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Rafale and Gripen are quite similar but the Eurofighter Typhoon has the canards far forward. I've been told that this was due to the shape of the air intake.

Apparently the Typhoon's air intake was designed to work in combination with Thrust Vectoring Control. This feature was never implemented so I believe the canards may be less effective than other aircraft, in terms of performance, (specifically turn/pitch rate).

Am I totally wrong?

close coupled canard Vs long arm canard

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  • $\begingroup$ Longer arm means less force needed from the canard, so less drag, especially at high speed when lift center shifts backwards and requires more lift from the front. Shorter arm means the wing can benefit more from the vortex. Basically if you want high speed then long, or high manuveribility then short. $\endgroup$ – user3528438 Aug 18 at 1:33
  • $\begingroup$ Do you have any sources for that? I would have expected quite the opposite. $\endgroup$ – hph304j Aug 18 at 6:04
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The Viggen was the first canard aircraft ever to be built in production quantities. Its close-coupled canard is fixed, with landing flaps being the only movable part. Its purpose is solely to maintain aerodynamic flow over the wing at high angles of attack and thus enhance both manoeuvrability and low-speed handling. Saab were not able to develop movable canard technology in time, nor was it necessary in order to meet the aircraft specification. Nevertheless, getting the darn thing into production after 60 years of failure was a staggering achievement.

The Gripen, Rafale and Typhoon canards are also used to maintain high-alpha airflow. However theirs have an additional function as control canards. Their own angle of incidence can be varied to help control aircraft pitch directly, to contribute to other more subtle manoeuvres, and (at least in the case of the Typhoon) to minimise radar cross-section.

The further forward a control canard is placed, the smaller it need be to provide sufficient control authority, just as a long rear fuselage allows a smaller tailplane. Its only real issue is that it interferes more with pilot visibility, but its smaller relative size minimises that.

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    $\begingroup$ The Grippen canard is, however, also an all-flying control canard. What Viggen has is largely irrelevant for this comparison. $\endgroup$ – Jan Hudec Aug 17 at 20:22
  • $\begingroup$ Thanks, I must have read the question wrong. I have edited my answer accordingly, but have left in the Viggen bit as it has got a couple of upvotes so must have interested somebody. $\endgroup$ – Guy Inchbald Aug 18 at 17:54

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