ELAHA - ELASTIC AIRCRAFT FOR HIGH ALTITUDES

Abstract

The group Flying Robots at the DLR Institute of Robotics and Mechatronics in Oberpfaffenhofen conducts research on solar powered high altitude aircraft. Due to the high altitude and the almost infinite mission duration, these platforms are also denoted as High Altitude Pseudo-Satellites (HAPS) or High Altitude Platforms (HAP). After the successful flight of HABLEG, which was presented at ESA PAC 2015, work continued with the goal to reach the stratosphere under own power with a reasonable sized platform. In order to achieve continuous flying, the overall goal with HAP designs is to obtain a very high battery-to-structure mass ratio. This leads to very fragile aircraft which greatly influences operational availability due to the dependence on calm weather conditions. In fact, thermals and wind have led to several catastrophic failures in the past. This overview paper proposes a new way of building high altitude platforms. The idea behind ELAHA (Elastic Aircraft for High Altitudes) is to build a segmented airplane with an extremely elastic wing, only elevators as control surfaces and appropriate control algorithms that allow it to survive in turbulent weather conditions. To date, a proof-of-concept has already been flown successfully and the construction of a larger 10m wingspan version is ongoing. This paper discusses the concept, what has already been achieved and the current status of the development.