First main size, with prior canopy experience in Safety and Training August 7, 2019 " when you play with the volume with slats " Sorry, that whole example with the diagram doesn't apply to this situation. A slat does a lot more for an airfoil than just extend the chord. The lift coefficient won't change much with a change in an airfoil's size, within some reasonable range close to the original airfoil's size and speed used. So just leave that diagram out of it. (Saying this as someone with an aeronautical engineering degree.) I don't think canopy volume is the way to characterize how hard a canopy is to fly -- at least in comparison to wing loading modified (in a not precisely mathematical way) by size Let's say you have a guy on a 200 canopy who weighs 200 lbs geared up. And a small girl on a 100 who weighs 100 lbs geared up. (Not trying to be realistic here, but to make the numbers easy.) Wing loading is the same, 1.0. We already know that a tiny canopy will be a lot trickier to fly, even though the wing loading is the same. We know not to say, "They fly the same because the wing loading is the same." But it is little use to talk about canopy volume instead. The canopy volume on the 100 would be about 35% of that of the 200 canopy. (Volume changes with the cube of the line length. Halve the canopy area, line length becomes 1/root(2) = .707. Cube that =.353) How does it help us to know the canopy volume is about a third of the original? "Same wing loading" sure doesn't mean "just as easy to fly", but "about a third the canopy volume" doesn't mean three times harder to fly?? (Canopy volume on its own is a small factor, and isn't entirely irrelevant, as there is a mass of air in the canopy that has to be accelerated around when maneuvering. It can be some pounds of weight, with much less mass in a smaller canopy. But I wouldn't make canopy volume the main focus.) We know line length changes less fast than the area of the canopy changes. (eg, half canopy size = 71% of the original line length, or 29% less length) And that line length will affect dynamic canopy behaviour -- shorter pendulum swing will affect turning and stability, and a shorter control range to deflect the canopy trailing edge to the same degree. And the combination of those effects will be something else again. So in this example we have all sorts of different size factors: - wing load is the same, 100% of the original one could say - line length is 71% of original (but maybe line length dynamic and control effects somehow multiply the difficulty for the jumper, creating a lower percent value) - area is 50% of the original - canopy volume is 35% of the original None of these numbers alone seem to be "correct" in giving a guide to a jumper how much different a 100 lb jumper is on a 100 canopy, compared to a 200 lb jumper on a 200 jumper. I think it will be somewhere between that 100% the same and the 50% change of the area. The volume change (of about 35% of the original) is way too much to be useful for this. In conclusion, while you might be concerned that "wing loading plus an adjustment for smaller canopies being trickier" is a vague way to give a guide to how a canopy will fly for a jumper, canopy volume isn't the way to go. So things are pretty much as wolfriverjoe already stated.