This is a good maneuver to help teach you how to perform cleanly while being aware of any corrections being needed for maximum points. As with most maneuvers, with lots of practice, you learn to correct subconsciously which is the goal for anyone wanting to be a serious aerobatic and or 3D pilot.
Enter Inverted straight and level
1 Apply about 80% power and push to an inverted 45-degree upline.
2 After a straight line segment of about 75 feet, switch rates and perform 1 1/2 negative snap roll.
3 After the snap, switch rates to low, reduce throttle and maintain straight, upright line segment (75 feet).
4 Pull up-elevator to perform 135 degree radius and establish inverted flight.
Exit Inverted straight and level
Climb to a safe altitude, roll to inverted, line up for the maneuver flying parallel to the runway and apply about 80% throttle. Push gently and establish a 45-degree inverted climb. After the radius and the climb is established, note the flight distance before the 1½ negative snap is started. You will have to fly a similarly long inverted flight segment after the snap roll. I usually count to myself and for this maneuver, a two-second segment seems about right. Flip to your Snap Mode and, all at the same time, apply down-elevator and opposite rudder and aileron. After the snap segment is complete, neutralize your inputs to establish a 45-degree upright climb. If you fly at a constant speed, then count to yourself again for two seconds. Now, pull 135 degrees to exit the top of the maneuver straight, level and inverted.
By the numbers
STEP 1: Enter the maneuver inverted and parallel to the runway. When ready, make sure that you apply at least 80% throttle and push down-elevator, ever so slightly, to perform a smooth radius and establish the 45-degree inverted climb.
STEP 2: After a line segment of about two seconds (about 75 feet in length,) flip to “mid-rate” and perform a 1½ negative snap roll. The key to performing the snap roll properly is timing and setup. If your airplane becomes too “deep” in pitch and is difficult to stop constantly on a 45-degree climb, you may need to dial the elevator rates down a touch. Also, for this segment of the maneuver, you may need to either increase or decrease the throttle to maintain constant flight speed.
STEP 3: After the snap roll, flip back to the “low-rate” setting, and perform a line segment that is equal in length to the first. Balance the throttle, as needed, so that the airplane maintains a constant flight speed and apply rudder input, if needed, to keep a constant heading. In a crosswind, you may notice the nose of the aircraft drifting into the wind. You will have to use just enough rudder to correct.
STEP 4: Exit at the top by pulling 135 degrees to establish inverted level flight. It will be necessary to hold a touch of down elevator to keep the altitude constant. You model’s CG location with affect how much down elevator is needed. Nose-heavy airplanes require more elevator input.
BY JOHN GLEZELLIS; ILLUSTRATION BY FX MODELS