[MJRitter]

They are Pratt & Whit J58-1s, built in 1955. It is a duel cycle design. Once up to speed it would bypass the compressor and become ramjet. The fuel is so stable they use another substance (I forget what it is) to inject on start up to get it to light. They also use it to fire off the burners. They only had something like 15 "shots" of the stuff.

[oxcart]

That substance was TEB (triethel borene). When injected it turned the exhaust gasses green when it lit things up.

There use to be a engine start video on one of the BB's sites...the sound of 2 racing engines starting up, then you heard the J-58 spool up and then boom! the TEB kicked in and wow!