>>11651068It wouldn't change the requirement for more chamber pressure. You'd have more thrust per engine but the same combined average thrust per unit area at the base of the rocket. In fact with a bigger engine you may end up with less efficient packing and less thrust per unit area overall.
To give a real world example, look at the massive F-1 engine on the Saturn V, and compare it to four little Raptors. The F-1 produces much more thrust than a single Raptor, but four Raptors both produce MORE combined thrust in a smaller area when clustered, and do it while weighing less.
As another example, look at New Glenn with its BE-4 engine, which is slightly more powerful than the current Raptor but much bigger due to having lower chamber pressure. If you removed the 7 BE-4 engines from NG and installed 9 Raptors, you' have greater thrust reduced weight and greater efficiency, too.
You can think of any rocket engine as needing to be strong enough to lift a column of propellant and structure above itself, and that column can not be so tall that it weights more than the thrust force of the engine. Scaling up Starship in width and height would increase the height of the column each engine would need to carry, even if you packed in as many engines as you could fit. However, scaling up ONLY the width is effectively like stacking more columns next to one another to get a bigger stage; that process can scale infinitely because each engine isn't being forced to do any extra work.
