Yeah it’s hard to comprehend how powerful those engines are. The booster is relatively light without all the propellant and starship when it’s attempting to land, but it’s still 30 stories tall and I’m assuming it weighs dozens of tons.
It blew my mind that just the fuel pump for just one engine has a power rated in the tens of thousands of horsepower/kW.
Yep, those pumps have to push the propellant into the explosion harder than the explosion pushes back. That takes serious power!
Not only that - spacex uses the highest chamber pressures, enormously high compared to almost any other engine.
So thinking where the leverage is - is it like hydraulics where the input cross-section is a lot smaller than the output cross-section? That's kinda what the nozzle looks like.
Yes, but also the propellant explodes after being pumped in, so you pump in a tiny volume and exhaust an enormous volume.
You pump in a huge volume and exhaust an inconceivable volume
That's fair, lol.
No, because the fuel is not a working fluid pushing a piston. All the "leverage" is at the turbopump impeller blade.
iirc only 3 ignite for the landing burn, those engines are freaking monsters. I love how small they are, the latest Raptor revision is so slim and compact. The power density is just mind boggling.
You can see for yourself in the video - all 13 center engines attempt to light, and all but one do so.
Similar to ship, they start up more engines than needed in case a few fail, then immediately shut down the extra engines.
Where is this visible in the video? EDIT: oh wait is it the diagram in the bottom left?