Recently, I broke the 3-minute barrier (192 sec or 3:12) with some low-CM tops based on one of the few LEGO parts with a metal weight inside -- the Spinjitzu turntable. (Post here.)
Now I'm up to 212 sec (3:32) by hand and 272 sec (4:32) by manual spin-up tool with the "Spinjitzu burger tops" below. The trick was to up the attack on the density and aerodynamic fronts simultaneously by using 2 turntables mounted liked buns on a burger. This allowed me to take full advantage of the smooth rocker bottoms found on some turntables.
Each burger packs ~68 g worth of mass into a maximum diameter of only 47 mm. Some of them look pretty cool under blacklight, too.
Details on blog page.
