3
$\begingroup$

Cessna 140's vertical rudder axis Cessna 152's leaned rudder axis Concorde's vertical rudder axis Tupelov Tu-144's vertical rudder axis Boeing B747's leaned rudder axis

I was thinking that canted rudder hinges are used for modern aircraft while the vertical ones are used for old slow airplanes. But it seems that I was wrong since the SST Tupelov Tu-144 and the Concorde also have that vertical (or almost vertical) rotational rudder axis. Then my question is, what is the advantage and this advantage of such a rudder? Which one is better?

$\endgroup$
3
$\begingroup$

The vertical tail of the A380 in the last photo is swept back. Surface sweep is used for high subsonic wings and tail surfaces, to postpone the effects pf compressibility when approaching the speed of sound. And when the vertical tail is swept back, the rudder hinge will be at an angle as well: the rudder chord will be a relatively constant percentage of the vertical tail chord, for aerodynamic and structural reasons.

The two photos of supersonic aeroplanes show vertical tails that are not swept back - they cruise faster than the speed of sound and do not have to postpone any compressibility effect, they fly right through it. No reason to sweep anything back here.

And the photo of the little Cessna with swept back vertical tail: it only looks as if it is trying to postpone any compressibility effects. Of course, it does so by flying way slower than the speed of sound, and the vertical tail is only swept back because it looks super fast.

$\endgroup$
  • 1
    $\begingroup$ Sweep helps to widen the beta range in which the vertical works well. It is not only for looks. $\endgroup$ – Peter Kämpf Oct 3 '19 at 1:46
  • 1
    $\begingroup$ Having flown a number of straight tail and swept tail single engine Cessnas, I can tell you the effect is not detectable on a GA airplane. Cessna went to swept tails in the 60s purely for styling reasons. $\endgroup$ – John K Oct 3 '19 at 2:59

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.