Yes I knew about that part bur
So I didn't get stuck on that. I'm talking about geometry which Nilgiri explained.
Basically, the spine is a big bigger than similar aircraft?
Yeah a bit bigger perhaps, but I see no issue..... its a baked in issue to begin with when you have two engines vs one especially
With one engine you can harness more of the intrinsic advantage in the spine being more flush to begin with given the engine centerlines with the cockpit naturally.
With two engines, the cockpit always has to jut out bit from body, otherwise making everything flush is just way too heavy design penalty.
One can notice the similar trade-off Su-57 and J-20 had to do here too along with F-22.
So it is design consideration rather than design concern IMO.
W.r.t the glass treatments, its a bit like tinted windows for a VIP car, can see out, not easy to see in....radar is partially absorbed and some is also reflected in more coherent (and thus low observable) way than glass letting it through and bouncing off pilot, seat, panels etc and give a much larger radar return and IR signature too.
Astronaut visors, sunglasses etc similar thing (but more to protect whats beneath)....just optimized to different wavelength.
TFX has all of this baked in and sorted out as best as it can be from what I can see (trust me I heard exact same shoptalk for F-22 before with the way its canopy sticks out from some angles many years ago, from both say F-117 purists and F-15 purists).
I would use 99+ times more manhours at this point on the AESA radar compared to canopy stuff basically.
Since non-optimal AESA (channel leakage, insufficient modes, improper mode, handling or selection logic etc) has chance to release 99+ times more emission than canopy+spine ever could.
The glas is not the problem as it is teansparent to radio waves. The problem is what's behind the glas, which is the cockpit. The cockpit bieng made out of flat surfaces in straight angles will act like a retro-reflect in essence. All aircrafts have this problem.
What is normally done is to coate the canopy with a transparent conductive film such that the shape of the canopy reflects away the incoming radio wave. The most common such material is indium tin oxide. You see these material even on commercial aircrafts but mainly for de-icing of cockpit windows.
Yup bascially where I was coming from is that the curved nature of the glass itself is not a reflector issue...given its material.
But yes the next part is what lies beyond the glass (pilot, MFD, cockpit panelling etc) and that is where the glass treatments come in.
i.e Absorb as much as possible in Radar and IR range, and rest reflect in more coherent way (one incident curved surface of the glass) than you otherwise would have (tons of incident curved surfaces behind the glass).
Decent further read:
Have Glass: Making the F-16 less observable
You can’t turn an F-16 into a stealth fighter, it will always show up on enemy radar, but by reducing its radar signature, you can make it a lot less visible. We explain how the USAF has set about
www.key.aero