Master the tailslide

The tailslide is flown in competition and as part of display pilots’ routines. To perform this manoeuvre, one first needs to have enough speed to be able to pull up and draw a nice vertical line in the sky. The aircraft loses speed and eventually comes to a stop. It then slides backwards tail first. This slide is usually only for a short distance −  about three to five fuselage lengths.

The plane then flips over into a vertical dive, from which you can effect a recovery and move onto the next manoeuvre. If the aircraft flips over backwards, this is known as a stick-forwardtailslide. If it tips over forwards, it’s called a stick-backward tail slide.

An unpredictable outcome

Hold a dart by the flight so that the sharp tip faces downwards and let it go. It will travel down straight and true, without any deviation. Now repeat the action, holding the tip so the flight faces down. The dart will fall for a short distance, wobbling in an unstable fashion before flipping over. Perfect stability achieved, it will continue its trip to the ground. No-one can predict which way the dart will flip; drop it 10 times and it will flip over in a different direction each time.  An aircraft performing a tailslide behaves much like a dart dropped flight-first.

If you’re unaware of the aerodynamic factors and best practice involved in performing a tailslide, your attempt will probably disappoint you. It could flip over the wrong way, backwards instead of forwards or vice versa. It could even go to the left or right.

Let’s fly the tailslide

A good tailslide begins with as much speed as possible and the aircraft pitched as close to a perfect vertical as you can get it. Achieve this with a sight gauge or by looking at the angle between the wing tip and the horizon. 

As the vertical line is achieved, bring the throttle right back to idle. This stops any torque reaction from the propeller that would cause the aircraft to roll in an opposite direction. Since the power is at idle on the way up, there’s no helical slipstream effect. The rudders can therefore be centred and held there.

Unusual effects

The aircraft soon runs out of speed and stops. In that instant, it begins sliding backwards, gaining speed at a rate almost equal to the acceleration due to gravity. The first thing you’ll notice as the aircraft stops at the top of the vertical line is that with the engine at idle and no airflow over the plane, the silence is almost deathly.

Then the aircraft starts sliding and you become aware of the relative wind from below and behind. In the open cockpit of a Tiger Moth or a Stampe SV4, a definite wind can be felt on the back of your neck.

In competition flying, nothing short of the perfect execution of a tailslide will be good enough.

The aircraft accelerates rapidly as it falls backwards

Three seconds after the slide begins, and depending on the amount of drag or resistance to the airflow, the aircraft could already be falling backwards at a speed of about 50 miles per hour or more. Another second later, the aircraft could be travelling at about 70 miles per hour. However, in spite of the speed, the aircraft would have slid for a distance of only a few fuselage lengths in those three or four seconds.

Hold the flight controls very firmly

The relative wind is now coming from behind and getting stronger by the millisecond. It starts playing havoc with the rudder, elevators and ailerons, all of which were never designed to have airflow from behind. The stick and rudder pedals tend to kick and buck and must be held very firmly − certainly with two hands on the stick. If the relative wind wins the battle, the control surfaces could be blown harshly up against a stop and damaged.

Instability settles in during the slide

The further the aircraft slides, the more likely it is that it will choose its own time to flip over. Before this happens, the pilot must either apply full forward elevator to get the aircraft to flip over backwards or full aft elevator to have it flip forwards. If you get this wrong in competition, a whole sequence can be blown.

The recovery

Once the aircraft has flipped over towards a vertically downwards attitude, it will oscillate once or twice like a pendulum before settling down. Power is restored and the aircraft is pitched upwards until it’s back in level flight.

Other factors

I did my first tailslides in the 1970s, flying Tiger Moths, the Stampe SV4 and Pitts Specials. On two occasions, because the engine idling had been set too slow and the relative wind was coming strongly from behind, the propeller stopped dead during the slide. On the Pitts I merely turned the starter’s key, but in the Tiger Moth I had to dive off a huge amount of height to get enough airflow onto the propeller to achieve an air start.

In competition flying, nothing short of the perfect execution of a tailslide will be good enough.