Subscale Super Cub advances drone integration

The NASA MicroCub (µCub) is a Bill Hempel 60-percent-scale Super Cub, modified to support research focused on the integration of unmanned aircraft into the National Airspace System (NAS).

NASA Armstrong’s Subscale Research Lab team began flying the µCub in January, successfully demonstrating the aircraft’s airworthiness. The NASA team took much the same approach to testing this somewhat-smaller Super Cub as they would with any full-scale aircraft, validating ground handling, flight characteristics, and the command-and-control system in a step-by-step process. Engineers also spent time on the remote controls, tuned the autopilot, and performed engine runs to gauge fuel consumption before launching to conduct additional tests on handling and stall speed.

“Our focus on this research is to support the development of regulations that will allow routine access for UAS in the NAS without the need for FAA Certificates of Authorization or special routes to conduct missions, and in general helping the FAA deal with flights beyond visual line of sight,” said Davis Hackenberg, deputy project manager of the Subscale Research Lab.

Though small, the µCub is a powerful vehicle compared to most small to midsize UAS and even most traditional radio-controlled aircraft. It has a 21-foot wingspan, a Piccolo autopilot guidance system, and a JetCat SPT-15 turboprop engine.

“We decided to use … the aircraft with a turboprop instead of the traditional internal combustion engine typical of the Super Cub due to the requirements for higher performance and a more accurate simulation of real-life conditions in the national airspace,” said Hackenberg.

The successful maiden flight Jan. 18 opened the door for additional aircraft modifications to validate risk reduction technology that will be eventually integrated into other NASA UAS, such as NASA Ames’ Sensor Integrated Environmental Remote Research Aircraft (SIERRA-B).

“In addition to helping with UAS integration into the NAS efforts, the µCub is a configurable aircraft that can be modified and utilized for a variety of flight tests at NASA and will be instrumental in the development of a reliable unmanned traffic management (UTM) system,” said Hackenberg.

The UTM platform being built by NASA and various industry partners will be capable of coordinating and analyzing inputs from dozens of sources, making valid and reliable assessments of the local airspace environment, and communicating traffic data and other information to pilots in the area.

Since the first flight in January, the Armstrong crew has installed an onboard smoke system, a see-and-avoid tool that makes this scaled-down Super Cub easier to spot from other aircraft during flight. By testing this technology on the µCub first, NASA can record visual detection data during test flight encounters, which will help researchers understand just how visible small UAS are from a variety of distances, without the risk or high cost that comes with testing such a technology on larger UAS like NASA’s Ikhana Predator B.

The µCub will also help provide the public with a tangible representation of what the future of unmanned flight could look like in the sky above them. As NASA expands its research and development of small unmanned aircraft vehicles, the µCub will continue to support UAS efforts that will ultimately change and redefine drone flight in the future.

A lot of work remains to meet NASA’s goals for the UAS integration in the NAS project that is ongoing at Armstrong and other NASA centers: Ames Research Center in California, Glenn Research Center in Ohio, and Langley Research Center in Virginia. However, with NASA, industry, and academia working together to provide information to assist the FAA in regulations to safely integrate UAS in the NAS, that day is getting closer.

NASA and the Nevada Institute for Autonomous Systems recently completed technical capability level (TCL 3) flights in a Nevada test site to continue advancing the groundbreaking work done in 2015 and 2016 with TCL 1 and TCL 2, respectively. This work by NASA, the FAA, and the NIAS will eventually merge with the UTM efforts involving the µCub and the SIERRA-B unmanned vehicles.

The next research phase will fly drones in airspace with more traffic over more populated areas, and have a stronger focus on responding to the presence of larger, piloted aircraft in a real-life scenario.