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ADDitive mAnufacturing oPTimized TAilored SEALS

Periodic Reporting for period 1 - ADDAPTTA SEALS (ADDitive mAnufacturing oPTimized TAilored SEALS)

Reporting period: 2018-10-01 to 2020-03-31

The influence of seals in the performance of the wing is very important. The flow of air through not desired paths can generate turbulence, drag or malfunction of the aerodynamic surfaces. We can find seals between most of the components of the wing (fix surface, flaps, ailerons, spoilers, pylons, etc), so its impact in the aerodynamic behavior of the aircraft is quite relevant.
Seals are usually placed in interfaces, very complex areas in which it’s quite difficult to predict the aerodynamic behavior of the airflow and the exact final geometry of the gap to be sealed. So it would be ideal to refine the design of the seals through an iterative development process, with cycles of tests and modifications, to be able to define optimized seals that fulfill their function in a stable manner. Today, most of the seals are manufactured by injection, by using very expensive molds with a long delivery time.

The main objective of the ADDAPTTA SEALS project will be to develop new concept seals for wing aerodynamic surface, with better performance than currently used and further advantages in terms of cost, time to market and maintainability of the aircraft. This will be achieved due to the benefits of additive manufacturing technologies and the usage of specific materials developed for this particular purpose.

In addition to improving the aerodynamic performance of the aircraft, the use of this technology for the manufacture of the seals provides another series of advantages, including an optimization in resources needed for manufacturing, in terms of personnel, energy needed, less need for tooling, etc. All this results in a minimization in carbon footprint.

On the other hand, the development of these new technologies helps to increase job creation around elastomeric components in additive manufacturing in Europe, one of the most promising technologies and with highest growth potential.
"The total scope of this project will cover the detailed design, manufacturing, optimization and qualification of a full set of seals adapted to the wing of FTB#2 Regional Aircraft Flight Demonstrator by Additive Manufacturing technologies.

From the beginning of the project until today (first period), of the total scope, the following phases have been completed:

1. Materials Development and Trade-Offs at the CSIC facilities
2. Design seals Trade-offs, Preliminary and Critical Design Review in ADATICA facilities
3. Coupons and Seals manufactured for tests in ADATICA facilities
4. Seals manufactured for Step-1 Functional Tests (pending testing)
5. Material Qualification tests in CSIC and APPLUS facilities
6. Endurance test definition and realization in APPLUS facilities"
After the completion of 69% of the project, we can make some conclusions regarding the results expected when the project was started.

Although the functional tests have not yet been carried out, not even in flight, the results obtained in the different laboratory tests, the most important being endurance tests, have been very positive. All the seals have performed as expected and have not been affected in any way during the tests. These laboratory results indicate, or make us think, that they are going to have the same behavior in the real plane tests, so we are optimistic in the final results of the project.
The real tests will also allow us to check the flexibility of this technology, at the moment that we find any difficulty in assembly, that implies us to make quick modifications in the design to be able to correct the model and to be able to be mounted without problems.
Currently, preparing the functional tests, we have already had the opportunity to verify the flexibility of this technology, since we have been asked for an extra seal for an area not contemplated and we have been able to design and manufacture the seal quickly. This action would not have been possible using traditional injection technology.
Until the end of the project we still have to carry out the real plane, functional and flight tests. After the functional tests and depending on the results, we have to design a new set of seals applying the necessary optimizations observed during the test.
As a last phase, the flight test will be carried out with the optimized seals.