During the project, several activities have been performed to mature the QualE-fly drivetrain. This includes to establish a basis for certification, to follow the systems development approach, manufacturing of prototypes and test beds:
Creation of the Development Plan and Phases: The plan outlines phases such as Concept Development, Joint Development, Concept Definition, Requirements Capture, and Requirement Review. These phases align with program milestones in the ES-30 Program Development Plan (PDP). Practically, this has resulted in the establishment of a Certification Department, engaging with EASA and successfully applying for a Design Organization Approval and creating the Design Organization Handbook (DOH).
Heart has engaged heavily with customers, to elicit commercial and operational requirements for a fleet of electric aircraft. This has resulted in market requirements on aircraft level, broken down on the electric drivetrain components and safety assessment according to ARP 4754. The system level design of the QualE-fly, includes aircraft functional development and system functional development, as well as establishing the interfaces towards other systems in the aircraft architecture
The supply chain for the QualE-fly drivetrain has been extensively analyzed through issuing Request for Information (RFIs), and Request for Proposal (RFPs) to several possible suppliers to scout the market for industrialized solutions and potential future partners (design partners, component suppliers, or manufacturing partners). The proposals are assessed and strategic partners for components of the drivetrain have been signed.
One of the major activities has been to construct the Integrated Test Facility (ITF). This iron-bird has enabled integration of the drivetrain and testing integration. The ITF is an environment created to integrate and test the QualE-fly drivetrain in terms of powertrain integration. It features a real-sized structure of the ES-30 aircraft with integrated components such as flight controls, avionics, ice protection, external lights, and the propulsion system. The ITF utilizes the flight simulator software X-Plane, which incorporates the ES-30's CAD model and flight laws. The cockpit includes Multi-Functional Displays, a joystick, throttle controls, and other necessary elements for simulating flight operations. The tests involved the integration of a CAN bus with receivers and transmitters, assessing the electrical and mechanical response of the electric propulsion system to cockpit throttle inputs and RPM. Successful verification of full integration was demonstrated through tests with two motors, Motor 4 and Motor 3, involving full flights with take-off and landing. Additionally, communication tests for Motor 2 and Motor 1 were conducted using TOGA. Data results indicate consistent communication between cockpit and powertrain, in both TOGA tests and full flight tests.
Through final system qualification at SEEL, we have achieved qualification in several aspects. The motors and inverters fulfill the temperature requirements at ground level (ISA requirements). In terms of temperature robustness, the results prove that the operating temperature for the inverter was well withing the limits and never exceeded 90 degrees Celsius, which is the target temperature for ensuring long term efficiency and safety. Through testing and acquisition of vibration data, the ground test proved that the vibration is well within the limits specific in DO-160G for all pitch angles and RPMs. The expected frequency range for this configuration due to propeller and motor mechanical vibration are between 0 and 560 Hz.
