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The Super Duty Gear Design

LANDING GEAR DESIGN: Chris Heintz has chosen over the years to equip most of his designs with tricycle gear, a decision in line with his design goal of easy, safe handling for the everyday low-time pilot, who is probably not experienced with tailwheel landing gear. The standard tricycle gear also gives excellent forward visibility while taxiing – an important consideration when operating the aircraft in off-airport environments. Despite the fact that tricycle gear is not necessarily the “standard” for a STOL aircraft, over thirty years of successful Zenith STOL flying has shown that it can certainly get the job done, as well as having some important advantages over tailwheel landing gear.

The STOL CH 750 Super Duty uses a high swept-up tail configuration to allow easy rotation of the aircraft in order to to achieve the high lift that comes with a high angle of attack during takeoffs and landings. In a tailwheel configuration this often requires a tall and awkward main gear to achieve the same high angle of attack (see illustration).

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Furthermore, the tricycle gear results in a level cabin area – this makes loading and unloading the aircraft much easier than with an inclined cabin.

In a tricycle gear configuration, the wing is at a neutral angle of attack while the aircraft is on the ground, as opposed to a maximum lift angle with a taildragger. Tailwheel airplanes are thus more susceptible to disturbance or damage by ground wind conditions while taxiing or even while parked outdoors.

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The STOL CH 750 Super Duty utilizes a heavy duty gear system developed specifically for offairport operation. The main gear consists of a simple single-piece aluminum spring leaf which is bolted to the bottom of the fuselage. The landing gear spring is not bolted on in the middle, enabling it to flex downward and absorb the force of a hard landing without damage. The main gear wheels have with independent hydraulic disk brakes activated by pilot-side toe brakes.

While it’s not the lightest gear system around, it provides excellent rough-field capability when combined with large tires, and is very durable, simple and virtually maintenance-free. Tires sufficient for normal off airport operations come standard, and the bulbous tundra tires seen on the factory demonstrator aircraft are an available option.

The nosewheel strut uses a single heavy-duty bungee for shock absorbency. The nosewheel column is linked with pushrods to the rudder pedals for direct, responsive ground handling and tight turns. Combined with differential braking of the main gear wheels, the direct linkage steerable nosewheel provides remarkably precise ground handling and steering.

FLOAT OPERATION: Zenair all-metal floats are ideal for use on the STOL CH 750 Super Duty, and are easy to attach to the aircraft. They are produced in Canada by Zenith’s sister company, Zenair, and are available as finished floats, predrilled kits, and parts kits. The floats are mounted on a monoleaf main spring just like the wheel gear, for retained shock absorption on water. Operation on both land and water is possible with amphibious floats, or simple straight (water only) floats may be used. The amphibious floats feature retractable pneumatically activated main wheels and a unique retractable steerable nose wheel.

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See the Zenair Floats page for details.