Late 1960s, probably '67 or '68, as an 'orrible Air Cadet we did a squadron visit to Finningly, then a Vulcan base. In the hangars a very patient tech explained the start sequence of the QRA Vulcans, with a neat onboard analogue device that appeared to switch the air start source to the next engine as soon as the previous engine was self sustaining. This may be the ripple start referred to. It allowed for, ISTR a four engine start in less than 2 minutes with the aircraft being well airborne before the famous "4 Minute Warning".
I can only thank the unsung heroes of ranks and officers who entertained Air Cadets on station visits and gave us enthusiasm and interest which we took into our aviation careers. I hold great memories of those times.