Thickening airfoil effects

[rakm]

If nothing else is changed what would the effect of thickening a semisymetrical, or cambered airfoil be?

Would it increase lift somehow?

[Dick Huang]

rakm,
It may increase the maximum Lift coefficient depending on the Reynolds number; however, increased thickness will increase the drag of the wing. Increase airfoil thickness is usually done to increase spar depth in order to strengthen the wing.
Dick Huang:)

[Gary Warner]

More wood :D

I've had good success thickening up S3021 airfoils. My 113" Quacker flies like a dream on a 12.9% S3021. It's very slow and has a very soft stall. I attribute this to the thickening up of the airfoil. What I liked most about this thickening up was that the spar height was increased and this went a long way in increasing the wing strength.

My line of thought has always been if I want to improve the slow flight characteristics of a particular airfoil, I thicken it up. The same goes for improving fast flight performance, except that I thin the section. I'm sure others out here know more about the actual aerodynamic effect and hope that they chime in on this.

Gary
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[Sparky Paul]

Thickening the airfoil doesn't make "more lift".. where you usually fly. It extends the alpha range so the stall occurs at a higher alpha, and the leading edge radius becomes larger making, as noted, softer stalls.
And thicker, more drag; thinner, less drag.

[Viper Pilot]

My favorite flying plane right now is a SIG Somethin' Extra (Slime . . . . soon to be electrified).

It has a very thick airfoil.

Like Dick, Gary and Sparky say above, the plane flies very well at slow speeds, has a gentle stall and yet perfoms extreme maneuvers.

VP

[Bob Baker]

What is Alpha? I would guess it is the angle of attack.
And, does this mean that the stall speed decreases? How much; or does that depend on the airfoil. My interest is in symmetrical foils at this point.