Browse Topic: Hybrid engines
Hydrogen-electric vertical takeoff and landing (H2eVTOL) (or fuel cell-electric VTOL) aircraft technologies are poised to emerge in the next coming decades and start operating from existing heliports and new vertiports. This paper assesses how key H2eVTOL design features interact with the ground infrastructure and how facility designers can address H2eVTOL specific facility requirements–especially the supply of hydrogen to the aircraft. Vertiport design should maximize compatibility are important to facilitate the accommodation of hydrogen technologies, minimize the need for extensive capital investments, and promote safety and operational efficiency. Considerations should be given to factors such as general aircraft configuration, electric and hybrid propulsion systems, and refueling infrastructure. The definition of notional aircraft concepts representing the evolution of critical VTOL aircraft over the next coming decades can help aviation facility planners and designers understand
In this paper, a comprehensive dynamic simulation of a parallel hybrid gas-electric single main rotor helicopter involving a motor/generator (MG) pair and a differential planetary gear transmission (PGT) arrangement forming an electronic continuously variable transmission (E-CVT) was performed. This notional hybrid electric helicopter was sized based on a retrofit of a dual engine, 10000 lb, 2500 Hp class helicopter. The total weight added by the electric components was 182 lbs which increased the propulsion system weight from 1184 to 1366 lbs. The simulation results found that at 110 kts cruise, the hybrid electric system enabled a 27% reduction in main rotor rpm which resulted in an 18% reduction in the fuel burn rate. It is concluded that use of an E-CVT parallel hybrid propulsion system offers potential for increased flight range and reduced fuel consumption in medium to large-scale helicopter applications.
Aircraft development efforts are rapidly shifting toward the use of distributed electric propulsion. As the industry moves along a path to full electrification, hybrid propulsion systems will be increasingly employed where battery technology does not support a fully electric design. The fuel systems in new aircraft designs can be challenging, and the existing regulatory framework may not be capable of dealing with unique aircraft designs that do not neatly fit within existing categories. This presents a challenge to aircraft designers. Fuel remains essential to the propulsion system, and an optimal, yet simple fuel system will be necessary to leave room in the design trade space for more challenging and risky functions. Understanding the certification requirements and having a basic knowledge of the tradeoffs in fuel measurement accuracy are the key elements necessary to support a systems approach to optimizing a fuel measurement subsystem.
High-fidelity computational fluid dynamics simulations of NASA's Side-by-side air taxi concept have been carried out. The three-dimensional unsteady Navier-Stokes equations are solved on overset grids using high-order accurate schemes, dual-time stepping, and a hybrid turbulence model. The flow solver has been loosely coupled with a heli- copter comprehensive analysis code in order to get the trimmed flight solution. The vehicle simulated is a six-passenger side-by-side intermeshing rotor helicopter with hybrid propulsion for air taxi operations, also known as urban air mo- bility applications. This concept vehicle is intended to focus and guide NASA research activities in support of aircraft development for emerging aviation markets, in particular vertical take-off and landing air taxi operations.
The document provides clarity related to multiple temperature coolant circuits used in on- and off-highway, gasoline, and light- to heavy-duty diesel engine cooling systems. Out of scope are the terms and definitions of thermal flow control valves used in either low- or high-temperature coolant circuits. This subject is covered in SAE J3142.
ABSTRACT With the progress of electric power generation systems (hybrid propulsion or all-electric), it becomes now possible to make fly new electric Vertical Take-Off and Landing (eVTOL) concepts of aircraft. This step forward is a technology rupture which should allow breaking through the locks preventing from using more the VTOL aircraft. Indeed, the use of rotorcraft, especially in areas with high population density, is still limited by the public acceptance mainly because of the noise and the risk of crash in case of failure. A new design paradigm is emerging pushing to use distributed electric lift/ propulsion systems composed of rotary wings (propeller or rotor blades) and electric motors combined or not with fixed wings. Numerical models and methods are needed for exploring this new design space. This paper presents the extension of the CREATION numerical workshop and associated simulation tools in order to be able to deal with the predesign of eVTOL. A methodology for the
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