Technology
Over twenty years ago, FP-propeller pioneered the in-flight variable-pitch hub for ultralight aircraft. Machined using state-of-the-art CNC technology, our hub components guarantee maximum mechanical precision and smooth pitch motion. Today, we offer various two- and three-blade hub models, designed to pair perfectly with blades of all sizes.
Electrically driven Hub
Blade pitch variation is achieved via an electric servo-motor, designed in-house and manufactured exclusively for FP-Propeller.
The key features of our servo-motor include:
- Guaranteed and tested functionality at propeller speeds up to 3,000 RPM
- All-metal epicyclic gearbox.
- High durability (over 2,000 hours of operation within a -30°C +50°C temperature range)
- Absolute operational reliability.
The FP-Propeller electric hub is designed to achieve a pitch variation speed of 3.5°/sec. This specific value was chosen because it represents the maximum pitch variation rate that can be comfortably and safely controlled manually.
Main Features:
- safety factor higher than 10
- mechanism motion over bearings, in order to eliminate wear and tear
- pitch range limits, upper and lower, adjustable
- safety block for the lower pitch limit, in order to prevent in any case the “reverse”
- manual tuning of the blade pitch in the case of electrical breakdown
- TBO of 2.000 hours
- Power supply: 12VDC or 24VDC
Hydraulically driven Hub
The electric motor in the hub has been replaced by a hydraulic piston, developed specifically for pilots who prefer this configuration.
In particular, our custom-engineered hydraulic piston ensures zero oil leakage across all sealing components. Propeller pitch control can be managed via a hydraulic constant-speed governor (e.g., Jihostroj).
Main Features:
- safety factor higher than 10
- mechanism motion over bearings, in order to eliminate wear and tear
- high speed in the blade pitch variation
- pitch range limits: lower, adjustable
- TBO of 2.000 hours
Blade anchorage technology
At FP-Propeller Srl, we design and manufacture a comprehensive range of in-flight variable-pitch propellers. Our goal is simple: to provide every pilot with the perfect propeller tailored to their aircraft’s specific needs.
Engineered for longevity, our hubs feature a TBO of 2,000 hours. Given the high-precision mechanics required for variable-pitch systems, the blade shank is designed to rotate with absolute rigidity and precision along its axis, a smooth motion guaranteed by premium ball and roller bearings.
Our hubs can be paired with two types of blades:
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-Proprietary FP-Propeller blades, featuring a metal shank securely bonded and embedded into the blade root.
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-Blades from world-leading brands such as Sensenich, Warp Drive, Whirl Wind, and Catto.
Benefits
Blades from other manufacturers often feature a composite root, which is unsuitable for precise anchoring within a variable-pitch hub. We solve this problem by structurally bonding the composite blade root into a custom metal shank, which serves as the secure anchoring interface between the blade and the hub.
This metal shank is then secured to the hub via roller bearings, allowing it to rotate freely along the blade’s pitch axis. The anchoring technology used to join the blade to its metallic shank is of paramount importance for both the safe operation and the overall lifespan of the propeller.
During assembly, the blade is perfectly aligned with the axis of the metal sleeve using a high-precision fixture, and then permanently bonded. This bonding process is achieved via resin injection into the tight tolerances between the blade root and the metallic sleeve.
Developed through extensive experimental research, this specialized bonding technique was tested and validated in cooperation with the Department of Industrial Engineering at the University of Bologna.
As a result, the blade and the metal shank become a single, monolithic body, ensuring zero relative movement between the components in any direction.
This advanced anchoring technique delivers the following key benefits:
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Unmatched Angular Precision: The angular alignment variance between individual blades is kept under 0.1 degrees and remains perfectly stable throughout the entire lifespan of the propeller.
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Vibration Elimination: Consequently, aerodynamic and mechanical vibrations caused by blade pitch discrepancies are completely eliminated.
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Plug-and-Play Installation: The blades are incredibly easy to mount into the hub, completely removing the need for tedious (and often inaccurate) manual adjustments by the installer.
Competitor Comparison
By comparison, some competitors anchor the blade within the metal shank without securing it permanently. While this approach offers the perceived advantage of being able to disassemble the components, this simplified solution presents a major drawback: the propeller blades must be periodically realigned.
Standard mechanical clamping is simply unable to inhibit the continuous, imperceptible rotation of the blade within its root, which is driven by the inevitable vibrations of aircraft operation. Typically, correcting this blade misalignment requires a complete overhaul, resulting in unavoidable downtime and costs.
Our philosophy is to provide pilots with a propeller built for long-term reliability and durability, paired with minimal maintenance costs. Of course, while our design minimizes wear, regular inspections and standard maintenance remain the safest way to fly.