PPRuNe Forums - View Single Post - Stabilizer Airfoil
View Single Post
Old 17th Sep 2005, 18:52
  #13 (permalink)  
Mad (Flt) Scientist
 
Join Date: Sep 2002
Location: La Belle Province
Posts: 2,179
Likes: 0
Received 0 Likes on 0 Posts
No, it's not a misnomer. Without the horizontal tail most conventional aircraft would be longitudinally unstable, at least at the rearwards portion of the cg envelope.

But the stabilizing effect comes from how the loads on the tail change with disturbances in angle-of-attack, not from the absolute load on the tail.

If you had movable ballast on a conventional jet, for instance, you could move the cg aftwards, eventually reaching a point where the tail load was zero for trim. You could then move it further aft, and the tail load would reverse, becoming an upload.

The cg for zero trim load is speed (Mach) dependent in most cases.

Now I can pretty much guarantee that most aircraft would still be STABLE at that cg position - damned hard to handfly, no doubt, as the stability is grossly reduced over what is normally considered acceptable, but nontheless stable. And that stability would still be being contributed to by the tailplane, regardless of the actual tail load.
Mad (Flt) Scientist is offline