Bernard, I have been absorbing your articles on thermalling, wing loading etc., but am concerned that you will not discussed data as far as I desire before the soaring season.
The question are ~ assuming I achieve a rate of climb on the day: 1. What is the preferred wing loading, 2. Given that rate of climb, what would be the interthermal cruise speed [given a thermal climb and interthermal cruise regime]? Many will have flight director type computers, but those who don't could work from the block interthermal speed concept as a first approximation [to be improved by street flying, avoiding sink etc.] Can someone fill in the attached table. or complete the table below, preferably for a Jantar Standard, but another standard glider would be a good first approximation.... For example a recent article by Colin Vassarotti had the following table. "How Much to Use? Pilots should decide the optimum wing loading for a given task taking account of the forecast likely climb rate. The relationship of climb rate, wing loading and water ballast quantity for a Discus A sailplane weighing 340 kilograms with pilot, parachute and other in cockpit equipment is shown in the following table: Discus 340 kg dry Climb (kts) 2 3 4 5 6 7 8 Wing ldg kg/sqm 32 36 40 43 45 47 50 Litres 0 50 80 105 130 150 190 [Crz Speed Kt not stated... Has anyone done the calculations on suggested interthermal cruise speed ?] As shown, on a day where 5 knot thermals are anticipated a Discus would be flown at a wing loading of 43 kgm/sqm. Depending upon pilot weight and the individual weight profile of the aircraft, this would need in the vicinity of 105 litres of water ballast. For the same aircraft, if 8 knot climbs are expected, the optimum wing loading would be 50 kgm/sqm requiring 190 litres of ballast." Alan Wilson confirmed Jantar pilot [cause that is what the club has]
ROC_CRZ Table.xls
Description: MS-Excel spreadsheet
