Michael You are after a strain gauge (also known as a load cell), and preferrably one connected to a data logger of some sort to take regular measurements. They are basically a sensitive resistance bridge coupled to an instrumentation amplifier and then some sort of A/D converter to turn it into a displayed/recorded measurement. Strain gauges come in different ranges according to the maximum load they are designed to measure. Don't go too high or else you'll have trouble with noise versus low signal output (and besides, they generally get physically larger too).
For an auto launch, the instrumentation can be attached to the rope/cable at the auto end of things, but for the winch launch, because the rope/cable is being wound onto a reel, you need to fit it to the glider end of things, which means it also has to be capable of withstanding the drop back to earth once the rope is released. To try and relate the periodic measurements with the glider's progress during the launch you may need to use a video camera to get a reference showing the glider during each phase. An interesting problem indeed ! My recommendation would be to start with the auto launch and then try and find someone who can build you a ruggedised instrumentation package for the winch later on. It should be an interesting project indeed. Regards Jason Armistead On Thu, 23 Dec 2004 10:36:24 +1100 (added by [EMAIL PROTECTED]), Michael Derry wrote > Is there anyone out there who uses some kind of tension measuring device > who can tell me the force in kgs at either end of the rope/cable for > a winch and auto launch at the various stages of the launch ? > > Cheers > > Michael Derry _______________________________________________ Aus-soaring mailing list Aus-soaring@lists.internode.on.net To check or change subscription details, visit: http://lists.internode.on.net/mailman/listinfo/aus-soaring
