Date: Tue, 5 Apr 1994 12:54:09 -1000 From: Peter H Loop Message-ID: <940405145409_3@ccm.hf.intel.com> Subject: David Lord's files Text item: Text_1 Inventory: lord2.txt: David's Spars selection charts Kite.BAS: David's Stunt kite Design Software, In Basic for PC P-Basic.com: Distributable PC Basic Interpeter Dave asked me to Post these for him Thanks. Peter_H_Loop@ccm2.hf.intel.com lord@eskinews.eskimo.com Text item: lord2.txt 4/5/94 2:21P How to use the spar chart: With this chart you have the capability to determine spar size for almost any kite size and for any wind conditions. Examples will show some of the many uses, but if you study the chart and examples you will see that its versatility is limited only by you understanding and innovation. Example 1: Scaling kite larger or smaller and maintain the same frame stiffness. The crucial step is to determine your reference. To determine a reference you must rely on your experience with a particular kite as regards a lower and upper wind range. Or alternatively you can use what I use as a references. For a full wind range kite my reference is a 64 inch leading edge using K75 fiberglass spars. For a light wind range kite my reference is a 64 inch leading edge kite using Clearwater 202-2 spars. Full wind range is defined as 6 to 20 mph. Light wind range is defined as 3 to 12 mph. And ultralight wind range is 0 to 8 mph. For this example let us use a light wind reference, we want to know what size kite we can build using AFC 2300 spares. 1) Go to the "Light Wind Range" chart, find the 2300. Scale Factor is 1.088 2) Multiply the AFC 2300 Scale Factor times the reference kite dimensions to get the scaled dimensions (1.088 times 64 inches = 69.6 inches). That is the length of the leading edge in the scaled kite that will maintain the same frame stiffness as the reference kite. Example 2: Finding a suitable spar I recently built an ultralight kite with a very high Aspect Ratio. The Clearwater 202-2 leading edge was 64 inches. Clearwater 202-2 (was stiffer than required for the spine but I used there also. But the lower spreader was 45 inches each side of the "T" connector. A conventional lower spreader is about 32.5 inches on each side. I used the chart to find a suitable spar for the lower spreader. 1) Go to the "UtlraLight Wind Range" chart, find the Clearwater 202-2. Scale Factor is 1.00 2) I divided the 45 in spreader by the standard 32 inch length Relative Length. 45/32.5 = 1.38 3) Multiply the Relative Length above by the Clearwater 202-2 Scale Factor 1.38 * 1 = 1.38 (the Scale Factor of suitable spars) 4) Find a Rod on the "UtlraLight Wind Range" chart with a Scale factor the matches the calculation (1.38). In this example 2540 CARBON(1.390) or CLWTR 283(1.414) would make suitable a lower spreader. Example 3: Increasing/decreasing the wind speed of a kite: The relationship between win speed change and spar stiffness change is as follows: RS1 = Relative Stiffness of the reference spar. RS2 = Relative Stiffness of spar for new wind speed. V1 = Reference wind speed. V2 = New Wind speed. RS2=(V2^2/V1^2)RS1 Suppose you have a kite sparred with AFC 1800 spars ("Full Wind Range" chart, Scale factor = .320). You notice that at 8 mph the frame distortion is at the upper limit you will tolerate. Lets determine the spar to move the upper wind speed to 15 mph. 1) RS2 = (15 mph ^2 /8 mph ^2)* .320 = 1.125 2) Find a Rod on the "Full Wind Range" chart with a Scale factor the matches the calculation (1.125). In this example PRSPR .352 (1.114) or CLWTR 315-3 (1.168). ========================= KITE SPAR SELECTION CHART ========================= RS = RELATIVE STIFFNESS SF = SCALE FACTOR UTLRALIGHT LIGHT WIND FULL WIND WEIGHT SPAR TYPE RS SF RS SF RS SF OZ./FT. ============= ============== =============== ======== 1580 CARBON 0.559 0.865 0.315 0.749 0.189 0.659 0.1152 1700 CARBON 0.754 0.932 0.425 0.807 0.255 0.711 0.1454 CLWTR 187-2 0.858 0.962 0.483 0.834 0.290 0.734 0.1000 A20 0.947 0.986 0.533 0.855 0.320 0.752 0.2032 1800 CARBON 0.947 0.986 0.533 0.855 0.320 0.752 0.1650 CLWTR 202-2 1.000 1.000 0.563 0.866 0.338 0.762 0.1100 1880 CARBON 1.124 1.030 0.633 0.892 0.380 0.785 0.1770 C30 1.201 1.047 0.677 0.907 0.406 0.798 0.2434 1960 CARBON 1.334 1.075 0.752 0.931 0.451 0.819 0.1947 SKSHK IIP 1.403 1.088 0.791 0.943 0.474 0.830 0.1062 E40 1.607 1.126 0.905 0.975 0.543 0.858 0.2695 ADV 250/2 1.775 1.154 1.000 1.000 0.600 0.880 0.1760 CLWTR 252 1.775 1.154 1.000 1.000 0.600 0.880 0.1465 2100 CARBON 1.716 1.145 0.967 0.992 0.580 0.873 0.2167 G50M 2.056 1.197 1.158 1.037 0.695 0.913 0.3061 2200 CARBON 2.071 1.200 1.167 1.039 0.700 0.915 0.2386 SKSHK IIIP 2.071 1.200 1.167 1.039 0.700 0.915 0.1459 A/C 3-30 2.231 1.222 1.257 1.059 0.754 0.932 0.2222 PCOMP .278 2.414 1.247 1.360 1.080 0.816 0.950 0.1927 CLWTR 282 2.471 1.254 1.392 1.086 0.835 0.956 0.1628 AERO-LITE 2.485 1.256 1.400 1.088 0.840 0.957 0.3255 2300 CARBON 2.491 1.256 1.403 1.088 0.842 0.958 0.2606 J65 2.692 1.281 1.517 1.110 0.910 0.977 0.3478 SKSHK VP 2.870 1.302 1.617 1.128 0.970 0.992 0.1953 SKSHK IIIP* 2.959 1.312 1.667 1.136 1.000 1.000 0.1458 K75 2.959 1.312 1.667 1.136 1.000 1.000 0.3594 2400 CARBON 2.959 1.312 1.667 1.136 1.000 1.000 0.2853 A/C 2-71 2.959 1.312 1.667 1.136 1.000 1.000 0.2331 ADV 250/3 3.145 1.332 1.772 1.154 1.063 1.015 0.2680 CLWTR C253 3.145 1.332 1.772 1.154 1.063 1.015 0.2054 SKSHK VIIP 3.225 1.340 1.817 1.161 1.090 1.022 0.2071 BEMAN 16 STRONG 3.284 1.346 1.850 1.166 1.110 1.026 0.2794 SKSHK VP* 3.284 1.346 1.850 1.166 1.110 1.026 0.1757 PRSPR .309 3.284 1.346 1.850 1.166 1.110 1.026 0.3165 CLWTR 315-2 3.462 1.364 1.950 1.182 1.170 1.040 0.1822 A/C 4-49 3.536 1.371 1.992 1.188 1.195 1.046 0.2515 2540 CARBON 3.728 1.390 2.100 1.204 1.260 1.059 0.3182 CLWTR 283 3.996 1.414 2.251 1.225 1.351 1.078 0.2504 ADV 250/4 4.201 1.432 2.367 1.240 1.420 1.092 0.3360 CLWTR 254 4.201 1.432 2.367 1.240 1.420 1.092 0.3072 PCOMP .309 4.231 1.434 2.383 1.242 1.430 1.094 0.2722 FL370 4.467 1.454 2.517 1.260 1.510 1.109 0.5326 PRSPR .352 4.556 1.461 2.567 1.266 1.540 1.114 0.3529 CLWTR 315-3 5.503 1.532 3.100 1.327 1.860 1.168 0.2740 PCOMP .352 5.917 1.560 3.333 1.351 2.000 1.189 0.3086 CLWTR 385-2 6.006 1.565 3.383 1.356 2.030 1.194 0.2100 SKSHK VIIP* 6.243 1.581 3.517 1.369 2.110 1.205 0.2891 FL414 6.657 1.606 3.750 1.392 2.250 1.225 0.6250 CLWTR 385-3 9.615 1.761 5.417 1.526 3.250 1.343 0.2800 FL505 13.935 1.932 7.850 1.674 4.710 1.473 0.8394 3/8 GRAPHITE 14.580 1.954 8.213 1.693 4.928 1.490 0.4170 FL616 30.059 2.342 16.933 2.029 10.160 1.785 1.2750 ----------------------------------------------------------------------- GRAPHITE BASED SPARS RELATIVE SCALE WEIGHT SPAR TYPE STIFFNESS FACTOR OZ./FT. 1700 CARBON 0.255 0.711 0.1454 1580 CARBON 0.189 0.659 0.1152 CLWTR 187-2 0.290 0.734 0.1000 1800 CARBON 0.320 0.752 0.1650 CLWTR 202-2 0.338 0.762 0.1100 1880 CARBON 0.380 0.785 0.1770 1960 CARBON 0.451 0.819 0.1947 ADV 250/2 0.600 0.880 0.1760 CLWTR 252 0.600 0.880 0.1465 2100 CARBON 0.580 0.873 0.2167 2200 CARBON 0.700 0.915 0.2386 SKSHK IIIP 0.700 0.915 0.1459 A/C 3-30 0.754 0.932 0.2222 PCOMP .278 0.816 0.950 0.1927 CLWTR 282 0.835 0.956 0.1628 2300 CARBON 0.842 0.958 0.2606 SKSHK VP 0.970 0.992 0.1953 SKSHK IIIP* 1.000 1.000 0.1458 2400 CARBON 1.000 1.000 0.2853 A/C 2-71 1.000 1.000 0.2331 ADV 250/3 1.063 1.015 0.2680 CLWTR C253 1.063 1.015 0.2054 SKSHK VIIP 1.090 1.022 0.2071 BEMAN 16 STRONG 1.110 1.026 0.2794 SKSHK VP* 1.110 1.026 0.1757 PRSPR .309 1.110 1.026 0.3165 CLWTR 315-2 1.170 1.040 0.1822 A/C 4-49 1.195 1.046 0.2515 2540 CARBON 1.260 1.059 0.3182 CLWTR 283 1.351 1.078 0.2504 ADV 250/4 1.420 1.092 0.3360 CLWTR 254 1.420 1.092 0.3072 PCOMP .309 1.430 1.094 0.2722 PRSPR .352 1.540 1.114 0.3529 CLWTR 315-3 1.860 1.168 0.2740 PCOMP .352 2.000 1.189 0.3086 CLWTR 385-2 2.030 1.194 0.2100 SKSHK VIIP* 2.110 1.205 0.2891 CLWTR 385-3 3.250 1.343 0.2800 GRAPHITE PULTRUDE SPARS RELATIVE SCALE WEIGHT SPAR TYPE STIFFNESS FACTOR OZ./FT. 1580 CARBON 0.189 0.659 0.1152 1700 CARBON 0.255 0.711 0.1454 1800 CARBON 0.320 0.752 0.1650 1880 CARBON 0.380 0.785 0.1770 SKSHK 4.9 0.430 0.810 0.1711 1960 CARBON 0.451 0.819 0.1947 2100 CARBON 0.580 0.873 0.2167 2200 CARBON 0.700 0.915 0.2386 SKSHK 5.5 0.750 0.931 0.2230 2300 CARBON 0.842 0.958 0.2606 SKSHK 0.950 0.987 0.2533 2400 CARBON 1.000 1.000 0.2853 SKSHK 6.1 1.080 1.019 0.2685 SKSHK 6.3 1.180 1.042 0.2885 2540 CARBON 1.260 1.059 0.3182 WRAPPED GRAPHITE SPARS RELATIVE SCALE WEIGHT SPAR TYPE STIFFNESS FACTOR OZ./FT. CLWTR 187-2 0.290 0.734 0.1000 CLWTR 202-2 0.338 0.762 0.1100 ADV 250/2 0.600 0.880 0.1760 CLWTR 252 0.600 0.880 0.1465 SKSHK IIIP 0.700 0.915 0.1459 PCOMP .278 0.816 0.950 0.1927 CLWTR 282 0.835 0.956 0.1628 SKSHK VP 0.970 0.992 0.1953 SKSHK IIIP* 1.000 1.000 0.1458 ADV 250/3 1.063 1.015 0.2680 CLWTR C253 1.063 1.015 0.2054 SKSHK VIIP 1.090 1.022 0.2071 SKSHK VP* 1.110 1.026 0.1757 PRSPR .309 1.110 1.026 0.3165 CLWTR 315-2 1.170 1.040 0.1822 CLWTR 283 1.351 1.078 0.2504 ADV 250/4 1.420 1.092 0.3360 CLWTR 254 1.420 1.092 0.3072 PCOMP .309 1.430 1.094 0.2722 PRSPR .352 2.000 1.189 0.3529 CLWTR 315-3 1.860 1.168 0.2740 PCOMP .352 2.000 1.189 0.3086 CLWTR 385-2 2.030 1.194 0.2100 SKSHK VIIP* 2.110 1.205 0.2891 CLWTR 385-3 3.250 1.343 0.2800 SPAR CODES SPARS DESIGNATED A20,K75,ETC. ARE FIBERGLASS SPARS FROM GLASSFORMS INC. SPARS DESIGNATED 1580,2300, ETC. ARE PULTRUDE CARBON FROM AFC. SPARS DESIGNATED ADV 250/2,ADV 250/3, ETC. ARE WRAPPED GRAPHITE FROM ADVANTAGE. SPARS DESIGNATED CLWTR 202-2, CLWTR C253, ETC. ARE WRAPPED GRAPHITE FROM CLEARWATER IN KINGSTON WA. SPARS DESIGNATED PSPR .309, PCOMP .278 ETC. ARE FROM GLASSFORMS INC. SPARS DESIGNATED SKSHK IIIP, SKSHK VP, ETC. ARE WRAPPED GRAPHITE FROM SKYSHARK, THE * IS FOR NEW 94 VERSIONS. SPARS DESIGNATED A/C 3-30, ETC. ARE EASTON CARBON/ALU. I have used this chart and the methods described in the examples to design and build many varieties of stunt kites and have always obtained reliable results. David O. Lord 15426 73rd ST. Ct. E. Sumner WA 98390 (206) 863-8435 lord@eskinews.eskimo.com