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How to Make a Deep Stall Elevator for a Remote Control Plane

A deep stall is a flight condition that occurs when an airplane flying at low speed noses up well past its normal stall angle. When this happens, the air flowing over the airplane's wing becomes turbulent and the low pressure needed to keep the airplane in the sky dissipates. An additional complication can happen if the airplane has a high-mounted or T-tail rear stabilizer. In that case, the wake from the main wing neutralizes the tail's ability to control the pitch of the airplane. Some RC pilots may intentionally induce a deep stall and attempt to lose altitude rapidly while still landing safely.

Things You'll Need

RC airplane model
Craft knife
Epoxy glue
RC model servos

Instructions

- 1
  Move the model airplane's elevators from the top of the rudder to the rear fuselage below the rudder if the airplane's usual configuration is a T-tail. If you do this while building a kit, usually you can simply relocate the elevators and glue them in the new spot with epoxy. If further reconstruction is needed for your particular model, use the craft knife to cut pieces of balsa wood or plastic to reinforce the tail structure, especially the non-moving parts.
- 2
  Calibrate the elevator servos so the control surfaces can rise to and hold a 45-degree angle. This will be critical to holding a deep stall during landing. Also calibrate your wing flaps so they can drop to a 45-degree downward angle. That will be necessary if you want to get out of a deep stall, such as to avoid crashing.
- 3
  Lower your airplane's speed while flying, then pull the elevators into a full 45-degree climb to induce the deep stall. This will force the nose up, the tail down and the wings will lose lift. Because you repositioned the elevators on your model, they will be out of the wings' wake and you can maintain the stall.
- 4
  Control the airplane with the rudder and ailerons while it is falling, keeping the elevators in full up position. As the plane approaches the ground, extend your plane's wing flaps fully. This should cause a rapid nose-down movement, and you will need to compensate by keeping the elevators up and goosing the engine slightly as the wings regain lift. If done right, your plane should come to a quick, hard but safe landing.
- 5
  Extend your plane's wing flaps fully if you get caught in an unexpected deep stall to force the nose down. If that doesn't work and you've lost elevator control, such as if you are flying an unmodified T-tail, bank your plane with the ailerons and rev your engine. This will change the energy of the flight path and put the plane into a side slip, which hopefully will break up the wing turbulence enough to restore normal lift on the wings and rear stabilizers.

Aviation