R. John Hansman

• Doctor of Philosophy
• Massachusetts Institute of Technology

NeuralFoil is an open-source Python-based tool for rapid aerodynamics analysis of airfoils, similar in purpose to XFoil. Speedups ranging from 8x to 1,000x over XFoil are demonstrated, after controlling for equivalent accuracy. NeuralFoil computes both global and local quantities (lift, drag, velocity distribution, etc.) over a broad input space, i...

The implementation of performance-based navigation instrument flight procedures at major U.S. airports has enabled aircraft to follow precise routes during departure and arrival operations. While these procedures offer increased efficiency and predictability in flight management, they have the side effect of concentrating aircraft noise over specif...

Significant variations in measured overflight noise levels are observed from airport monitor networks for similar aircraft types flying the same departure and arrival procedures. Various factors, including aircraft configuration, airline, weather, and flight procedure, as well as their interactions, have the potential to impact recorded noise level...

This work introduces a noise abatement procedure for reducing aircraft community noise during departures based on the control of climb profiles via procedural level-offs. The proposed procedure consists of enforcing an altitude restriction along a departure path such that aircraft maintain level flight when overflying strategically selected regions...

This paper proposes an end-to-end differentiable model for infrared radiant emission for low-altitude exhaust plumes. Considering plume radiant emission during the design phase is important for ensuring vehicle design constraints and objectives can be met while accounting for the coupling of plume radiant emission with other aspects of vehicle desi...

Low-thrust, end-burning solid rocket motors have applications as propulsion systems for a class of small, transonic, uncrewed aerial vehicles. This paper provides new experimental measurements for characterizing small, low-thrust, end-burning motors. Four static fires measured the effects of motor chamber pressure and propellant oxamide content on...

Aircraft weight estimation is a common problem facing researchers working with aircraft surveillance data. Although knowledge of an aircraft’s weight and thrust is required for many types of analyses, such as those evaluating aircraft acoustic noise, fuel burn, and emissions, these parameters are typically not available from surveillance sources. I...

Traditional runway condition reporting is limited due to its reliance on runway contamination information and pilot reports of braking action. A database of 4.9 million aircraft landings by Aviation Safety Technologies, labeled with runway condition codes computed from aircraft sensor outputs provides a unique opportunity to enhance and modernize c...

On-going work in examining the potential use of on-board calculation of remaining control power margin (RCP) for distributed electric propulsion (DEP) aircraft is described, where that metric may be an indicator of the capability of the vehicle to accommodate operational disturbances and avoid loss of control (LOC) events. Analysis and simulation m...

Advanced operational flight procedures have been proposed to reduce the impact of aircraft operations on community noise. Recent work has led to the development of noise abatement procedures like the delayed-deceleration approach for arrivals. Causes of variation in airport noise monitor network measurements due to departures remain an important so...

This paper addresses the noise-minimal trajectory optimization problem for a specific type of aircraft: rotorcraft. It relies on a realistic noise footprint computation software provided by industry that is black-box. Locally optimal trajectories are computed through a tailored solution approach based on the Mesh-Adaptive Direct Search algorithm. W...

Traditional runway condition reporting is limited due to its reliance on runway contamination information and pilot reports of braking action. A database of 4.9 million aircraft landings by Aviation Safety Technologies, labeled with runway condition codes computed from aircraft sensor outputs provides a unique opportunity to enhance and modernise c...

Causes of variation in airport noise monitor network measurements due to departures remain an important source of uncertainty in the development of departure noise abatement procedures. Variation is observed to be between 10-15 dB at individual noise monitors for Airbus A320 and Boeing 737NG aircraft flying the same departure trajectories. In order...

An aircraft noise modeling framework is presented and used to perform a data-driven exploration of factors correlating with measured aircraft community noise and a model-based validation of the variables found to have the greatest noise impact. Aggregate departure and arrival noise and flight procedures were examined so that factors correlating wit...

View Video Presentation: https://doi.org/10.2514/6.2022-3937.vid This work presents a new computational framework for conceptual aircraft design called AeroSandbox. This framework leverages modern techniques for automatic differentiation developed in the optimal control and machine learning communities. By combining these efficient gradient calcula...

A validation methodology and evaluation of delayed deceleration approach performance and noise-impact modeling using noise measurements and radar data are presented. Advanced procedures such as delayed deceleration approaches, where aircraft maintain higher speeds and therefore remain cleanly configured and at lower thrust levels for longer flight...

Aircraft weight estimation is a common problem facing researchers working with aircraft surveillance data such as ADS-B and ASDE-X data. Although knowledge of an aircraft's weight and thrust is required for many types of analyses, such as those evaluating aircraft acoustic noise, fuel burn and emissions, these parameters are typically not available...

View Video Presentation: https://doi.org/10.2514/6.2022-2495.vid Certain conditions such as rain, snow or wet runways can cause a decrease in wheel braking action of landing aircraft. In extreme cases this phenomenon can result in runway overrun events. The relationship between landing conditions and braking action is complex and there currently ar...

Traditional airport noise modeling is limited in its ability to analyze large quantities of flight tracks due to high computation time. As a result, yearly noise reports are often limited to modeling flights from a single “representative day,” which lacks detail arising from the natural dispersion of flight tracks and variety in airport operations...

Small, low-thrust, long-burn-time solid propellant rocket motors could provide propulsion for a new class of kilogram-scale, transonic, uncrewed aerial vehicles (UAVs). This paper investigates technological challenges of small, low-thrust solid rocket motors: slow-burn solid propellants, motors that have low thrust relative to their size (and thus...

This work presents a new computational framework for conceptual aircraft design called AeroSandbox. This framework leverages modern techniques for automatic differentiation developed in the optimal control and machine learning communities. By combining these efficient gradient calculations with robust optimizers such as IPOPT, multidisciplinary air...

View Video Presentation: https://doi.org/10.2514/6.2021-2871.vid The concept of regional and intra-city mobility using small aircraft, commonly known as Urban Air Mobility (UAM), has rapidly become one of the primary interests in commercial aviation; the idea focuses on passenger travel using small, electric aircraft able to operate in constrained...

View Video Presentation: https://doi.org/10.2514/6.2021-2389.vid This paper explores opportunities to leverage existing aviation surveillance infrastructure to characterize airspace utilization by legacy aircraft as a means to support Advanced Air Mobility (AAM) integration in congested urban airspace. A methodology is developed to identify differe...

View Video Presentation: https://doi.org/10.2514/6.2021-3220.vid Electric short takeoff and landing (eSTOL) aircraft and electric vertical takeoff and landing (eVTOL) aircraft are being developed for missions where availability of ground infrastructure is a critical design driver. Because eSTOL aircraft can generate high effective lift coefficients...

View Video Presentation: https://doi.org/10.2514/6.2021-2135.vid A validation methodology and evaluation of delayed deceleration approach procedure performance and noise impact modeling using noise measurements and flight radar data are presented. Advanced flight operational procedures such as delayed deceleration approaches, where aircraft maintai...

View Video Presentation: https://doi.org/10.2514/6.2021-2451.vid High-Altitude Long-Endurance (HALE) aircraft are uniquely equipped to fill some of the major lapses in the current understanding of rapid and irreversible climate change. Given a current understanding of solar-electric HALE vehicles, the feasible space is limited by solar flux. This n...

Advanced operational flight procedures that utilize modifications to thrust, airspeed, altitude, and configuration can be implemented to mitigate noise impacts for communities surrounding airports. Evaluating and designing such procedures requires accurate modeling of the aircraft performance, source noise, and atmospheric propagation of the source...

The modeling, assessment, and flight demonstration of delayed deceleration approach procedures for airport community noise reduction are presented. In conventional approach procedures, aircraft decelerate and therefore configure early, resulting in the need to operate at above idle thrust levels to maintain the final approach speed before touchdown...

Low-thrust long-burn-time solid rocket motors may be useful as propulsion for small, fast, uncrewed aerial vehicles. These motors require a slow-burning propellant that can operate at unusually low chamber pressures (0.3–2 MPa). Slow-burn propellants were developed using ammonium perchlorate oxidizer and the burn rate suppressant oxamide. By varyin...

The modeling and assessment of the community noise impacts of a representative hybrid-electric aircraft implementing windmilling motors as drag generators on approach is presented. An increasing desire to reduce emissions caused by aviation has motivated the development of hybrid-electric aircraft that have some degree of their traditional gas-turb...

This paper investigates how existing arrival and departure procedures can be directly used or adapted to enable high-volume instrument and visual urban air mobility (UAM) flight operations at major airports in the United States. Viable procedures are restricted to those that enable simultaneous and non-interfering UAM flights with conventional airc...

This paper discusses the concept of reducing aircraft noise on departure through changes to climb profiles. The idea of a procedure level-off is introduced, which consists of restricting the climb of aircraft in a departure procedure so that aircraft maintain level flight in specific sections of the procedure. Due to the lower thrust demand of leve...

The current air traffic control (ATC) system is human-centric and voice-based. As a result, separation minima, controller workload, and radio frequency limitations may restrict the number of emerging unmanned aircraft system (UAS) or urban air mobility (UAM) operations that can occur within congested airspace. Limited ATC capacity will be especiall...

Small, uncrewed aerial vehicles (UAVs) are expanding the capabilities of aircraft systems. However, a gap exists in the size and capability of aircraft: no small aircraft are capable of sustained fast flight. A small, fast aircraft requires a propulsion system which is both miniature and high-power, requirements which current UAV propulsion technol...

This paper presents the results from initial flight tests of a 30% scale demonstrator of a blown-wing SuperSTOL concept aircraft, intended for operation from extremely short runways of 100 ft or less. The subscale demonstrator is aimed at investigating the maximum achievable in-flight lift coefficients with the blown wing, as well as the control an...

Distributed electric propulsion (DEP) is an emerging set of technologies which enable new vehicle configurations by allowing the efficient distribution of many smaller propulsors around the airframe. One application of this technology is to greatly enhance the short takeoff and landing (STOL) capability of a fixed-wing aircraft. STOL aircraft may h...

There is widespread interest in the use of electric aircraft for short missions in and around urban areas. Most of the vehicle configurations proposed for these missions are electric Vertical Takeoff and Landing (VTOL) configurations, due to perceived limitations on the available infrastructure. Several recent studies have proposed electric Short T...

This study presents a means of assessing unmanned aerial vehicle (UAV) control in various environments using control margin. The metric gives an instantaneous measure of control authority and is defined by dividing required torque by maximum available torque. Required torque is the sum total of torque developed by a vehicle's rotors and residual te...

A gap exists in the design space for aircraft mass and speed: no flight vehicles with a mass of less than 10 kg and speed greater than 100 m/s are available. The small, fast "Firefly" flight vehicle is being developed to explore the capabilities and challenges for aircraft in this gap. The compact Firefly aircraft is configured around a long-endura...

This paper investigates the use of low altitude airspace by conventional flight operations in proximity to the San Francisco, Boston, and Atlanta international airports. The purpose of the investigation is two-fold. First, the study presents an approach to develop lateral and vertical containment boundaries for arrival and departure flight trajecto...

The implementation of Performance Based Navigation (PBN), such as Area Navigation (RNAV) and Required Navigation Performance (RNP), has led to aircraft being able to fly designed flight tracks very precisely. This has led to communities citing the concentration of aircraft along one flight track as a noise issue because of the frequent overflights...

Aircraft turnaround operations is a key determinant of both airline and airport performance. Airlines incur both direct and indirect costs from poor on-time departure performance, particularly when these delays propagate through an airline’s schedule and additional resources have to be utilized for schedule recovery. As for airports, poor stand uti...

It was determined that a complete CA system utilizing cooperative surveillance could weigh less than 70 grams and require less than 2 W of average input power. Because cooperative surveillance broadcasts from sUAS could overload the spectrum currently used to share aviation information, signal transmissions were simulated for a population of sUAS b...

The Air Traffic Management (ATM) system enables air transportation by ensuring a safe and orderly air traffic flow. As the air transport demand has grown, ATM has become increasingly challenging, resulting in high levels of congestion, flight delays and environmental impacts. To sustain the industry growth foreseen and enable more efficient air tra...

A framework for analyzing aircraft community noise impacts of advanced operational approach and departure procedures was developed. In this framework, the altitude, position, velocity, thrust, and configuration profiles of procedures to be assessed are specified by aircraft performance. These profiles are input to the NASA Aircraft NOise Prediction...

This study develops an Integer Programming (IP) approach to analytically estimate vertiport capacity envelopes. The approach is used to determine the sensitivity of vertiport capacity to the number and layout of touchdown and liftoff pads, taxiways, gates, and parking pads (i.e. the vertiport topology). The study also assesses the sensitivity of ve...

Efficient planning of Airport Acceptance Rates (AARs) is key for the overall efficiency of Traffic Management Initiatives such as Ground Delay Programs (GDPs). Yet, precisely estimating future flow rates is a challenge for traffic managers during daily operations as capacity depends on a number of factors/decisions with very dynamic and uncertain p...

Future Air Traffic Management systems can benefit from innovative approaches that leverage the increasing availability of operational data to facilitate the development of new performance assessment and decision-support capabilities. This paper presents a data analytics framework for high-fidelity characterization of air traffic flows from large-sc...

A cruise altitude and speed optimization decision support tool, based on the concept of a minimum cost altitude tunnel, was developed to aid flight crew and dispatcher situational awareness and decision-making in vertical trajectory planning in order to reduce fuel and time costs. As the optimal altitude for an aircraft changes with speed, weight,...

Safety and certification considerations which impact the design of an emerging new class of small, electric aircraft were investigated. Based on an assessment of the different emerging aircraft designs, vehicles were grouped based on lifting and propulsive architecture. Likely certification pathways and the associated airworthiness requirements wer...

This paper assesses how the introduction of urban air mobility services and unmanned aircraft systems may challenge Air Traffic Control (ATC) in the United States and what opportunities exist to support these forthcoming operations. Four attributes unique to these emerging operations were identified that may challenge effective ATC. Each attribute...

Urban air mobility (UAM) refers to a set of vehicles and operational concepts proposed to provide on-demand or scheduled air transportation services within a metropolitan area. This paper investigates potential operational constraints that could arise during the implementation or scale-up of a UAM system. Literature on helicopter passenger networks...

Air Emergency Medical Service (Air EMS) provides unique and important medical trans- port capabilities to society. Air EMS can move patients or live organs more rapidly than surface modes over long distances or congested areas. Air EMS also provides unparalleled access to accident scenes in regions where surface transportation is compromised such a...

Electric Short Takeoff and Landing (eSTOL) vehicles are proposed as a path towards implementing an Urban Air Mobility (UAM) network that reduces critical vehicle certification risks and offers advantages in vehicle performance compared to the widely proposed Electric Vertical Takeoff and Landing (eVTOL) aircraft. An overview is given of the system...

The scalability of the current air traffic control system, the availability of aviation ground infrastructure, and the acceptability of aircraft noise to local communities have been identified as three key operational constraints that may limit the implementation or growth of Urban Air Mobility (UAM) systems. This paper identifies the primary mecha...

Aircraft noise is a growing source of community concern around airports. Despite the introduction of quieter aircraft, increased precision of onboard guidance systems has resulted in new noise impacts driven by overflight frequency effects. Noise issues present a potential barrier to the continued rollout of advanced operational procedures in the U...

Efficient planning of airport capacity is key for the successful accomplishment of traffic flow management. Yet, the dynamic and uncertain behavior of capacity-determining factors makes it difficult to estimate flow rates precisely, especially for strategic planning horizons. Metroplex systems impose additional challenges in this decision-making pr...

On-Demand Mobility (ODM) for Aviation is an emerging concept that proposes to provide aircraft-based, point-to-point transportation to consumers within a metropolitan area. This paper explicitly identified key operational constraints facing ODM Aviation networks and assessed how new vehicles and technologies could mitigate or reduce the severity of...

This paper investigated three key operational constraints anticipated to impact On-Demand Mobility for Aviation markets in the Los Angeles basin including: community acceptance issues resulting from aircraft noise, the availability of takeoff and landing areas, and the scalability of operations under Air Traffic Control. The analysis provided insig...

Recent developments in navigation and surveillance technology have enabled new high-precision approach and departure operational procedures using GPS and Required Navigation Performance (RNP) standards. These procedures have proven effective for reducing fuel consumption and streamlining some aspects of air traffic control. However, flight tracks t...