Hi Genghis
But, the excessive Lv and inertia coupling seem to be mutually exclusive - high Lv should damp rolling oscillations, but a large SUSTAINED roll due to beta could be a problem. It sounds to me that this is a phenomenon that should be / have been seen on Concorde and the HP115. Am I right? If I am, then presumably the high alpha protection system is to prevent getting into an unsustainable high drag regime, and ultimately a large pitch-down which is likely to upset the Pax and require a fair number of thousands of feet to recover - but probably isn't related to lateral excursions?
If you trimmed the HP115 into a S&L high alpha condition (say 80 kts) hands off, it was interesting to then do a little (say left) rudder kick, stay hands and feet off and watch. The initial kick might produce a bank to the left of say 20 deg, at which point the roll rate would be stopped by the transfer of alpha into beta from the left which generated a large roll rate to the right (your point above) The subsequent roll to the right, however, would be a bit bigger than the initial one and so off it went in a divergent dutch roll. The thing stabilized at order of +/- 60 to 70 bank (depending on the initial speed). Trying to stop this with instinctive movements of the stick was a far from certain exercise as it was hard to get the phasing right. So what to do? Answer, stuff the stick forward, dump the alpha and the oscillation stopped at once.
Flown as a run down a display line at 1000ft most ordinary people thought the pilot was demonstrating some sort of incredible aileron response (Jack Henderson did this first at SBAC 1961), whereas the aircraft was hands off.
Clearly such a characteristic is a bind, but I suspect it turned out not to be problem for Concorde because that aircraft’s alpha had to be restricted for a variety of reasons to the range where the DR was less divergent.
There has been an awful lot of analysis over on the other thread of how the accident aircraft finished up rolling/stalling/spinning etc etc. In my view that is all meaningless. When a slender delta is at high alpha virtually any beta will cause it to depart in roll. End of broadcast.
As to the second part of your quote above do you mean pitch-down? I thought the traces showed that it pitched up, rolled over and effectively fell through? All academic – what matters is that it departed at high alpha just as predicted. The game was over then.
Regards