...I've got a question or two for you.

I've been puzzled as to how they got some of the early rocket turbopumps revved up.
Granted! I know during WW2, the German rocket scientists under WVB used H202 pressure-fed into a catalytic chamber to generate high-pressure steam to operate the V2 rocket's turbopump.

The problem is...What did engineers devise for rockets in the 1950's, 1960's, etc to build up the rotational-energy in the turbopumps...

PLEASE...PLEASE....PLEASE...don't regurgitate the Encyclopedia Brittanica's
'explanation' that they "siphoned" some of the rocket-motor's hot-
exhaust to operate the turbopumps!!!...
I already know that!!
That ONLY explains how they SUSTAINED the turbopump's operation,
it doesn't explain how they revved up those turbopumps prior to the
start of the rocket motor's ignition.
I have a theory on how they did it.....I just want to read an 'expert's' take on how it was actually done.
cheers.

Jacob

"We choose to go to the moon and do those OTHER THINGS, not because they are easy, but because they are hard."
John F. Kennedy