The two main factors of reserve parachute performance are the rate of descent (vertical speed) and stability in rocking (swinging) after opening. Both of these factors can be significantly influenced by a suitable canopy construction. The designers of reserve parachutes have been tuning their products for many years and strive to balance these parameters with the requirements for minimum weight, price and packed bookmarks volume.

If we stay with the square designed reserves constructions and the main parameters in their main advantages are low weight, small packed volume and reasonable price, we get to the recently for paragliding discovered construction of the canopy of the reserve parachutes.

Due to the larger coefficient of resistance of the square compared to the circle, the regression is slower under the same area load. Holes in the corners of the canopy “leak” air whose flow helps to stabilize the flying / falling system against unwanted rocking / swinging. Even on a reserve parachute with a theoretically acceptable vertical speed, the landing may be hard if it takes place in the unfortunate phase of the pilot’s swing under the canopy. From this point of view, the parachute cross structures clearly play a prime role.

The speed of the reserve parachute opening, a parameter that many pilots ask, is not accurate enough for accurate and independent testing. Therefore, the list of reserve parachute features is not given in numbers, but only as a more or less subjective comparison of observations of competing structures. In the world, square tabs have been used and tested for some time, and it has been shown that they open a little faster than standard circular tabs. This helps, most likely, the shape irregularity for folding during packaging. They simply have more pleats of fabric that can be filled with air – similar to the so-called double-shell circular parachutes.

The procedure for packing a square parachute is almost the same as for a round parachute and an experienced packer will master it during a short training session. So there is no reason to worry about finding someone to repackage the parachute.