What is the sweep angle? Angle between the line of 25% chords and a perpendicular to the root chord.
A swept wing is fitted to allow a higher maximum speed, but it has an increased tendency to stall first near the tips. Loss of lift at the tips moves the CP (Centre of Pressure) forward, giving a nose-up pitching moment.
If the downwash impacts the tailplane the nose-up pitching moment increases.
The tendency of a swept wing to tip stall is due to the induced spanwise flow of the boundary layer from root to tip. The design features shown in the next pictures can minimise this effect and give more accettable stall characteristics.
Picture 1: Wing Fences
Picture 2: Vortilon
Picture 3: Saw or Dog Tooth - 2 minutes ago