Hi Alan! I see Miles Gore Brown has already volunteered to dig into his archives and submit tables for the Jantar. GREAT!!!!
Please keep in mind that the optimum speed to fly is NOT related to thermal strength but to your achieved rate of climb. The next few issues of Soaring Australia will contain a few hints for extracting the maximum rate of climb from a given thermal. Sure, speed to fly is an issue - but not as important as most pilots think. More or less the same applies to water ballast. Getting your speed to fly wrong by 10 % or misjudging your optimum wing loading by 10 % is only going to result in an overall speed reduction of less than 1% (one percent). The real race in a gliding contest is not in a horizontal but in a vertical direction. Pilots who locate the strongest thermals and work them in the most efficient manner usually have their nose in front. (Unless of course they make some other blunders) Bernard Eckey Ph. (08) 8356 8565 (W) Ph. (08) 8449 2871 (H) Fax (08) 8356 8705 (W) Fax (08) 8242 3698 (H) E-Mail: [EMAIL PROTECTED] ----- Original Message ----- From: "Alan Wilson" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Saturday, November 02, 2002 2:29 PM Subject: [aus-soaring] Bernard Eckey ~ Weight and Speed to fly? > 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] > -- * You are subscribed to the aus-soaring mailing list. * To Unsubscribe: send email to [EMAIL PROTECTED] * with "unsubscribe aus-soaring" in the body of the message * or with "help" in the body of the message for more information.
