The Vertical Flying Society (VFS) is hosting the third annual Design-Build-Vertical Flight competition. It has full-time university and college students designing and building racing VTOL UAVs to compete in the fly-off event in July 2023, in addition to writing Preliminary and Final Technical Reports and giving a design presentation. Lambach has withdrawn from the competition, however the plan is to still build and flight-test the prototype.
The competition flying course
The aircraft will be flying the course given in the figure above: vertical takeoff, 1km of flight, and vertical landing. There are four main objectives for the aircraft design:
- Maximizing the number of course laps completed in 10 minutes
- Flying a single lap in the shortest possible time
- Minimizing payload-to-weight ratio
- Flying one lap completely autonomously
Additionally the aircraft is to meet requirements set out by the competition organizers. For example it must:
- Not exceed a takeoff weight of 25kg
- Fit within a circle of 10ft diameter
- Carry a SoftGrip weight of at least 2lb
- Be powered electrically
The Lambach DBVF team, currently consisting of eight bachelor aerospace engineering students, has started the design in september of 2022. The following is a short description the design concept chosen. For updates on our progress, please see our Instagram.
The Design Concept
The aircraft not only has to be able to fly at speed for a considerable amount of time, it must also be able to transition back and forth between horizontal and vertical flight quickly. With this in mind, a biplane tailsitter layout has been chosen. Though it would be more accurate to describe the top wing as a vertical stabilizer: its main function is not to generate lift but to aid in stability and maneuverability during takeoff/landing transitions as well as during the tight turns of the flight course. On top of that it provides tip-over stability while landing and on the ground.
The aircraft will be stabilized by a Matek F765 flight controller running ArduPilot. The flight course presents a problem however: at the farthest corner the aircraft will be 400m away and the pilot will not be able to see the relatively small aircraft well. Hence the horizontal portion of the flight will be flown through a FPV video link; using a buddy system control will be transferred to a second pilot for takeoffs and landings.
The general layout of the initial design. The payload has been moved to above the fuselage for the prototype.
A combination of traditional balsawood structures and composites will be used for the structures of the aircraft to minimise weight. Though minimizing weight is not our top priority due to the scoring mechanism, for aircraft performance and maneuverability it still is important. If necessary for strength, a full glass-fiber main wing may be used instead. Another option would be simple foam wings for crash resistance and easy repairs, which could be of great value during the competition.
The prototype design.