The F-117 has reduced airflow, the radar blockers on the Silent Eagles and Super Hornet do not seem to have the same issues. The radar blocker on the pak-fa is yet to be seen.
OK, but the cause of the reduced engine performance is "the radar blocker" itself;
See this explanation:
The F-117 also makes use of special screens on the engine inlets that block radar waves from reaching these surfaces. However, these screens are difficult to design because of their adverse impact on engine performance and have been abandoned in later stealth aircraft. More recent stealth designs use S-ducted inlets that bend off center to hide the blades from being seen.
Aerospaceweb.org | Ask Us - Stealth Technology
That is not true, The F-22 has a much smaller RCS compared to the smaller F-35. The B-2 has some clever features such as no vertical stabilizers to reduce RCS.
If F-22 RCS is much smaller than F-35, then moreover it is much much smaller than B-2. Then it means B-2 RCS is very very much bigger than that of F-22.
So my point is: the rcs contribution of metal canopy of B-2 is negligible for that big RCS of B-2, but it is not negligible for very much smaller RCS like that of F-22.
It is
very round you are just viewing it at a wrong angle, take a look:
http://www.airforceworld.com/bomber/gfx/b2/b2_10.jpg
Nope. On the contrary if you want to know the fuselage shape is round or not, you should see from the cross section, or at least from front angle, not from side angle.
Besides as I have explained to you, the fuselage of B-2 doesn't reflect radar wave coming from bellow (ground radar) as the fuselage is blended and covered by the wing. Therefore it wont contribute RCS from downward direction.
There is no principle that says you can not have curvature. In fact it is heavily used in aircraft such as the F-35 and to some extent the F-22 such as rear fuselage. But again, the question comes down to secular reflection and why aircraft such as the F-22 and F117 were never effected by it when they banked or were inverted. Remember, the F-22 has a bubble canopy as well as curvature around the engines, and when it banks or is inverted its flat fuselage is irrelevant since ground based radars looking at an inverted aircraft and not one in level flight.
As a matter of fact Continuous Curvature is the way to prevent radar wave back to the sender.
For bomber like B-2 the flat bottom of / wing blended fuselage and metal frame canopy is still very relevant because it doesnt bank or inverted like fighter plane. Thats why I said we cant use bomber for the air fighter benchmark.
Therefore the round part of the B-2 top fuselage (if it really round) doesn't much concern as it is covered by the wing.
The picture you posted contradicts that statement, Martian’s picture tried to claim that the pak-fa has more specular reflection from the side because its fuselage sits higher, but that is not relivant what is relivant is how much physical surfaces are there to cause this specular reflection. Remember the J-20 has a much thicker fuselage and an adition of large tail fins, so if you disagree with me then how do you agree with the picture you posted?
By putting fuselage higher + bigger gap between fuselage and airduct, it will create bigger surface and exposed angle that will reflect radar wave greater. Angle shape is minimized in F-22//J-20/F-35/B-2 by applying continuous curvature.
In the case of F-22, the corner/angle of the airduct and fuselage is not exposed, therefore doesnt reflect radar way back.
How does that make sense? The pak-fa’s intake is semi receded, meaning there is less of a gap running down the fuselage because the rest of the intake is hanging underneath the fuselage. Moreover, the size of the gap is approximately the same width.
As the matter of fact, this semi receded intake will create exposed corner that will reflect radar wave way back to the sender.
On the other way round the corner/angle of the fuselage with airduct on F-22 is not exposed, then will not send back the reflected radar wave.