Is it recommended to forward slip an aircraft wth a v-tail just above stall speed at a maximum angle of attack?

A forward slip requires crossed controls, eg. Full right rudder and full left aileron and then adjusted to maintain forward flight.

However executing at maximum angle of attack requires "full elevator", which in the case a vtail, is also the rudder acting as the elevator.

As a side note, forward slips are not recommended by the manufacturer of Velocity Aircraft, an aircraft with twin rudders, as the leeward rudder may become in-effective as it may blanketed by the fuselage and become stalled or have unclean airflow.

So is this recommended? I would think no, as it would have the same problems as the Velocity.


2 Answers 2


You don't forward slip at all close to stall. You will be at your final approach speed, roughly 1.3 Vₛ, and when you slip you will normally add a few knots of extra energy as a safety margin by lowering the nose at the same time.

The only time you are in that condition close to stall is in the landing flare in a crosswind, side slipping to counteract the drift. The V tail airplane has to be as capable of doing that as any other. The main effect that owners of V tails have to live with that is unique to the configuration is annoying lateral yawing moments in turbulence. The V tail Bonanzas are famous for this.

As far as control authority for rudder and elevator goes, the range of motion of the control surfaces (called "ruddervators") is quite large and the ruddervator surfaces are oversized (bigger than a regular horizontal tail would be, but smaller than the horizontal tail plus vertical tail), to accommodate the need of the control linkage mixer unit to sum pitch and yaw inputs to achieve the same result as a regular tail.

Say, for example, you apply full up stick with no rudder; both ruddervators are up about, say, half-travel. Adding left rudder pedal while holding full up stick will make the right ruddervator go up more while the left ruddervator goes down a similar amount (that is, less up), to create a net nose left yaw moment without changing the net pitching moment.

Apply full right rudder with the stick at neutral, and the left ruddervator goes half up, and the right ruddervator goes half down. Pull full back stick while holding the rudder input, the left ruddervator goes up more, while the right ruddervator comes up to a less down position.


V-tail or not:

Flying at full elevator deflection, at maximum angle of attack isn't recommended unless you are intending to demonstrate stall recovery.

Flying at full elevator deflection, at maximum angle of attack and then entering unbalanced flight using rudder isn't recommended unless you are intending to demonstrate spin recovery.

  • 3
    $\begingroup$ This is a good answer, but I think it can be made even better if you add information specifying why a V-tail does not result in a difference. $\endgroup$ Mar 18 at 21:59
  • $\begingroup$ @EndAnti-SemiticHate, thanks for the feedback, but: 1.) I'm going for brevity and pointing out the [obvious] risk in any aircraft, and 2.) I don't have the specific aero expertise to explain why the risk is not less with a V-tail. I'm just going to leave it as-is. $\endgroup$ Mar 19 at 16:01

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