Aernnova Composites, leader in composites R&D

This online sidebar to the 2024 article, “Plant tour: Aernnova Composites, Toledo and Illescas, Spain”, details selected achievements in the company’s long history of developing new technologies for composite aerostructures.

Clean Sky/Clean Aviation

As a founding and continuing member of the public-private Clean Sky, now Clean Aviation innovation program, Aernnova proposes new ideas and participates in the development of integrated technologies to decarbonize aviation. Such technologies include various enablers for electric propulsion, more optimized lightweight composite structures and more efficient aerostructures production, including digitalization. Highlights of Aernnova Composites’ participation in Clean Sky 2/Clean Aviation projects are described below.

OUTCOME (Jan 2016 – Dec 2023)
In the OUTCOME project, Aernnova produced two highly integrated “one-shot” composite torsion boxes with high-curvature, press-formed spars. 

One was for the full-scale winglet installed on the fixed-wing Airbus C-295 regional aircraft as a multi-technology demonstrator, and the other was for the rear fuselage of the RACER compound helicopter demonstrator.

MFFD (2017-2024)
Aernnova Composites produced thermoplastic composite parts for the multifunctional fuselage demonstrator (MFFD) including upper shell Z-stringers and the door surround structure (DSS) for the lower shell (DEWTECOMP project) — both in partnership with CETMA. Aernnova also produced the first four butt strap laminates using AFP and vacuum bag consolidation for the BUSTI project’s left hand longitudinal fuselage joint, connecting the upper and lower shells.

ARE (2017-2024)
Aernnova produced the upper shell demonstrator for the Advanced Rear End (ARE) project. The multi-flange frames used press-formed dry fiber preforms in an RTM process. This patented technology replaces traditional machined metal in these highly loaded frames as part of the ARE project’s goal to reduce weight by 20% versus the rear fuselage used in conventional single-aisle aircraft. 

HLFC-WIN (2019-2023)
Aernnova Composites use an innovative combination of metal and composite components to achieve laminar flow control in a wing leading edge for improved aerodynamics in the HLFC -WIN project,  which succeeded in reducing drag, fuel burn and emissions.

HERFUSE (Jan 2024-2027)
Aernnova will apply forward its current activities in sustainable manufacturing and digitalization within the HERA project for hybrid-electric regional aircraft, to develop a more optimized design solution for the joining of the vertical tail plane (VTP) to the fuselage in the HERFUSE project. This solution will use thermoset composites to reduce airframe weight  while meeting goals for mechanical performance and improved sustainability. Aernnova will also contribute to the final sizing and digital 3D models of the composite joint structure. Aernnova Engineering Division (AED) will design and optimize the fittings for the composite VTP to fuselage joint. Structural dimensions together with material combinations will be evaluated.

Graphene Flagship (2015-2023)

In the Graphene Flagship project, Aernnova Composites, along with partners Grupo Antolin-Ingenieria and Airbus, explored the use of graphene-modified resins.

The team looked at different graphene doping schemes in the manufacturing of composite components and produced an A350 wing leading edge. “The graphene behaved differently depending on which supplier provided the materials and how they were made,” says Sanchez.

Wing of Tomorrow (2018-2022)

Aernnova also participated in the Airbus Wing of Tomorrow (WOT) program, which aims to mature technologies for the next-generation of single-aisle aircraft. Through the FLAP project, Aernnova Composites delivered a full-scale technology demonstrator in November 2021, and through its Hamble Aerostructures acquisition in 2020, Aernnova was part of the WOT trailing edge technology developments, completed in 2022.

The 7-meter-long outboard flap demonstrator was developed and produced in collaboration with FIDAMC and the Aitiip Technology Center (Zaragoza, Spain).

The three-spar structure had no ribs but included the flap mechanism and brackets for three support stations, explains Dr. Miguel Castillo, vice president of technology development for Aernnova. “It was made using AFP dry tape preforms and an RTM process that can be automated for rate 100 [aircraft/month]. Aitiip worked with us to make a self-heated tool plus inserts to achieve the integrated structure. It uses 4.0 technology and is optimized for reduced recurring costs.”

During the development, Aernnova compared Syensqo (Heanor, U.K.) TX-1105 and Hexcel (Stamford, Conn., U.S.) Hi-Tape materials, proving they were equivalent. “We characterized both, not just mechanical properties but also how they behave in the manufacturing process,” says Castillo.  “We used Rohacell foam [Evonik, Essen, Germany] in the close-out of the trailing edge section, similar to a wind blade construction.”

What about using two-part resins? “This type of part is weight-optimized, so you must have full mechanical properties,” he explains. “This is why the mix ratio must be accurate across every millimeter of the part. In order to use 2K resins, you must not only prove this accuracy but also that you can achieve a real reduction in cycle time.”

The program began at the end of 2018. Aernnova worked with Aitiip to design and manufacture metal tooling and also completed design for assembly. “We’ve done trials with inflatables, but they weren’t as reliable as metal inserts at high rate,” says Castillo. “There are more parameters to control with inflatables.” Aernnova produced a half-size demonstrator during 2019-2020. “Key developments were using AFP with TX1105 dry tape for complex shapes and how to do material handling after layup,” he notes. “Also, integrating three stations for attachments in a rate 100-capable process was a big challenge. We produced the full-scale demonstrator next, delivering that to Bremen in December 2021.”

Aernnova used PAM-RTM software (ESI Group, Rungis, France) for flow simulation and TeamCenter software (Siemens Digital Industries Software, Plano, Texas, U.S.) to manage the product development. “We also used virtual reality to test assembly, which saves time proving out tool clash, jigs and handling versus building physical systems and doing trial and error,” says Castillo. “The jigs and tools were equipped with sensors to enhance best fit and avoid stresses at the hinge line. We performed dimensional inspection using photogrammetry which is quicker versus laser scanning and provides surface location of any irregularities. We used all soft shimming because hard shimming is a horrible process that can’t be used at rate 100.” For inspection of the closed box construction, Aernnova worked with the Center for Advanced Aerospace Technologies (CATEC, Seville, Spain), which had developed a magnet-based system for inspecting where the corners of the multiple spars connected to the skins.

Aernnova also developed a one-step drilling and countersinking process for the composite laminates stacked with dissimilar materials. Achievements included:

• Single-cycle process monitored via sensors and data analysis.
• Reduction of waste of material, energy and pollutants in the manufacturing process.
• Reduction in the number of parts to be assembled, improving lead time and thus enabling high-speed manufacturing.