Tapered Edges
#1
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Join Date: Jan 2003
Location: Sarnia, ON, CANADA
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Tapered Edges
When I was learning to build (some 10 years ago) I was told to taper the Trailing Edges of the Ailerons, Rudder and Elevator.
Tapering was to ensure a smoother flow of air as it left the plane, which would give better control response due to a smaller burble around the TE etc. (the explanation got technical here).
SO; if all of that is true (and I do believe it) why are a growing number of kits using squared off control surfaces? Easier to build? Less work? Faster to build? Lack of knowledge?
How many builders out there are tapering the TE, even when NOT told to by the manufacturer?
Tapering was to ensure a smoother flow of air as it left the plane, which would give better control response due to a smaller burble around the TE etc. (the explanation got technical here).
SO; if all of that is true (and I do believe it) why are a growing number of kits using squared off control surfaces? Easier to build? Less work? Faster to build? Lack of knowledge?
How many builders out there are tapering the TE, even when NOT told to by the manufacturer?
#2
RE: Tapered Edges
I do it on all of my planes. I'm not sure if it has any effect on the aerodynamics of the plane, but it looks better. I refuse to embarass myself with a junky looking airplane at the field!
#3
My Feedback: (2)
RE: Tapered Edges
In my opinion it depends on the plane. On a lot of my sport models i leave them squared off, actually the thought being that the control will be "crisper". I am not sure that it is but it does make some degree of sense. As far as looks go on a sport model, who cares? It is your plane you do what pleases you. On a scale model, that is a different story, the scale model should replicate the full size as closely as possible.
#4
RE: Tapered Edges
You will get a better handleing plane if you taper your trailing edges IMO,
I make airfoils for a living, the better the leading and trailing edge shape the better the performance of the airfoil. That being said the leading edge shape is more critical to performance than the trailing edge. I taper my trailing edges down to 1/32" on all my planes and I try to make my leading edges as smooth of a radius as possible. You will pick up some speed with a model that has very clean airfoil shapes(smooth radius leading edges, sharp tapered trailing edges) and the control should be crisp and smooth. For even better control try sealing your hinge line gaps.
Anthony
I make airfoils for a living, the better the leading and trailing edge shape the better the performance of the airfoil. That being said the leading edge shape is more critical to performance than the trailing edge. I taper my trailing edges down to 1/32" on all my planes and I try to make my leading edges as smooth of a radius as possible. You will pick up some speed with a model that has very clean airfoil shapes(smooth radius leading edges, sharp tapered trailing edges) and the control should be crisp and smooth. For even better control try sealing your hinge line gaps.
Anthony
#5
Banned
RE: Tapered Edges
NASA did a study some years ago that pointed out that there two optimum conditions for trailing edges: either razor sharp, or square cut. Other configurations led to air burbling at the trailing edge, leading to flutter.
Les
Les