STO-Activities: (no title)
Activity title:
Integration, Evaluation and Flight Testing of Hybrid Electric Propulsion Technologies for Unmanned Aerial Systems
Activity Reference:
AVT-SP-012
Panel:
AVT
Security Classification:
NATO UNCLASSIFIED
Status:
Active
Activity type:
SP
Start date:
2024-01-01T00:00:00Z
Actual End date:
2026-12-31T00:00:00Z
Keywords:
green energy, Hybridelectric propulsion, unmanned aerial vehicles
Background:
The Integration and Evaluation of Hybrid Electric Propulsion Systems for Unmanned Aerial Systems project represents an exciting collaboration that unites expertise from both the Canadian UVIC Centre for Aerospace Research and the Polish Lukasiewicz Institute of Aviation. This joint endeavour builds upon the significant strides achieved through previous NATO collaborative research projects exploring the application of HEPS in various experimental configurations.
In the series HEPS configuration, the propeller is only driven by the electric motor. Mechanical power is produced by the internal combustion engine, being fully used to supply power to an electrical generator to supply power either directly to the electric motor or stored in the batteries through a charging process.
In a parallel HEPS configuration, the internal combustion engine and the electric motor are mechanically coupled to the output shaft; the electric motor and combustion engine can both contribute torque to the output shaft through mechanical coupling.
From their collaborative efforts UVIC CFAR and ILOT have conducted detailed bench-testing and performance characterization of their custom designed series and parallel configuration HEPS apparatus in the 2021-2023 NATO collaboration. (SP-009) The next phases of research to explore include taking learnings from the smaller-scale systems and explore performance of larger-scale HEPS, aircraft performance modelling and optimization, as well as bridging the divide between laboratory setups and the real-world flight testing on unmanned aerial vehicles.
HEPS research is being conducted by academic and industry groups globally, with early notable contributions from Harmon in 2005. The group proposed a conceptual design and sizing of a hybrid UAV with 13.6kg MTOW, a wingspan of 4.65m and a 220Wh battery. Simulations showed that a 3- hour ISR mission would consume 54% less energy compared to a gasoline powered UAV. In 2017, Top Flight Technologies launched the Airborg H8 10K, a quadcopter vehicle equipped with a series HEPS for use in inspection and surveillance missions or in agriculture. This vehicle has a flight time of more than 2 hours with a 4 kg payload, or more than 1 hour with a 10 kg maximum payload .
More recently, larger scale vehicle applications have begun conceptual testing with hybrid electric VTOL vehicle for urban air mobility. Moog SureFly, has been presented by the Workhorse Group with their first flight test took in 2018. However, it should be noted that this parallel architecture equipped with 8 electric motors and a 150kW combustion engine only flew for 10 seconds. In June 2019, the Ampaire 337 aircraft, a hybrid modification of the Cessna 337 Skymaster, conducted its first flight. Ampaire’s design has the ICE and the electric motor decoupled so the combustion engine cannot charge the batteries, although the performance of the 337 is similar to the Skymaster with less overall noise and fuel consumption .
While a multitude of test bench designs have emerged within the automotive sector, only a limited number of flight test prototypes for aeronautical hybrid propulsion systems have been introduced. The challenge confronting aircraft-based HEPS is primarily attributed to the considerable weight penalty imposed by battery systems in contrast to hydrocarbon fuels. Li-ion battery technology, in particular, lags considerably behind other fuel types in terms of specific energy and energy density, while being restricted in terms of both over-charging and over-discharging, thereby limiting its effective energy utilization range. Notably, Airbus has reported instances of thermal management and electromagnetic interference issues .
* See "Conclusions" for the follow up on "Background"
Objectives:
The core objectives of this project are to evaluate the performance of HEPS on small flight test demonstrators and compare with data collected from larger scale laboratory setups. Secondly, the objective is to assess the challenges and obstacles that may hinder larger-scale adoption of these technologies on commercial and passenger aviation aircraft. Many potential advantages exist over conventional propulsion systems for HEPS, and thus the project also has objectives to explore feasibility of increased endurance, increased system robustness, thermal and acoustic noise reduction, and novel configurations such as distributed propulsion.
Topics:
Modelling and aircraft performance scaling: Thorough and meticulous examination of the data acquired from the HEPS test benches is imperative to gain understanding of the impacts from design parameters inherent in hybrid-electric propulsion systems (HEPS), particularly concerning the crucial aspect of system scalability. The resultant models, meticulously crafted through this analysis, will assume a multifaceted role encompassing more than propulsion performance evaluation.
These models will find application in the realm of flight vehicle dynamics simulation, contributing significantly to the intricacies of optimizing and fine-tuning autopilot systems. This intricate synergy, ultimately contributing to augmented flight performance, underscores the far-reaching significance of this analytical process.
Larger scale test apparatus: Significant advancements can be achieved in enhancing the comprehension of Hybrid Electric Propulsion Systems (HEPS) performance through the exploration of more expansive and more powerful components during bench testing. Notably, within the laboratory facilities at both ILOT and UVIC CFAR, five different testing apparatuses are available spanning diverse configurations and scales. This collaborative effort bestows upon the project a distinct advantage as it harnesses resources from multiple test benches of varying scales. Consequently, these collaborative findings can be amalgamated to formulate comprehensive and coherent conclusions.
The project scope will include experimental work and data collection of a variety of components including two different sized series hybrid systems at UVIC CFAR, a larger parallel test bench system with larger clutch system and a 50kW system at ILOT.
Scaled Flight Demonstrators: In order to create a holistic understanding of the challenges and opportunities of HEPS in unmanned aerial systems it is critical to explore a range of flight test vehicles. This project plans a comprehensive approach to test both series and parallel configuration HEPS on multirotor aircraft as well as a fixed wing aircraft.
The UAV's HEPS system needs sophisticated power electronics and controllers to work effectively in different modes. The power electronics are crucial for maximizing the HEPS efficiency and enabling quick shifts between modes, including regenerative braking. Furthermore, the scope of flight demonstrators will include simulated in-flight failures and reversion (such as engine restart) to better demonstrate robustness. As well, a regiment of maximum endurance experiments will be conducted to fully explore each vehicle’s operational envelope. As various architectures and configurations exist for a HEPS UAV, the project will conduct in-depth analysis of each systems design to evaluate the trade-offs.
Contact:
Open2Partners:
Title:
Created at 24/10/2023 18:00 by System Account
Last modified at 16/05/2024 12:00 by System Account
Go back to list
Home(NATO STO)