- How do we define 2D and 3D thrust vectoring?
- What are the differences between the two?
- Is there anything called 1 D thrust vectoring?
As previously seen in a comment section, there are two main schools of thought:
The dimensionality indicates the actuation Degree of Freedom (1D has 1 DoF per exhaust vector, 2D has 2).
The dimensionality indicates the aircraft attitudes that can be affected (2 exhaust vectors with 1 DoF each can affect pitch and roll, hence this would be a 2D thrust vectoring, 2 exhausts with 2 DoFs can affect all 3 attitude angles, hence 3D)
Using the definitions of these two approaches, to make a couple of examples, the F22 thrust vectoring is 1D for the first group and 2D for the second, while the Su30 is 2D and 3D respectively.
$\begingroup$ I might be missing something: Are the F-22 engines independent? If so and giving your definition, I understand that each engine has a 1D thrust vector (act only on pitch and only one degree of freedom), and combining both made it a 2D thrust vector (1 DoF per engine, combination acting on both pitch and roll as if they were elevons) $\endgroup$– Manu HJul 2, 2015 at 14:07
$\begingroup$ @ManuH yes, that's what I have written. I admit that I trusted the other answer on this and I have not personally checked if the F22 TV is independent. $\endgroup$– FedericoJul 2, 2015 at 16:04
An aircraft traditionally has three "degrees of freedom" in aerodynamic maneuverability; pitch, yaw and roll. The number of "dimensions" of thrust vectoring relates directly to how many degrees of freedom can be manipulated using only the vectored engine thrust. Therefore, 2D vectoring allows control over two degrees of freedom (typically pitch plus either roll or yaw) while 3D controls all three.
As previously mentioned, the difference between 2D and 3D is the number of degrees of freedom that can be controlled using thrust vectoring.
Yes, there is such a thing as 1D thrust vectoring. It was seen on early-block F-22s, whose thrust-vectoring nozzles can redirect thrust only up or down, and on these early blocks the nozzles of the two engines moved together in the same direction. Later F-22s (and I believe a retrofit of earlier ones) allowed the nozzles to move independently which also granted roll control using thrust vectoring, making the system 2D.
The F-16 VISTA tech demonstrator allowed vectoring of the engine's thrust in any direction behind the aircraft, but because the aircraft was single-engined and used a system based on the engine's existing "turkey feathers" (which allow the engine to regulate internal combustion pressure and exhaust velocity by restricting the diameter of the nozzle), the craft did not have roll control in a post-stall situation. Later single-engined experimental craft like the X-31 used a different vectoring system with paddles behind the engine exhaust, which can be rotated as well as pivoted allowing thrust to be vectored in a "spiral" fashion, providing roll control and thus full 3D vectoring from a single engine.
From Aircraft Wiki:
A plane has got thrust vectoring when it is able to direct its engine thrust in another direction to give it better maneuverability. If the plane is able to direct the thrust only in one direction it has 2D thrust vectoring control. If it's able to direct the thrust in all directions, (pitch,yaw and roll) it has 3D thrust vectoring.