In February, the team transitioned to the next stage of airframe structures testing, which involves validating the connection between the wing and the fuselage. In parallel, coupon tests were conducted on aramid honeycomb panel samples to validate new panel construction to be used in kit production. Additionally, a video summarizing the landing gear drop test campaign was released to YouTube. 

Airframe Testing
A number of load tests have been performed on the wing and fuselage of the DarkAero 1 prototype, but the interface between these structures has not yet been proof loaded. The wing and fuselage of the DarkAero 1 are connected by four AN6 bolts that transfer lift loads from the wing to fuselage through four structural wing attach lugs. Similar to the wing proof load tests, the wing attach lugs need to be proof loaded to ensure they can handle the full envelope of positive G, negative G, and asymmetric loads the aircraft can experience in flight. 

A test rig is being built to apply loads to the lugs and surrounding fuselage structures in a controlled manner. The rig consists of a set of frames constructed from aluminum T-slot extrusions. One of the frames bolts into all four wing attach lugs in the same way the wing does. A second frame is positioned either above or below the fuselage depending on the load configuration under evaluation. Turnbuckles running between the two frames are used to pull the two frames together, which generates reaction loads in the wing attach lugs. Load cells connected in series with the turnbuckles allow accurate measurement of the applied loads.The test loads that will be evaluated include standard positive and negative G loads, as well as pitching moments and asymmetric loads.  

The rig will also bend the wing attach lugs laterally, similar to how the wing will load them due to wing deflection under G load. A test is planned to verify the angular deflection per G of wing root ribs that interface with the wing attach lugs. 

Panel Testing
Composite sandwich panels make up a large percentage of the internal ribs and bulkheads in the airframe of the DarkAero 1. These panels are exposed to a range of loads and environmental conditions throughout the lifetime of the aircraft. As the manufacturing processes used at DarkAero to construct sandwich panels have changed and improved, continued testing and evaluation of panels is critical to verify that their mechanical properties remain in alignment with requirements. Recently, coupon testing was conducted on a series of panels to compare in-plane compressive strength between current and new experimental panels. This testing establishes a baseline dataset on the new panels to inform broader decisions and to build confidence in new panel assemblies designed to improve manufacturing efficiency in DarkAero 1 kits. 

DarkAero YouTube
A new video summarizing the landing gear drop test campaign was released on the DarkAero YouTube Channel. The video highlights test methods and landing gear design changes and also shows some hardware that broke in testing! The latest video can be viewed here:

Courses
The March 27-28 session of the DarkAero Aerospace Composites Course is now full! The next session of the course has not been scheduled yet, but in the meantime, interested students can still enroll in the online version of the course. The online version covers the in-class theoretical portion of the in-person course, and it also includes a number of guides to support hands-on manufacturing of composite components. Students who enroll in the online course and later attend an in-person session will be discounted the price of the online course from their in-person session. You can view the first few lessons of the course for free and enroll here:

DarkAero Online Aerospace Composites Course

DarkAero Careers
The team at DarkAero is continuing to grow! Interviews have been ongoing and applications for manufacturing technicians and engineers are currently being accepted. Individuals with a strong work ethic, hands-on skills, and a desire to work on challenging projects are an ideal fit at DarkAero. If you want to be part of a dedicated team designing and building new aircraft, check out the DarkAero Careers page and apply today!

DarkAero Careers

Looking Ahead
In March, the team will continue working to validate the wing attach lugs. Proof load testing of the wing attach lugs will commence once rig construction is complete and the angular deflection per G of the wing root ribs is confirmed. Expanding the team, increasing manufacturing capacity, and fulfilling contract projects will continue in parallel.