Originally Posted by drdisc
I really wish you all would us the term "stable" to indicate a super straight flight. When you all say more stable, you mean more "overstable", but no one sems to like the word.
A Frisbee flies flat , that is "stable". A Firebird is "overstable" Some time it is hard to understand just what everyone really means. A Roadrunner and SW are "Understable" , not less stable. Please lets' get the terminology correct so everyone understands.
We need to develope a different language as we can't be correct using aerodynamic language meant for a wing, referring to disc flight. Aerodynamics has stable vs unstable. Those are insufficient for disc flight description. We have high speed and low speed descriptions of instability that don't really work.
Stable for high speed works fine, but unstable would refer to any non stable flight including over stable, a term we coined. (as a side note, imo, less stable or understable are just fine). The problem is really with the unstable type we describe as over stable.
It gets a little more off from wing aerodynamics when we describe the low speed instability as over stable. This is more like a combination of stall and over stability. The term "fade" is sometimes used here.
I do agree that over stability, in lieu of a better term, does help to differentiate from stability meaning straight and stable. This would help to differentiate between discs that are stable at certain speeds, (eg. Roadrunners, Sidewinders, etc) and discs that are stable at all speeds except stall (fade) speeds, (TeeBirds, Rocs, Aviars, Cros) etc.
I never really liked "fade" as it conflicts with the term fade used in ball golf. I've used crash, dive, or stall to describe that phenomenon to my students as it seems to be more in accordance with my conception of the stalling effect. Nevetheless, we do differentiate different low speed stalling with the term fade as we haven't as yet come up with a more accepted term.