Tandem VTOL Prototype
Tandem wing VTOL prototype
Introduced to an already started project (based on two Mini Talon airplanes), several things needed to be done.
The first prototype had flight dynamics issues to be addressed like motor and wing positions producing CG balance conflicts in vertical and horizontal flight modes. Some other hands-on tasks were done to solve structural problems.
Once fixed on that very first prototype, navigation system tweaks were done (ArduPilot) for the flight tests. All good.
Since that prototype was a bit deteriorated and had non-fixable design issues, it was time for a more mature design.
A 1940s research on a tandem wing concept was useful for a first theoretical stage. Relative wing positions were calculated from that. A small hand launched demonstrator proved with consistency the calculated effect of the front wing's downwash on the location of the neutral point of longitudinal stability. Therefore, the most aft CG location was defined for passive stabilization and motor positions could be thought for multirotor flight mode.
Rough weight and propulsion estimations were quickly done taking into account propulsion systems available and using eCalc apart from theoretical calculations. From that point, an OpenVSP model could be design for further development having in mind vertical and horizontal flight attitudes, manufacturing, structures, tilting mechanisms and practicality.
Tandem wing theoretical aerodynamic calculation.pdfAlfa prototype flight test.mp4