Al,
Thanks for the info - the most informative response to date. In the
meantime since my first post, and based on the reponses I got here, I've
gone with the Softie seat pack. Confirmed the order last week and it should
arrive soon. Looking forward to receiving it and seeing how it all fits.

Cheers,
Shawn
"Al MacDonald" wrote in message
news:0YRKc.43754$2i3.11107@clgrps12...
Shawn,

My Pitts S1- C (with D fuselage) came with a National chairpack. What I
didn't know at the time was the previous owner had set a piece of plywood
across the seat bottom frame to increase his eye height. This is a good
combination, as the visibility is as good as it can be, and when I'm
hanging
upside down I can just feel my dangling hair touch the canopy. I took the
plywood out to try some circuits one day, and the 1.5" less height
seriously
reduced the visibility (and the quality of my landings). This chairpack
doesn't give me good lumbar support, which I can feel on a cross-country
flight, but it's fine for g's. I can actually feel the diaper through my
rear end, but because the packed parachute is quite firm on the bottom
portion it doesn't tend to move or squish on higher g's. Without the
plywood, I think a seatpack would be the best for this aircraft and me
(6'160#). I don't think any type of backpack would be comfortable in this
aircraft, and even worse in a 'C' fuselage.

The parachutes are all tested and TSO'd in different categories. Older
style systems were either low speed (under 150mph) or standard category.
Military surplus are all standard category. Drop testing was done to a
standard that (theoretically) imparted a shock load on the system, which
decided in which category the system fit. 3000 and 5000 lbs seems to ring
a
bell here. Later TSO requirements of C23c allowed for 3 different
categories, cat B being the most common -- a drop testing of 300 lbs at
175kts, with placarding at 254lbs at 150 kts. TSO C23D allowed for more
categories with different weight/speed restrictions, which was great for
the
extra lighter or heavier user who may need different requirements.
Current
day standards call for a "full-stow" diaper on a round parachute, which
stages the parachute deployment, thus increasing the reliability of the
opening. Without a diaper the parachute is allowed to open before the
lines
become taut -- imagine the shock when the lines finally tighten up on a
parachute partially open already! In the days before the full stow
diaper,
the lines were unstowed from the pack tray, which allowed for the
potential
of arms and legs to get tangled up in the unstowing lines (especially for
a
pilot making his first jump and not maintaining balance/stability on the
relative airflow). The full stow diaper carries all of the line stows on
it, so the lines unstow from the top down, and once the parachute is out
of
the container the the lines are well out of the reach of an unstable
pilot.

The opening speeds here are very important, as the drag from the opening
parachute increases in square to the speed increase. My Pitts has a VNE
of
203mph/176kt, which could easily cause damage to a parachute rated at only
150 kts. Higher speed parachute systems incorporate other staging devices
to inhibit the opening of the parachute for a very short period of time
while the parachute and user slow down; all to reduce the opening shock to
an acceptable level. Altitude above sea level plays a part here as well,
as
parachutes tend to open faster/harder in thinner air (don't ask me why)
and
they land faster too. Landing a parachute may be a consideration here as
well. While the cockpit may only have enough room for a 24' parachute,
the
200 pound user may find extensive lower leg and back injuries a real
possibility after a successful bailout, and our bones take longer to heal
as
we get older....

I manufacture, repair, repack and sell all kinds of parachute equipment
for
my business. Good luck on picking the 'right' system for you and your
Pitts.

Al MacDonald
Flying High Manufacturing Inc.




"ShawnD2112" wrote in message
news:AnZDc.1369$Dq1.851@newsfe6-win...
Was hoping to get a bit of expertise here. I'm in the market for an
emergency bailout chute for flying in my Pitts S-1D. The top US
contenders
seem to be National and Softie but with no experience in the field, and
parachutes not exactly being the kind of object you can try on for size
in
the shop, I don't really know what to look for and what to avoid. I'd
appreciate any tips anyone out there could provide. Are there any
European
models that anyone has any experience with? Obviously comfort and space
in
the cockpit are major considerations.

Thanks!
Shawn