Report

Teaser, summary, work performed and final results

Periodic Reporting for period 2 - POLITE (Powered, modular Wind-Tunnel model for low and high Reynolds tests)

Teaser

POLITE focuses on designing and building a WT-model for delivering aerodynamic data that allows to analyse the aerodynamic performance of innovative control surfaces and high-lift devices.The model built in POLITE will be used in a low-Re WT. This first test-campaign will...

Summary

POLITE focuses on designing and building a WT-model for delivering aerodynamic data that allows to analyse the aerodynamic performance of innovative control surfaces and high-lift devices.
The model built in POLITE will be used in a low-Re WT. This first test-campaign will deliver aerodynamic data of the baseline solution and already include a first iteration of innovative control devices. Following the results from this first campaign a second campaign in a high-Re WT will be performed using a second iteration of innovative devices. The wind tunnel tests are not within the scope of POLITE but the model has to be designed so that efficient testing in the chosen test facilities is ensured. Therefore, shortly summarizing, POLITE has to:
• design a WT-model that is powered and usable in both low and high-Reynolds test-campaigns
• develop solutions that increase test-efficiency
• manufacture the model
• prepare the WT-test campaign by planning the integration of the models into the WT and delivering solutions for the interfaces

POLITE will contribute to validate the feasibility of an aerodynamic improved design develop by the JTI-CS2-REG consortium. It will therefore support the development of methods to increase aerodynamic performance and efficiency, resulting in a positive ecological impact. This helps fulfilling the ACARE goals, which are fundamental for all H2020 projects and will support the competitiveness of the European aeronautic industry.
The magnitude of the expected impact can be appreciated considering the envisaged, but realistic, advantages to improve aerodynamic efficiency of small aircraft both in cruise and in High Lift Conditions. These aspects have a reasonable impact in terms of direct and indirect costs, making the aircraft of new generation a competitive product. Technical solutions here implemented, tested and validated makes them suitable and profitable for other business areas (aeronautical and non). It is therefore expected that this project will contribute to the development of European technical leadership in aircraft manufacturing and will increase competitiveness of EU companies on a worldwide market, helping in the realization of more efficient and less expensive aircraft.
The coordinator of this project is also supporting a university by giving lectures. This impact goes beyond technical benefits/ impacts and produces social benefits by transferring knowledge to next generations of engineers.

Work performed

The design activity for low-Re tests was already completed by IBK, having in charge fuselage, tail and central wing, and ARA, having in charge the outboard wing, during the first period.
The design activity for flap and flap-tab mechanisms have been almost completed by IBK. Laboratory tests demonstrated the design concept of inboard flap mechanism in CS2 configuration, while a final inboard flap in LEGACY configuration has been demonstrated and the design validated in the WT during the power-on tests in RUAG LWTE in October 2018.
The design of the inboard wing for high-Re tests is almost complete, apart from details on the interface with the fuselage (strut box region) and with the turbines.
After the development of first design concepts, and review meetings with the TM and ONERA, the internal development of the support system for high-Re tests has been judged by ARA too challenging and risky for a successful test in ONERA F1. Subcontracting the development of these subcomponents to Airbus Operations was considered as a risk mitigation measure since AO already developed a similar system for the FLA10 model. A technical and financial proposal has been sent by AO to ARA, activities are going to start in 2019.
Correction factors to account for the strut interference during WT tests have been calculated by DREAM in low-Re conditions, power-on. Data will be released after the low-Re power-on test campaign.
The WT model for low-Re power-on tests has been completely manufactured, assembled, instrumented and installed in the WT (RUAG LWTE) for the power-on WT test campaign. Unfortunately, propeller blades, designed and manufactured by ONERA under subcontract failed in the preliminary tests in RUAG LWTE in June 2018, they were sent back for repair and the test campaign was cancelled and shifted to October 2018. Unsatisfactory results from the 1P RSB measurements in October 2018 led to a further test shift. Indeed, improved hub-RSB interfaces were needed. In agreement with the TM, a new wind tunnel entry was scheduled for February 2019.
Concerning exploitable results, the developed solutions for increasing WT test productiveness have a huge exploitation potential. Indeed, the developed solutions for flap actuation are very promising and have been already demonstrated in low-Re tests.
Furthermore, the determination of strut influence corrections for powered configurations in both low and high Re conditions is playing a crucial role for the development of skills and the triggering of new business opportunities for the SMEs involved.

Final results

Beyond relevant progress with respect to the current state of art, POLITE is targeting to design and manufacture a model that is able to deliver aero-data in subsequent test-activities in two different Wind-Tunnels, one of them being a low-Re solution, one a high-Re solution. This requirement is sensible and not common especially in the case of the two WT used here (RUAG LWTE in combination with ONERA-F1). The technically ambitious part required here is that the model itself is powered and equipped with two different engines due to the existing infrastructure of the two WT. This would involve in general the design of two WT-models (at least w.r.t. to the critical components). On the contrary, POLITE will perform the design of a unique modular WT model suitable for the purpose of the present activity, by complying with requirements coming from different wind tunnels and infrastructures. This requires consolidated capabilities in wind tunnel model design associated to a consolidated experience in wind tunnel testing and engine propulsion systems.
Experimental tests on scaled complete A/C model typically use unpowered engines providing only main aerodynamic characteristics without simulating the interference between the propulsion system and both the airframe and aerodynamic surfaces. Moreover, modern computation methods are mainly based on ideal fluid theory, and are not able to fully reveal and take into account the above-mentioned effects. Experimental activities are therefore the main way to study the problems of Propellers and airframe interaction and in particular to assess the magnitude of the aerodynamic interference, to understand the aerodynamic phenomena associated with the installation, and to develop an analytical and experimental data base for numerical comparisons.
From a project point of view, the project will deliver innovative technologies suitable for WT-testing. Although wind tunnel models are sometimes tested in different WT, this option is often not available for models equipped with powered engines. POLITE therefore will enable such tests and deliver ideas how to design parts in a way to reduce the number of parts. Although of minor relevance this also increases the ecological performance. Another strong argument for this approach is the reduction of model development time, the reduction of development cycle time and a strong cost-reduction, since only one model is needed.

Website & more info

More info: https://www.ibk-innovation.de/polite.