CEF’s Flexible Shafts usually consists of a rotating core shaft with metal end fittings for attachment to mating parts. A protective outer casing is used when necessary. This outer casing has its own ferrule fittings that keep it stationary while the flex shaft spins inside it. The flexible shaft transfers torque via a bi-directional wrapped wire system with almost unlimited connection ratios and no u-joint connections. In practice the flexible shafts should always be operated at the fastest possible speed. This lowers the torque load and increases life expectancy.
CEF Flexible Shafts are designed for rotary power transmission through, around, under, and over structural members, bulkheads and other aircraft obstructions. CEF’s Flexible Shafts are the simplest, most efficient and most economical way to meet difficult rotary motion transmission requirements. The flexible shaft is stiff and responsive in applications requiring both forward and reverse operation and acts much like a solid steel shaft but comes with many added benefits.
Typical Applications:
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Flap-Slat Actuation Systems
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Engine Thrust Reverser- Afterburner Nozzle Vane Control Systems
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Manual Pilot Controls- Landing Gear, Nose Wheel Steering, Canopy
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Aircraft Scavenger Pumps
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Variable Bleed Valves
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Capabilities/Benefits/Advantages
High Degree of Design freedom: Flexible shafts allow for limitless possibilities in the location of drive sources, whether electric/hydraulic motors or manual. This design freedom provides engineers the advantage of having only one piece to work on, eliminating complex coordination of gearboxes, chains, pulleys, universal joints and torque tubes. When designed into an aircraft, flexible shafts can reduce design time and cut unit costs dramatically. They simplify power transmission designs and applications.
Alignment and Large off-sets: Most flexible couplings only allow 5 degrees of off-set and most U-Joints only allow 30 degrees of off-set. However to accommodate this off-set declines in efficiency can reach 40%-50%. Flexible shafts however permit a full 180 degree off-set while maintaining their high efficiency. Flexible Shafts additionally have no need for the tight alignment tolerances that solid shafts require.
High efficiency: Flexible Shafts are 90 %-95% efficient. Belts, Pulleys Gears and, U-Joints, have much lower power transmission efficiencies due to greater frictional losses thus requiring larger power sources.
Power to weight ratio: Flexible Shafts can have over a 3:1 weight advantage compared to other design solutions for the same power loads. Torque tubes are stiff and heavy when compared to flex shafts, which provide a lightweight option with complete flexibility.
Better rigging and installation costs: Flexible Shafts can be often installed in minutes without special tools or skills. They eliminate the need for precise alignment and this in turn helps accommodate aircraft tolerance stack-ups.
Reduced parts cost: Bearings and housings for torque tubes and gears require precise machining operations and additional purchase, assembly, maintenance and qualification costs.
Safer to Operate: Since flexible shafts can be enclosed units they are much safer to operate in open areas compared to exposed gears, belts or spinning torque tubes.
Vibration and Torque Shock Resistant: Flexible Shafts are designed to withstand the shock of sudden load changes due to starting and stopping. They can absorb and isolate vibration. Vibrations do not affect the flexible shaft’s performance.
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