the clark y aero foil is the best with reflex for low speed stall resistence and delay due to the reflex at the tail and a rounded nose to gentle the stall caracteristics and the maximum thickness and camber position one quarter of the cord back from the leading edge allowing a rectangular plan form for a neat delay of stall all along the wing so washout mimimisiation can still give smooth stall feel and warning as the stall creeps up to the maximum thickness position .as wash out accualy causes divergents at speed due to the conflict between the angle of incidence and the wing tip angle of attack .so less is better even though nice stalls can be made by wash out but better perforemance is with out it .standard ruffness friction coeficient of 0;02 ..is required by this aerofoil due to the forward center of pressure position and camber-thickness position so the transistional flow over the foil reaches the trailing edge with out separation so trips and vorticies gates are not needed which is a down fall when desighners make nice smooth wings only to find the air flow separates because forward thickness foils need ruffness to keep the air flow energised to the trailing edge .opposite to laminar rear thickness and camber air foils which need smooth surfaces down to one thousandths of an inch so the boundery layer wont separate but do even if a fly hich-hicks a ride up to 2 feet of the laminar flow is disturbed .worse luck plus out of wak aerodynamic conciderations are a night mare to ballance which is not the case with a less effeicient air foil the clark y which still has good low drag and a c-l of 1;4 ..and the reflex area is where the ailerons and flaps can be supported as well naturaly .the c-p center of pressure and a-c the aerodynamic center and the c-g center of gravity all tie up neetly at the quarter chord position with the maximum camber and thickness position giving trouble free aerodynamis ballancing ..rand kr langfield site on the net is a good example of laminar flow over a home built aircraft .symetrical tail chords are a must unless you are an experienced engineer so the negitive elevator foil on the teeni is done for many good reasons so cant be experimented with where as the rand kr has a symetricalm tail air foil and it all comes down to tail slides and tail stalls so the c-g isnt artificialy mounted in a crazy way but licenced to lift under angle of attack less the total weight formular ..comprehendi ?? modified clark y has been done all through out the histotry of aircraft and will continue as experimentation is what it is all about and the only other metal aircraft worth there weight in gold are the davis da.1 and the mott tailor mini imp and the quail and scamp all scrounge up mentality which is the original idea of the home built hobiest world but getting harder due to designer mentality and over regulation by cowards . the tirriny of distance is the measure of male madness and if you cant do it give it back as they say in pirates of carrabene movie ..yuk yuk .
Posted on Feb 17, 2008, 4:37 PM from IP address 136.153.2.6