Single Airplane Research Articles

Robotic automation and unsupervised cluster assisted modeling for solving the forward and reverse design problem of paper airplanes

Although often regarded a childhood toy, the design of paper airplanes is subtly complex. The design space and mapping from geometry to distance flown is highly nonlinear and probabilistic where a single airplane design exhibits a multitude of trajectory forms and flight distances. This makes optimization and understanding of their behavior challenging for humans. By understanding the behavior of paper airplanes and predicting flight behavior, there is a potential to improve the design of aerial vehicles that operate at low Reynolds numbers. By developing a robotic system that can fabricate, test, analyze, and model the flight behavior in an unsupervised fashion, a wide design space can be reliably characterized. We find there are discrete behavioral groups that result in different trajectories: nose dive, glide, and recovery glide. Informed by this characterization we propose a method of using Gaussian mixture models to extract the clusters of the design space that map to these different behaviors. This allows us to solve both the forward and reverse design problem for paper airplanes, and also to perform efficient optimization of the geometry for a given target flight distance.

Optimum problems in environmental emissions of aircraft arrivals

We propose the solution of optimal problems in aircraft noise and environmental emissions on arrival and landing at a major international airport. We present two distinct cases: 1.) arrival flight of a single airplane; 2.) flight planning for a fleet of four different airplanes. Mathematically, they lead to a constrained optimal control problem: either initial-value or a two-value boundary problem. The cost functions are either noise emission or a combination of noise, engine exhaust emissions (including NOx) and health value functions. Official population statistics are used to quantify the overall effect on communities around the airport. In the second case, we demonstrate how the optimal solution leads to a Pareto front that requires post-optimal analysis techniques. We determined that the solution with lowest noise level is not always the one with the lowest number of awakenings; the solution with lowest CO2 emissions might not be the one with the possible shortest operation.

NUMERICAL MODELLING OF TURBOFAN ENGINE DETERIORATION AS A FACTOR IN THE AIRLINES FUEL CONSERVATION

The boosting of the fuel efficiency of in-service aircraft is an issue of great commercial and ecological importance. One of the ways to achieve this is by adjusting the flight parameters and flight planning to the particular performance level of every single airplane. Main contributors to the aircraft performance deterioration are the aerodynamic and power plant deterioration. In this paper a mathematical modelling approach for the estimation of the effect of turbofan engine deterioration on passenger aircraft performance is proposed. Based on previous flight models developed by the authors, the present model simulates the deterioration of CFM-56-like turbofans on an Airbus A319-like airplane, and makes possible to compare the performance of airplanes with deteriorated and not deteriorated engines over various flight missions. A representative scenario is explored as an illustration. The model can be further developed to include the aerodynamic deterioration of the aircraft as well as other operational factors.

Defining an intra-operative blunt mesenteric injury grading system and its use as a tool for surgical-decision making

BackgroundThe mesentery may be injured in trauma and few grading systems describe mesenteric injury severity. We aimed to develop and validate an intra-operative mesenteric injury grading system. MethodsA modified Delphi technique was used to generate an intraoperative grading system for blunt mesenteric injury called the mesenteric injury score (MIS). We performed a retrospective review (2010–2016) of patients >15 years old with blunt abdominal trauma. Patient demographics, injury severity score (ISS) and mechanism, clinical, operative, and outcome data were abstracted. The intraoperative grading system was used to describe patient outcomes including duration of stay and management approach. We compared the correlation of abdominal abbreviated injury score, Blunt Injury Prediction Score (BIPS) and the MIS with clinical outcomes using Spearman’s rho. ResultsThere were fifty-one patients of which 86% were male. Injury mechanisms included motor vehicle accidents (n = 37, 73%), pedestrian vehicle accidents (n = 7, 13%), assaults (n = 4, 8%), falls (n = 2, 4%), and a single airplane crash (2%). Median [IQR] ISS was 16 [10–25] and GCS at hospital admission was 15 [15–15]. The median [IQR] international normalized ratio was 1.2 [1.1–1.5], lactate was 2.7 [1.7–4.9], and hemoglobin was 11.4 [8.6–12.2]. The distributions of MIS included Grade I (3, 5%), Grade II (10, 20%), Grade III (10, 20%), Grade IV, 5 (10%), and Grade V (23, 45%). Increasing mesenteric injury grade was associated with longer duration of stay, need for bowel resection, and damage control laparotomy. ConclusionsWe developed an intra-operative mesenteric injury grading system (MIS) and provided an initial retrospective validation using a series of patients with blunt abdominal trauma. The proposed MIS corresponded with both the AIS and the BIPS. Future study comparing cross sectional imaging and operative findings based on MIS criteria is needed.

A multi-criteria repair/recovery framework for the tail assignment problem in airlines

Given a list of flights to be operated, the tail assignment problem aims at assigning each flight to a single airplane. When dealing with tail assignment problems, airline companies are willing to define assignments which minimize not only operation costs, but also robust solutions which are able to “resist” perturbations. Even with robust solutions, unexpected events can occur requiring to reconsider the plan under execution. This paper presents a general methodology for repair/recovery in tail assignment problems. When considering repair/recovery solutions for the initial plan under implementation, the decision maker may want to minimize operating costs, but also limit the changes with respect to the initial plan, minimize flights cancellations etc. Hence, we formulate the repair/recovery problem as a multiobjective integer linear programming problem minimizing specified functions for various repair criteria. The choice among the efficient solutions of this multiobjective program is supported by a multi-criteria model based on an additive value function elicited indirectly from past repair/recovery instances. The proposed repair framework applies to tail assignment, and is sufficiently generic to apply to any operations management problem formulated as a compact integer linear program.

Returning to Addis Ababa

Returning to Addis Ababa Dinaw Mengestu (bio) The first time I saw Ethiopia since I was two years old was while looking out the window of a British Airways flight as it headed into the capital's new airport at 3am. Twenty-five years had passed since I had left Addis Ababa, and in that time I had attached an almost mythical significance to what it would be like to see the city again. In my imagination I pictured myself looking out onto a vast vista of low-lying mountains, with a ramshackle city built in the middle. My father, who had worked for Ethiopian Airlines before fleeing the country in 1978, four years into the Communist Revolution, had once shown me a postcard of an Ethiopian Airlines plane sitting on a tarmac with an enormous lion crouched next to it. From that moment on that was the image I had when I thought of returning back home: a bright sunny day with a single airplane sitting on the tarmac, lion and all. I was surprised to see the streetlights from the plane. They sprawled into the distance, and from a thousand feet, made Addis resemble any one of a dozen small cities that I could have been flying into that night. Even then I was on the lookout for any sign of familiarity, for things that I could hold onto to make the country familiar and therefore manageable. Despite the late hour I knew someone would be there to meet me at the airport. With the exception of my uncle Berhane though, I did not know what any of them would look like. I had never met my aunt Aster or her daughter. The same was true of my aunt Rosa and her three children, along with a long list of other relatives, all of whom were strangers to me. I had seen only a few pictures here and there, none at all in at least a decade. I had never once heard any of their voices. I would realize later, after two months of never being without a relative near me, just how much had been lost during all those years away from one another, how much could never be regained, and at the same time, just how easy it was for a family to claim you as one of their own. At the time though, there was only an implacable fear of not knowing who or what to expect. We were strangers, and yet we carried all of the expectations and customs that came with close family, which in this case translated to a half dozen faces, only one of whom I had met, standing shoulder to shoulder behind a black rope at a few hours before dawn, waiting for me to get out of customs. In the other imagined scenarios-over the years I had built up dozens-I was supposed to walk directly out of the plane, onto the ground, hesitating at the last step because in two seconds I was going to touch Ethiopia's soil, and like the prodigal son, drop to my knees and weep. My aunt Aster's face was essentially my mother's. They both had the same high cheekbones, petite noses, and flawless skin. I knew it immediately, as I did my uncle Berhane, who fifteen years earlier had spent a week with my family in Chicago, and apparently had not aged since. I had taken him on the EL into the city, to the top of the Sears Tower, and [End Page 15] on a ferry ride around Lake Michigan, all of which to my thirteen-year old eyes seemed like the greatest things to do in the world. We all walked out of the airport together, completely silent after a brief round of customary kisses and hugs, into a misty early morning. This was late July and the middle of winter in Ethiopia, which meant chill damp nights that with time eased into the very fiber of one's skin, leaving no real hope for warmth. My uncle, who as a teenager had spent five years in jail during the Revolution, had been rewarded later in life...

2 Systems Engineering and the Joint Strike Fighter: The “Flagship” Program for Acquisition Reform

ABSTRACTThe Joint Strike Fighter (JSF) program represents the largest potential aircraft contract for the U.S. Department of Defense (DoD) in the foreseeable future. It will provide replacement strike fighters for the U.S. Air Force, the U.S. Navy, and the U.S. Marine Corps, as well as for the United Kingdom and probably many other non‐U.S. services. The objective of meeting the different needs of many services with variants of a single airplane is a very difficult challenge, especially when the number one consideration is affordability.As part of the plan to achieve an affordable solution, the JSF program will be conducted under the DoD's acquisition reform initiatives begun in 1994. These initiatives mandate a new and innovative way of doing business, canceling many government military

Airborne Range Stations for Control of Nuclear Missile Test Vehicles

A cardinal principle of nuclear ramjet powered missile flight tests is full-time, radar tracking and radio-command control of the missile's flight path supplemented by multiple, fail-safe flight termination systems to maintain the missile within a localized test area where nuclear radiation will not endanger the civilian population. The number of range stations to fulfill this service would become excessive if surface stations were used due to radio-line-of-sight limitations. Airborne range stations represent the best solution; and, under certain conditions of very low altitude flight, the only practical approach to fulltime tracking and control. A turbojet airplane of the Boeing C-135 type suitably equipped with radar, telemetry receivers, radio-command control and communications equipment can function as an independent command control center or as a relay station between the missile and a surface control center. This flexibility of operation enhances the reliability of the overall range system. Existing range technology is adequate; however, integration of functions with a high degree of reliability onboard a single airplane is necessary.

A Note on Flight Flutter Testing

An attempt has been made to correlate theoretically calculated decay effects of wing oscillations at subcritical flutter speeds with results obtained during actual flight flutter testing at these speeds. The theory discussed has been found to give reasonably good agreement with the limited number of test data obtained in flight from a single airplane. Conclusions of a general nature are as yet unwarranted, but a t least a new point of view is presented which applies to interpretation of both test and theoretical results.

Some upper‐air observations made in the Pacific

For many years the Navy has made upper‐air observations at their various air‐stations but observations at sea were few and far between, chiefly because of the great amount of work required to launch and land a single airplane on a carrier. Commanding Officers were loath to burden their crews with the additional work required to shift airplanes all over the flight‐deck, for the launching and recovery of one airplane was practically as much work as 75 airplanes.In recent years with the increased interest in weather‐information in the Fleet and the support of various admirals in command, the ship aerological units have been able to obtain a few consistent dally soundings. With the aim of bringing some of this information out into the light of day before it gets too deeply buried in the files, I have prepared a composite picture of some of the observations made in the Pacific.