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Qualified Drivetrain for Electric Flight

Periodic Reporting for period 2 - QualE-fly (Qualified Drivetrain for Electric Flight)

Reporting period: 2021-12-01 to 2023-06-30

Aviation is a significant contributor to climate change, responsible for 2% of global CO2 emissions and 3.7% within the EU. To deliver sustainable regional and global air connectivity emissions need to decrease through a mix of technical innovations, more efficient flights, and new sources of energy. Electrification of aviation is a key element to reach the aviation sectors global goals to 2050.

Electric aviation offers solutions to address these global challenges, by presenting the following advantages:
• High speed – Makes high-speed mobility accessible outside large cities by utilizing the vast stock of general aviation airports located closer to the passenger’s origin and destination. Halves door-to-door travel times. Enables transport of high value, time sensitive cargo.
• Accessible and Equitable – Electric aircraft can operate from very short runways, connecting remote populations and industries separated by geographic barriers such as fjords and mountains or without land-based infrastructure such as road or rail.
• Clean Skies – Feasible to electrify all short haul flights by 2035, making them zero direct emissions. Public health benefits of reduced pollution and noise and cleaner skies.
• Affordable – 50 to 70% lower direct operating costs benchmarked to comparable fossil fuel powered aircraft, underpinned by lower energy and maintenance costs.

Heart Aerospace’s innovation is called QualE-fly - a self-contained certifiable electric drivetrain module which is being developed according to stringent regulatory requirements. A certifiable electric drivetrain is the key to unlock the clean power and disruptive economics of the electric airliner, which has the potential to supercharge the long-atrophying regional air travel market while cutting emissions.

The EIC Accelerator Green Deal’s support of Heart’s QualE-fly proposal will mature the certifiable electric drivetrain to Technology Readiness Level TRL7. This will enable Heart to undertake an extensive flight test validation program in 2026, certify and commercialize the innovation by 2028.
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.
In terms of societal impact, the project aims to grow awareness of the climate crisis and the urgent need to decarbonize our entire economy, including aviation. We aim to raise the need for large scale introduction of both biojet and electric aircrafts to change negative public perception of air travel as people link flying to their carbon footprint and the impacts of climate change. To address this, we have communicated our results in public press as well as dedicated forums for aviation. A few examples of communication about the seriousness of the company are:
- Collaboration with AernNova as supplier for structures https://aviationweek.com/air-transport/aircraft-propulsion/aernnova-provide-airframe-hearts-electric-regional
- Orders for 200 airplanes from United and Mesa Airlines https://www.bloomberg.com/news/articles/2021-07-13/united-air-mesa-ink-deal-for-up-to-200-small-electric-planes
- Talks of Electric Aviation in general https://cleantechnica.com/2021/10/29/heart-aerospace-ceo-talks-electric-airplanes-200-plane-pre-orders-part-1/

The real innovation beyond state of the art is getting electric aviation done. This is achieved through the signing of customers (orders of 250 airplanes, with an option of 120 more) and suppliers that can deliver certified parts for the drivetrain. Specifically, signing a partner that can certify the motor, which will be proprietary for Heart Aerospace, shows that this is well on the way of becoming reality.
Full powertrain in the SEEL testbed
The integrated test facility
The motor mounted for integration and HIL testing
The cockpit used for controlling the electric drivetrain