PVC does. Wood framing is a vastly superior material for a project like this.

Another good method, especially for a more permanent trailer, would be to build the skeleton out of foam ribs, and then wrap it and skin it with fibreglass.

I am also curious to know how this project turned out. Wonder why he didn't follow up on this thread.

[hypermiler01]

Originally Posted by Xringer

Did he just tie the bike down on the trailer and head out, or did he make a nose-cone?

Considering ALL energy and money, including from the beginning of design and all of the time and materials used to make the enclosure, and the fact that this was a single trip, there is no possible way that this was more energy or money efficient than just loading the motorcycle on the trailer and tying it down.