DSpace Repository

The ERF

The European Rotorcraft Forum is one of the premier events in the rotorcraft community’s calendar bringing together manufacturers, research establishments, academia, operators and regulatory agencies to discuss advances in research, development, design, manufacturing, testing and operation of rotorcraft.

The ERF International Committee is providing free access to the available papers presented at the past ERF conferences. Two years after each ERF, the conference papers are uploaded to the repository.

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ERF
European Rotorcraft Forum

Recent Submissions

Evaluation Of The Velocity Potential-Based Finite-State Model For Ground Effect Using A State-Space Free Vortex Wake Model
(2025) Metry, A.; Prasad, J. V. R.; Cannone, C.; Bugday, B.; Saetti, U.
A velocity potential-based finite state model (VPBFSM) has been developed to analyze an isolated rotor in ground effect. The model uses mass source distributions to represent the ground and imposes the non-penetration of flow boundary condition. In this study, evaluations are performed by comparing the VPBFSM inflow distribution to that predicted by a high-fidelity free wake model for both full and inclined ground effect cases. The analysis is conducted for the UH-60 rotor using geometric and aerodynamic data from the literature. The VPBFSM exhibits good agreement with the free wake model in both ground effect cases, capturing the expected trend of decreasing inflow as the rotor approaches the ground, particularly on the side closest to the surface. Some discrepancies in magnitude are observed between the models however, these remain acceptable, as they stem from the VPBFSM's reduced-order assumptions compared to the free wake model's higher geometric and wake fidelity.
Lattice Boltzmann Simulation Of Transonic Rotor Aerodynamics And Acoustics
(2025) Pisharoti, N.; Romani, G.; Casalino, D.
This paper presents the validation and assessment of rotorcraft High-Speed Impulsive (HSI) noise prediction using a high-fidelity Lattice Boltzmann / Very Large Eddy Simulation (LB/VLES) transonic solver, SIMULIA PowerFLOW®, coupled with the time-domain Ffowcs-Williams Hawkings (FW-H) solver, SIMULIA PowerACOUSTICS®. A benchmark transonic rotor case featuring high-subsonic and transonic tip speeds is used for the analysis. Flow predictions reveal the formation of localized supersonic pockets on the blade surface and the development of a shock spiral in the rotor plane. As the tip speed increases, the solver accurately captures the associated shock de-localization characteristic of transonic rotors. The resulting HSI noise-driven by these shock dynamics-is well predicted by the computational framework, demonstrating good agreement with experimental data.
Evaluation Of Vortex Ring State (Vrs) Onset And Entry Fidelity In Helicopter Flight Simulators
(2025) Sotiropoulos-Georgiopoulos, E.; Payan, A.; Johnson, C. C.; Mavris, D.
Helicopter flight simulators offer the potential to train pilots in recognizing, avoiding, and recovering from hazardous flight conditions such as Vortex Ring State (VRS). However, current FAA and EASA simulator qualification standards lack objective fidelity requirements for VRS onset representation, relying primarily on subjective assessments. Thus, this paper presents an objective evaluation method to assess how accurately different simulation models represent VRS onset. Using flight test data, from dedicated flight tests on a Robinson R66, and flight test results from the literature, fidelity criteria were established for key VRS onset aspects: collective trim position, vertical acceleration fluctuations, and sudden increases in descent rate. These criteria were used to evaluate three models: an H125 VR reduced-motion platform simulator, a FLIGHTLAB model with Peters-He inflow, and a more advanced but non-real-time FLIGHTLAB VVPM model. Results showed that while the VR simulator and VVPM model captured important VRS characteristics, they both had limitations. The Peters-He model failed to represent VRS onset cues. These findings highlight the need for improved simulation models to enhance VRS avoidance training effectiveness.
Additive Manufacturing Component Certification Strategy
(2025) Agostoni, G.; Gianneo, A.; Montagnoli, F.; Pesetti, M.; Tirelli, M.
The certification strategy for the selected component highlighted multiple challenges: firstly, the lack of international and agreed material allowables for AM Inconel 718, secondly, the usage of a known but yet to be standard technology such as AM-LPBF. Lastly, in accordance with FAA guidance, also the safety assessment of the selected component. This activity has covered a robust qualification program for both the L-PBF system involved in component production and the related Inconel 718 material. It has provided the minimum material properties required for the use of this alloy processed using the L-PBF process. This strategy included characterization of the mechanical properties of the material at high temperatures and following a thermal cycle as well as process related discontinuity. In this scenario a unique and innovative solution to powder reuse was proposed: instead of binding powder reuse to manufacturing lots, a multi-parameters powder control was developed.
Automatic Landing From Hover For Conventional Helicopters
(2025) Gadarco, T.; Capocchiano, S.; Zampini, M.; La Barbera, A.; De La Mata Chico, A.
The paper presents an advanced Flight Control System capability developed by Leonardo Helicopters, enabling automatic landing from hover. The novel function is designed to assist pilots in Degraded Visual Environment (DVE) conditions. Beginning with the operational requirements, the paper retraces the development and certification process. The automatic landing function is first described from an operational perspective, followed by a technical explanation of its state machine and control algorithms. Emphasis is placed on the innovative characteristics of the function. The flight testing methodology, particularly for demonstrating the wind envelope, is then described in detail, with major results summarized. Finally, the conclusions highlight the operational benefits of this new capability.