As I recall, the Soviet moon rocket failed because it had a cluster of engines that they could never get to work together. The Saturn V had a cluster of only 5, and barely were able to get that to work.
Falcon 9 has 9 engines, it’s not like Spacex is unfamiliar with putting multiple engines on a rocket. That being said we have yet to see more than 3 raptors in flight at a time, so the upcoming orbital test flight will be interesting to watch.
> As I recall, the Soviet moon rocket failed because it had a cluster of engines that they could never get to work together. The Saturn V had a cluster of only 5, and barely were able to get that to work.
N-1 rocket had many troubles with the engines, but it wasn't specifically due to the number of engines: the NK-15 engine couldn't be test fired, vs the Raptor definitely can. You can read more about the four failures here[1].
Similarly, the biggest issues with the F1 engine (powered the first stage of the rocket) was with the injector plates: there was a lot of combustion instability due to uneven mixing in the giant combustion chamber. The Raptor, by virtue of injecting both fuel and oxidizer in gaseous form, will mix better (and it has much smaller combustion chamber anyway)
Having two launch pads (they're starting work on a second tower at the Cape) is also a big help, as they would have backup launch site in case there's an explosion.
The discussion was about Raptor and Starship, but you're right that the falcon heavy has some similarities in having to synchronize 27 engines. Regardless, the rest of my comment was the more interesting part.
The N-1 failed partly because the engine were untested and had high failure rates. The could not be tested on the ground and had a lot of manufacturing issues.
The N-1 failed because the on board computers couldn't handle engine shut downs very well. They basically just shut down the opposite engine.
In some flights that problem lead to complex piping being broken as well, but its by far not the reason the rocket failed.
And SpaceX has already done the Falcon Heavy with 27 engine and its perfectly fine.
What matters is that your engine work well and that if something happens to one engine the computer can figure that out and perfectly adjust all other engines to that new reality.
Raptor 2 has melting issues that prevent many of reuses. It not just gone melt during operation. They have tested Raptor 2 full flight cycles many times.
What they are doing is trying to figure out how much cooling they need to make many reuses possible but still have the highest possible performance.
How did Musk solve this problem?