In November we continued working through fuselage tasks including the installation of the cabin air ducts, the initial machining of our engine mount, and the installation of our rudder pedal mount hard points. Construction was also completed on our upgraded canopy mold, and we were able to perform an initial test form on it. In between these tasks, we investigated possible spaces for moving our operations when we transition to producing kits.

Manufacture and Installation of Cabin Air Ducts
The Polymer Engineering Center (PEC) at the University of Wisconsin-Madison has become a valuable resource for us as we have explored 3D printing some of the small components on the DarkAero 1. There are certain parts that are better suited for 3D printing rather than being CNC machined. The PEC has helped guide us on which manufacturing process to use and how to better design components that are 3D printed. Two of these parts were the ducts that will carry fresh air into the aircraft cabin. The PEC printed the prototype ducts for us using a Carbon 3D printer employing their EPX 82 resin.
We are evaluating polyamide as the duct material in production. The ducts were successfully installed and we were even able to complete a simple test to confirm their functionality.

Rudder Pedals
The rudder pedals are mounted on the bottom of the forward baggage floor. We installed the hardpoints that the rudder pedal assembly will be mounted to and purchased the required materials to fabricate the rudder pedal assembly. Our original design for the rudder pedals was constructed around an assembly of welded steel tubes, but we have devised a method to make them using carbon fiber tubes that will shave a few pounds off the original steel design. We are looking forward to completing assembly on the rudder pedals and the remainder of the control system in December.

Engine Mount Construction
Machining has begun on the engine mount for the DarkAero 1. We had an engine mount design early on that resembled a traditional welded tubular steel construction. We ultimately decided to redesign it using a machined flat plate design after we incorporated features that allowed for an integrated nose gear mounting. There are five main components to this engine mount design that are all precisely machined to final dimensions. The first part we machined out was the most complicated as it exceeded the travel limits of our CNC mill and required multiple setups. However, now that all the CNC machine tool paths and setups are finalized, it is straight forward making this same part over again. The big advantage this engine mount has over our original design is the improvement in manufacturing and repeatability of components which will simplify engine mount assembly. With the most challenging part out of the way, we will be quickly cranking out the rest of the engine mount components.

Revised Canopy Mold
Since last month, we have been in the process of constructing an upgraded version of our initial canopy mold. Our first mold was made from high temperature tooling board that was assembled in multilayer sections. This mold worked for producing the basic canopy shape but left subtle layer distortions in the canopy optics. After weeks of small scale testing, we settled on a new material composition for a revised mold that would solve the defects we ran into with the original multilayer mold. Building the new mold required that we first create a female mold using the original male mold as a pattern. We used the intermediate female mold to produce the final canopy mold. This was the most challenging mold we have ever made due to the geometry and critical dimensional requirements at high forming temperatures. We attempted a form on the new mold to get an initial assessment of the design. The results of this test gave us insight as to how we want to structure the internal heating elements of the mold. We will be installing these elements and performing a follow up test in the coming weeks.

Production Space Research
We've been building the DarkAero 1 prototype and creating the production tooling in a hangar at the Dane County Regional Airport. As we've progressed through this process, we have pushed up against the space and power limits of this shop. In the coming months we will begin production of the first DarkAero 1 kits, which will require moving into a larger space. Our operations will remain in Madison, WI, so we have been investigating a number of interesting locations around the city. Our top choices have stemmed from locations that will allow us to get up and running the fastest to begin production of kits.

Wind Tunnel Work
In November we made a visit to the wind tunnel at University of Wisconsin-Madison to test our strategy for interfacing our model with the mount in the wind tunnel. This was a good time to perform the fit check as the tunnel is currently undergoing some renovations and upgrades. We identified a few adjustments we plan to make before the tunnel is back up and running.

Looking Ahead
In the next month we're aiming to finish the installation of the control system on the DarkAero 1. We will be conducting more canopy form tests and we plan to produce a final form we can install on the aircraft. Additionally, we will finish machining the engine mount and install it.