Born: N/A
Primarily active in: N/A

From Leadership Profile: Vertiflite, July/August 2024

Dr. Noah Schiller, Project Manager, Revolutionary Vertical Lift Technology, NASA

Overseeing NASA’s Revolutionary Vertical Lift Technology (RVLT) project, Dr. Noah Schiller supports over 200 investigators working at four of the agency’s aeronautical research centers. He explained, “Basically, our goal is to enable a future where vertical takeoff and landing vehicles operate quietly, safely, efficiently, affordably and routinely as an integral part of everyday life.” RVLT researchers work on propulsion, acoustics, safety, and modeling and simulation tools aimed at electric multirotor aircraft, tiltrotors and other air taxi and cargo drone concepts. Schiller observed, “We can’t look at everything, so we have to narrow our focus currently to advanced air mobility [AAM]. A lot of the work we do is fundamental in nature, so it supports a variety of different vehicle configurations.”

Before he became the RVLT project manager last year at NASA Langley Research Center in Hampton, Virginia, Schiller served as a technical lead for acoustics research and associate project manager for the broader RVLT effort. “We really try to leverage the capabilities that all the NASA centers bring to the table,” he said. Investigators at NASA Ames Research Center, for example, partnered with Joby Aviation and the Air Force’s AFWERX Agility Prime program last December to measure the all-electric tiltpropeller’s acoustics in California. Propeller noise measurements continue in the Langley and Ames wind tunnels.

Psychoacoustic tests are conducted in the Langley Research Center’s Exterior Effects Room to investigate people’s response to AAM sounds. The tests are conducted a few times each year with about 40 test subjects from the local community. Schiller offered, “Something that the team looked at recently was the effect of background noise — what happens when you include ambient background noise along with a flyover. They’ve come up with a discount function, which models the masking effect of the background noise, which tends to reduce annoyance.”

Langley experimenters deliberately crashed a generic air taxi fuselage at their Landing and Impact Research (LandIR) Facility in 2022 with surprising results (see “Melding Old and New Technology: Impact Testing for Crash Safety,” Vertiflite, March/ April 2023). Schiller observed, “Our pre-test predictions did not show the collapse of cabin occupant volume that was observed in the test, so the team went back and did component-level tests to better characterize the structure. They found, for example, that the forming foam that remained within the frames after fabrication needed to be included in the model. They also needed to adjust some of the composite material brittle failure parameters based on results of the component-level tests. After updating the model, they got very good correlation with the observed deformation.”

RVLT plans call for a second drop test with the same composite design in 2025. Schiller explained, “In the first test, we made some assumptions about how the mass was distributed. We assumed that much of the mass from the wing and batteries would be on top of the fuselage. We did not assume that the wings would break away and reduce some of the load transferred to the cabin. We’re going to change some of those assumptions in the second test and will test with different impact conditions. Basically, the test will assess the predictive capabilities and limitations of our updated model.”

Bird strike research at NASA Glenn Research Center in Ohio likewise seeks to inform modeling approaches and test methods, ultimately leading to safer AAM vehicles.

The RVLT Ride Quality Laboratory at NASA Armstrong Flight Research Center and handling qualities studies in the Ames Vertical Motion Simulator investigate AAM safety and comfort issues. The advanced reconfigurable electrified aircraft lab (AREAL) up and running at NASA Glenn has inverters, high- voltage emulators and an electric motor test stand, allowing RVLT researchers to assess the performance and reliability of electric vertical takeoff and landing (eVTOL) propulsion components. Schiller said, “We work on projects distributed across the centers, and that gives us the ability to leverage their unique capabilities and facilities.”

RVLT deliverables include datasets, publications, and software shared with government, academia, and industry. Investigators commonly use Small Business Innovative Research (SBIR) and Small Business Technology Transfer (STTR) contracts to leverage industry expertise. Schiller explained, “One of our new tools will allow designers to better integrate flight dynamics and control into the conceptual design process. The initial version of that software was developed under contract with CDI [Continuum Dynamics Inc.]. There are many other companies we work with to advance modeling and analysis tools as well.”

The RVLT manager added, “Another important deliverable is related to support for industry standards organizations.” The AREAL with its 200 kW, 800 VDC bus has begun testing high-power eVTOL propulsion architectures. “We’re getting very good data from that laboratory, informing two different standards efforts. “We would like to accelerate our work in all of these areas,” Schiller offered. “Certainly, industry is moving fast, and to maximize our impact we want to share data and findings sooner rather than later.”

Sound Studies
Noah Schiller grew up in Dyke, Virginia, about 20 miles north of Charlottesville, the son of arborist Gerald Schiller. The NASA engineer noted, “My father is passionate about science and engineering, although he never formally studied in those areas. That stuck with me and motivated me to pursue engineering in school.” Dr. Schiller acknowledged, “I had an interest in aviation from early on, but when I went to school, I went into mechanical engineering in hopes of being a jack-of-all-trades — a little bit of fluid dynamics, a little bit of structural dynamics. I liked the idea of being able to do different things.”

Schiller recalled, “I’ve always been excited by aircraft, and one of the schools I considered was Embry-Riddle in Florida to become a pilot, but I didn’t go that route.” Virginia Tech in Blacksburg provided a practical, in-state school with a distinguished engineering program. “I followed my older brother there. He also studied mechanical engineering a year ahead of me.”

Noah Schiller earned his Bachelor of Science degree in mechanical engineering and immediately pursued graduate studies on familiar grounds. He explained, “I had an excellent controls professor, Will Saunders. He inspired me to focus on control theory, so that’s what I wanted to do in grad school for my master’s. I stuck around Virginia Tech specifically to work with him. He had a project focused on active combustion control to reduce combustion instabilities in gas turbines.”

After receiving his master’s degree in 2003, Schiller started on his government research career. “Initially I was looking for a job as a researcher and my professor had contacts at NASA. I took a tour of NASA Langley, but they weren’t hiring at the time. There was, however, a graduate research position that would allow me to do research at NASA while pursuing a PhD. That got my foot in the door. There was an opportunity for a co-op position a couple of years later. I applied for that and got it. Once I graduated, they converted me to a full-time employee.”

A PhD in mechanical engineering from Virginia Tech in 2008 led to a job as a research engineer at NASA Langley. “I was in the Structural Acoustics Branch, initially continuing research I had been doing as a graduate student. My focus was on reducing interior noise in different types of aircraft and space launch vehicles. I was developing models to predict interior noise and then developing technologies to reduce the acoustic levels in the vehicle without adding a lot of extra weight.”

Schiller went on at NASA Langley to publish 50 technical papers and four patents. “There was a lot of testing in acoustics facilities to evaluate different structures and control technologies. Some of the tests were conducted in anechoic chambers, others used a transmission loss facility. For transmission loss testing, you have a loud reverberant room on one side of your structure and on the other side an anechoic chamber where you measure how much sound is transmitted through the structure. We used transmission loss as one way to evaluate the performance of different concepts.”

Listen Up
Interior and exterior noise remain key to AAM public perception, and the RVLT project manager observed, “I think that the acoustic measurements we’ve seen so far have been encouraging, largely driven by the focus on lower tip speed, which has resulted in lower noise levels and reduced tonal content.” NASA and industry are developing computer tools to model multirotor acoustics, performance and aerodynamic interactions between propellers and structures. Schiller offered, “Today, we have streamlined toolchains that allow us to predict many of the dominant noise sources. Predictions are faster which allows us to evaluate additional vehicle configurations. We also have better coupling with high-fidelity tools that allows us to more accurately assess component-level noise sources."

Computational fluid dynamics (CFD) grid generation nevertheless remains time-consuming. Schiller explained, “We have been focused on and are close to releasing a tool that will automate the grid generation process for structured grids. We have also spent a lot of time improving our design tools, enabling them to better capture interaction effects and other unique physics you see on advanced air mobility configurations.”

eVTOL developers simultaneously promise clean aircraft that are easy to fly and cheap to operate. The RVLT project manager said, “There are indications that some of these vehicles are going to be easier to fly. That remains to be seen, but it appears to be the trend. I think cost is very much to be determined — I don’t think we’re able to speculate on that at this point.”

Noah Schiller joined the Vertical Flight Society more than a decade ago. “It’s been extremely helpful in terms of networking. It’s a fantastic organization to be involved with. It’s been supportive of advanced air mobility from the start and provides a great forum to interact with the larger community.”