February 27, 2012

Designing the shape

There is no one standard shape for a teardrop trailer.  Some exaggerate the 'tear' shape, some are more swoopy and rounded, some are more boxy and everything in between.  We found we liked the more simple, traditional style shown in our design post.  Since we aren't working from a plan, I decided to use a design principal I learned in college I never though I would find a practical use for - the golden section!

Diagram from my favorite architect guru - Francis D.K. Ching

Sure architects supposedly use this and other fancy design ideas (don't forget the Modulor Man!) - but I have yet to work with one who utilized any outside of college and studio.  It's really all about eyeballing it and using standard lumber/framing sizes. Anywho, for me though, this worked really well for easily measuring out proportionate arches in cad that could be translated onto plywood.  That and I made my math whiz Dad very happy :)

Step one was to layout my 4'-0" x 8'-0" sheet of plywood in cad.  I snapped a guide line 3" up from the bottom to account for the floor system (this actually should have been 1 1/2" because the design changed from when I drew this out - but I decided to leave it 3" anyway).  I then drew out a 3'-9" square.

Next I drew a circle with the center at the midpoint of my 3'-9" box.  Where the circle intersects the line I snapped 3" up from the bottom will be the start of my next rectangle.

To finish drawing out my next rectangle, I drew a line from the intersection of the circle to the top, right hand corner of the 3'-9" square.

Next, I got to draw my arches.  The larger arch has the radius of the 3'-9" square and the smaller arch has the radius of the smaller rectangle.

Then to get my traditional teardrop trailer shape, I simply dragged the smaller arch left to the edge of the plywood.

Yay!  The final shape is a little boxy but still swoopy like the trailers we used for our examples.  And yes, swoopy is a technical term.  The next thing to do though was to see if this shape looked as good full scale as it did in the computer, so we made a cardboard template.

Its perfect!  Even our kitty Sophie seams to like it... I think... Next step will be a dry run with some scrap plywood we have then on to cutting out the real thing!


  1. Thank you for posting this! I've been wondering how I would get the shape right and this was a great tutorial. I'm hoping to start my build in January and will be using this blog throughout the process. Y'all did a great job, I hope you're enjoying it!

  2. I've been thinking of building a teardrop and I just discovered your blog. This post and others answer some of my basic design questions and other stuff I hadn't thought about at all so far. Thanks for putting this out for the rest of us to learn from!