Laboratory Tests of Stand-Alone Hydraulic Piezo-Valve


Flow control inside the aviation landing gear shock absorbers is nowadays performed by fixed orifices or by the half-active spring based valves located inside of the device. All of the mentioned solutions are optimized on limited, mostly to one, landing scenarios due to their non-adjustable nature (even spring based valves are treated as passive due to their lack of actual real-time controllability). The easiest way of full hydraulic fluid flow control is to mount in its way a valve, which is able to seamlessly open and close causing the flow to change in wide range. Unfortunately, most of the used solutions are too large or not fast enough to fit the shock absorber requirements. The most promising way is to design tailor-made valve based on a piezo crystal actuator, which is most suitable due to its size and speed. Such a design has been made and tested by the engineers of the Institute of Aviation in Warsaw in Landing Gear Laboratory. In this article, the author describes test campaign of the hydraulic piezo-valve. Several tests have been made in order to assess the design correctness and to determine the basic parameters of the valve. Achieved results, presented in this article, show the full functionality of the solution in laboratory tests according to the design assumptions [8].

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  • [1] Currey, N. S., Aircraft landing gear design principles and practices, Washington AIAA 1988.

  • [2] Kowalski, W., et al., State of the art in landing gear shock absorbers, Transactions of the Institute of Aviation, No. 181, 2005.

  • [3] Kowalski, W, Skorupka, Z., et al., Landing gear active shock absorption, AVT STO-170, 2011.

  • [4] Skorupka, Z., Paprzycki, I., Laboratoryjne badania podwozi lotniczych, Transport przemysłowy i maszyny robocze, Wroclaw 2014.

  • [5] 0169/53/ZTET/2017/PRG – Program prób piezozaworu do śmigłowca W-3/W-3A, Test program, ILot, Warsaw 2017.

  • [6] Certification Specifications for Large Rotorcraft, CS-29, European Aviation Safety Agency (EASA), 2008.

  • [7] Isolated Piezo-valve Preliminary Tests, Report, ILot, Warsaw 2018.

  • [8] Technical Requirements for the PZL W-3A Helicopter Adaptive Landing Gear System Design, Świdnik 2017.


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