wrote:
LCT Paintball wrote:

http://dsc.discovery.com/fansites/my...pisode_07.html



Lawn chair Larry really made his flight though it may not always
be reported accurately--e.g. no helicopter rescue, he came down
on his own by shooting the balloons as planned.

However OP was talking about folks contemplating a sub-flight
balloon-assisted jumping. I think this would be a bit less
spectacular than one might imagine as the balloon will not
rise as fast as the person does when jumping so that the
jump would be only a little higher than normal, followed
by a rapid drop until the slack in the lines is used up,
followed by a a slow drop the rest of the way to the ground
which I think won't be very far.

A very rigid connection between the jumper and the balloon
would have a smoother effect but wind resistance being
much greater and inertia also greater than for the unassisted
jumper I expect that would still be disappointing.

Long jumping will be hampered by wind resistance. However,
downwind long-jumping might be a real gas, stopping would
be the hard part.

Oh, OP said negative net lift. That means the pilot would not
need to jump, he will rise on his own and should give careful
consideration as to how to get back down. Keep in mind also
that on a sunny day the lift may increase as the gas in the bag
heats up. It will also increase if the pilot loses his lunch
or pees in his pants in flight.

--

FF

Sorry about the net lift mixup. I actually meant the person jumping
would have 3-5 lbs of net weight. So yes, he would be on the ground
but barely. In this case, even the slightest nudge with his toes would
make him airborn...so I don't think there will be much rope slack to
deal with, unless he tries to jump upwards very violently (although my
gut reaction was the same as yours). We would have at least 2
tethers...one to the ground and one to another person. This seems
pretty failsafe to me, barring shoddy tethering, with we would take the
necessary precautions for. Perhaps the jumper could also have a pair
of scissors in his pocket as an emergency solution to an airborn
accident. It seems like this would have appealed to more people...I
know it exists at some amusement parks. Here's the inspiration to my
friend's idea: www.parabounce.com

It clearly works there with no slack problem. You'll notice there are
two kinds of harnesses used. One is mostly rigid, allowing for a more
direct transfer of unward movement, while the other seems to be a more
straightforward setup...like a parachuter's.

The increase in lift due to heat is a good point...our tethers should
have no problem with the additional pull...right?

Does anyone have a cost estimate for this? They would be starting from
stratch.

JumpingMan