Comment by avmich
1 day ago
The thrust vector control (TVC) subsystem is usually considered a part of the engine. The major change the Soviet NK-33 underwent for a USA model was the addition of TVC, and the engine was named differently, so there are two engines, named differently, which mostly differ by the presence of TVC.
Raptors can be used without TVC. Be that by using differential thrust, or just not needing that - because rocket is controlled using other means, or other engines - it's possible. Tory Bruno specifically explained that he meant - among other things - that absence.
A picture of the engine working on the test stand can be that for the engine - or for the chamber, a significant component of the engine, with or without turbopumps involved.
Tony Bruno, when referring to the partially assembled engine, was complaining about the lack of engine controllers, fluid management, and TVCs [1].
In addition, SpaceX isn’t cheating by not including TVCs. They purposely designed their rocket to need a minimum of them and fully take advantage of the space savings the lack of TVCs affords them.
[1] “So, there is no need to exaggerate this by showing a partially assembled engine without controllers, fluid management, or TVC systems, then comparing it to fully assembled engines that do.”
https://x.com/SawyerMerritt/status/1821679540973765026?s=20
Oh yeah, Tory Bruno made that gaffe of a comment publicly, and completely unprompted, before he abruptly quit. I had forgotten, but you’re right of course.
https://www.spacex.com/content/starship/holy-grail-of-rocket... at 13:35 has a good view of a raptor 3 with TVC, do you think that adds substantially to what is pictured at the top of the article?
TLDW but TVC for rocket engines is usually achieved by like one hydraulic suspension rod each for X and Y axes(Y and Z in rocketry? idk) serving as parts of the engine mounting frame. It shouldn't add a lot to the system.
I didn't have a particularly good view from 13:35 frames. TVC is a relatively simple subsystem, but it's there.
Yes, that's the usual way. With SpaceX, however, Raptor engines are gimbled with electric actuators.
And yes, the TVC adds very little to the complexity of Raptor 3's appearance: it still looks like science fiction, even when operating in Starship. Had TVC been present in the original SP1 image that had Tory accusing SpaceX of misleading everyone, it would have made no difference.
> TLDW
That video has beautiful shots of Raptor 3 firing and gimbling. It's worth watching.