The best thing to do when a snow day is announced is head straight to the Sullivan wood shop and grab materials for a makeshift sled. I left with 3 sheets of mis-vacuum formed plastic and two foam cushions. I invited Cass over and she brought Kate, so we started with 3 makeshift sleds and 3 crash test dummies. (We were later joined by some kids in the neighborhood.)
Test 1: The cushioned, square polystyrene sled worked, but developed cracks after a few runs.
Test 2: The cushioned, square PETG sled worked better; it was faster and controllable.
Test 3: The uncushioned, bump-riddled PETG was slow but worked.
Lessons: Smoother, less interrupted surface areas make for faster sleds. Grooves on sled bottoms increase control.
I made a quick trip to the dumpster for more materials. I took several large cardboard boxes and two medium USPS flat rate boxes in a plastic Blick bag.
Test 4: The uncovered cardboard sheet did not work without a running start.
Test 5: Two cardboard boxes in a Blick plastic bag slid faster than cushioned plastic and gave the impression of floating on snow. Control was limited.
Lessons: A smooth surface area is essential.
I ran upstairs to find a large garbage bag to cover the larger sheets of cardboard but only found a convention bag (made of tarp) and an IKEA bag (also tarp).
Test 6: The convention covered cardboard barely worked.
Test 7: The IKEA bag covered cardboard did not work.
Conclusion: The fastest path down uses the smallest rigid surface area with the smoothest coating. While grooves on the bottom of plastic sleds offered greater control, they added surface area and slowed descent. Cushions were not more comfortable than plastic covered cardboard.