In Riblett's GA Airfoils section "Design Notes for Tapered Wings," he asserts that NACA's conclusion that tapered wings stall at the tip first is invalid. The reason he gives is that not only the planform of the test specimens was tapered; the section thickness was tapered from root to tip. He says the thin (percentage) sections near the tip were responsible for the tip-stalling tendency, not the planform taper. His conclusion is that a tapered wing without variation in the percent thickness of the sections does not require washout (or additional camber at the outer section) in order to have good stalling characteristics.
I am tinkering with a tapered planform, and it sure would be nice not to have to deal with washout or blending to a more cambered foil at the tip. But I'm not sure I buy his conclusion. I think he's probably right that the thickness variation muddies the waters, but it's not clear to me that an untwisted, tapered, constant percent-thickness wing will automatically have pleasant manners. Riblett points to the example of the PA-24 Comanche, which has planform taper only (no percent thickness taper) and no washout, with its docile hadling, as evidence of his position.
What do you think?
I am tinkering with a tapered planform, and it sure would be nice not to have to deal with washout or blending to a more cambered foil at the tip. But I'm not sure I buy his conclusion. I think he's probably right that the thickness variation muddies the waters, but it's not clear to me that an untwisted, tapered, constant percent-thickness wing will automatically have pleasant manners. Riblett points to the example of the PA-24 Comanche, which has planform taper only (no percent thickness taper) and no washout, with its docile hadling, as evidence of his position.
What do you think?