Nate, On Fri, 2009-09-04 at 09:39 -0600, Nate Duehr wrote: > > We (AF6IM and KF6WRW) have been keeping our toggles stowed until we > > get to about 3000 ft. > > If you pulled at 3000' MSL here, well... you'd be dead/underground!
1. Unlike pilots, skydivers always use AGL, not MSL. When we are headed straight at the ground at 120 mph (or possibly a lot more depending on body position), we really want to know how far away the ground is without having to remember and subtract the ground elevation. Since we almost always land at the same location we took off from, and are not in the air long enough to worry about significant barometric pressure changes, it makes sense to use AGL. 2. When Mark says "keeping our toggles stowed", he is not talking about deploying the parachute. The toggles are the steering controls. Parachutes are packed with them locked partway down in order to improve the deployment. Once the canopy is open, the jumper releases the toggles to allow the canopy to go to full flight. Leaving them stowed will result in slower flight and a lower descent rate, useful to give Mark more time to play with the radio, as well as reducing wind noise that the mic will pick up. Brian
