Dedicated to the Promotion of Electric Propulsion in all types of Aeromodeling

Stick Patter by John Forester

 

Angle of Attack

 

Every wing has a slope toward the wind at which it produces no Lift. That is called the Zero

Angle of Attack (AOA). Since a plane has weight, it can fly only by using a positive AOA to generate Lift.

 

Lift and Drag

 

Remember this well. You can’t get Lift with- out producing Drag. That’s a law of science. To get more Lift by increasing the angle of attack, you have to either slow down or use more power.

 

Circles

 

Just like a bicycle on a curve, a plane has to bank into a turn. To make a gentle circle to the right, move the stick gently Right until the plane has achieved a small banking angle, less than 10 degrees. At this moment the plane will enter a right circle. Lift, being perpendicular to the wing, will be pulling the plane towards the center of the circle, and the drag of the tail will be causing the plane’s body to turn around following the circle.

If you were to continue this for a full circle, you would see that the plane had lost altitude. To circle while maintaining altitude, you need more Lift, which means Pull, a little bit, on the right stick. For many primary planes, you Pull the stick about 1/4 of the distance you moved it Right (or Left, for a left circle).

 

Lazy Eights

 

This is a useful exercise for any student. Make a full circle, say right, followed by a full circle in the opposite direction, left. Each circle must maintain altitude, and be without bounce or drop as you switch from one circle to the opposite cir- cle. This trains your coordination of Right or Left with Pull and then Push, so the plane moves smoothly.

 

Stalling

 

Until now, you have been making gentle movements, climbing or turning, relying on the safety reserve of speed and power that you have when flying at cruising speed. If you needed much more lift, you might Pull much more, thus increas- ing the AOA to get more Lift. That’s fine for a bit, but when the wing gets to an AOA of about 18 degrees to its movement through the air, the air flow around it just tumbles into turbulence and Lift disappears. Then there’s no Lift to hold the plane up, and it falls. This is called Stalling. Unpleasant at any time, and very dangerous when near the ground.

While stalling is affected by load carried and speed of flight, the only thing that causes stalling is pointing the wing to too far up, which is done by Pulling the stick excessively when trying to get more Lift.

Remember this well. The way to end a stall is to Push the stick somewhat forward. That decreases the AOA until the wing gets a grip again on the air and the plane becomes controlla- ble.

 

More Vigorous Movements

 

You are now ready to make more vigorous turns, turns with smaller radius. That means more bank angle (stick more to the side) and more Pull. Since Pull increases Lift, and increased Lift increases Drag, you need more Power to counter that increased Drag.

You need more Lift for two reasons. With increased Bank, Lift is no longer pointing away from Weight, gravity, so it has to be stronger to keep the plane in the air. To turn the plane quicker and sharper requires still more Lift to pull it around quicker. When the plane is banked 45 degrees in a turn you need about twice as much power as for slowest level flight.

Therefore, before beginning practice in vigor- ous turns, increase Power, so you have excess Power available during the critical parts of the turn. Then practice Lazy Eights at higher and higher angles of bank until the plane feels uncer- tain. This depends on the Power you have avail- able, and the general design of the plane.

aerobatic and fighter planes can stand higher angles of bank than can general aviation and trainer planes.

If you get into a stall, with the plane getting uncontrollable and falling, then Push somewhat, reducing the AOA, until the wings get a new grip on the air and the plane becomes controllable. You are likely then to have the nose down with still a lot of bank. First level the wings by sideways movement of the stick, then Pull until the plane is level again.

 

Loops

 

If your plane has sufficient Power to make loops, here’s how you do it. Start level flight with wings level. Go to full Power. Wait for speed to increase. Then Pull. The plane will make a loop. When it comes back to level, center the stick to level out and return to cruise Power. You should recognize that all around the loop, Lift is pulling the plane toward the center of the loop, just as in a turn it pulls the plane toward the center of the turn.

 

Turns at Low Speed and Altitude

 

Landing approaches are the most dangerous part of flying. You are flying slowly, using little Power or just gliding in. On the typical circuit you must make two 90 degree turns: Downwind leg to base leg, base leg to landing strip. Flying slowly you have very little reserve Speed or Power. That means that these turns must be made gently. If a turn is made too sharply, with little reserve speed or power, the plane will stall, and you don’t have sufficient height above the ground to recover.

On landing approach turns, limit banking and Pull to gentle levels because of the danger of stall- ing the plane at low speed and altitude.