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Choosing a Reserve Parachute

Q:How do I choose the correct reserve?

        Parachute manufacturers test reserves pretty carefully before the FAA approves them, and then they must survive the even-more-daunting court of skydiver opinion. So almost any reserve should meet your primary expectations: reliable openings and reasonable ease of landing. That’s not to say that all reserves are created equal, but your main consideration for choosing one should be its square footage based on your weight and experience.

Chances are you’ve already had this discussion regarding the size of your main. If you’ve settled on a 170-square-foot main, for example, then you want a 150- to 190-square-foot reserve—something within one size of the main. If you’re a big boy or girl with a big, 250-square-foot main, then you want your reserve to be pretty close to 250 square feet, as well.

        If you’re flying a 90-square foot main, then you need to consider flying a small reserve to go with it. If it makes you nervous to jump a 100-square-foot reserve, then you should probably re-examine your logic for jumping a 100-square-foot main. Though some might argue that a bigger reserve makes sense in a stressful situation, why should that be any different for a main? After all, you could easily have just as stressful of a situation while under either your main or reserve canopy—a bad spot, a stunningly hard opening or a panic pull after getting your bell rung in a freefall collision. Admittedly, little testing has been done with dual deployments in the 100-square-foot-and-smaller range. However, consider this industry-wide recommendation for two-canopies-out scenarios taken verbatim from “Dual-Square Report,” the Parachute Industry Association’s Technical Bulletin 261: “Choose a reserve that is similar in size to the main canopy.”

        Most manufacturers match their main and reserve containers by size, and the gear can’t handle a great range of difference between the two canopies you pack inside. Though some container manufacturers can accommodate big main-reserve differences on a custom order, generally speaking, a main and reserve of about equal square footage will fit into any particular harness and container system. And although one company’s canopy might pack smaller than another’s at the same square footage, it usually won’t be a full container size, with a few exceptions.

        Sandy Reid, co-owner of Rigging Innovations, is also co-chair of the Parachute Industry Association Technical Committee. His company manufactures harness-and-container systems but not canopies. Reid has been measuring canopies and providing pack volume information to the industry for more than a decade. He explains that during his work with volume chambers, he has found that a number of factors—not all of which are understood—have put pack volumes “all over the place” through the years.

        Reid has found that lower-bulk reserve fabric—a recent arrival on the scene—has more effect on bigger reserves. In the 100-square-foot range, Reid has found a difference of only about 2 to 3 cubic inches between the bulk of conventional-fabric and low-volume-fabric parachutes from the same manufacturer. (The tested canopies had the same number and type of lines and reinforcement tape.) He observed that in reserves of 150 square feet and up, low-volume fabric can make the difference of about a container size.

        It might actually make sense to choose your reserve size first, then choose your main and container sizes accordingly. If you really want to apply due diligence, you’ll find manufacturers eager to set you up with a reserve for you to evaluate as a main for a jump or two.

        Don’t over-think your downsizing strategy when choosing a reserve size. Buy equipment for the skydiving you’re doing today, and keep the main, reserve and container system within a size or so of each other. Sell the entire system when you get serious about downsizing. As you take skydiving to the next level, a lot more than canopy size is likely to influence your equipment choice.

—Kevin Gibson | D-6943
Master Rigger
Orange, Virginia

Source: Parachutist Online