I have a general idea on some of these, I think I know a few of them and I know I should know more of them. However there are a few terms that I would like some definition on so tha I can feel like I at least have little better understanding of what some posts are talkingabout. Some of you may recognize a scrap of your own sentence here and there too. Some of the ones I think I have an idea about I just left as a word. I bolded a few in the sentence they were used in to give a little perspective.

Guess this is the part where I have to lay claim to the phrase that, "The only dumb question is the one that isn't asked".So I'll ask


a good way to compare the characteristics of two aircraft is by their wing loading ("cubic wing loading" may be better, but that's a different story).

figuring "wing area "-- then how do we figure span loading??

Powerloading , wing aspect ratio and wing loading probably get my vote as the three most influential points in developing almost any powered model.

For a fully symmetrical airfoil wing with the CG location aft of the 25% chord of the MAC the tail lift is UP.
chord thickness

(reflex camber in the wing is another way, but that is often less efficient).
Camber
Tail Camber

Not using the fuselage aft or forward of the wing is desirable since the CLalpha curves of the fuselage are not those of the wing

variable sweep wing

Usually the lowest sweep angle is used as it is most likely to be theoretically correct and the glove or leading edge strake is not considered.

There is another good reason for not adding the area of the horizontal tail to the aircraft reference area

Both tails would need to generate roughly the same down force to balance the wing's pitching moment.

Dihedral vs anhedral

Incidence (pos and neg)

wing washout vs wash in

slipstream off the prop

The aerodynamic term involved is Clbeta - rolling moment due to sideslip

Winglets

vortex

Also, what are the little fin looking things some people have on the tips of the wing and what do they do?

I can provide help with most of them..

Wing Loading - This is how much the wing has to work or how much lift each square inch has to generate for the plane to stay in the air. Higher wing loading means that there is more weight per square inch necessary to keep the plane in the air. So small wings have a higher wing loading than larger ones. (Of course the design of the wing factors in there too.)

Wing Area - Just like it sounds. If a wing was rectangular, then the wing area would be the length (span) times the width (cord).

Wing Aspect Ratio - The ratio of a wing's span to its cord.

Camber - The characteristics of the underside of a wing. If the wing has a flat bottom, it has no camber. If it curves inward, somewhat following the upper surface, it is under cambered. If it curves outward, opposite the upper surface, it would be over cambered but it is not usually refered to like that. A wing whose underside is "over cambered" to the same degree at the upper surface is a symetrical wing.

Variable Sweep Wing - Wings that pivot just as in an F111, F14 or a B1b

Dihedral - If you look at a plane face on, if the wing tips are higher than the center (root), then the wing has dihedral. If they are lower, then the wing has anhedral.

Washout - This is the curving of the top surface tip of a wing to reduce it's lift. This produces better stall characteristics.

Slipsteam - This may be referring to prop wash or the blowing air back from the prop.

Winglets - The little wing thingies at the tips of wings.

Vortex - The turbulent swirling air that is created off of the tips of wings. (Winglets reduce this.)

Those should be good enough for "government work".

What Chevelle said. Except, washout is when the underside of the wing's trailing edge, at the last few bays, sweeps upward slightly in relation to the inner trailing edge. By adding washout, the air slips out from under the outer edge of the wing more quickly than the inner trailing edge, and that helps reduce tip stalls.
Dennis-

I know you know exactly what you are saying, and you are right, but I have an "easier to understand" explaination of washout.

Three factors are critical for wing stalls... Airspeed, angle-of-attack, and proximity to the wing tip (because air can "wrap around" the wingtip disrupting laminar flow). Thus the wing-tips are more vulnerable to stalling than the wing root.

Washout decreases the angle-of-attack of the wing tip relative to the rest of the wing, reducing it's vulnerablility to stall.

gus

I'll take a few (and correct one along the way). Some of my answers may be more RC shorthand than absoltuly technically correct.

Powerloading - the amount of power compared to the weight of the airplane. The same as power-to-weight ratios, though in different units. High power loading means lots of engine power available compared to the weight of the plane.

Chord - distance "front to back" of a wing.

MAC - Mean Aerodynamic Chord - The average chord of the wing. On a straight wing, it's the same as the chord. On a tapered and/or swept wing, you have to figure it out by averaging the tip and root chords. Often you also want to average the location of the MAC compared to the root, or fuse, as CG (center of gravity) is figured in terms of the MAC. (ie, 25% of MAC)

Chord Thickness - I'm not 100% sure on this one. I THINK they are talking about the thickness of the airfoil, usually expressed as a percentage of wing chord. So a particlar airfoil would be, maybe 12% thick. That means that the thickest part of the airfoil is 12% of the wing chord, so a 10in chord wing would be 1.2in thick.

Camber - The amount of curve of the center line of the airfoil. Take an airfoil picture, and measure a point exactly half way between the top and bottom surface of the airfoil. and do this all the way from the LE to the TE,and you get a line. Any curve in this line is Camber. A symetrical airfoil has a perfectly straight center line, and thus has 0 camber.

The term "under-cambered" referring to an airfoil means the bottom surface of the wing is concave, but it's actually a kind of mis-nomer and shouldn't be confused with the airfoils actual camber. Usually an airfoil is spec'd by it's max camber, ie, the farthest from a straight line that the camber line gets. Any unber-camber effect that results is really just a side effect of the camber and the thickness of the wing.

Leading Edge Strake - The big that sticks out from the LE near the root on planes like the F/A-18, making the wing root look really large compared to the rest of the wing. (I think I got that one right)

Pitching Moment - When an airfoil generates lift, it also creates a tendancy for the wing to twist. If you've ever seen a wing fall off a plane in flight, you've seen that the wing will spin, usually moving the LE upwards. That's the pitching moment in effect with nothing to counter it. Different airfoils have a larger or smaller one. The larger the pitching moment, the harder the horizontal tail has to work.

Incidence - Angle of (usually) an airfoil (wing, tail, whatever) to a reference line (usually a line on the fuse that should be level in level flight, or a line that is convenient to the design, such as a fuse center line, but any arbitrary line will work). The airfoil is measured on a line drawn from LE to TE. (A flat plate, such as a sheet stab is still an "airfoil")

Winglets - As mentioned, they are the little thingies sticking up (or down, or both) on the wingtips. They mess with the tip vortex that is formed by the wing, as air trys to go around the wingtip from the bottom of the wing to the top. (which forms the wing tip vortex). The winglets have several effects, depending on the plane in question. On a swept wing, espcially a flying wing, they serve as extra vertical stab area and help with yaw stability. They can also help the wing generate more lift for the given wingspan. They can also help a tip-stalling tendancy. I also use them to reduce aileron flutter, as it smooths out the tip vortex in the area the ailerons operate.

Well that covered most of them and I was way off on a couple and pretty close on a few.
Thanks all