In May, the team continued work on the main landing gear drop tests for the DarkAero 1 prototype. Several contract engineering projects were fulfilled in parallel to this drop testing, and progress across all projects accelerated with the addition of new team members that came onboard in April and May. 

Landing Gear Drop Testing
The majority of May was spent setting up the main gear drop tests and validating the test rig before proceeding to initial drops onto the landing gear. Several test-specific hardware items had to be manufactured and proven out to safely conduct the testing. 

The wing was removed from the drop test setup to protect it from potential damage, but it had to be replaced with a stub wing skin segment that replicated the contribution of the wing to the fuselage structure. This skin section is an important part of the test because it carries loads through the underside of the fuselage. The stub wing was formed by using the lower wing skin mold to sandwich a foam core between several layers of carbon fiber and infusing the laminate stack with epoxy resin. After trimming, sanding, and fitting the skin section onto the airplane, it matched perfectly with the existing geometry of the rest of the fuselage just as the wing had. 

A frame made from aluminum T-slot extrusions was bolted into both the stub wing and the wing attach lugs to create a floor that weight could be loaded onto to simulate the mass of fuel, occupants, and the original wing.

The engine was also removed for testing and replaced with a mass simulator that was constructed from concrete and steel. The mass simulator was integrated onto a CNC machined plate, allowing it to be bolted to the engine mount on the firewall.

Before drop testing the main landing gear, the right amount of shock pressure had to be dialed in. Too much pressure makes the shocks stiff, which leads to a higher likelihood of bouncing during landings, while too little pressure makes the shocks soft and allows them to bottom out on impact. Ultimately, the wrong shock pressure will result in more load transmitted into the airframe.

Achieving the right pressure involved loading weight onto the airframe and measuring the static shock deflection. As a starting point, roughly one third shock deflection was targeted at gross weight. It took a few iterations, but nitrogen was added and subtracted from the shocks to narrow in on the optimum pressure and static deflection. 

While performing this task, footage was captured of the trailing link suspension mechanism in action. It was fun to look back and see how the physical hardware matched the original animations created in the CAD realm.

After all the test rig pieces were fabricated and assembled, mini drops were performed with the airplane only a few inches off the ground to understand the basic behavior of the rig and the release mechanism. This helped build confidence in the setup before adding more mass to the airframe and progressing up to greater drop heights.

In June, drop tests will be increased to greater heights at the full target mass and a range of impact pitch angles will be explored to simulate different landing conditions. Additionally, side loading conditions will be tested as specified in FAR 23.485.

YouTube Community Membership Phase Out
Over the past several years, the YouTube community membership program has helped DarkAero grow and advance the company mission. However, DarkAero has matured as a business, allowing the YouTube community paid tiers to be phased out. A final exclusive livestream will be held for paid tier community membership on Monday, June 3rd. After phasing out the paid tiers, DarkAero content will still be shared, but under a unified public page.

All of the latest updates can be seen by clicking the “Subscribe” menu icon on the DarkAero channel page and select “All” here:

DarkAero YouTube Channel

DarkAero posts are also shared on Instagram, LinkedIn, and X. You can find the links to these platforms at the bottom of this page.

Thank you to YouTube community members for your support over the years! Community members are invited to join in on June 3rd for a livestream to discuss the latest progress on the DarkAero 1, learn more about plans for flight testing, and ask questions about the program. See you there!

Courses
The next session of the DarkAero Aerospace Mold Making Course will be held on June 13-14. This course covers an often overlooked aspect of building high-quality composite parts, which is how to make high-quality molds. This course complements the Aerospace Composites Course, but each can be taken independently. Sign up for the next session of the Aerospace Mold Making Course using the link below:

Sign up for the DarkAero Aerospace Mold Making Course!

Looking Ahead
In June, the team will continue airframe testing with the aim to conclude drop tests in the first half of the month and progress onto remaining load tests of the tail and control system structures.