ED MOORMAN'S

SNAP ROLLS

MANEUVER CARD

UPRIGHT SNAP ROLLS

Now we're getting to the real hot dog/barnstorming maneuvers, snaps. My dad's old Flight Instructor Handbook, circa 1942, defines a snap roll as a "horizontal power spin." (My old USAF Flight Instructor Handbook, circa 1964 didn't even have a snap roll in it.) We know that snaps don't have to be horizontal, they can be any direction, but they really are a power spin, that is, the controls are in the same position as for a spin.

To perform a snap roll from any position, "snap" the sticks over to the positions shown. Look below to see the stick positions for upright snap. The plane should flip around in a fast, angular looking roll. Release and the snap will stop.

LEFT UPRIGHT SNAP ROLL

RIGHT UPRIGHT SNAP ROLL

If you are trying to stay on line with a snap, like in the top of a loop, add some opposite rudder after you release the sticks to stop the snap. The loop with a snap at the top is called an avalanche, by the way.

Good crisp snaps depend a lot on light wingtips and fast servos. Build the outer wing panels as light as possible. The more the weight, the more inertia the wings will have. Inertia will slow the entry and make you over roll on the exit. Also use the fastest servo you have for the aileron servo. Trying to stop a snap roll at a certain position with a slow servo in really hard.

INVERTED OR NEGATIVE SNAP ROLL

The stick positions for the inverted snap are probably a little different than you thought. The ailerons and rudder are opposite! This is correct. The rudder reverses when the plane is inverted. If you want to verify this, put your plane upside down in a cradle like you are going to take the wing off. Turn the radio on and put in inverted snap controls. Notice how the controls work to make the plane roll in the correct direction. For left aileron, you need right rudder! The plane will actually snap in the direction of the ailerons.

LEFT INVERTED SNAP ROLL

The figures above show the left negative snap. Notice that the sticks are together at the top. Snap the sticks into this position and watch the plane tuck under. Release the controls to stop the snap. You will lose some altitude with this one if you enter it from level flight. Try it from a climb, first.  

RIGHT INVERTED SNAP ROLL

Here is the right inverted snap. The sticks are apart at the top. If you like loops with snaps at the top, try an outside loop with an inverted snap at the top. I call this a Blizzard.