Com on. Keep up. lol It's really just figuring out what it would take to determine motor performance through actually flight testing. I do like your idea though. Just measure things like temperature, humidity, and pressure on the way down so you can correct for air density. Thanks Shawn Michael -------------------------------------------- On Mon, 2/23/15, shawn.mchatten@xxxxxxxxxxx <shawn.mchatten@xxxxxxxxxxx> wrote: Subject: [sugpro] Re: Verifying Motor Performance Through Flight Tests To: sugpro@xxxxxxxxxxxxx Date: Monday, February 23, 2015, 3:54 PM Not sure I'm following all this conversation but instead of a balloon can you gather data from a parachute recovery on the way DOWN instead of on the way up to establish air density etc. For that matter are there any papers that show air density or viscosity based on a specific parachute and mass configuration. If not that would be a cool standard to create for the community. Shawn