Report

Teaser, summary, work performed and final results

Periodic Reporting for period 1 - Wimper (Windshield with improved bird-strike, erosion, de-fogging, de-icing and IR performance)

Teaser

The ambition of the project is the developing, testing and manufacturing of a complete set of pilot windshield and lower cockpit windows for the new developed high-speed helicopter of Airbus Helicopters called RACER (Rapid And Cost-Effective Rotorcraft). The requirements for...

Summary

The ambition of the project is the developing, testing and manufacturing of a complete set of pilot windshield and lower cockpit windows for the new developed high-speed helicopter of Airbus Helicopters called RACER (Rapid And Cost-Effective Rotorcraft).
The requirements for a High Speed Helicopter (min. impact on drag & max. operational performance) and the requirements for bird-strike resistance have to be fulfilled.
The windshields will be mainly designed to have a lightweight design with superior optical quality, which withstands bird-strikes and is resistant to erosion.
Furthermore anti-fogging and anti-icing functional passive coatings will feature effective inflight requirements, which are critical safety features of modern rotorcraft.
These coatings on the inside and outside of the windshields will help increasing the performance of the designed windshield. The operation time can be increased and preparation time reduced.
Further advantage of a passive water repellent fog and ice protection is a significant reduction in air conditioning devices and therefore a reduction in weight and power consumption.
The impact on the air conditioning system can be dramatic and an estimated weight reduction of this system (incl. tubing) by up to 30%.
The power consumption of the system can be reduced, too, which has an additional impact to the engine of the helicopter performance itself.
Preparation time under icing conditions will be same as under normal conditions, because no special de-icing pre-flight activities need to be carried out.
Another main objective is the development of a fast installation and replacement technique of all the windshields resulting in a reduction of the down time of the helicopter during maintenance.
These specific objectives have to be verified by testing and simulations to enable the production of the pilot windshield and the lower cockpit windows.

Work performed

The project consists of 6 different work packages, which are strongly connected to each other.
Work Package 1 was the definition of the Technology specification. The first two month of the project did address the technology specification as scheduled. The research, the definition of the requirements and the later discussion about the specification of the windshields lead to the start of the development phase.

The development of the new windshield design (Work package 2) comprised in the first 18 months the upper windshield (base and fall-back solution), the lower cockpit windows (various attachment concepts) the assembly, the maintainability and the coating development (Anti-ice,-fog, IR). The planned designing activities are almost finished and all the results from simulation and testing tasks had been included. The windshield design will be fixed at the design freeze review (CDR).

The simulation tasks (Work package 3) started as planned in parallel to work package 2. Dynamic and impact simulations were carried out for several windshield design developments. This includes various frame and screw materials, windshield shapes, sizes, thicknesses, position and quantity of bolts, adhesive properties, thermal properties and impact requirements. Material data generated through Work package 4 – testing was integrated in the simulations.

The testing activities (Work package 4) within the first 18 months started as planned in month 7 and will be concluded early 2019 with the bird-strike test of prototypes (upper windshield). A sucessful lower cockpit window bird-strike test already lead to the acceptance of the developed lower cockpit window design. The “permit to fly” demands numerous testing and documentations, which were performed within this work package. The testing included material testing, coating testing, adhesive testing and impact testing with artificial birds.

The work package 5 - Production will mainly start after a successful criticial design review with the production of the set of windshields and test articles for mock-up.

Within the first 18 months the tasks of the project coordinator in Work package 6 – Project management included the communication towards the JU-Project Officer and the Topic manager. With this work package 6 the accurate submission of the deliverables was also successfully monitored.

Final results

Specific advances expected to result from this project include:
• Rising safety standards of crew and air traffic (better visibility in fog or icing conditions)
• Less / no iced windshield over night
• Weight impact by effective design for windshield and canopy
• No active or less active systems needed, with this, a reduction of power consumption of heating and air conditioning (power and weight)
• New testing and constitutive modelling for low temperature composites damage/failure
• Advances in strain rate modelling for ply and delamination failure of both windshield and frame
• New contributions concerning the damage/failure of hybrid composite materials under dy-namic loading conditions
• Advances in state-of-the-art for bird-strike test fragmentation modelling
• Enhancement and assessment of a simplified analytical tool for design purposes to estimate damage tolerant hybrid composite laminates
• Validation of advanced finite element methods for bird-strike simulation of transparency and composite structures
• Reduction of animal testing by substitute bird with improved reproducibility
• Marketing issue cause of outstanding better visibility
• Technology transfer possibilities to other and future helicopter models or even other vehicles with comparable requirements

Procedures and standardisation for testing and modelling:
• Currently, there are no standardised test procedures for materials strain rate testing. The partnership will publish test methods and results created and used in this project. Thereby help contribute to future development of new materials strain rate testing methods
• Similarly, there is no applied standard for testing and modelling bird-strike for windshields. Standardised procedures and numerical models for bird substitutes would be of great bene-fit to research and industry. Results will be published that this work can usefully contribute to any future standards for bird-strike testing and simulation

Website & more info

More info: https://www.dlr.de/bt/en/desktopdefault.aspx/tabid-2478/11208_read-50152.