The 2020 SAE Aero Design East competition was sponsored by Lockheed Martin, and many of the event personnel were employees of Lockheed Martin (LM). This allowed the team a unique opportunity to interact with industry professionals.
Many people were impressed and excited to see an airplane produced using additive manufacturing, and just as many people sneered at the idea. It is rather unfortunate that the crash of our airplane seemed to further enforce the negativity projected to the idea of using additive manufacturing to produce an entire RC airplane. The airplane structure we manufactured was still heavier than larger airplanes constructed from balsa wood, foam, and monokote (monokote is a stressed plastic skin used to cover the airplane structure). However, that was not the cause of the crash.
Review of the crash video shows evidence of the elevator in the neutral position despite the controller signalling maximum throw. The control surfaces were checked prior to the flight for functionality and rechecked after the crash. Examination of the elevator revealed the servos had blowback. Servo blowback is when the servo cannot hold the control surface deflection under load. Thus the elevator remained in the neutral position during takeoff attempt, resulting in the airplane being unable to change pitch and takeoff. Additionally, the airplane was observed to slightly nose heavy. The faster the airplane went, the more it dove towards the ground. A combination of improper placement of the center of gravity, alignment of incidence angles, and failure of a servo resulted in the crash.