Tri Village RC'ers
Radio Waves
May 1996
The Snap Roll
Hello, and welcome to this new series describing how to do intermediate level aerobatic maneuvers.
Before we get started, a little bit about myself. I began flying five years ago in Florida. My dad was getting into the hobby, and I was interested, so I learned how to fly. Since then, I have become a Pattern flyer and Sport pilot. I have a "Nice Try" pattern plane and a Goldberg Extra 300. I'm 15 years old. I feel that it's time to put back into this hobby what I took out, in the form of this series. I hope you find it informative and fun to read. Here we go!
You can solo and do basic aerobatic manuevers, such as loops, rolls and inverted flight. Now you are looking into more challenging stunts, such as snap rolls, spins, knife edge and point rolls. All of these will be covered in this series, plus a few that I haven't thought of yet. Let's begin with snap rolls.
A snap roll is defined as "a rapid rotation of an aircraft in a stalled attitude". In order to do a snap roll, you must first stall the airplane, then apply full aileron and rudder in the same direction. Snap rolls are done in the upper end of the plane's speed envelope, so to stall the airplane, full elevator must be quickly applied. Snap rolls can be done in four direction: up/left, up/right, down/left, and down/right. When you first start doing snap rolls, it is best to do inside snaps at pretty good altitude in case you get into trouble. Fly the airplane at full throttle, and when you're ready, quickly apply full up elevator, full left or right aileron, and full rudder in the same direction as the aileron. You must be ready to release all controls back to neutral when the airplane completes one rotation. You may be surprised at how fast this happens. It is important that when you do your first few snap rolls, you only do one rotation. Many snaps in succession will bleed off the plane's airspeed and leave you in an unusual attitude, with little airspeed.
Once you are comfortable doing inside snap rolls left and right, and can do two or three snap rolls in succession, it's time to start doing outside snap rolls. Outside snap rolls are the same as inside ones, except the rudder must be applied opposite the aileron. When you first start doing outside snaps, it's best to do them from inverted flight, because when the plane is stalled with down elevator, the nose will point up for the maneuver. Fly inverted wide open at a decent altitude. Quickly apply full down elevator, full left or right, and rudder opposite the aileron. The plane will snap in the direction of the aileron. Neutralize all controls after one rotation. Some high wing planes or low wingers with a lot of dihedral won't do an outside snap. The ideal plane is a low or shoulder wing and has a symmetrical airfoil with little or no dihedral. After you are completely confident snapping all four ways, have some fun with them. Do outside snaps from right side up, and vice-versa, or do them from a vertical line.