Final Report Summary - MISPA (Proposal for the development of an applicator for microstructured paint coatings resulting in significant drag reduction of treated surfaces)
Executive summary:
As subject of extensive research riblet structures have been investigated in the past in terms of achievable efficiency, best geometries, materials and basic application techniques. Based on that, applicators for limited scale applications under laboratory or other controlled environments were successfully developed thus extending the usability of the riblet technology towards plane or slightly curved structures with limited sizes.
As promising technology for reduction in aircraft fuel consumption the existing limitations in the available riblet applicator designs were to be identified with a subsequent proposal of several designs for subsystems addressing each topic. With this the previously intended content of the MISPA project shifted slightly towards more basic development rather than heading straight for an all new applicator. For without the identified basic subsystems performing reliably it would be of no use to create the next generation of applicator. The three subjects identified for further development were:
(a) active guiding of the embossing belt;
(b) paint application to the embossing belt;
(c) cleaning of the embossing belt.
A system for active guiding of the embossing belt was found to be necessary as the silicone belt tended to constantly move towards one side of the rollers around which the endless belt is driven inside the applicator if left running freely. Without it only short distances could be supplied with riblets before the belt position had to be corrected manually.
Paint application to the embossing belt had already been addressed by using a slotted tube across the belt. It was found that it was not sufficiently possible with this system to control the flow and placement of paint on the belt. As a result excess paint started to contaminate the inside of the applicator with the risk of ultimately also dropping onto the surface to which a riblet structure should be applied.
Clearly the process of applying riblet structures onto the desired surface would have to be an utterly stable process before being used on actual aircrafts. However former investigations had shown that when the applicator crossed an opening in the surface the cured paint would remain stuck to the embossing belt. Without removing these residues from the embossing belt before paint was applied again the continuing riblet track would be disturbed.
For all three aspects mentioned above several possible approaches were identified, weighted against each other and ultimately the most promising one was developed into a test system. Each test system was then examined on its own.
Very promising results were obtained for each individual subsystem such that they underwent another further development in order to be incorporated into the advanced applicator. For this an existing applicator was used as basis to which the subsystems were adapted. In the end the applicator is capable of using all three subsystems simultaneously. A future test phase is thus possible.
In socioeconomic terms the work performed under the MISPA project has led to the solution of some essential impediments of using the technology of riblet application on an automated level. Based on the results obtained during the project the basis has been laid on which progress is possible that will yield a system that is capable of applying riblet structures on extended aircraft surfaces. The resulting reduction in fuel consumption is then not only a significant monetary advantage but also an appreciable factor in protecting the environment by considerably cutting down on the production and release of carbon dioxide and other chemical compounds.
Project context and objectives:
In the framework of the MISPA project an existing applicator prototype for application of riblet structured paint coatings was examined in order to identify aspects which needed further development. This development was intended to culminate in an applicator capable of being used on a robot for automatic application of riblet structures. However a number of aspects were found which were to be closely worked on and for which solutions had to be found prior to the development of an automated applicator. Therefore the focus of the project was shifted towards the investigation of and solution for the following applicator subsystems:
(a) active guiding of the embossing tool, in order to establish a constantly self-aligning embossing belt within the applicator;
(b) paint application, as the application of paint onto the embossing belt needed to be controlled in a way that the applicator itself and its immediate surroundings are kept free of contamination from excess paint;
(c) cleaning of embossing tool, as within regular application residues would be sticking to the embossing tool and no approach on ridding the tool from these residues prior to the next paint application had previously been developed.
Related to the latter subsystem an additional preliminary investigation on camera based solutions for the detection of paint residues has been carried out.
Potential impact:
As a society, strong efforts have to be undertaken in order to meet the challenge of global climate change and increased fossil energy consumption. Reaching these goals can be achieved only by a combination of lots of different approaches each optimising a singular topic. In this respect the forward momentum on the usability of the riblet application technology generated by this project can be seen as a small but important part in the larger overall subject area of aviation.
In socioeconomic terms the work performed under the MISPA project has led to the solution of some essential impediments of using the technology of riblet application on an automated level. Based on the results obtained during the project the basis has been laid on which progress is possible that will yield a system that is capable of applying riblet structures on extended aircraft surfaces. The resulting reduction in fuel consumption is then not only a significant monetary advantage but also an appreciable factor in protecting the environment by considerably cutting down on the production and release of carbon dioxide and other chemical compounds.
List of websites: http://www.optoprecision.de(si apre in una nuova finestra)
Contact details: OptoPrecision GmbH
Michael Baumgarten
Auf der Höhe 15
D-28357 Bremen
Germany
As subject of extensive research riblet structures have been investigated in the past in terms of achievable efficiency, best geometries, materials and basic application techniques. Based on that, applicators for limited scale applications under laboratory or other controlled environments were successfully developed thus extending the usability of the riblet technology towards plane or slightly curved structures with limited sizes.
As promising technology for reduction in aircraft fuel consumption the existing limitations in the available riblet applicator designs were to be identified with a subsequent proposal of several designs for subsystems addressing each topic. With this the previously intended content of the MISPA project shifted slightly towards more basic development rather than heading straight for an all new applicator. For without the identified basic subsystems performing reliably it would be of no use to create the next generation of applicator. The three subjects identified for further development were:
(a) active guiding of the embossing belt;
(b) paint application to the embossing belt;
(c) cleaning of the embossing belt.
A system for active guiding of the embossing belt was found to be necessary as the silicone belt tended to constantly move towards one side of the rollers around which the endless belt is driven inside the applicator if left running freely. Without it only short distances could be supplied with riblets before the belt position had to be corrected manually.
Paint application to the embossing belt had already been addressed by using a slotted tube across the belt. It was found that it was not sufficiently possible with this system to control the flow and placement of paint on the belt. As a result excess paint started to contaminate the inside of the applicator with the risk of ultimately also dropping onto the surface to which a riblet structure should be applied.
Clearly the process of applying riblet structures onto the desired surface would have to be an utterly stable process before being used on actual aircrafts. However former investigations had shown that when the applicator crossed an opening in the surface the cured paint would remain stuck to the embossing belt. Without removing these residues from the embossing belt before paint was applied again the continuing riblet track would be disturbed.
For all three aspects mentioned above several possible approaches were identified, weighted against each other and ultimately the most promising one was developed into a test system. Each test system was then examined on its own.
Very promising results were obtained for each individual subsystem such that they underwent another further development in order to be incorporated into the advanced applicator. For this an existing applicator was used as basis to which the subsystems were adapted. In the end the applicator is capable of using all three subsystems simultaneously. A future test phase is thus possible.
In socioeconomic terms the work performed under the MISPA project has led to the solution of some essential impediments of using the technology of riblet application on an automated level. Based on the results obtained during the project the basis has been laid on which progress is possible that will yield a system that is capable of applying riblet structures on extended aircraft surfaces. The resulting reduction in fuel consumption is then not only a significant monetary advantage but also an appreciable factor in protecting the environment by considerably cutting down on the production and release of carbon dioxide and other chemical compounds.
Project context and objectives:
In the framework of the MISPA project an existing applicator prototype for application of riblet structured paint coatings was examined in order to identify aspects which needed further development. This development was intended to culminate in an applicator capable of being used on a robot for automatic application of riblet structures. However a number of aspects were found which were to be closely worked on and for which solutions had to be found prior to the development of an automated applicator. Therefore the focus of the project was shifted towards the investigation of and solution for the following applicator subsystems:
(a) active guiding of the embossing tool, in order to establish a constantly self-aligning embossing belt within the applicator;
(b) paint application, as the application of paint onto the embossing belt needed to be controlled in a way that the applicator itself and its immediate surroundings are kept free of contamination from excess paint;
(c) cleaning of embossing tool, as within regular application residues would be sticking to the embossing tool and no approach on ridding the tool from these residues prior to the next paint application had previously been developed.
Related to the latter subsystem an additional preliminary investigation on camera based solutions for the detection of paint residues has been carried out.
Potential impact:
As a society, strong efforts have to be undertaken in order to meet the challenge of global climate change and increased fossil energy consumption. Reaching these goals can be achieved only by a combination of lots of different approaches each optimising a singular topic. In this respect the forward momentum on the usability of the riblet application technology generated by this project can be seen as a small but important part in the larger overall subject area of aviation.
In socioeconomic terms the work performed under the MISPA project has led to the solution of some essential impediments of using the technology of riblet application on an automated level. Based on the results obtained during the project the basis has been laid on which progress is possible that will yield a system that is capable of applying riblet structures on extended aircraft surfaces. The resulting reduction in fuel consumption is then not only a significant monetary advantage but also an appreciable factor in protecting the environment by considerably cutting down on the production and release of carbon dioxide and other chemical compounds.
List of websites: http://www.optoprecision.de(si apre in una nuova finestra)
Contact details: OptoPrecision GmbH
Michael Baumgarten
Auf der Höhe 15
D-28357 Bremen
Germany