Lapyx 1

On May 14, 2023, 60 days after the Lapyx 0 flight attempt, the team headed to the airfield to attempt a launch of Lapyx 1.

Despite its structural failings, the geometry, airfoil choice and general layout of Lapyx 0 were sound. As such, L1 is also a 3m-wingspan monoprop aircraft designed to be launched and landed in the exact same way as L0. To address the key stiffness issue, the wings on this aircraft were designed around larger diameter spars. The wing skin was formed by plastic segments 3D-printed in lightweight PLA. A new motor and prop arrangement was used, and all internals were housed inside a fuselage made of nylon 12 (SLS).

Lapyx 1 was able to take off successfully and climb for several meters. However, as clearly shown through the onboard footage, it encountered wing flutter as it entered a turn. The wings shook violently, rendering the ailerons useless and creating unpredictable flight behavior. Thankfully, the pilot was able to regain control and skilfully crash-land the aircraft such that only minor damage was taken.

This aircraft represented a significant leap from L0, but a key issue remained: the wings needed to be much more torsionally stiff, not only for flight behavior but also to prevent damage to the eventual solar panels.

To solve this and a myriad of other smaller issues (weight reduction, drag reduction, surface smoothness), the team opted for a fundamental redesign of the wings for Lapyx 2.