It makes sense from a reliability perspective to have more smaller semi-redundant parts, especially since it sounds like they have the whole control system down, "scaling up" from managing and controlling 3 engines probably isn't all that different from managing 9, and eventually 31. (obviously this is still rocket science, and nothing is "easy")
I'm curious if there are other benefits. I'd imagine that manufacturing the smaller engines gets easier and faster and more reliable as they make more of them.
Also, I wonder if this plays into their reusability? If there is a defect found in one of the 9 F9 engines, theoretically you could replace just that one and refly the rest. I have no idea if this is even possible, but it seems like it could be.
But there has been talk in the past, including from Musk if memory serves, about the limits of reliablility.
We aren’t talking about hard drives here. You throw a couple more in and if one fails you just turn it off. Hard drives don’t explode and destroy the hard drive next to them or cause the enclosure to fail.
More rockets is more things trying to explode in only the same direction.
The other responder talked about the operational excellence that can’t be achieved if the numbers get too small. That seems more likely.
Just an addendum, while Musk in fact compares the rockets to computers, I have found that what the management takes away from conversations with engineers is often not the most important part.
But typically everyone on the team has opinions about success or failure of the project and we all discount something important. Managers doubly so. They rarely credit the spotters who keep them from falling when their process has huge holes in it.
I'm curious if there are other benefits. I'd imagine that manufacturing the smaller engines gets easier and faster and more reliable as they make more of them.
Also, I wonder if this plays into their reusability? If there is a defect found in one of the 9 F9 engines, theoretically you could replace just that one and refly the rest. I have no idea if this is even possible, but it seems like it could be.