There are some really fine experienced designers (which I will not mention for fear of leaving someone out) that tend to lurk in RCSE and the F3F mailing list. My hope is that a few of them will join this discussion and offer nice suggestions. I will offer the following two wing designs in an effort to be of help (and possibly take some flack and learn something from my friends). For all around balance I am not aware of a better airfoil than RG15 for the F3F course. You can experiment with thinner lower cambered airfoils like HQ10/08, RG14, or SD6062 which indeed are marginally faster on the straights but tend to lose it in the turns. I would suggest you consider the following two wing designs Wing One - Aspect Ratio 13.4 RG15 Root with SD7003 Tips Root Chord 21 cm (8.3") Root Panel Length 50.8 cm (20") First Break Chord 20 cm (7.9") Mid Panel Length 38.7 cm (15.25") Second Break Chord 15 cm (5.9") Tip Panel Length 27.3 (10.75") Tip Panel Chord 08 cm (3.15") This wing uses RG15 for Root, First Break, and Second Break airfoil - Tip airfoil is SD7003 which performs a little better than RG15 at very low reynolds numbers and should make the wing slightly faster than a straight RG15 wing. No geometric washout (twist)is used in this wing but the difference in airfoils between the root and tip yeilds about .8 degrees of aerodynamic washout and should improve handling and reduce the tendency of tip stall. This wing rather closely approaches elliptical lift distribution but in my opinion has tips that are too small and will cause more drag and handling problems then a slightly larger tip (a very small chord tip suffers higher profile drag and stalls at a reduced angle of attack because it is operating at very low reynolds number). For speed and F3F I would compromise on a slightly lower Aspect Ratio and slightly wider chord tip and live with the slightly reduced lift efficiency. Wing Design Two - AR=12.95 - Slightly larger Tip Chord RG15 Root with SD7003 Tips Root Chord 21 cm (8.3") Root Panel Length 50.8 cm (20") First Break Chord 20 cm (7.9") Mid Panel Length 45.7 cm (18") Second Break Chord 15 cm (5.9") Tip Panel Length 20.3 (8") Tip Panel Chord 10.8 cm (4.25") RG15 is used for Root, First Break, and Second Break Airfoils - SD7003 used for the Tip. The lift distribution of this wing is not quite as good as for Wing One but the improved handling indicated by the local lift distribution charts and the improved reynolds number that the Tip operates at should make this wing faster and easier to fly. No geometric washout (twist) is used on this wing but as in Wing One the use of diferent airfoils produces an aerodynamic washout of about 0.8 degrees which should help reduce the tendency to tip stall. Best wishes with your project. I must be beautiful to soar in Norway (during the months when the sun shines)! > > From: [EMAIL PROTECTED] > > > > Hi fellows. > > I intend to make a wing, designed for speed and turns on slope i.e. F3F > > > > 1) What airfoil will be best suited for this? > > > > 2) Below you are able to consider my new wing layout > > IM not sure Help and Comments are Highly Welcome. > > > > WS 236cm (92-92 inch) > > Chord 1 (root) 21cm (8.3) (max due to fuselage pylon support ) > > Chord 2 20cm (7.9) > > Chord 3 15cm (5.9) > > Chord 4(tip) 08cm (3.15)(washout 1,5 ?) > > > > regards > > Kjell-AAke Alfredsen, > > City of Tromsoe Norway > > 69degree of latitude north > > Up here at the top of the earth; > > from the 21november until 21jan > > the sun disappear and a small amount of daylight is visible > > At a part summertime the sun shines all the night and day > > and we fly at all hours around the clock. ______________________________________________________ Get Your Private, Free Email at http://www.hotmail.com RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED]
