26 ft lopo round

[riggerrob 643]

Early Strong Lopos were made with (Type 2) 2-stow diapers while current production Strong round reserves (26 foot Mid-Lite, etc.) have (Type 4) full-stow diapers.

Type 2 diapers are packed with only the left line group in (two or three rubber bands) in the diaper, while the rest of the lines are stowed in the pack tray.
Most of the Pop-Top containers (early SST Racers, Strong Pop-Top chest and most of Strong's Para-Cushion series of pilot emergency parachutes) require Type 2 line stows with only the left line group in the diaper, to hold the skirt closed until line stretch. The remainder of the lines are stowed in the center of the pack tray to provide a firm base for pilot chute launch.

Just to mess with you ... Strong does make one version of Para-Cushion PEP - the 311 Wedge Back that is so thick across the bottom that all the lines are stowed in the (Type 4 full-stow) diaper. Aerobatic pilots like the extra bulk (of line stows) to support thier lumbar spine when pulling Gs.

Now we get into a grey area. While most manufacturers INSIST that diapers be packed in accordance with the manufacturers' instructions, a couple of PEP manufacturers give riggers the option of packing Type 4 (full-stow) diapers as Type 2 (only the left line group) or full-stow.
The dilemma only arises when packing long (e.g. 40 inches) thin (zero to two inches thick) long-back (aka chair) type PEPs.
To make chair type PEPs as thin as possible, some container manufacturers (e.g Butler) say to stow the dipaer as Type 2 and stow the rest of the lines in the pack tray.
This produces the thinnest possible container ... when stuffing LARGE pilots into CRAMPED cockpits.

Strong does not seem to care, deferring to the container manual.

[erdnarob 1]

Not quite the safest place to try a round reserve on a base jump like the bridge. Round parachutes inflate differently than square parachutes and certainly way slower than square without slider or with mesh slider. A round parachute inflation is like the following :

1) some air enters the wind channel (inside along the longitudinal axis)
2) while the skirt or bottom of the parachute is still relatively tight, the air goes up and give the round parachute a pear shape with a bulge at the top and narrow at the bottom
3) Since the round parachute is travelling vertically thru air at a good speed, Bernouilli's law then comes to work making less pressure outside the bulge than inside (just like an airfoil)
4) the pressure inside the parachute being more important than outside the pear shape increases and the bulge get bigger and bigger and at the end the bottom starts to expand. What can happen at this time (if the opening is too fast) is to have the top of the round parachute bounce down and slip under the skirt of the parachute creating an inversion. You have to understand that there is almost not force to expand the bottom of a round parachute. Therefore should something at the skirt hold slightly the lines together like a thread or few turns of a pull cord and no inflation will occur. Military got that better in installing quick opening band at the skirt.
Note. Some round parachute (military) have been equiped with slider.

Learn from others mistakes, you will never live long enough to make them all.

[airtwardo 7]

Quote

Wall strikes aren't quite as big a deal under a round.

Relatively speaking maybe....but I know I'd think it was a pretty big deal!

~ If you choke a Smurf, what color does it turn? ~

[RiggerLee 63]

I'm a big fan of slider reefed rounds. The millatary were I think the last people to adopt the tecnology. The earliest one I can recall is the Starlite. I think BRS really pushed that tecnology with there ring sliders. And then Buttler and his Sombrarow, less of a fan of that one. It seems like the millatary stuck with there proven systems useing large porrus canopies and balistic cutters. Prior to this latest revamp I don't recall them useing any type of slider reefing system. Any one else know of other early ring slider reefing systems?

As to round openings... Yes all that is perfectly true but none of that adversly affects the useability of round systems for base. By closeing off the apex with rubberbands or tailgates or even sewing a patch across it you can speed the filling time of the canopy. By short lineing it you can reduce time to line streach. You can further reduce the volume by pulling down the apex on some models, did that to my k22. And the NRG bridge is high. Like so high even a stock 26'lopo would be like no problem what so ever. In comparison to most of the objects we jump with rounds where these issues are more critical bridge day is almost a skydive. For lower stuff we generally jump more specalized rounds with smaller volume and faster oppening times.

Lee

Lee
lee@velocitysportswear.com
www.velocitysportswear.com