What ways do you control your descent? How do you know what size of parachute to use? Can I use wings instead of a parachute?
Almost all HAB teams will use a parachute to control their descent rate. A good rule of thumb is about 1foot/1pound of payload.
This isn’t a hard and fast rule, but it tends to be generally true, depending on your operational requirements. Obviously if you want your payload to come down fast you can use a smaller chute (for some of my operations I will use a 7’ chute for a 10-12lb payload). This leads to a fairly fast descent rate, but we haven’t suffered any significant damages.
As far as where to buy, take a look at Rocketman. Included on their page is a descent rate chart you can use to determine the impact you’re willing to accept for a given payload size.
Thanks for the tip on the Rocketman parachutes. We used one on our flight and it worked great!