Is there an aerodynamicist in the house?
Jo90,
I'm no expert, so I cannot answer fully.
On a conventional wing, with a conventional profile, at subsonic speed, everything is done to keep the airflow 'attached' to the wing as long as possible, and for as high an angle of attack as possible.
Such a wing stalls because above a certain angle of attack the airflow 'breaks away' from the upper surface of the wing, leading to a sudden loss of lift.
On a very thin slender delta, the airflow already is made to detach right at the leading edge, even at low angles of attack.
Rather than "ruining" the airflow, hence the lift over the entire wing, the result is a vortex that rolls up and re-attaches the airflow to the wing.
At high subsonic speeds, hence low angles of attack, the vortex is located just behind the leading edge, and the rest of the wing produces "conventional" lift.
With lower speeds, hence higher angles of attack, the vortex
grows, and ends up covering most of the wing during take-off and landing, as one sees in some photos.
So there is no real
sudden transistion from "conventional" to vortex lift.
At no time does the vortex 'break away', so there is no stall in the conventional sense. However, drag increases rapidly, and controllability doesn't improve either, so there are still angle-of-attack limits, even on Concorde.
At supersonic speeds, the entire flow is totally different, and totally unlike the vortex flow.
My own question to an aerodynamicist would be :
Looking at the subtle camber of the leading edge, is there any vortex lift at all during subsonic cruise (Mach 0.95+) or is there a fully attached airflow at that speed / angle of attack to obtain the best possible subsonic cruise?
And if so, when does the breakaway first start?
CJ