Skip to main content

Environmentally friendly high speed aircraft

Final Report Summary - HISAC (Environmentally friendly high speed aircraft)

The objectives of the 'Environmentally friendly high speed aircraft' (HISAC) project were:
- To identify the characteristics of aircraft that could meet the prospective requirements
- To provide policy makers with a set of recommendations for future environmental regulations (several sets of commercial characteristics of the aircraft will be considered)
- To provide progress on: Elementary technologies; Associated design and optimisation multidisciplinary methods
- To identify the roadmaps for further technology maturation
- To provide general trade-offs

The project was structured into 5 work packages, which in turn included several sub-tasks:
Work package 1
The work package included the following sub-tasks:
WP 1.1: Noise criteria
WP 1.2: Atmospheric emissions criteria
WP 1.3: Sonic boom criteria
Eurocontrol, ONERA, NLR, and CIAM participated in the analysis of future noise constraints and concluded that progress in technology would seem realistic, and a new class for noise certification is likely to be created. Maximum noise level limits for depend on the aircraft weight: higher levels are allowed for heavier aircraft, with constant levels below and above some critical weights.
The correspondence between the two levels (ground level for environmental airport protection purposes, and aircraft certification level), using different metrics, needs to be verified; furthermore, a short safety margin must be added to the certification level as a technical precaution.
Regarding future local noise constraints, a review of the current local noise constraints has been performed. This overview of the practices of about one hundred airports, and their development over recent years, has been used to establish a draft typology of airports based on the effective combination of elementary actions to cope with noise.
The initial objectives were to identify future international emission standards and policies, including airport requirements, to summarise different impacts from aviation: airport, climb, cruise, descent, airport, and derive from this synthesis emissions data sets, giving an assessment of permissible emission index regulations for S4TA. This database provided by the studies enable a comparison for an assessment of influence of fleet of small high speed jets dependent on altitude and latitude.

Work package 2
The work package included the following sub-tasks:
Task 2.1: Noise modelling
Task 2.2: Emission modelling
Task 2.3 Sonic boom modelling
Task 2.4 Engine modelling
Task 2.5 Aerodynamic modelling
Task 2.6 MDO process
The objectives of WP 2 were:
- to select and validate analysis and design models, tools and methods,
- to perform focused improvements, in the fields of noise, emissions, sonic boom, engine models, aerodynamics, and multidisciplinary design optimisation (MDO). Input to this task are pre-existing modelling tools available at each partner.
Results from this WP have been used:
- for the detailed configuration assessment in WP 4,
- for the MDO process in WP 5.

Work package 3a
The work package included the following sub-tasks:
WP 3.1 - Variable cycle engine technologies
WP 3.2 - Nozzle noise reduction technologies
The work started on definition of requirements to CCV modelling tool update. It was done upon CCV cycle and performance analysis. First loop cycle analysis of CCV engine was performed on a base of pre-existing engine cycle model in WP2.4 for engine specifications coming from WP5.1.
The conclusion was made that modelling of CCV engine requires higher degree of model resolution and fidelity to be confident that engine cycle and performance are adequate. The work continued for model adjustment in respect of multi fidelity.
The analysis showed that advantages of CCV cycle with respect to performance, jet noise, dimensions and etc. over CONV cycle, that were given in WP2.4 still exist. Geometry models of variable confluence component were delivered to SENER in order to have the first preliminary mechanical considerations.
During the first phase, all partners worked on different designs based on thermodynamic data of gas generators provided by Snecma. Particularly, the aerodynamics, the acoustics, and the mechanical feasibility of each concept had been studied, in order to select one of them, following a given selection process, for acoustic WTT.

Work package 3b
The work package included the following sub-tasks:
WP 3.3 Forced laminar flow
WP 3.4 High lift devices
WP 3.5 Variable geometry wing
WP3B focused on wing airframe technologies that are critical and specific to supersonic aircrafts. The aim of WP3B was to optimise the global efficiency of the wing along the different phase of a mission by identifying technologies that are able to meet both requirements for supersonic cruise and low speed configurations (take-off, transonic flight, landing).

Work package 4
The work package included the following sub-tasks:
- Aerodynamic design and assessment
- Sonic boom design and assessment
- Acoustic design and assessment
Work package 4 (key integration issues) focus was on the "key issues" (e.g. "hard points") of the integration in the aircraft shape of the noise, boom and drag requirements: reduction of uncertainties on fuselage/nacelle/wing acoustic and aero-interactions, calibration of global models of the latter, combined local shape design for simultaneous noise/sonic boom/drag minimisation, investigation of high performance shape designs compatible with extended laminarity, and/or with very low sonic boom. Airworthiness issues have also been addressed in this WP.

Work package 5
- The work package included the following tasks:
- Technical aspects
- Description of the exchanges between wp5 and the other work packages
- Design activities
- Trade-off activities
- Synthesis task
WP5, over the span of the project, focused on the following aspects:
- Proposing rationale and coherent designs of the aircraft and its main components, meeting conflicting operational and environmental constraints and requirements
- Assessing at the aircraft level the overall gains obtained on the design through the use of advanced key technologies (engine, airframe) or key integration solutions
- Managing at the aircraft level the trade-offs between operations requirements, the environmental constraints and the global performance of the aircraft.

Related documents