bagmaker wrote:
Is there a good way to determine a 10000' height when falling, to pull a
ripcord? Surely there is enough go-gas available at even 15000 for a
minute or so of slow decent under a canopy to survive the fall?

I should think that's OK. I've driven directly up to 14000 (during a
visit to Denver I was given the car keys and told to drive up Pikes
Peak). I felt a little weak on first arrival, but after a coffee and a
donut I was happy walking round up there for a half hour or so. I've
also walked up Poon Hill (Nepal) before breakfast to see sunrise on
Daulagiri. Poon Hill is 10,500 ft. We were staying at Gorepani (9000 ft)
after a three day walk from under 1000 ft. Climbing Poon Hill was no
problem either. I'm not much more than averagely fit: chasing Free
Flight model aircraft on foot and rigging gliders are my main forms of
exercise.

The South Col on Everest is 7980m (26000 ft) and I've heard that most
climbers think the Death Zone starts about 800 ft higher. The Death Zone
is the point above which oxygen lack will kill you, no matter how well
acclimatised you are, if you stay there for too long. I'm guessing that
what that means for us is that a bail-out at 20,000 or lower is
survivable under a parachute provided frostbite doesn't cause permanent
damage and you aren't in a cu-nim with up-currents slowing your descent
rate, but I'll gladly take correction on this. I've never jumped and
don't intend to: I see no reason to step out of a correctly functioning
aircraft

Does anybody know a typical sink rate for the sort of chutes we use?

As a non-jumper, how long does one actually have freefalling at our
glider flying heights before hitting the ground?

120 mph seems to be generally accepted as the terminal velocity for a
free-falling, fully dressed person: that's 176 feet/sec, or 5.7 secs per
thousand feet, or 17 to 28 seconds from typical UK xc heights.

I fear over-complicating such an emergency is a step backwards, but I am
open to the conversation.

Same here. Other points that occur to me:

- I've heard that skydivers have a good stopwatch/watch with
sweep second hand and an altimeter with them. If this is true,
is it sensible to try free fall without these aids?

- are our emergency chutes designed to be opened at terminal velocity?
Would the chute and/or pilot survive the shock loading?


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |