ZupAir Zulu

The EPP Zulu can be built with or without control surfaces along the leading edge, dubbed here as “drooperons”. The drooperons can be actuated by the same servo as the elevons, making setup fairly simple. With drooperons installed, the Zulu can reach a much higher lift coefficient, ~80%, before stalling, both right-side-up and inverted. This allows for tighter turns, loops, a lower sink-rate, and slower stall speed. The drooperons are also effective at increasing roll-rate, especially at low speeds. With drooperons, the Zulu is also more stable during the deep-stall maneuver, making landings and altitude control easier. Disadvantages of installing the drooperons include higher drag from the extra control surface gap, increased build-time, and higher likelihood of breaking a servo during impact (although this is rare with metal-geared servos).