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#24
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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 |
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