A few questions

[Spaced Out]

How many degrees can most rocket engines gimbal?

How many gimballed engines does the Falcon 9 have and which of them are?

How many engines does a Falcon 9 use to land?

 

[sevenperforce]

20 hours ago, Spaced Out said:

How many degrees can most rocket engines gimbal?

How many gimballed engines does the Falcon 9 have and which of them are?

How many engines does a Falcon 9 use to land?

 

Most rocket engines gimbal from 0 to 4 degrees in any direction, although early models (and NK's current models) use multiple control engines with only one axis of gimbal freedom each. The SSME engines had a ridiculous 10+ degree gimbal in every direction because of how much the CoM changed during ascent.

All the engines on the Falcon 9 gimbal, but the center engine has more gimbal than the outer ones because it has slightly more clearance.

Although all the engines on the Falcon 9 are reusable, only three are plumbed with ignition fluid for in-air restart. It uses one engine for most landings but it sometimes uses the other two for part or all of the landing burn when it needs extra thrust for low-margin suicide burns.

Edited August 21, 2017 by sevenperforce