I was thinking more along the lines of something better than pressurized vinyl as a support structure. Maybe a semi-rigid shell made of lightweight materials like Kevlar that could distribute the load forces from wind more evenly between the people controlling the balloon.
That’s total lift; minus 400 lbs of balloon (fabric) weight means only 350 lbs of ‘free’ lift; sounds about right because as the balloon rises it’s also lifting up the weight of the fabric.
Doubtful it could be lighter than fabric only.
But under TT-Bonham’s proposal the balloon has to lift only itself - no basket, and people, burners & fuel all stay on the ground.
I’m not sure how well it would work with, essentially, piping the hot air up to the balloon.
That said - even lifting “just itself” the balloon is going to be huge because hot air isn’t as efficient a lifting gas as helium.
Sure, hydrogen is flammable, but then, most things humans make are flammable. Nobody’s aghast at making things out of, say, wood. Even pure hydrogen is acceptably safe, as long as you don’t do anything stupid like make the envelope out of thermite.
Hydrogen is not only flammable, it’s among the leakiest substances known. Extraordinary precautions are required to use it; to float balloons in a public parade simply isn’t going to fly (no pun intended).
Chronos (or Stranger On A Train, whenever he comes back) would know this, but wouldn’t even a modest portion of one balloon’s worth of hydrogen, mixed with atmosphere and ignited, be enough to shatter a lot of the windows along the parade route?
That strikes me as a bad thing.
A hot air balloon flys because it’s roughly 100° degrees above ambient air temp. This is accomplished via a 12-15,000,000 BTU burner. A small passenger hot air balloon is 77,000 cu ft, or (for size comtparison a basketball is 1 cu ft). Sure, they could be smaller w/o the weight of humans, baskets, tanks, & burners but not having the burner on board but having that air pumped in means one heckuva large fan. In a real hot air balloon if it gets too hot/we start rise when we don’t want to, we merely pull the vent line in the top of the balloon to let some of the hot air escape. The further the pilot is from that point, the tougher micro control would be; I fear an oscillating ride of too high (straining the handlers) & then hitting them in the head if too much hot air is released.
Hydrogen can be dangerous when filling but should be stable once in the balloon. A small leak would go up, into the atmosphere, away from people. However, a terrorist standing on a balcony on CPW with a flaming arrow could end that balloons trip in a hurry. I don’t see NYPD ever allowing this.