In August we achieved several key milestones in the development of the DarkAero 1, the most significant of these being the successful positive G proof load test of the wing. We also completed our primary electrical system wiring harness, installed the pilot side control stick, and started construction on our new canopy plug.

Wing Proof Load Test
We performed our largest and most important test to date, which was the positive G proof load test of the DarkAero 1 wing. The main objective of this test was to simulate a range of expected aerodynamic flight loads on the wing and prove the wing structure could withstand them. Over the past couple of months, Ryan wrote up a thorough plan for the test and coordinated the resources required to complete the test. Beyond the planning time, it was a several day effort to set up and carry out the test. 

The wing was positioned inverted on a test fixture and sand bags were stacked at specific locations along the wingspan to apply load to the wing, mimicking aerodynamic forces. Foam sections were CNC cut to match the wing contour and positioned under the sandbags to more evenly distribute the load. A series of load conditions were simulated. Scissor jacks were positioned under the wing to safely control the full weight of the simulated load on the wing. The deflected shape of the wing under load was measured and documented at 20 locations and we also confirmed the aileron motion remained free and clear throughout the load envelope.

We tested the wing up to our proof loading condition, which it recovered from with no damage or permanent deformation in the structure itself. This was an important piece of validation for the non-traditional approach we have taken to manufacturing the wing with no main spar using our Hollow Grid design. We are extremely excited and proud of this result as it gives us further confidence in our novel manufacturing approach.

We are working through editing and releasing several new YouTube videos based on the hours of footage we collected of the test. A more formal summary of the load test results will be released after we complete the negative G proof load test. 

Primary Wiring Harness
The wiring harness that connects the primary nodes of our avionics network was constructed. We used the exterior wall of our cure oven as a workspace to construct a 1:1 scale map of the fuselage as viewed from the bottom up. It was more comfortable to construct the harness on a free face of the oven instead of having to operate inside the fuselage throughout the process. We were able to temporarily install the completed harness into the fuselage in order to perform fit checks. Next we will be moving on to installing Click Bond standoffs and P-clamps to hold the wiring in place off the walls of the fuselage and prevent abrasion under vibration. 

Custom Antenna Fabrication
One of our design goals with the DarkAero 1 has been to make it as aerodynamic and aesthetically clean as possible. This means placing all the antennas that would normally sit outside the airframe on the inside of the airframe. Given the DarkAero 1’s all carbon fiber construction, we made the canopy fairing specifically out of fiberglass in order to have an area for a number of these internal antennas to “see” out of. One of the more difficult antennas to conceal in this space is the radio communications antenna. To meet our space requirements, we will be custom making this antenna based on our own low-profile design. We will be finishing construction of this antenna as well as ground testing it next month. We have an off-the-shelf backup planned for installation in the event that this design is not viable. 

Canopy Plug Construction
In early August we made another visit to Airplane Plastics in Dayton, Ohio to finalize discussions on the new canopy plug and mold designs. During this trip, we also picked up a new shipment of tooling board to use in constructing the revised canopy plug. Starting with the 3D CAD model for the new plug design, we generated 2D plug “slices'' that could be cut from the tooling board to form the initial rough plug shape. The 2D plug slices were cut on the CNC router, and we progressed on to bonding them together to form the plug subsections that will be finished machined on the router. The final plug design is too tall to machine as a complete assembly on the router so the subsections will be assembled after each one is final machined. Once the plug is complete, we will be able to use it to construct the new canopy mold. 

Control Stick Grip Installation
Progress on the control system continued as we purchased and installed one of the control stick grips. We had some unanswered questions on the ergonomics and fit of the stick grips so we initially only purchased one to test it out. In order to interface the stick grip with the rest of the control system, a custom carbon fiber mount was constructed by hand. We were able to install the stick grip to confirm its fit and feel as well as assess the manufacturability of the carbon fiber mount. Next, we will CNC machine and manufacture final versions of the stick grip mounts from carbon fiber plate and carbon fiber tube as well as install both the pilot and copilot stick grips. 

Carter’s Projects
August was the last month of Carter’s summer internship before returning back for his senior year of high school. He kept busy over the summer with a number of projects including the fabrication of our oil dipstick door and its hinge mechanism. He completed the fireproofing of inside face of our cowling halves, made equipment upgrades, worked on the engine exhaust system, repurposed several pieces of manufacturing equipment for use in our load test fixture, and manufactured the raw stock for our main gear mount points. Outside of these projects, Carter contributed whenever needed as an extra set of hands around the shop and his help was a huge benefit to us. 

Ryan’s Projects
August was also Ryan’s last month at the shop before he enters his senior year at The University of Minnesota where he plans to graduate in the spring with a major in aerospace engineering and minor in astrophysics. Building upon the experience he gained at DarkAero last summer, this summer he was able to take on larger and more involved projects, contribute in design reviews, and gain leadership skills within the shop. He took on the role of helping transition Carter to the DarkAero intern life, and helped identify and guide projects for him along the way. Ryan’s biggest project for the summer was planning the wing proof load test as referenced above. He prepared the wing for testing, researched testing standards, and created a test procedure to follow through the testing project. One of Ryan’s original tasks this summer was to make the airplane’s prototype seat cushions. This summer he built a cockpit mockup, shaped and cut the seat foam, and upholstered the cushions. He also worked on a battery box that will mount the batteries to the firewall as well as direct cooling air around them. Some of his other projects included fuselage and cowling modifications, assisting with engine systems installation, fuel pump mount manufacturing, and both filming and speaking in the company YouTube videos.

YouTube Join Button
We recently launched our YouTube membership program for those that want to support our mission of bringing the DarkAero 1 to market. Beyond this, we also want to create a community to grow interest in engineering, manufacturing, and aerospace and enable you to accomplish your goals in these areas. Joining our YouTube membership program allows us to use our YouTube channel to share more of what we have learned while building the DarkAero 1. Those that join also get to see exclusive photos and videos, behind the scenes footage, early access to progress updates on the DarkAero 1, and live Q&A sessions. 

We already have great content currently available exclusively to members including our latest shop life video, which you can get early access to before it goes public later this week. If you are interested in becoming a member use the join link provided below:

https://www.youtube.com/darkaeroinc/join

Tablet Display Mount Installed
We received our tablet display holder by MyGoFlight and installed it into the instrument panel. This mount is infinitely adjustable and was paired with their tablet holder that can accommodate up to an 11” display, allowing us to swap out a different tablet device down the road. Having this display gives us a second display to show maps or serve as a secondary EFIS that communicates with our iLevil 3 backup ADAHRS.

DarkAero Knowledge Base Updates
We continue to add more to the DarkAero Knowledge Base. Roughly every two weeks new information is dropped in. This month we added the “Standards” section which includes a list of many of the standards we reference in building the DarkAero 1. We will continue to add more standards to this new section of the knowledge base and improve the organization of the standards currently listed. We also added the beta version of our build tool list for builders of the DarkAero 1. This excel document is meant to serve as a complete list of all the PPE and tools required to build the DarkAero 1 from start to finish. It is a dynamic tool that allows you to interact with it and “check-off” the PPE and build tools you already have and which ones still need to be purchased.

Lastly, we have added a donate button to the knowledge base. In the process of building the DarkAero 1 we have learned a lot. We have done our best to take as much of that learning and distill it down into useful tools and videos to help others with their own engineering, manufacturing, and aviation projects. If you find this information useful, please consider donating. Donating is one of the best ways to support us. All donations go directly towards helping us continue our mission and add even more great tools to the knowledge base.

Looking Ahead 
We have more exciting progress planned for the month of September! We will be finishing the installation of the fuselage wiring and building the flap controls. The canopy plug will be completed and shipped to Airplane Plastics to begin the process of manufacturing our prototype canopy. Additionally, there will be more YouTube videos released documenting the build progress of the DarkAero 1 as well videos on engineering and manufacturing.