Kinda toying with designing a TA-152 inspired aircraft. I was reading on the wiki page (not sure if that's a good start) that the TA-152 has 3 degrees of washout. Is this on about the right track? I appreciate any help or advice. Thanks in advance.
Welcome to HBA.The nasty stall of the wing was likely a side effect of the 23 series airfoil.
Yes BUUUT that's because 3D planform effects can override 2D airfoil effects. The Ta-152 wing planform is NOT helpful because it tapers (a lot) in both chord and thickness, both of which aggravate tip stall. The only saving grace of the wing geometry is the washout which, as llemon stated in post #7, is nonlinear and probably doesn't go far enough for a general aviation machine.all the declarations about its “nasty stall characteristics” simply are not valid.
Yup, real world; I’ve never yet seen a wing with an infinite span.Yes BUUUT that's because 3D planform effects can override 2D airfoil effects.
Yup, planforms do have significant effects, especially those that result in a tip with a sharper LE radius operating at half the Rn of the inboard wing.The Ta-152 wing planform is NOT helpful because it tapers (a lot) in both chord and thickness, both of which aggravate tip stall.
I changed the rigging of the ailerons on my Sportsman from matching the LS(1)-0413 airfoil to having the TE up about 1/2 inch. I gained 2 knots top speed.... a lot of German gliders of the day would set the controls up such that as the stick came back, the ailerons would lift to increase washout. The only time you really need washout is when flying slow or pulling G.
By doing that you remove some aft camber which tends to move minimum drag to a lower CL, it's a camber effect not a washout effect. That's the idea behind trim flaps which are used on some sailplanes to widen the speed range.I changed the rigging of the ailerons on my Sportsman from matching the LS(1)-0413 airfoil to having the TE up about 1/2 inch. I gained 2 knots top speed.
trim flaps which are used on some sailplanes to widen the speed range.
But I still would not taper the 23015 down to a much smaller chord and to 23010, even with 3 degrees of washout. This is tempting fate on a couple different levels. If you just have to hold planform and use 23015 at the root, hold the 23015 to the tip to give yourself a better chance at decent stall behavior.There are also several other airfoils in the world than the 23 series, and aircraft designers are thankfully aware that there is in fact no magic law which mandates the same airfoil at the tip as the airfoil at the root or mid-span. Twist is only one of several things that you can adjust and alter to arrive at a desired stall outcome.
Well... I would notice but I'm a geek. The 230 mean line produces a pretty distinctive double chin that is pretty noticeable to even casual observers looking at the tip but, yeah, if they didn't know that "nobody" would notice. I do agree though that a different airfoil at the tip would make for a better handling wing. There are several airplanes named "Provost" in the UIUC database that used 230xx root and thinner 44xx tip. This type of wing absolutely must have twist to get zero aerodynamic washout because the 44s have much lower zero lift angles than the 230s. This makes for a later stall of the outboard panel with no performance penalty. In fact it may be a slightly higer performance wing than all 230xx airfoils because the 44xx have batter L/D than the 230s. Since the last 5% of the span is basicaly stalled all the time anyway you could make a tip faring that reproduces the underside of a 230xx if that little cosmetic detail is really important.Agreed. There's potential for trouble here.
A different airfoil entirely at the tip may be the way to go - no-one will notice.
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