Jon: Somehow I missed your very comprehensive reply about a month ago to my query. Thank you for explaining more about how it is managed to pop off the ground like that!The height of the jump depends on density altitude, load, and wind. I've gotten some impressive heights when all the factors were in my favor. I'll attach a video showing a fairly typical two-on-board "jump". I put that in quotes because in that particular video I actually let the aircraft roll a few feet before punching the button, but you can tell it's not much of a run and it wasn't necessary. I picked it because it's the easiest one for me to find. This one was shot at Santa Paula while I was giving some instruction to Al Ball in his nicely restored ship and giving rides to some of his friends. I'm flying from the front seat, because that's where the spin-up controls are (when instructing, the student starts in back for a few flights until he / she has basic aircraft control mastered, then moves to the front and learns the spin-up process).
It jumps nicely at sea level, but needs some roll above 4000' elevation. Roll is NOT done to get rpm, but to get a little airspeed, so you do it full throttle and only go as far as needed to get 30 mph or so, which happens very quickly with 180 hp. The blades are about 55 lbs each (with three of them), 35 ft diameter, and are spun up to over 150% of flight rpm while sitting still, so there is lots of momentum on board before you get moving.