In the hands of a good pilot, the barrel roll is one of the nicest and most comfortable aerobatic manoeuvres to ride through. It can be flown very smoothly and perfectly balanced from beginning to end.
You sit comfortably in the centre of your seat and watch the world roll slowly around you. It’s also flown with far less gthan for a loop, with about 2.5gbeing the normal amount required.
There are many different versions of the barrel roll, and a vast number of opinions on how one should be executed. I’ve flown with pilots from all over the world, most of whom were trained in the military, and I’ve noticed that they all flew their barrel rolls somewhat differently.
Within the sport of competition aerobatics, the barrel roll is listed in the catalogue of manoeuvres. However, since those who judge at these competitions have never been able to establish or agree on a worldwide standard for the flying and judging of the barrel roll, no pilot has ever flown one as part of a competition sequence.
The way that all of our local aerobatic display pilots fly a barrel roll bears a close resemblance to how the manoeuvre was defined, taught and flown by the instructors at the South African Air Force’s Central Flying School. The only difference is that air show pilots fly it somewhat more loosely and use up more sky.
The first half of the manoeuvre
The barrel roll is often described as a “spiral loop”. It begins with the same sort of positive pull-up as for a loop, after which a roll into a very steep climbing turn is introduced. The idea is for the aircraft to change direction through 90°, while simultaneously pitching and rolling.
As the 90° point is reached, the aircraft should be upside down with its wings level to the horizon. The first half of the spiral loop, so to speak, is now reaching its conclusion.
The pilot reduces the back pressure on the stick slightly to avoid the wing reaching the stalling angle of attack, but keeps the nose of the aircraft pitching towards the top of the canopy. This means the nose will soon cut the horizon heading towards the ground below.
The second half of the spiral loop is now commencing
The aircraft is in a dive and the roll input is ultimately going to bring the aircraft back to the erect attitude. So, with the aircraft now in a steep diving turn, it is pulled out of the dive and turned through another 90°, having rolled back gently from being inverted, into the erect attitude. It then ends up on the same heading that it was on at the beginning of the first half of the manoeuvre.
Flying the barrel roll
The manoeuvre needs about the same speed that a loop is started at. The best way to maintain one’s orientation is to select two prominent visual points or features such as mountain peaks or high buildings on the horizon. One point must be on the nose and the other 90° away from it on either the left or the right wing tip.
Reaching the target speed, the aircraft is pitched upwards and bank is applied at the same time to establish a steep climbing turn towards the chosen point on the left or right wing tip. The pilot needs to keep the aiming point in full sight.
The pilot aims to reach the inverted attitude with the wings level and the nose above the horizon, while at the same time having the aircraft pointing at the chosen feature or point. Continuous, but light back pressure on the stick continues to be applied so as to keep the nose of the aircraft traversing downwards towards the horizon. The pilot now turns his head to look for the original point that was in the 12 o’clock position and which was used on the run-in at the very start of the barrel roll.
The second half of the spiral loop begins as the nose of the aircraft passes through the horizon, diving towards the ground. The roll input is maintained and this is co-ordinated with the continued recovery from the dive so that the plane arrives back in the straight and level attitude, heading towards the original point.
Perfection is not easy!
The barrel roll may be easy and comfortable to ride through, but at first it’s somewhat difficult to fly properly. It takes some time to achieve perfection in its execution. Pilots tend to become a little confused and disorientated if they fail to keep their aiming points in sight.
It’s worth hanging in until you achieve perfection because the barrel roll truly is the epitome of aerobatic grace and harmony.
HAVE YOU READ: The Stall Turn