While our "flaps" should be included in the wing's chord measurement, I ask how many full sized aircraft have a similar wing airfoil contour to our stunt ships? Can you show me a picture of just one?
I use the measurement to the flap leading edge, for the simple reason that I create the thicker front portion of the wing using a "standard" (?) simple airfoil shape (e.g. NACA00xx) which I chop off as needed ahead of its zero height trailing edge, and rescale in chord, to get the non-zero height trailing edge, a place for our "flap" control surface to connect..
Since that is the portion of the wing where I'm setting the maximum thickness of the wing, it doesn't seem unreasonable not to include the flaps.
I don't think it makes much difference, does it? As long as we are clear on what we are talking about? In conjunction, I haven't seen much problems due to confusions about the definition of chord. Have there been? Just curious as to WHO was confused and subsequently designed a stunt airfoil and built a wing of the wrong thickness? ;->
There are a few "standard" measurements we use in CL Stunt that don't make much sense in the grown up airplane design world. Like back of spinner to wing leading edge ("nose length" or "nose moment" <??>) and hingeline to hingeline distance ("tail moment" <??>). These are not really aerodynamic parameters, rather what has evolved for the convenience of modelers.
I'm aware of efforts of several technically oriented folks here who have tried to help by describing such things as mean aerodynamic chord, and I respect their efforts, but it has very little impact.
Consider this - quite a few of us have quoted wing area values, which may or may not include the portion of the wing hidden inside the fuselage, are frequently coarse guesses, and at best are perimeter outline area measurements. Considering the exaggerated thickness of our modern stunter wings, wing VOLUME might be more meaningful. What's the value anyway, beyond some relative comparative wing size?
I mention it because when I first used AutoCad to measure the actual perimeter area of a Roadrunner wing and arrived at ~593 square inches (which included flaps and the portion inside the fuselage), I was pounced upon by a couple of good friends who just were completely sure it was a lot larger.. This measurements seems somewhat subjective to me.
While perhaps we *ought* to be settling on more meaningful measurements, only guys like our recently deceased Wild Bill (one of my heroes) would find any real application with them. They're simply not terribly useful to those of us lacking aeronautical design credentials. Remember what Bill said about Stunt News readers "not wanting the math".. (I submit that we "design" are model airplanes largely by cut and try, and/or tweaks to well established "numbers". Those "numbers" are what we created for comparative measurements.)
Sorry, I'm with Jimmy Stewart's character Frank Towns in "Flight of the Phoenix" on this one, who finally concluded "He's crazy Lou, he builds toy airplanes." But a "toy airplane" is pulled on the floor by a string and moves along the ground! And I do remember what Heinrich Dorfmann said about model airplanes needed to be better designed than the Big Jobs..
I think it is time to chop very accurate models of our stunt models into thousands of tiny triangles and get with some serious finite element analysis. Either that, or take the actual model out and fly a pattern or two with it.. ;->
L.
"Mr. Towns, you behave as if stupidity were a virtue. Why is that?" -Heinrich Dorfmann