Step 1: Get A Trailer
Step 2: Build A Frame
I also wanted it to be wide enough to fit a queen 57"x 77" x6" matress, but the trailer is 48" so I built the frame a bit wider...
Two sides 2x4x73
Front and rear 2x4x57
Interior crossbraces 2x4x54 and 2x2x54
Lengthwise 2x2's added because of the wheelwell cutouts.
Step 3: Attach To Frame
Going to use lag bolts and/or u bolts to hold in place depending in the trailer we are using (have a catamaran sailboat trailer that this could fit on when camp-sailing)
Step 4: Cut Out Walls
Here was exact one I used to model mine
Drew the ellipses using string and sharpie
Front and rear corners are Circle radius 30"
Front roof curve is small ellipse using two focal points the front of which uses same center as circle and the back one 30" from the rear edge. Adjust length as required to get height desired.
Rear roof curve used rear focal point and another beyond the front wall to get a more gradually sloping line.
Rear lower is also 30" radius circle
(See drawing pictures added)
Then began cutting
long razor/box cutter
Optional tools: hot knife (foam carving specialty tool) $30 or soEDIT***GET THE HOT KNIFE!!!
EDIT*** the best way to cut foam is to get a hot knife- details later*** ...previous comments: The best way to carve is heat up knife with torch and cut a few inches at a time. Takes a while but works well. Clean off the blade whichever way you please... (Xps- extruded polystyrene- will melt onto blade then won't cut as well if covered)
More details on ellipse drawing will be added to this step later.