Installing the flap actuation hardware and refining the flight controls of the DarkAero 1 prototype were the primary projects for the team in November. Session 20 of the DarkAero Aerospace Composites Course was held as well.

Installation of the flap actuation hardware continued in November. A series of torque tubes, bellcranks, and linkages transmit the flap handle motion into an angular displacement in the flaps. The forces carried by the flap actuation components are high, which means the structures that support these components must be sufficiently strong and stiff to handle the loads transmitted into them. 

The area at the wing root in particular was modified and reinforced after initial testing of the flap system revealed excessive compliance in the structure. These reinforcements will also generate more stiffness in the aileron controls since the aileron torque tubes are supported by the same structure at the wing root. 

Control System Refinements
The pilot and copilot control stick travel stops were recently installed. These components provide a solid structure for the control sticks to stop against and prevent potential damage to the control system if large forces are applied to the sticks. The stops were additively manufactured from durable Nylon 12 as single piece units. Since the stick travel may change from lessons learned during flight testing, the stop was designed to be easily modified and swapped out.

Several of the aileron control system components were redesigned and rebuilt to increase stiffness in the system and produce more deflection at the aileron control surfaces. The upgraded components included a number of brackets and bellcranks that were CNC machined from carbon fiber plate and aluminum. The new components were then rebuilt into their respective assemblies and installed in the airframe. 

All of the control system refinement has been tedious and time consuming, but it is important to get right since the control system is flight critical and must operate correctly in all phases of flight. 

Aerospace Composites Course
Session 20 of the DarkAero Aerospace Composites Course was held in November. Each session brings a new group of students with unique and exciting projects, and the latest group was interested in motorsport and industrial composite applications as well as aviation composite repair methods. A new module on boron fiber reinforcement was added in the latest session, since this material is showing renewed appeal in UAVs, military aircraft, and spacecraft. Boron fiber can be added to a composite laminate to improve compressive strength beyond what can be achieved with carbon fiber alone making it an appealing option in high strength applications. The new boron fiber module was also added to the online version of the course to allow students who have already completed the course to access this new material.

Additionally, several comprehensive course guides are nearing completion and will be accessible to course students before year end. These include a Composite Drilling, Trimming, and Sanding Guide as well as a Composite Repair Guide.

The next session of the DarkAero Aerospace Composites Course will be held on January 25-26. Sign up for the course using the link below:

Sign up for the DarkAero Aerospace Composites Course!

Looking Ahead
In December, the team will continue wrapping up the remaining work installing and testing the flap actuation system and control system. The list of outstanding tasks on the DarkAero 1 prototype has been shrinking, and the team focus will soon transition purely towards ground tests, taxi tests, and ultimately flight testing.