Jack Womack writes: >The fact is that some full scale ships have >a better L/D or glide ratio when fully >ballasted. It's a function of the airfoils and >configurations used. They also have a higher sinking speed >in the ballasted condition, and that's why they have >dump valves. They are now optimized for fast cruise, >with thermaling a secondary consideration. There have >been 300 mile tasks flown where the pilot never >circled in a thermal, and achieved better than >100 mph in average speed.
Full-scale sailplanes are fast and heavy because that's what the soaring contest rules favor. The mammoth Eta sailplane is the logical endpoint of this development. http://www.leichtwerk.de/eta/en/project_eta/ The unfortunate outcome of this development is that top-level competition soaring seems like a $$$ arms race, and this "most advanced" sailplane is a very rich man's toy. Perhaps it's not a cooincidence that there has been a steady decline in full-scale soaring participation over the years (according to an article in Soaring or Sailplane&Gliding I saw a while back). The Eta is accessible only to those who have too much money and too much hangar space. Partly in response to this trend, there is a significant grass roots movement back towards ultralight gliders which give up speed and range for exceptional thermalling ability. The 13.5m span, 145 lb Carbon Dragon is one of the earliest examples of this. See http://www.isd.net/sadkins/index.htm I've seen video footage of Gary Osoba pulling off a save from 200 feet in this glider, in an RC glider-type thermal, called "microlift" by soaring pilots. A more recent development is the 15m span, 150 lb Light Hawk (about 1/3-1/4 the weight of normal 15m gliders). See photos and test pilot report at http://www.glidersport.net/ OSTIV is on the verge of sanctioning a new "Ultralight Sailplane" category, if they haven't done so already. http://www.anla.gr/greek/library/ULSailplanes.htm This class should make competition soaring more attractive to a larger number of people. Sorta reminds me of the RES saga. - Mark RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED] Please note that subscribe and unsubscribe messages must be sent in text only format with MIME turned off.
