There is no denying the lethality and flexibility of a F-35. What I was trying to suggest is that there are certain elements which analysts believe to be necessary for a plane to be a 5th Gen aircraft which has been compromised on the F-35. That doesnot mean it's not a lethal aircraft. F-22, J-20 and T-50 are a whole different category of aircraft. Only the future J-xx series and the conceptualized AMCA would fall in the category of F-35. But till they see the light of day, F-35 will rule in the Mid weight category.
The problem here is that there is no 'committee' of any kind who sat down and produced an agreed upon criteria and standards of those criteria on what is a 'fifth generation' design.
Still...There are unofficial criteria and standards:
- Radar low observability. The design must have radar low observability as primary consideration. Since this is an aircraft, flight control surfaces are obviously necessary, so we can rule aerodynamic demands as primary consideration. The question then is how are the flight control surfaces designed and overall planformed to reduce their contributorship to the aircraft's radar cross section (RCS)? Remember, flight control surfaces are so required that they not allowed to have degrees or gradations of necessity. The B-2 does not have a vertical stabilator, so many erroneously believes that yaw axis control and stability has been eliminated from that design. Nothing could be further from the truth. Instead of vertical stabilators, the B-2 designers opted for split wing tip ailerons to effect yaw axis control and stability.
Flying wing - Wikipedia, the free encyclopedia
Yaw control
Split ailerons. The top surface moves up while the lower surface moves down, to create an air brake effect.
These create their own issues of being RCS contributors. So how should we design the system to minimize the ailerons' contributorship to overall RCS?
What is the primary method of RCS control? Angled faceting, ala F-117, or curvatures, like the B-2, F-22, and F-35? We can look at these aircrafts and see they are blends of both with one method as primary. The F-117's is obviously 'angled faceting'. The latter designs' are obviously curvatures. Flight control surfaces, the cockpit area, and the engines are major contributors to the final RCS, then comes minor ones like assorted communication antennas or air data sensor ports. How are they designed to reduce their contributorship despite their necessity for flight?
A fighter aircraft cannot carry as large and powerful a radar system as an AWACS. The acceptable radar range for the majority of fighter aircraft class is 150-200 km. At that distance, a clean F-16 has an RCS of about 1 meter square. Anything below that figure, at 150-200 km distance, and an aircraft can be reasonably qualified as 'stealthy'.
- Weapons. The days of 'stealth' weapons are not yet here. So we must reduce weapons contributorship to overall RCS somehow. The best method is to enclose them and so far we do that by carrying them in the fuselage. There are proposals for a 'stealth' pod to enclose missiles and bombs but they remains to be seen. For now, any so-called 'fifth generation' aircraft will have to internalize its weapons with external carry as an option when the need for low radar observability in an arena is reduced.
- Sensors. The most powerful and versatile sensor is the radar. The more advanced form is the electronic scanning array (ESA). Under the ESA type are the passive (P) and active (A) designs with the AESA the clear superior by wide margins, especially in the versatility area. Any so-called 'fifth generation' aircraft must at least have the PESA. The US is not settling for the PESA. We want and will have AESA radars, even in the older aircrafts. Infrared (IR) sensor is no longer an option like before but a necessity.
- Network capable. The days of sharing what one see in one's area of view and responsibility via voice only is over. Any so-called 'fifth generation' aircraft must be able to share raw data with each other and be able to process those data into a coherent situational picture for the pilot.
- Inherent instability. Being aerodynamic does not automatically equate to stability, which is the quality of an aircraft being able to return to level attitude. Inherent instability allow the aircraft to have a higher command response rate which in turn equal to higher maneuverability. This require the more complex fly-by-wire flight control system (FBW-FLCS). The concept is proven since the F-16A/B models with an analog FLCS avionics. Today's FLCS is entirely digital with correspondingly much more complex flight control laws software.
If you believe these major items are somehow 'compromised' in designing the F-35, I would like to see how.
