Composite Rotor Blades Tests Essential Before Mounting on Gyroplane

Abstract

The article presents the course of the composite rotor blades tests. Object of study was designed in Institute of Aviation, new airfoil for gyroplane rotors and technology of manufacturing carbon rotor blades were made. When the test program was developed, we focused for special test to check not only typical rotor blades properties but also composite structures thereby technology of manufacturing. One of the basic rotor blades test is to determine the breaking force, which, taking into account the safety factor, cannot exceed the maximum centrifugal force occurring on the rotor blades during flight. The first step of rotor blades tests was static test, which gave us answer about stiffness in plane of low stiffness and torsional stiffness, it's very important properties related to vibrations. Another mechanical properties measured during tests were centre of gravity and mass moment of inertia in rotor blade. Next step was dynamic test-tracking and balancing verification. After static and dynamics, which has proper resultsgood balance and no vibration on the entire range of rotational speed-rotor blades can be use on fly object. After getting proper results of static and dynamic test next step was a specially prepared test, which defined the time needed for delamination to take place. During the delamination tests, the rotor blade was subjected to adequate loads that occur in horizontal flight. That kind of test is basis to determine service life of rotor blades.

Ground Test Stands for Testing Rotors in Insulated Conditions

“…5. The whirl tower system for gyroplane main rotor tests (left) and stiffened construction for testing helicopter rotors (right) [4,5].…”

A Prototype Test Stand for Testing Insolated Rotor Systems

“…5, left) specially designed and constructed for gyroplanes rotors is equipped with three-axis acceleration sensor to control the vibration of stand, four force sensors to measure thrust, reflective optical sensor, which measures the speed of the rotor. A rotor mounted on the position was powered by engine through shaft, oneway clutch, gearbox and rubber clutch protecting the rotor against temporary overload propelling torque [5]. The maximum power of the stand was 180 HP.…”

“…The distance between the blades and the ground was 3 m. 5. The whirl tower system for gyroplane main rotor tests (left) and stiffened construction for testing helicopter rotors (right) [5] Whirl tower for the needs of another project, concerning the implementation of new composite (made in prepregs technologies) rotors for light and ultra-light helicopters was modernized. During the preliminary tests, it turned out that the resonance that occurs during the test achieves dangerously high level.…”

“…The research stand, whirl tower, has been designed considering: -lack of mechanical gearbox, -vertical installation of the electric engine, -size of the Helicopter Stand (HS), so called 'Rotunda', describe in literature [5,7], -required stand mobility, -occurrence of construction resonance.…”