---------------------------------------------------------- KIS-List Digest Archive --- Total Messages Posted Sat 01/26/13: 2 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 02:13 AM - Re: KIS TR-1 Airfoil (Propellerjan) 2. 04:12 AM - Re: KIS TR-1 Airfoil (Propellerjan) ________________________________ Message 1 _____________________________________ Time: 02:13:35 AM PST US Subject: KIS-List: Re: KIS TR-1 Airfoil From: "Propellerjan" Yes it give more drag with the cuff at speeds higher then the CL 0,3 as I wrote in previous post. and I realize it is not for Scott's light and fast plane. To the "pure" CL given from weight, speed and density alt, we have to ad 0,02- 0,03 due to tail down force. (about 10%) There is 2 NACA 63-215 airfoils, the one with a A is the one used on the KIS-1 this is the one without cusp, straight or almost straight upper and lower rear surface. said to have 0,0002 Cd more then the cusp'd airfoil, (like a mosquito shit on the LE) but simpler, more structure and more effective ailerons with the A model. this is the basic airfoil I used in this example. The related Riblett airfoil would be GA 35A215, it is using Ribletts mean line and NACA 63A015 thickness distubution. I am curious how much drag the modified wing with cuff will make, say at WOT 8000I0-240, 1450 lb, My Propeller software say 179 mph 155kts TAS, thats what you guys say too, CL 0,25+0,02 = 0,27 The total drag will be 80 kg/ 176 lb. the delta drag coefficient from the cuff is at CL. 0,27 = 0,000857 if the X-foil program is correct. with the exposed wing area this give a Fo of 0,00594 m2 (sorry for using metric system) the q is 314,3 kg/m2 and then delta drag is 1,86 kg at 175 mph q is 300,4 = drag is 1,78 kg so new speed will be 174-175mph/151-152 kts BUT at that speed CL is 0,27 + 0,02 = 0,29 where the drag penalty is less then half of what it is at CL 0,27, so real slow down 1,5-2 kts. At faster speeds the drag penalty will be higher! The goal with the cuff isn't to reduce drag but enhance handling, slower stall speed, better climb, less erratic moment coefficient, It is a quick fix for a faulty airfoil. if it paying off? Flying slower than 150 mph IAS it will, maybe a cuff with half the LE drop will be better? I just used the example in the book. realising the concave spot under the nose where the cuff fair into the original airfoil would create drag at small alpha. and sure it did. This have to be seen in relationship to the drag with VG's on the wing, any one with real numbers? Jan -------- www.jcpropellerdesign.com Read this topic online here: http://forums.matronics.com/viewtopic.php?p=393078#393078 ________________________________ Message 2 _____________________________________ Time: 04:12:39 AM PST US Subject: KIS-List: Re: KIS TR-1 Airfoil From: "Propellerjan" Okay, always goes faster second time. Riblett talks about his mean line have 0,3% nose drop on the CL 0,2 mean line, so I used that, and it is half of the first one. Very interesting result. I used single Re Nr. 2 and 6 million. 47,5 & 143 kts SL to make the graph clear, and zoomed in the interesting parts at the speeds at 2 mill the original and the full cuff airfoils polar curve just stop at CL 1,2 and 1,4 but not the half cuff, why i don't know. maybe the half cuff is good? at Re 6 mill the half cuff have half the drag penalty of the full cuff at CL 0,15 and brake even at 0,25 with original airfoil. at CL 0,6 the half cuff is better. Higher CLmax at higher alpha, and Cm curve more even. Okay good exercise. Jan -------- www.jcpropellerdesign.com Read this topic online here: http://forums.matronics.com/viewtopic.php?p=393079#393079 Attachments: http://forums.matronics.com//files/half_cuff_992.jpg http://forums.matronics.com//files/close_up_at_re_6mil_410.jpg http://forums.matronics.com//files/cuff_at_re_6mil_538.jpg http://forums.matronics.com//files/cuff_at_re_2mil_193.jpg ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message kis-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/KIS-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/kis-list Browse Digests http://www.matronics.com/digest/kis-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.