Technique: Nose up, unload, roll!

And beware the split-S

June 1, 2013

A roll is the first aerobatic maneuver an aerobatic student learns, and it should be a confidence booster as well as a clean break from the past. It boosts confidence because rolling shows students they are capable of getting the airplane upside down and right side up again, and it’s not disorienting since the horizon is plainly in view throughout the maneuver.

The roll differs from normal maneuvers because it’s often the first time a student is encouraged to use full aileron deflection and hold it throughout the maneuver. Previously, students have been rewarded for subtle, smooth, and gentle control inputs. The roll—and aerobatic flight in general—is about maximum performance, so it’s imperative pilots use all available control authority.

Aerobatic trainers vary widely in performance from Citabrias or Cessna Aerobats with glacial roll rates to Pitts S–2Cs and Extra 300s with blindingly quick ailerons. But regardless of what airplane you’re flying, an introductory or “primary” roll begins the same way.

Step one: At cruise speed, raise the nose of the aircraft well above the horizon. Airplanes with slower roll rates require higher pitch attitudes than faster ones, but 20 degrees is a good target. If your airplane doesn’t have an attitude indicator (and many aerobatic trainers don’t), simply pitch up to put your “heels on the horizon.”

A roll is a great confidence boost for new aerobatic pilots, and getting the airplane upside down and right side up again requires decisive control inputs. Illustration by Charles Flyod.

Step two: Unload the wings. Once your heels are on the horizon, stop pulling on the stick. You don’t want to pull and roll at the same time because doing so slows the roll rate and puts greater stress on the airframe. So stop the back pressure and draw a momentary straight line with the airplane in a 20-degree climb. If you have a G-meter, it should be reading no more than one G at this point, just as it does when the airplane is parked on the ramp.

Step three: Roll! Use full aileron deflection—every bit of it—and hold it until the wings are right-side up and level again. Some tentative aerobatic students resist using full deflection. Others start out all right but lighten up, or even neutralize the ailerons completely, when confronted with the novel view of the inverted horizon. And just about all first-time rollers stop about 45 degrees before reaching the wings-level position. They instantly recognize this mistake and correct it, and then do the same thing on their very next roll, but they quickly get the hang of it.

What about rudder? Use coordinated rudder to counter adverse yaw at the start the roll, but after that the pilot’s feet might as well be flat on the floor. The point of this exercise is using full aileron deflection to get the airplane upside down and then safely rightside up again. Rudder will play a central role in future slow rolls, point rolls, and snap rolls. But in this introductory maneuver, emphasize full aileron deflection to keep the roll as simple as possible.

Once they start rolling, even formerly reluctant aerobatic students tend to become wildly enthusiastic.

What about elevator?

Keep the elevator neutral once you begin the roll. If you start the maneuver 20 degrees nose up, you may finish 20 degrees nose down, and that’s OK. Without timely rudder and elevator inputs the heavy nose of the airplane is going to fall. Accept that for the greater good of making the maneuver easy.

One useful trick involves elevator trim. Add more nose-down trim than you really need in cruise flight before the roll ever starts. That extra nose-down trim will help keep the nose up through the inverted portion of the roll, and the airplane will finish in a shallower descent than it would have otherwise.

What about engine power?

Use a high power setting throughout the roll, but be wary. The most dangerous mistake any aerobatic student can make while rolling is to become confused or disoriented, neutralize the ailerons while the airplane is inverted, then panic and pull on the stick. That reaction leads to a split-S (a half-loop started from the inverted position) in which the airplane can gain excessive speed, exceed G limits, and lose thousands of feet in altitude—all at the same time. Only by reducing engine power to idle (or near idle) during a split-S entered from a botched roll can an instructor prevent potentially catastrophic airframe and/or engine damage.

Make sure aerobatic students thoroughly understand the perils of the split-S as well as the absolute necessity for raising the nose, unloading, and using full aileron deflection before performing their first rolls.

Also, make sure they practice rolling both left and right. (Most pilots have a built-in predisposition—like being right- or left-handed—and, if given the choice, will always roll in that direction.)

Once they start rolling, even formerly reluctant aerobatic students tend to become wildly enthusiastic—and the hardest part is getting them (eventually) to stop.

Email dave.hirschman@aopa.org.

Jay scenario
How would you fly this flight? This scenario is available on the AOPA Jay from Redbird.