Experimental Investigation Into the Ability of Uncrewed and Air Mobility Vehicles to Autorotate

Durai raj, Vijay Mohan

Abstract

Any flying vehicle needs to be able to demonstrate a clear capability of being able to land safely in conditions of total power loss. Fixed-wing aircraft are able to glide to the ground and perform a dead-stick landing. The equivalent manoeuvre of a rotary wing aircraft is autorotation, a mandatory requirement of the airworthiness of the aircraft upon complete power loss. To date, most UAS and their larger human-carrying counterparts - AAM vehicles seem to rely on motor redundancy with parachutes to address this essential flight safety issue. Since multi-electric motor UAS and AAMs have identical motor propellor combination configurations, this paper presents the findings of the study conducted on a typical high static thrust propeller in a free-wheeling unpowered configuration in forward or lateral flight. The propeller was tested experimentally over a range of angles of the plane of rotation with respect to the global horizontal. Two significant novel conclusions were derived from the data obtained from the wind tunnel experiments. The first is that the 2 mandatory requirements of autorotation which are the direction of rotation and direction of airflow, are not satisfied simultaneously. This is significant for the class of propellors used in electric fixed-pitch UAS and AAM vehicles. The second is that any positive lift force that is generated in the flow regime is negligible despite a significant noticeable rate of rotation of the propeller.

• Presentation Conference Type: Conference Paper (published)
• Conference Name: AIAA AVIATION FORUM AND ASCEND 2024
• Start Date: Jul 29, 2024
• End Date: Aug 2, 2024
• Online Publication Date: Jul 27, 2024
• Publication Date: Jul 29, 2024
• Deposit Date: Jan 17, 2025
• Publisher: American Institute of Aeronautics and Astronautics
• Book Title: AIAA AVIATION FORUM AND ASCEND 2024
• DOI: https://doi.org/10.2514/6.2024-4343