Don't forget the Yak-25RV 'Mandrake' of the late '50s. It was reportedly capable of reaching 65000ft, but that was close to its coffin corner. Operational in the USSR for about 15 years until the advent of the MiG-25R.
Last edited by BEagle; 18th Oct 2019 at 15:36.
Reason: Wrong decade!