TAIL DESIGN: The STOL CH 750 Super Duty tail section incorporates many features designed specifically for excellent STOL performance and control at low speeds. A good aircraft designer knows that the overall usability of a STOL airplane depends on more than just low stall speed. While many aircraft designs often boast a low stall speed, many of these same designs have minimal control effectiveness at these lower speeds. However, good control authority is absolutely necessary for a pilot to safely utilize those low speeds. Like all Heintz STOL designs, the STOL 750 Super Duty tail section is engineered to provide maximum control effectiveness at slow speeds and high angles of attack.
The Super Duty features an all-flying vertical stabilizer/rudder section. This means the rudder and vertical stabilizer are combined so there is only one big surface. The resulting large rudder area gives the pilot excellent control, especially at low speeds. The all-flying rudder gives good yaw response while also minimizing weight and complexity, since the whole vertical tail section can be built at once. Two rudder bearings bolt the rudder to the fuselage.
The horizontal tail sections, the stabilizer and elevator, are unique and developed specifically for maximum effectiveness at low speeds and high angles of attack. The stabilizer is an inverted airfoil section that maximizes downward lift to help achieve the high angles of attack at which the high lift design of the wing performs best. The elevator is designed to produce additional lift when deflected. It is hinged relatively far back, so its nose protrudes above or below the stabilizer surface when it is deflected, as shown above. The protruding airfoil-shaped nose changes the shape of the stabilizer-elevator airfoil and produces additional lift to move the tail in the direction necessary. Incorporating these features into the tail section makes the design do more aerodynamical work per square foot of area, minimizing the actual size of the tail.
The Super Duty’s large, effective control surfaces give excellent controllability at very low flying speeds – a necessity for good short take-off and landing performance – while still providing pleasant handling and relatively light control forces. Good handling characteristics are easy to overlook when evaluating an airplane’s performance information, but are a very important feature for ease of flight, and even general satisfaction with the overall flying experience (which is a large part of why recreational pilots fly in the first place). It would be difficult to find another plane with the same level of STOL performance that is as fun to fly as the CH 750 Super Duty.
(Drawings are of the CH701, similar to the Super Duty)
Click Here for a detailed schematic of the STOL CH 701’s tail sections.
Click here for optional electric elevator trim tab details.
Rudder Tail Section Assembly
Horizontal Tail Sections