Gollevainen said:
Someone else can propaply help you more but at least the case with tailess delta designs, mostly older Mirages was that the adoption of Fly-By-Wire really gave the best performance of delta wings. Perhaps Crobato or someone else can tell you more why it is so...
Tailless delta was something the US and the Russians abandoned early. Problem with a tailless delta is that you have two wing control surfaces doubling as ailerons (roll control) and elevators (pitch control).
FBW can only do so far with delta designs. The best it can do is to prevent the pilot from pulling the plane into an angle of attack that is too excessive, keeping the AoA at the edge of threshold. Beyond that, the plane would lose both speed and lift. Even with experience, the pilot cannot not mentally compute everytime for all the speed, altitude and other factors, especially during combat.
The Mirage 2000 has an unstable profile and low wing loading which give it good instantaneous turn ability, but not sustained turning ability. Once you go turning deeper into a circle or continue to maneuver after successive maneuvers, the plane easily loses bleeds speed. Again that is due to the unassisted delta wings. This is something rectified with canards, double delta or cranked delta designs. The Mirage 2000 does have variable camber (leading edge automatic slats) in the front of the wings, which improves lift at lower speeds and reduces edge wise bleed of the airflow. So the effects are somewhat offset. Still nothing beats vortice generation flowing on top of the wings, which you can have with a canard, LERX or double delta.
