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More electric, advanced hydromechanics propeller control components.

Periodic Reporting for period 3 - PROPCONEL (More electric, advanced hydromechanics propeller control components.)

Reporting period: 2019-09-12 to 2020-05-11

Turboprops in the range of 1,800 to 2,000 shaft horsepower (shp) class are currently controlled by hydromechanical components. The equipment for this class of engines generally allows a maximum of two different propeller speeds, they are mechanically connected for pitch control and the oil pressure is provided by a mechanically driven oil pump.
Jihostroj designed, manufactured and tested advanced components for propeller control, namely propeller control unit and overspeed governor. These components were tested at Safran Helicopter Engines ground test facility.
- The propeller control unit is based on hydromechanical control (flyweights and beta valve), but integrates electric actuation for speed target and pitch target. It also allows synchronising.
- The overspeed governor is based on hydromechanical control, with electrical overspeed test and feathering. It is compatible with the propeller control unit.

Fuel consumption reduction, lower noise emissions and low operational costs of the aerospace turboprop engine propulsion unit and therefore of the aircraft using it are in great accordance with preferences of modern society and its demand for transport activities.
The principal objectives of the project which fullfillment was verified can be summarised in the following items:
- Development of the new advanced propeller control based on electronic components that enables introduction of a new generation of turboprop engines to the market. Current competitor´s engines are, despite several modernizations, based on design and technology of 1960-1970´s. New sophisticated engine products can significantly contribute to the competitiveness of European companies.
- Significant increase of time between overhaul (TBO) - by approximately 70% compared to currently available products. Maintenance costs reduction has also a positive impact on the environment, as compensation of the product after its life a new product can be realised only after almost double the time comparing to the original solution. Thus, energy and material sources will be saved and environmental burden connected with production of new product reduced.
- New advanced technical solutions for propeller control unit and overspeed governor improves overall functionality of the turboprop engine and contributes to better overall engine efficiency and pilot workload reduction.
The first project period was devoted to the Preliminary Design Review (PDR) and Detailed Design Review (DDR) documentation creation. Based on frozen technical specification and existing both-side confirmed architecture, Jihostroj engineers started to work on 3D modelling. 3D models of the major propeller control system technical nodes were developed. 3D design and modelling, Strength analysis and Preliminary test plan were linked to the resulting material, which was submitted to the designers and representatives of Safran Helicopter Engines within the PDR document. All previous steps were summarized in document presented to project partners from Safran Helicopter Engines in form of DDR document. The second period was focused on the production preparation, manufacture, asembly and verification the expected resultes by JSV internal tests of PCU and OSG. The FMP went in very shrtened approach through all development phases up to 80% finished work package of parts manufacture.
The results of all three periods materialized the goals set at the beginning.
Propeller blade speed, meeting the specifications of AA 146419, which has so far only been verified by internal JSV tests, combined with more electric ability to control, provides a prerequisite for more efficient instrument intervention than has previously been the case with manual control of turboprop engines.

Synchrophasing ability, meeting quite narrow requirements of AA146419, which is enabled again only by more electrical control, contributes to noise reduction objective.

Significant weight reduction is in aviation always considered a contribution to engine fuel consumption. Compared to current technology, savings of up to 50% are achieved in this characteristics.
PCU subassembly example
OSG on testing bench
OSG subassembly example
PCU manufactured part
PCU assembly
PCU concept design
OSG subassembly example
PCU on testing bench
PCU final assembly
OSG subassembly example
OSG subassembly example