text: There are several items which may con- 
  tendency. Sweepback 
  tribute to a pitch-up 
  of the wing planform can contribute unstable 
  moments when separation or stall occurs at 
  the tips first. The combination of sweepback 
  and taper alters the lift distribution 
  to produce 
  high 
  lift coefficients and low energy 
  boundary layer near the tip. Thus, the tip 
  stall is an inherent tendency of such a plan- 
  form. 
  In addition, if high local lift coefficients 
  exist near the tip, the tendency will be to incur 
  these 
  the shock induced separation first 
  areas. Generally, the wing will contribute 
  to pitch-up only when there is large sweepback. 
  Of course, the wing is not the only item con- 
  to the longitudinal stability of the 
  tributing 
  airplane. Another item important as a source 
  of pitch-up is the downwash at the horizontal 
  tail. The contribution of the tail to stability 
  depends on the change in tail lift when the air- 
  plane is given a change in angle of attack. 
  Since the downwash at the tail reduces the 
  change in angle of attack at the tail, any in- 
  crease in downwash at the tail is destabilizing. 
  For certain low aspect ratio airplane configura- 
  tions, an increase in airplane angle of attack 
  in 
  may physically 