In article ,
says...
In fact, the design is inferior in performance to the X-15 of over 40
years ago.

Yes. But. There hasn't been an X-15 flight in this decade. Nor the
previous decade. Nor the decade before that. Nor ....
--
Kevin Willoughby lid

Imagine that, a FROG ON-OFF switch, hardly the work
for test pilots. -- Mike Collins