Yet again the old and bold put youngsters like me into our places.
Yes John, I was thinking in terms of tailless deltas, which wasn't entirely the subject under discussion. The Javelin, if memory serves, had a tailplane, which could balance trim change due to flaps and allow a reasonably flat approach attitude.
A subsidiary issue, is that although they generate lift at very high AoA, deltas generate huge amounts of drag. This is almost certainly beneficial when trying to stop a monster like Concorde, but might be another reason why you needed a high initial approach speed in the HP115 - to stop you running out of flying speed. When I fly my flexwing microlight (essentially a tailless delta) I have to fly an approach at about 1.7Vs otherwise you end up with no control in the flare (and can potentially stall). Also lateral stability becomes excessively high in a tailless delta at high-AoA, offering severely reduced roll authority and excessive rolling gust response. Neither of these will be very helpful when trying to land on a less than perfect day.
I wonder though if the Tu-144 didn't use the flaps to shift CP aft, so it was more similar to the 50% chord supersonic position, thus reducing the trim issues as it changes speed regimes. (It also, perhaps on a different tack, had a retractable canard, which would allow control with the pitch changes with flap). Not a simple subject really.
G
[ 24 July 2001: Message edited by: Genghis the Engineer ]