The project INARAS (Intregal Automated Riblets Application System) aimed to find out an automatic and cost-effective way to paint riblets on an aircraft surface.
The research and development to carry out in this project developed, integrated and tested an Integral System to be used on real aircraft parts or mock-up to paint riblets. Riblets are a drag reduction technique that consists of small grooves with sharp ridges and a height in the order of about a hundred microns which are laid on the aircraft surface. This strategy had proved to be efficient in terms of skin friction reduction in areas under turbulent flow, thus a saving in fuel consumption can be achieved.
This project took advantage of previous investigations covering several aspects related to riblets performance and application techniques. Progress on riblet application techniques to date has shown the need to develop new application strategies that comply with the requirements of the aeronautical industry in terms of surface quality, application, maintenance costs and delivery rates, when successful implemented INARAS addressed all these concerns.
The INtegral Automated Riblet Application System, henceforth “INARAS”, whose development is targeted in this project, painted riblets automatically applied on a relevant part of an aircraft surface. This simplified the application process, which was included into the final painting phase, of an aircraft and reduced related times and costs. Schematically, the INARAS consisted of the following components:
- Riblet Application Head (supplied by FRAUNHOFER IFAM);
- Robotic System;
- Displacement Platform = Movement System;
- Integration Components.