This Drone Uses Its Propeller Guards as Wheels and Flies Only to Hop Obstacles
AeRove: A Compact Bimodal Aerial-Terrestrial Drone with Rapid Bistable Reconfiguration for Close-Range Pipeline Inspection
Image: Caleb Polillio, Petras Swissler
Usage terms
CC BY 4.0AeRove is a compact drone that turns the guards surrounding its propellers in flight into wheels after landing, allowing it to roll along pipelines. It normally travels on the pipe and takes off only when it needs to hop over an obstacle.
A spring-loaded mechanism switches between flight and ground configurations in about 200 milliseconds. The researchers report roughly 14 times lower current draw while rolling than during continuous flight, and demonstrated straight and curved traversal, obstacle hopping, and simulated leak-marker detection on a 51 cm steel pipe. It was developed by NJIT researchers Caleb Polillio and Petras Swissler.
Details: arXiv / Caleb Polillio, Petras Swissler ↗

It can fly, but most of the time it rolls along the pipe on its propeller guards. It saves the expensive flying part for the obstacles.