Hydraulic MT-Propellers
Hydraulic constant speed propeller installations are certified as 2, 3, 4, 5, 6, and 7-blade models for engines producing up to 5000 hp, that have an hydraulic oil supply to the propeller controlled by a governor. All MT hydraulic propellers are optionally available with our patented feathering and /or reverse system and can be equipped with electric or alcohol deice boots.
The single piece hub is made from forged or solid aerospace aluminum alloy. It is corrosion protected and the hub's outside can be additionally painted for sea applications. The blade bearings are special design ball bearings, where the balls act as split retainers for holding the blades into the hub, which creates an increased safety factor against blade loss. The propeller construction has a simple and light-weight design without any unnecessary part. All weights required for static propeller balancing are installed on the front spinner bulkhead.
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The blades are built with MT's natural composite design. Highly compressed, thin layered laminated beech wood, (which has a similar tensile strength as steel) is used in the root section, and selected lightweight laminated spruce wood is used in the remaining portion of the blade. The wooden core is reinforced by layers of epoxy fiberglass, Kevlar® or carbon fiber and sealed by several coatings of acrylic-polyurethane paint. The propeller system is single acting. The servo pressure necessary for changing pitch is generated by a gear pump located inside the propeller governor.
An aluminum blade ferrule is attached to the blade root by using special design patented lag screws. The pitch change of the blade is enabled by an excenter pin installed in the blade ferrule. Propellers for aerobatic aircraft are built with feathering capability and equipped with counterweights, which are installed on the blade ferrule. An unfeathering accumulator, which is directly connected to the propeller governor, is optionally available for Feathering Propellers.
The critical section of the blade's leading edge is protected by a bonded on stainless steel erosion sheath. The inboard section of the leading edge is protected by a self-adhesive PU-strip. All of the above makes the blade all weather operable. The spinner dome is a single piece part made from fiber reinforced composite (Kevlar®). It is extremely light-weight and crack resistant.
