Aerodynamic Testing of Helicopter Novel Air Intakes (ATHENAI)

The ATHENAI project belongs to the sub-project Green Rotorcraft Consortium (GRC) which is part of the Clean Sky Joint Technology Initiative (JTI). This Initiative is a Public-Private Partnership (PPP) between the European Commission and the European Aeronautical Industry. The purpose of Clean Sky is the development of new technologies which significantly improve the environmental performance of aircraft. Furthermore, a reduction of the time to market through full scale demonstrator model testing is an important aim.

GRC2  - “Drag reduction of airframe and non-lifting rotating systems”

The Green Rotorcraft Consortium sub-project 2 (GRC2) primarily aims at improving the
aerodynamic characteristics of helicopter and tiltrotor aircraft fuselages including installation effects. In this context, the investigation and optimization of engine installations and engine air intakes plays an important role to ensure and foster fuel-efficient engine operation. To cover a wide range of the future helicopter fleet weight classes from light to heavy are treated within GRC2. Numerical optimization of several configurations will be carried out using Computational Fluid Dynamics (CFD) and expected benefits of identified solutions will be assessed by means of wind tunnel tests.

ATHENAI - "Contribution to the aerodynamic design of a helicopter air intake through wind tunnel testing"

The main objective of ATHENAI is the enhancement of the aerodynamic performance of novel engine air intake concepts for helicopters by shape optimization. Comprehensive wind tunnel tests are performed on a full scale model of a helicopter fuselage section at the Institute of Aerodynamics and Fluid Mechanics of the Technische Universität München (TUM-AER). For that purpose a new wind tunnel model comprising a fuselage cowling part and all air intake components and flow passages is designed, manufactured and instrumented. It features a high degree of modularity to easily compare various air intake components. In two wind tunnel campaigns aerodynamic characteristics of three baseline air intake configurations and several design variants are analysed in detail. The design modifications concentrate on flow guiding elements like fillets, vanes, spoilers and scoops. With a five-hole pressure probing system total pressure and three component velocity fields are measured at the aerodynamic interface plane (AIP) to quantify total pressure losses and inflow distortions. Additionally, steady and unsteady surface pressures on cowling and air intake regions are recorded. The incoming flow is investigated by field measurements of mean and fluctuating velocities. Data analysis and evaluation will provide highly required guidelines for helicopter air intake design.

Methodology of Work

Three different baseline intake configurations will be selected by the GRC using CFD-methods. After the design and manufacturing of the model components, TUM-AER will perform preliminary testing of all subsystems used in the wind tunnel campaign including the multi-hole pressure probing system, the suction system to provide the engine mass flow rates and additional measuring devices. Based on the analysis of the first wind tunnel campaign, retrofit solutions will be suggested by TUM-AER to improve flow conditions at the AIP. In the second wind tunnel campaign the benefit of spoilers, inlet scoops etc. is evaluated and compared to CFD-results. 

  • Task 1: Administrative and Financial Management
  • Task 2: Design, manufacturing, instrumentation and test section integration of the wind tunnel model
  • Task 3: Model preliminary tests and functionality tests.  First wind tunnel campaign: testing of three baseline engine air intake concepts. Detailed analysis of acquired data to identify optimization potential
  • Task 4: Design, manufacturing and testing of retrofit solutions such as guide vanes, spoilers or inlet scoops aiming at optimizing the baseline configurations