Canted 2D nozzle to achieve 3D movement characteristics

[ranmit11]

I found here posted by @overscan (PaulMM)
https://www.secretprojects.co.uk/threads/rockwell-pre-atf-and-atf-studies.331/post-220455

what is the disadvantage of this nozzle ? looks easy to manufacture and able to make 3D movement

 

[ThePolishAviator]

Hello,

this design while ingenious and simple has the disadvantage of being considerably less efficient than other thrust vectoring variable area nozzles. This nozzle needs an adapter that turns a circular cross section into a square one over a distance long enough to prevent separation from the walls. Therefore:

-there is a considerable amount of space wasted
-due to it's shape i doubt the adapted could serve as the afterburner
-thrust energy is wasted to drag
-a square tube has more surface area compared to it's cross-section therefore more heat from the exhaust will enter the aircraft so it need to be dealt with

The only aircraft I believe exists that uses a similar design of the nozzle is the F-22 which is a designed hobbled by the stealth requirement (aerodynamically, I'm not trying to criticize stealth).