I couldn't find the descent rate chart but I'll look for it. I would think it would higher?
here ya go...got so many of them, keep it on my desk top.
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Also remember Julie measures her parachute in a different way she measures the size over the top of the canopy. 1/2 circumference. This means the actual opening of the canopy in diameter is quite a bit smaller. For example my parachute which is measured as a 120" chute is actually 76" in diameter.
Also keep in mind that Cd is merely a fudge factor to make the force equation work. Listing Cd without the reference area is meaningless. In fact, the product CdA is a more complete description of the performance.
Correct. The nominal Cd is not the same as the actual Cd, and that’s true for almost every brand of chute, not just Spherachutes. She picked an odd measurement system that makes the nominal chute size unusually big for the actual chute size, so it means her nominal Cd has to be unusually low. If she had picked diameter of the opening instead, then she could say her say her Cd was something like 1.2 instead of .75. All the chute makers are using different systems to calculate their “reference diameter” and that means it’s really hard to compare chutes from different makers. A 36” Fruity Chute is not the same size as a 36” Spherachute or a 36” Top Flight. You would expect them all to have a different Cd due to differences in design, but it’s also due to differences in how they are measured.
Wouldn't her chutes still have a higher CD that a flat sheet parachute? Most flat type chutes come in at .750?
In reality, I’m sure her chutes do have a higher Cd than a flat sheet.
It does make it difficult to input data. I figure if kit came with a flat 36" chute than a size smaller of hers would still work well or same would be even better?
The best information to have for picking chutes is a graph of descent rate versus payload weight. The Cd and reference sizes are all so screwy across the chute industry.
I couldn't find the descent rate chart but I'll look for it. I would think it would higher?
https://www.spherachutes.com/decent-rate-chartI couldn't find the descent rate chart but I'll look for it. I would think it would higher?
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