On Sat, 24 Sep 2005 14:07:22 -0500, Curtis wrote in message <[EMAIL PROTECTED]>:
> Dave Martin wrote: > > >Ouch! :( > > > >Just a thought, many years ago I watched a demo of a BRS for a model > >plane at Cosford in the UK. Apparently it was very lightweight but > >had clever triggering. In the event that the radio signal > >(controller to plane) was lost, the system cut the fuel off to the > >motor and released a spring loaded BRS which brought the model down > >for a vertical but gentle landing. > > > >Could you fit something like this on the UAV for loss of contact > >events? > > > > It's definitely an interesting thought. Anyone know what size > parachute a person would need to gentle let down about 15 lbs (7kg)? ..AFAIR, the MATS-C drone chutes are round, about 2 meters diameter, I'll need to chk that. The MATS-C is a pussycat, about 5.5 kgs plus fuel, so we usually bellyland it. I have had 5 or so failed chute deployments, so you want a spring or something to throw your chute into the breeze, you cannot trust airflow to be strong enough to suck out the chute. > Many R/C receivers have a failsafe mode so you can trigger the servos > to go to preset locations in the event of a transmitter signal loss. ..which should be timed. In the old days, I suggested prompt idle, and kill power and shoot out the chute at say 5 seconds, 10 second tops. Now, with computers onboard... ;o) > The danger is probably similar to the danger the full size BRS units > have ... if you deploy the chute at a high speed, you are going to > tear your airplane to shreads. ..ahem, the big guys use opening shock damper rings to keep chute loads safe throughout the speed range, these rings use the chute opening loads to slow the chute opening. ;o) -- ..med vennlig hilsen = with Kind Regards from Arnt... ;o) ...with a number of polar bear hunters in his ancestry... Scenarios always come in sets of three: best case, worst case, and just in case. _______________________________________________ Flightgear-devel mailing list [email protected] http://mail.flightgear.org/mailman/listinfo/flightgear-devel 2f585eeea02e2c79d7b1d8c4963bae2d
