DarkAero, Inc

Latest video is live!

The last test on the landing gear structure completed in January was brake load testing. This test was designed to simulate the loads on the airframe during an aggressive braking operation. Simulated braking forces were generated by gradually applying loads to the gear from the base of the wheels through straps and turnbuckles, while simulated inertial loads reacting the brake loads acted through a strap around the engine mount. Load cells, connected in series with the turnbuckle, were used to provide feedback on the amount of load being applied. Throughout the course of conducting side load and brake load tests, no major issues were detected and no additional design changes were made to the airframe or landing gear. A contributing factor to the rapid progression through these tests came from landing gear and airframe modifications that were implemented previously during drop testing. Read more in our January update here: https://lnkd.in/gu7VNJ5j

After completion of the drop testing campaign in January, the team transitioned to conducting the remaining landing gear load tests to simulate the range of landing loads the DarkAero 1 might encounter. The landing gear side load test simulated lateral loads on the main landing gear, which could occur during a crosswind landing if the airplane touched down while being yawed away from the runway centerline. The test setup involved loading the airplane up to a target weight above the gross weight of the aircraft and applying a force directly sideways on both main landing gear. A strap, turnbuckle, and load cell were used to apply loads, and both main gear were placed on automotive dollies to allow them to slide freely sideways. The scope of this test was much more limited compared to drop testing, and the landing gear passed without major events. Read more in our January update here: https://lnkd.in/gu7VNJ5j

The final phase of main landing gear drop testing was completed in January. This marked the culmination of several months of work to explore the capability of the DarkAero 1 prototype landing gear structures across a range of hard landing conditions. A number of changes were made to the landing gear and airframe structures over the entire test campaign, and several major updates materialized in the final phase of testing. Three of the major updates that were made during the last phase included lengthening the main gear struts, modifying the upper shock mount, and implementing a fifth design revision of the trailing links. These changes were made to increase the amount of energy absorbed by the shocks during nose-high landings and also to allow for longer shocks to be installed to further reduce landing loads on the airframe. One of the recurring themes throughout the drop testing campaign has been the value of obtaining physical test results. With each test, the behavior and performance of the landing gear were more thoroughly characterized, allowing the team to anticipate and implement the next set of design revisions. The drop testing campaign provided a controlled approach to refining the landing gear design and ensured it met airworthiness criteria. By gradually increasing drop heights and testing across different pitch angles, it was possible to systematically evaluate performance and implement necessary design improvements. Inspections were conducted after each drop, guiding iterative changes to optimize the strength and energy absorption of the landing gear. In total, over 125 drops were performed on the DarkAero 1 prototype, leading to more than 15 significant design updates that shaped the final configuration for flight testing. A new video summarizing the entire testing campaign is in the works and will be released in the coming weeks! Read more in our January update here: https://lnkd.in/gu7VNJ5j

The next session of the DarkAero Aerospace Composites Course will be on March 27-28! Since our last session, we have added new hands-on prepreg demos as well as more in-depth information on composite repair and manufacturing composites in a scaled production environment. The course size is limited so reserve your seat now! https://lnkd.in/gc-SZY6d

In November, main landing gear modifications were implemented on the DarkAero 1 prototype to enhance performance during nose-high landing scenarios. Contract projects fulfilled through DarkAero Services continued to progress last month as well, with more airframe deliveries completed. Full post below.

The DarkAero 1 utilizes a trailing link suspension, and the behavior of this articulating landing gear arrangement varies depending on the aircraft pitch angle upon landing impact. The energy absorption in the landing gear comes from both the tire and the shock working together. The relative angles between the shock, trailing link, and ground heavily dictate how the shock and tire behave dynamically as a system. The geometry of the trailing link and shocks on the DarkAero 1 is designed to provide the best performance during hard landings with a drag load from wheel spin-up on initial impact. It was predicted that the absence of a drag load would alter the performance of the suspension, but it was left up to testing to verify the true numbers. Initial testing showed that the landing gear geometry would not provide sufficient energy absorption at a nose-high attitude with higher drop heights. To address this, a bolt-on bracket was quickly designed and temporarily installed on the gear strut to test the effectiveness of changes in shock angle. Subsequent tests with the new shock mount geometry confirmed that even small changes in geometry could significantly improve the landing gear behavior in nose-high impact conditions. Read more in our October update here: https://lnkd.in/gDpWvWNt

Each phase of drop testing the DarkAero 1 prototype has been designed to simulate different landing conditions. The first two phases both focused on level landing scenarios: in phase one, all three landing gear touched down simultaneously, while in phase two, only the main gear made contact with the ground. The third and final phase of drop testing began in October, with the airframe dropping in a nose-high attitude and only the main landing gear contacting the ground. This condition simulates flaring the airplane too high and stalling onto the runway at a high vertical descent rate. The test setup was guided by FAR 23.481. The test rig was reconfigured to position the airframe assembly in a nose-high attitude, and sand bags strapped inside the fuselage for mass simulation were adjusted to give the desired center of gravity position for the test. Testing proceeded in the same manner as earlier phases, starting with low initial drop heights and moving incrementally to higher heights. Video and accelerometer data were collected during each drop to reveal any trends and project what loads the airframe would experience at higher drop heights. The nose-high drop test is different from previous test cases in that the ground reaction load is purely vertical and does not include a drag component due to wheel spin up. This condition can occur when stalling the airplane onto the runway during a second impact after a bounced landing that already spun up the wheels. Even though it is an edge case, this scenario represents a challenging condition for the DarkAero 1 landing gear that must be explored. Read more in our October update here: https://lnkd.in/gDpWvWNt

Validating the DarkAero 1 landing gear structures has involved drop testing the airframe across a range of pitch attitudes and drop heights in three main test phases. To date, over one hundred airframe drops have been completed. While this is a large number, each drop serves a specific test objective. The landing gear behaves as a dynamic system, with tires, shocks, and airframe interacting in ways that are difficult to accurately predict in the absence of physical testing. The high volume of drops reflects both the complexity of the system and the validation required to achieve reliable performance across varied landing conditions with a new design. The drop testing campaign has led to over a dozen design improvements and refinements that were implemented in the prototype and will ultimately be carried forward into the production design. Read more in our October update here: https://lnkd.in/gDpWvWNt

Outside of our YouTube channel and social media pages, we consistently publish a monthly newsletter on work at DarkAero! Our website was recently updated to better chronicle these articles. Check it out here: https://lnkd.in/gnk8gF9X