Which Trailer shape is better??

[Sven7]

Originally Posted by Frank Lee

I'd call Sven's proposal (c)- it looks quite good... now put radii on the leading and upper edges.

Thank you. I didn't put radii on partly because I'm pressed for time and partly because building a consistent radius in real life would probably be a struggle with metal HVAC ducting, if you could even pull it off. I'd go sans the radii and see how it does. With that shape it should give some pretty awesome mileage right out of the box

[Frank Lee]

Originally Posted by Sven7

Depends what Ed wants to make- an aero pull-behind that also hauls cargo, or a trailer that is also aerodynamic. Yours, Frank, is the former, and mine is the latter. Two different ways to approach the same problem.

Hah?

[Sven7]

Originally Posted by Frank Lee

Hah?

It's a statement about sacrifices. You can have great aero or great cargo capacity... the more of one, the less of the other.

I decided to design a trailer with decent aero and decent capacity.

[Frank Lee]

I described the same thing you sketched. It's a convergence, like it or not.

[Sven7]

K. I didn't worry about "[keeping] the front of the trailer to the back of the tow vehicle". But they accomplish the same goal.

[Ed-in-Maine]

That's a nice design you built Sven7. I have a hard time seeing how the interior accommodations would be installed. Bed and Galley. Can I get that model in to Sketchup to play with?

And yes radii at edges are better BUT, ease of construction is also a requirement. A radius in one direction is easy, two is very hard, given time, materials and tools at hand. That's why I was curious which direction of leading edge might be better, horizontal vs vertical.

I like the idea of bringing the trailing edge up to aero profile and chopping the end off. I'm limited to about 10'-12' total length.

Does anyone know if that aero shape is in the Google Sketch up library? And if so the name.

This camper is to be towed 90+% of the time behind a small car like our Toyota Matrix hence the limited size and weight.
Thanks for the input.
Ed

[Frank Lee]

I think a or c or some blend thereof for the front, and c for the back would work best behind the Matrix.

[Ed-in-Maine]

Sorry I've lost track of a,b,c. Here is a new model incorporating the raised rear.
Do these look better?
Thanks
Ed

[Sven7]

Still way too steep of an angle at the rear. Can you insert canvas images into Sketchup to build over? If so, do that. If not, overlay the aero template from last page until it matches. Print them out if need be. I posted that image because it's pretty close to the "perfect" low drag vehicle shape. Any steeper an angle will detach the airflow, resulting in eddies and vortexes.

I don't know how to build in Sketchup or convert from Alias, if it's even possible. The best way to do it would be building over an image. Also, if you're making it 4x4x10, define those dimensions in the model! My model is built almost exactly to those dimensions and you can see how much longer it is than either A or B. (That is, unless 4' is measured from the axle up)

If you only make a curve in one direction I'd do A because it will have a smaller frontal area in crosswinds.

Edit: As far as accommodations go, you should be able to fit a bed in there with a little space to walk around, especially if you cantilever the body over the wheels for an extra 10 inches or so.

[Ed-in-Maine]

Sven7-Thanks I figured out getting that aero image in to sketchup. And WOW I didn't think the trailing edge would be that high. With the rear that high I have to really rethink the layout.

As for accommodations I should have been clearer. Bed for two, min 48" wide 6ft long.
Thanks
Ed