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If we compare the SEPECAT Jaguar's design with the latest jet fighters, what aerodynamic shortcomings do we find in its design? (I'm only asking about aerodynamics, not AESA radars, electronics suites and so on.)

For instance, in what way is the Jaguar inferior to the SAAB JAS 39 Gripen, PAC JF-17 Thunder, or the HAL Tejas? Is it inferior at all?

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    $\begingroup$ What makes you think that Jaguar 'lacks' something in its design? $\endgroup$
    – aeroalias
    Commented Jan 7, 2017 at 18:02
  • $\begingroup$ @aeroalias: It predates computational aerodynamics; it would be unexpected if they'd got it right without simulations. $\endgroup$
    – MSalters
    Commented Jan 9, 2017 at 1:13
  • $\begingroup$ Apocryphal info - SR-71 "Blackbird" also predates computational aerodynamics. For a test, its parameters were entered into the computational model at a much later date, and the shape was found to be optimal, they did "get it right". $\endgroup$
    – SF.
    Commented Mar 10, 2017 at 7:42
  • $\begingroup$ @SF raises a solid point. The SR-71 was designed not only before we had complex computers in which to calculate scenarios more complex than basic flow equations, but also before we thoroughly understood the behaviour of air and its interaction with airfoils and engines at speeds exceeding Mach 2. Even more unbelievably, the adjustable nose cones used to slow down the supersonic airstream entering the engines are still considered today as one of the few effectively practical solutions for this level of high speed flight. $\endgroup$
    – Jihyun
    Commented Apr 20, 2018 at 20:57

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Only aerodynamics? Then the answer is simple: It lacks artificial stability.

In a paper by Ray Whitford on fighter design he published a comparison study between the conventional Jaguar and an advanced version optimised for relaxed static stability. The improved version is slightly unstable at subsonic speeds and much less stable at supersonic speeds, resulting in much less horizontal tail downforce and reduced size of all lifting surfaces.

conventional Jaguar and CCV version

Both configurations have the same airfield and combat performance! However, the smaller surfaces and the reduced trim drag improve performance noticeably. Note that this optimization was for the ground attack role; an optimized fighter version would had maintained a larger wing and horizontal tail for higher agility.

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  • $\begingroup$ How do Gripen, JF-17 and HAL Tejas score in that area of artificial stability? $\endgroup$
    – user8792
    Commented Jan 7, 2017 at 18:41
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    $\begingroup$ @anonymous: The Gripen is an unstable design, but I do not know enough about both the JF-17 and the Tejas. Given that the Tejas has its roots in the LCA (which was basically conceptualised by MBB), it is most likely unstable, too. I would be surprised if the JF-17 is still a stable design - no self-respecting combat aircraft developed after the F-16 is stable. Given that it has a quadruplex FCS, the JF-17 is most likely unstable, too. $\endgroup$ Commented Jan 7, 2017 at 19:08
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Jaguar is a highly capable aircraft with designated nuclear strike role (In RAF and IAF)- not something that would be assigned to 'inferior' aircraft.

If you are comparing the Jaguar with modern multirole aircraft (like Gripen), the point is that the Jaguar was designed for a completely different set of roles compared to these aircraft. The Jaguar was initially designed for training and tactical support, something reflected in the name itself- SEPECAT stands for Société Européenne de Production de l'Avion d'École de Combat et d'Appui Tactique, which translates into European company for the production of a combat trainer and tactical support aircraft.

When the project was started, the British were looking for a new supersonic advanced trainer aircraft, while their french partners were looking for an advanced trainer/affordable strike aircraft. Finally, they ended up with a supersonic, low level deep penetration strike aircraft, which performed its role perfectly well. However, the airframe is based on a French trainer, the Breguet Br. 121.

Breguet Br. 121

Breguet Br. 121; image from tdpri.com

The similarities are obvious from the above image. Because of its design, it had higher wing loading- leading to reduced maneuverability, but improving stability and munitions carrying capability ar low altitudes, where it is supposed to operate.

Another important difference is that the pilot has to 'fly' the Jaguar- not some thing that happens in modern fly-by wire aircraft (which are inherently unstable, improving maneuverability further). In the words of the last RAF Jaguar pilot:

"A large amount of the pilot's capacity was taken up with actually flying the Jaguar," says Daubs, "then there was a small splash of systems management and then a decent dose of situational awareness (SA).

"In Typhoon there is, the majority of the time, a small splash of flying the aircraft because of its advanced control systems and a huge surplus of thrust, and then there is a decent dose of systems management."

The aircraft is perfectly fine and is no way inferior to the modern aircraft- it performs the roles specified for it quite well. The only difference is that modern combat aircraft has better thrust and maneuverability due to their inherently unstable design.

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