Multi-Configuration Landing Gear (Triphibious)
Gevers Aircraft, Inc. * GENESIS *

Convertible in flight between wheels, skis, and amphibious hull.

In cruise with the gear retracted, the ski surfaces are flush with the hull and become the gear doors making an efficient retractable ski-plane. This makes a relatively inexpensive and easily replaced skid in the event of a gear up landing on a hard surface. The absence of gear doors simplifies the design and eliminates the gear extension speed limitation, which allows the gear to also act as a speed brake if desired. The stabilizing pontoons (outriggers) also completely retract in such a way as to fill in the area behind the step providing an aerodynamically efficient amphibian in cruise.

When landing on water, the main skis remain retracted and form the aft hull forward of the "step". Since the gear is shock mounted even when retracted, the skis and the hull step are also shock mounted. This feature absorbs water-landing impact. During water landing the outriggers are fully extended (raised) so they do not drag in the water. After landing, the outriggers can be partially retracted down into the water, which stabilizes and levels the plane for taxiing. The main gear components are made of buoyant structures which constitute sealed compartments.

For hard surface and snow landings the extremely strong tire/ski combination is extended. The ski height relative to the tire is adjustable from the cockpit (while stationary or moving). The skis are fully raised for dry surfaces, partially lowered for intermittent snow patches on hard surfaces, & fully lowered for deep snow conditions. The adjustable ski height is also beneficial to keep tall grass from wrapping around the axles and to prevent the tires from falling into holes or deep ruts. Both the nose and main gear have the same basic mechanism for extension/retraction, support, and energy absorption and are completely retractable in flight.

For those pilots operating strictly from developed land bases there is no penalty for having the added water & snow capabilities since the entire gear assembly is a simple rugged design which completely retracts into the aerodynamic hull.

Most of the weight of the aircraft is supported by the main center landing gear, which is a single assembly, (dual wheels and brakes), positioned on the centerline of the aft fuselage. The outrigger gear are freely castoring and used only to stabilize the aircraft. A main tire or wheel failure does not compromise directional control of the aircraft during takeoff or landing since they are near the centerline. The design of the strong center main landing gear placed directly beneath the engines provides two major capabilities for the aircraft.

1. Tremendous inherent strength. Most of the landing shock loads are from the engines. Since the engines are mounted in the fuselage above the main gear the engine mount support structure is attached directly to the main gear. So, the major landing loads from normal or hard landings go directly to the main gear and not through the aircraft structure.
2. A single center main gear structure allows the landing gear to be "trim steered" (not freely castoring) to match the crab angle before landing, thereby eliminating the need for a cross-controlled crosswind landing. The aircraft is landed (and taken off) level and coordinated.

Cockpit Controls:
Although the landing gear has several configurations - dry land, snow, intermittent snow/dry land, water, and retracted, the control is simple. A single multi-position lever is used to select the desired configuration. The configuration must be selected each time the gear is extended. This eliminates the complexity of having separate selectors for extend/retract and configuration. The pilot can visually check the position of all configurations by looking out the window over his shoulder and also by conventional position lights on the instrument panel. There is no maximum gear extend or retract speed so the gear can be used as speed brakes.
Both the nose and main gear are steerable. The nose wheel is steerable by using the rudder pedals and the main is steerable from a trim switch.

Advantages:

• The landing gear is reconfigurable in flight between water, snow, and hard surfaces - no modifications required.
• The amphibious hull is strong and absorbs energy during hard landings.
• The gear can be converted from wheels to skis and vice-versa while stationary or moving on both snow and dry surface.
• The skis can be partially lowered around the wheels to lift the wheels over intermittent snow patches, to keep tall grass from wrapping around the axles and to prevent the tires from falling into holes.
• The outrigger arms can be partially lowered to provide a stable water taxi configuration.
• The entire landing gear is extremely rugged and easily maintained.
• Landing shock loads from engine weight do not stress the wing or fuselage structure.
• A main tire, wheel, or brake failure does not compromise directional control of the aircraft during takeoff or landing
• The steerable center gear virtually eliminates crosswind landing limitations.
• Landing and takeoff in crosswind conditions is done with coordinated controls.