Takeoff Gross Weight Research Articles

GreatBlue: a 55-Pound Vertical-Takeoff-and-Landing Fixed-Wing sUAS for Science; Systems, Communication, Simulation, Data Processing, Payloads, Package Delivery, and Mission Flight Performance

As small, uncrewed systems (sUAS) grow in popularity and in number, larger and larger drone aircraft will become more common–up to the FAA limit of 55 pound gross take-off weight (GTOW) and beyond. Due to their larger payload capabilities, longer flight time, and better safety systems, autonomous systems that maximize CFR 14 Part 107 flight drone operations regulations will become more common, especially for operations such as imagery or other data collection which scale well with longer flight times and larger flight areas. In this new paper, a unique all-electric 55-pound VTOL transition fixed-wing sUAS specifically engineered for scientific data collection named “GreatBlue” is presented, along with systems, communications, scientific payload, data collection and processing, package delivery payload, ground control station, and mission simulation system. Able to fly for up to 2.5 hours while collecting multispectral remotely-sensed imagery, the unique GreatBlue system is shown, along with a package delivery flight example, flight data from two scientific data collection flights over California almond fields and a Utah Reservoir are shown including flight plan vs. as-flown.

Sizing Approach with Flight Time Comparison of An Electric Multirotor Propulsion Chain with Batteries and Fuel Cells

The concept of electric vertical take-off and landing (E-VTOL) aerial vehicles is gaining more and more attention, thanks to their non-polluting operation and simple air traffic management. Indeed, around the world, there are currently more than 500 projects that concern the development and improvement of their performances. Development of sizing methods for rapid selection of the propulsion chain components remains an important task in this process. In this paper, an approach for sizing and selecting the propulsion chain components of an E-VTOL aerial vehicle is developed and validated. First, the optimal pair motor/propeller is selected using a global nonlinear optimization in order to maximize the specific efficiency of these components. Second, two energy storage technologies are considered and sized in order to assess their influence on the aerial vehicle flight time. Finally, based on this sizing process, the optimized propulsion chain gross take-off weight (GTOW) is evaluated, using regression methods based on propulsion chain supplier data.

Fast Sizing Methodology and Assessment of Energy Storage Configuration on the Flight Time of a Multirotor Aerial Vehicle

Urban air mobility (UAM), defined as safe and efficient air traffic operations in a metropolitan area for manned aircraft and unmanned aircraft systems, is being researched and developed by industry, academia, and government. This kind of mobility offers an opportunity to construct a green and sustainable sub-sector, building upon the lessons learned over decades by aviation. Thanks to their non-polluting operation and simple air traffic management, electric vertical take-off and landing (eVTOL) aircraft technologies are currently being developed and experimented with for this purpose. However, to successfully complete the certification and commercialization stage, several challenges need to be overcome, particularly in terms of performance, such as flight time and endurance, and reliability. In this paper, a fast methodology for sizing and selecting the propulsion chain components of an eVTOL multirotor aerial vehicle was developed and validated on a reduced-scale prototype of an electric multirotor vehicle with a GTOW of 15 kg. This methodology is associated with a comparative study of energy storage system configurations, in order to assess their effect on the flight time of the aerial vehicle. First, the optimal pair motor/propeller was selected using a global nonlinear optimization in order to maximize the specific efficiency of these components. Second, five energy storage technologies were sized in order to evaluate their influence on the aerial vehicle flight time. Finally, based on this sizing process, the optimized propulsion chain gross take-off weight (GTOW) was evaluated for each energy storage configuration using regression-based methods based on propulsion chain supplier data.

Weight assessment for a blended wing Body-Unmanned aerial vehicle implementing boundary layer ingestion

Boundary Layer Ingestion (BLI) has been studied extensively for implementation in Blended Wing Body (BWB) transport aircrafts, and it has been reported that BLI offers potential benefits mainly in terms of energy, improving the propulsive efficiency of a propulsion system and reducing the fuel consumption. This paper examines potential benefits of BLI related with a reduction on the Take-Off Gross Weight (TOGW) for a BWB-Unmanned Aerial Vehicle (UAV). It is discussed the methodology for weight estimation of a BWB-UAV through parametric models. To evaluate the benefits of BLI in terms of weight reduction, it has been taken into account the removal of pylons and the nacelle weight reduction when embedding nacelles into the airframe. The validation of the parametric models, and the case of study have been carried out for the aircraft NASA X-48B. The results show a reduction in TOGW between 8% and 19% when removing pylons and embedding nacelles into the airframe.

On the benefits of lower Mach number aircraft cruise

AbstractThe paper reviews the issue of cruise Mach number and addresses the benefits of operating subsonic commercial aircraft at speeds below the long-range cruise speed. The case considered is the flight of transport aircraft for flight segments up to 1,000nm. It is shown that the fuel burned is decreased by as much as 1·8% on a nominal 1,000nm stage length for operation around the long-range cruise Mach number, or below. This is achieved at a cost of a marginal delay on each flight segment (less than three minutes). The longer flight time is likely not to affect the daily operation of the aircraft. The fuel saving is compounded, because the gross take-off weight (GTOW) is recalculated to take into account the reduced fuel consumption at each flight segment. The analysis into the environmental benefits includes the reduction in,andemissions, and the heat released in the high atmosphere. Sensitivity analyses are carried out on the take-off weight, on the aerodynamic coefficients, on the transonic drag rise and the weight uncertainty. It is predicted that the optimal operation of the example aircraft over a nominal 1,000nm route can reduce the fuel consumption by as much as 150,000kg per year in comparison with an operation at the long-range Mach number. The aircraft model has a maximum take-off weight of 170,000kg and is powered by two GE CF6-80C2 engines.

Integrated Vehicle Comparison of Turbo-Ramjet Engine and Pulsed Detonation Engine

The pulsed detonation engine (PDE) is a unique propulsion system that uses the pressure rise associated with detonations to efficiently provide thrust. A study was conducted under the direction of the NASA Langley Research Center to identify the flight applications that provide the greatest potential benefits when incorporating a PDE propulsion system. The study was conducted in three phases. The first two phases progressively screened a large matrix of possible applications down to three applications for a more in-depth, advanced design analysis. The three applications best suited to the PDE were (1) a supersonic tactical aircraft, (2) a supersonic strike missile, and (3) a hypersonic single-stage-to-orbit (SSTO) vehicle. The supersonic tactical aircraft is the focus of this paper. The supersonic, tactical aircraft is envisioned as a Mach 3.5 high-altitude reconnaissance aircraft with possible strike capability. The high speed was selected based on the perceived high-speed fuel efficiency benefits of the PDE. Relative to a turbo-ramjet powered vehicle, the study identified an 11% to 21% takeoff gross weight (TOGW) benefit to the PDE on the baseline 700 n.mi. radius mission depending on the assumptions used for PDE performance and mission requirements. The TOGW benefits predicted were a result of the PDE lower cruise specific fuel consumption (SFC) and lower vehicle supersonic drag. The lower vehicle drag resulted from better aft vehicle shaping, which was a result of better distribution of the PDE cross-sectional area. The reduction in TOGW and fuel usage produced an estimated 4% reduction in life cycle cost for the PDE vehicle. The study also showed that the simplicity of the PDE enables concurrent engineering development of the vehicle and engine.

Setting Design Goals for Advanced Propulsion Systems

Significant reduction in the life cycle cost (LCC) of advanced weapon systems can be achieved without sacrificing combat capability by setting design goals for propulsion system that are balanced with the traditionally emphasized performance goals. This design philosophy was evaluated as an integral objective of the Advanced Technology Engine Studies (ATES) program under joint U.S. Navy/Air Force cognizance. This paper documents the methodology and results of ATES program conceptual design studies that set balanced cost-effective propulsion system design goals for durability, reliability, maintainability, and operability for several advanced aircraft weapon systems. URING the past two decades, the life cycle cost of aircraft weapon systems has increased dramatically. This cost escalation, together with funding limitations, makes it difficult for the United States military services to replace aircraft lost through attrition or to introduce new systems. Clearly, the challenge in the design and development of future propulsion systems is to provide for superior performance weapon systems, while at the same time reducing their life cycle cost. In response to this challenge, the Advanced Technology Engine Studies (ATES) program is a currently ongoing 18- month study effort tasked to identify cost-effective design and development philosophies for advanced propulsion systems and to reflect these philosophies in a long-range propulsion plan. The program is under joint U.S. Navy/Air Force cognizance. Pratt & Whitney Aircraft (P&WA) is a prime contractor in this program for the study of propulsion system requirements for 11 advanced aircraft weapon systems. The P&WA study encompasses a wide range of potential ap- plications, including advanced fighters, subsonic bombers, transports, and subsonic and supersonic V/STOLs. To properly assess the propulsion system impacts upon each aircraft weapon system, P&WA has subcontracted to four major airframe companies: The Boeing Company, Grumman Aerospace Corporation, McDonnell Aircraft Company, and the Vought Corporation. Aircraft takeoff gross weight (TOGW) typically has been the figure of merit for evaluating previous weapon systems, largely because it is representative of airframe related development, acquisition, and support costs. In this com- petitive environment, engine manufacturers have placed emphasis on maximizing engine performance to minimize TOGW while placing less emphasis on the engine As a result, engine maintenance costs have escalated and have contributed to the elevated life cycle cost of today's weapon systems. As an integral objective of the ATES program, an advanced design philosophy was applied whereby goals for the engine ilities are established during the conceptual design phase of propulsion system development. Balancing these ilities goals with the traditional engine performance criteria should result in minimum overall weapon system cost of ownership. P&WA developed and applied this conceptual design methodology to identify cost-effective design goals for the engine ilities.

Interior Noise Control by Fuselage Design for High-speed Propeller-Driven Aircraft

An analytic study was performed to define the acoustical treatment weight penalties that are required to provide an interior noise level of 80 dBA in propfan-power ed aircraft at Mach 0.8 cruise. The prediction method, described in a companion paper, combines Koval's theory for cylindrical shell noise transmission loss (TL) with Beranek and Work's method for multilayered acoustic treatment analyses. Three fuselage diameters are studied which represent commuter, narrow-body, and wide-body aircraft. The calculated acoustic treatment weight penalties range from 1.7 to 2.4% of aircraft takeoff gross weight (TOGW) for add-on designs. Advanced noise reduction designs, those which permit structural modifications, reduce the acoustic treatment weight penalties to 1.5% TOGW for aluminum aircraft and from 0.74 to 1.4% TOGW for composite fuselage construction. The wide-body results agree with the weight penalty estimates of an earlier turboprop aircraft study.

Performance Evaluation of an Air Vehicle Utilizing Nonaxisymrnetric Nozzles

An extensive nonaxisymmetric nozzle design and performance data base were utilized to evaluate the performance of a vehicle designed for an air-to-air mission. Performance was evaluated through comparative sizing analysis for selected nonaxisymmetric nozzle installations vs a baseline axisymmetric nozzle installation. The nonaxisymmetric nozzle/vehicle with a single, external expansion ramp was found to be lighter in takeoff gross weight (TOGW) than the axisymmetric baseline. The lighter TOGW resulted primarily from the use of thrust vectoring at the transonic maneuver condition used for engine sizing. Both jet lift and thrust-induced lift or supercirculation were the main contributors to improved performance at this flight condition.