Fórum Defesa Brasil

Não é a toa que o F-111 tem mais de 7000km de alcance, e o SU-34 tem os seus 4000km. É muito combustível!

Sukhoi T-50 PakFa - Saturn have been developing a new engine for the PAK-FA since 2006, labelled as the “Fifth Generation Fighter Engine”. Clearly this will employ technology from the existing 39,600 lbf class Al-41F, developed initially for the MFI

Sukhoi T-50 PakFa - workshare breakdown for the developmental fifth generation engine; below: intended applications for same. The Russian language legend shows a common core [Basic Gas Generator] exploited for a range of other applications, including maritime surface combatant powerplants, and fixed power station or gasline pumping applications (NPO Saturn).

Diagram 1: The Agat Panorama TsM Air Defence Area / Sector Mobile Command Post (above, below) is a good example of the highly integrated systems approach taken in the design of contemporary IADS. It also illustrates the level of penetration achieved by COTS computing technology in modern Russian designs. Note that both legacy and contemporary missile batteries are supported, as well as VHF band and microwave radars (Agat).

Diagram 2: Engaging a VLO/LO target (above) using the 1L119 Nebo SVU as a VHF band acquisition and tracking radar, and the 30N6E Flap Lid as a missile uplink channel

Diagrama 3 - The first major departure from established shaping conventions is the angular or aspect dependency of the Joint Strike Fighter’s radar signature.


Diagrama 4 - Study of the shaping of the aircraft and comparison with other designs shows that the Joint Strike Fighter can provide genuinely good stealth performance only in a fairly narrow ~29° sector about the aircraft’s nose, where the shaping of the nose, engine inlets, panel edge serrations, and alignment of the leading and trailing edges of the wings and stabilators results in the absence of major lobes or “spikes” in the radar signature. The ±14.5° angular limit is constrained by the principal reflecting lobe of the leading and trailing edges of the wings and stabilators. The signature degrades rapidly due to the influence of the lower centre fuselage as the angle swings past ±45° off the nose

Diagram 5: Very Low Observable airframe shaping should be optimised to produce best effect, i.e. lowest radar cross section, from those angles from which the aircraft is most likely to be illuminated by a threat system such as an engagement or acquisition radar in a Surface to Air Missile battery. This diagram shows the cardinal depression angles for an aircraft at the tropopause, accounting for the curvature of the earth and atmospheric refractive effects which 'bend' the ray path between the aircraft and threat radar. The specific angles in this diagram are determined using Russian specifications for missile range, the SBF refractive model for short ranges, and an exponential CRPL refractive model for ranges in excess of 100 nautical miles. It is important to observe that in straight and level flight all surface based threats are firmly in the lower hemisphere, putting a premium on low Radar Cross Section in the angular range between 3.7 and 36.5 , as area defence missile systems will illuminate the aircraft within this angular range. Point defence missiles systems and 'trash fire' such as AAA and MANPADS are generally altitude limited to 10 - 15 kft and are a much less critical threat. A smart IADS operator will not radiate until a potential target is close enough to get a steep elevation angle for a shot, a tactic commonly associated with 'shoot and scoot' operations - the cardinal example being Serbian ZRK Kvadrat / SA-6 operations in 1999

Diagrama 6: Joint Strike Fighter Best Case SAM Engagement Geometry and Timelines
This diagram depicts the best case engagement geometry and timelines for an attack using the Small Diameter Bomb against a target colocated with a long range SAM site, or the SAM battery itself. Level turn escape manoeuvres do not minimise the exposure time of the F-35 and in addition present a larger depression angle to the threat. The single best escape manoeuvre after bomb release is to roll inverted, and pull through. Airspeed is constrained to 500 KTAS to minimise nozzle RCS. The difficulty is that even for the best case and worst case SAM parameters for SA-10, SA-12, SA-20 and SA-21 the missile battery gains a robust firing opportunity. Within the ranges of interest the F-35 from this aspect can still be tracked for a missile shot by the 59N6E, 67N6E, 96L6E, 36D6, 64N6E2, 5Zh66 and 1L119 3D acquisition radars and the 9S19, 30N6E1/E2 and 92N6E engagement radars. At this range the aircraft can be tracked by the Vostok E, JY-27, 1L13, 5N84AE and P-18M 2D acquisition radars. A large fraction of these radars post date the initial requirements definition for the Joint Strike Fighter. In the contemporary IADS environment it is therefore abundantly clear that the Joint Strike Fighter cannot survive by stealth alone, as the threat radar technology has evolved considerably over the last decade.

Espero não ter fugido do tema do tópico com estes últimos posts!

F-35B - JSF STOVL - Cutaway

In comparing the JSF and F-22A in air-combat roles, the F-22A is vastly superior. In long range BVR combat the F-22A has major advantages in sustained energy performance, stealth, radar range and missile kinematic performance - an AMRAAM goes a lot further if launched from twice the altitude at supersonic speed. In close in combat the F-22A's greater agility cannot be contested - on dry thrust the F-22A outclimbs and outaccelerates an afterburning F-15. The JSF is designed to achieve similar performance to the F-16C, itself inferior to the F-15 series. In any Combat Air Patrol scenario, supercruise permits the F-22A to cover four times the footprint of a JSF. It can engage and disengage opponents at will, unlike the slower and less stealthy JSF. The F-22A outclasses the JSF across the board and is several times as effective in most air combat regimes.
In comparing the JSF and F-22A in strike roles, the divergent deep strike optimisation of the F-22A and battlefield strike optimisation of the JSF are telling. The F-22A is much more survivable as it is stealthier and supercruising. However, the F-22A in its current configuration lacks the extensive electro-optical suite and radar modes of the JSF, required for battlefield interdiction and close air support. The JSF will have better loiter performance, especially at low altitudes, and carries a larger internal bomb payload, where these are JDAMs, but identical where these are the SDB. Yet on long range strike profiles, the F-22A achieves similar 'productivity' in bomb deliveries as the JSF as it can transit to and from targets almost twice as fast, both requiring generous tanking to achieve F-111 class strike radii or on station persistence.

This is the pitfall of economy 'narrowband' stealth - it can defeat upper band radars used for the engagement control, but is much less effective in defeating the long range systems used to acquire targets. If an Su-30 can be positioned close enough, it can engage the JSF regardless of stealth, and with a kinematic and missile performance advantage the odds are unlikely to favour the JSF.
While having any real stealth always beats having no stealth, Australia should not develop unrealistically high expectations of the JSF's stealth capability, especially in relation to the principal regional capabilities like the Su-27/30, A-50 AEW&C, S-300/S-400 and supporting long range radar systems. The only fighter optimised for that threat environment at this time is the F-22A Raptor