Mary.Shaw%CMU-CS-A@sri-unix.UUCP (07/14/83)
Here are some numbers for Schweizer sailplanes. Schweizer is the dominant American manufacturer, and most rentals in this country come from this list: MODEL MAX WING WING WING GLIDE RATIO GR WT AREA LOADING SPAN L/D @ speed (lb) (sq ft) (lb/sqft) (ft) (ratio) (mph) 2-33 1040 219 4.75 51 23:1 @ 50 (std 2-place trainer) 1-26E 700 160 4.38 40 23:1 @ 53 2-32 1430 180 7.94 57 34:1 @ 66 1-34 840 151 5.56 49 34:1 @ 55 1-35 930 104 8.94 49 39:1 @ 47 1-36 710 140 5.05 46 31:1 @ 53 They are rated for loads from about -2.5 or -3g to around +5g. However, a "progressive-failure" design allows them to hang together under much higher stress. Last weekend I got a look at one that had had its wing roots twisted about 30 degrees and structural rivets sheared. In addition, the seat failed and there was structual damage to the fuselage. The pilot had dived about 2000 ft at high speed and done a sharp pullup; the factory estimated that it would take 11g forces to do the damage. Mary Shaw
mark@hp-kirk.UUCP (07/14/83)
#R:sri-arpa:-288300:hp-kirk:5500010:000:426 hp-kirk!mark Jul 12 07:17:00 1983 Are you sure about the numbers on the 1-35. It seems counter-intuitive to me that the plane with the highest wing-loading would have the lowest best glide speed. Can anyone explain this? not an aeronautical engineer Death Rowe hp-pcd!hp-cvd!mark Corvallis, Oregon
Mary.Shaw%CMU-CS-A@sri-unix.UUCP (07/19/83)
All the numbers except the 1-35 were from my Schweizer manuals; the 1-35 numbers were from Jane's Sailplanes. However, many high-performance sailplanes have wing loadings in the 8-10 lb/sq ft range. Here are some more numbers from Jane's: What Best glide Wing loading ratio (lb/sq ft) Schneider ES 52 Kookaburra 20 5.36 PIK-20B 42 9.21 Akaflieg SB-9 Stratus 48 5.53 Akaflieg SB-10 Schirokko 53 7.98 (tandem, 29m wings) Akaflieg Mu 27 47 8.19 Akaflieg FS-24 Phoenix 40 3.79 Glaser-Dirks DG-200 42 9.22 Glasfluegel 604 49 8.6 Schemp-Hirth Nimbus 49 8.25 Schemp-Hirth Mininimbus 42 9.34 Schleicher Rhoenadler 20 2.84 (1932 design) Schleicher ASW 12 47 6.57 Schleicher ASW 17 48.5 7.86 Schneider Grunau Baby 17 3.62 (1932 design) Schweyer Rhoensperber 20 3.46 (1935 design) SZD-42A Jantar 2 47 8.52 ICA-Brasov IS-32 46 8.31 FFA Diamant 45 6.31 Neucom AN-66C Super-Elfe 48 6.8 Sigma I 48 11.79 (1971 design) Slingsby T.31 Tandem Tutor 18.5 4.87 (1950 design) Vickers-Slingsby Kestrel 22 51.5 8.74 Bede BD-5S 23 7.09 (BD5 with no fan) Bryan HP-15 45 7.99 LAK-9 48 7.92 Looks like design counts for something, too. Mary Shaw