I've been using Rocksim to design a rocket, and I am running into issues concerning parachute size. I was looking at an Estes 24" plastic parachute. I add it in Rocksim, but it doesn't appear to change anything in the general tab. I had to use mass override to get the correct mass. Rocket weighs about 6.89oz coming down. I've selected medium descent rate, and ran 10 sims. 3 out of 10 times, the descent rate is way too high - 18 to 19 fps. The others are about 13fps. Avg drift is 223 feet. I change the option to low drift rate and Rocksim suggests a 27" parachute, which doesn't appear to actually exist. This improves things so that only 1 time out of 10 is the descent rate too high (17 fps), with avg drift being 266 feet. Trouble is, nobody sells a 27" parachute. I haven't seen any 30" plastic parachutes, and nylon is probably going to be too heavy, lest I redesign the rocket again. So my questions are these: How accurate is Rocksim concerning parachute size and descent rate? Given that I am generally launching my rockets on a grassy field, and the typical area rockets drift into are farm fields/grassy fields, is it likely that the higher descent rate with some of the 24" parachute launches will cause damage to my rocket?