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From: kas@hp-pcd.UUCP (kas)
Newsgroups: net.rec.skydive
Subject: Re: wierd canopies
Message-ID: <41800060@hpcvlo.UUCP>
Date: Fri, 7-Feb-86 12:54:00 EST
Article-I.D.: hpcvlo.41800060
Posted: Fri Feb  7 12:54:00 1986
Date-Received: Tue, 11-Feb-86 05:33:26 EST
References: <650@wjvax.UUCP>
Organization: Hewlett-Packard - Corvallis, OR
Lines: 46
Nf-ID: #R:wjvax:-65000:hpcvlo:41800060:000:2982
Nf-From: hpcvlo!kas    Feb  7 09:54:00 1986


     I think the remarks made in the "Conclusions" section of that report said
it best.  There wasn't enough data presented to ascertain the cause of that
accident.  As I said before, it is physically impossible for the canopy to
"weird out" totally on its own.  It MUST be acted on by some external force
for it to do what it did.  Downdrafts, wind gusts from behind, too deep in the
brakes, turbulence, following too close behind another canopy, etc., etc., all 
could be factors in a situation like that, whether or not the canopy was in
a turn at the time.  My point is, it is imperative to understand and recognize
all the things that COULD go wrong, and then make sure you don't get yourself
into a situation that invites disaster.  The best hedge against such problems
is AIRSPEED.  The faster the canopy is going relative to the air, the less
likely it is to be affected by one of those gremlins.  That's why it is so
important to make your final approach at nearly full airspeed, and flare only
when you are 3 or 4 seconds from touchdown.  (Canopies vary, so the time may
vary.  You should try to use the same type of canopy on each jump, if possible,
and learn how to fly it well.)  Whatever you do, DON'T go into deep brakes
when you are below 100 feet or so, especially if you are landing in an area
that has objects large enough to cause turbulence nearby.  One of the paradoxes
that we skydivers must deal with is the fact that most turbulence occurs near
the ground, where we want it the least.  Cars, buildings, trees, parked planes,
any kind of "bump" on the ground will create turbulence as the breeze passes
over or around it.  Plowed fields and concrete runways will likely cause large
updrafts on a sunny day, but an adjacent green field is likely to have a
corresponding downdraft.
     Again, the key is airspeed;  so stay outta those brakes near the ground,
OK?  I usually approach the target at about 1/4 brakes, and flare when I am
3 to 4 seconds from touchdown.  It takes practice to judge that well, but you
will get a feel for it as you gain experience.  I would suggest you do the
following:  On your next jump, when you still have plenty of altitude, go to
zero brakes and let the canopy build up full speed for a few seconds.  Then,
pull the toggles all the way down and begin counting "1000, 2000, 3000...",
until the canopy stalls.  Recover from the stall and repeat the procedure
from 1/2 brakes, 3/4 brakes, and full brakes, and you'll find how long it
takes for a stall to occur from each brake setting.  At 3/4 and full brakes,
you'll find that the stall occurs almost instantly.  That is why you don't 
want to be that deep in the brakes near the ground!
					Happy, and soft, landings!...
 
             *
            / \
       |---/---\---|            Ken Scofield    C-9355
       |   Gone    |            Hewlett-Packard PCD
       |  Jumpin'  |            Corvallis, OR
       |-----------|
			{ucbvax!hplabs, harpo, ogcvax}!hp-pcd!kas