Use Of Aircraft Research Articles

The Algorithm of Rational Planning and Resource Allocation in Preparing a Group of Aircraft for Use in Conditions of Uncertainty

The article considers the algorithm of rational planning of work on preparing a group of aircraft for departure, provided that the duration of each of the work is random. The work is carried out by specialists of different profiles with restrictions — it is not allowed to simultaneously perform two or more work on one aircraft and the simultaneous work of a specialist on two or more aircraft. To evaluate the preparation plan for a group of aircraft for departure, the following indicators are taken: the time required to complete all work with a given guaranteed probability and the probability of all work being completed within a given time. To conduct a probabilistic analysis of the sequence of events that determine the progress of work, at the first stage a graph of work is built. When constructing the work graph, the restrictions imposed during the statement of the problem are taken into account by introducing fictitious works. At the second stage, on the basis of the constructed graph of work performance, a stochastic model is developed in which the duration of each work is modeled in accordance with a given distribution law. For many implementations, a distribution function of a random variable is constructed — the total time of preparation of a group of aircraft for departure, by which the values of the required performance indicators are determined. Peculiarities of constructing a graph of work performance are analyzed on the example of preparation for the departure of four aircraft. A detailed probabilistic analysis of a rational plan in conditions of uncertainty — with a random duration of work — was carried out on the example of a rational plan of work on a group of two aircraft. As a result of stochastic modeling, the distribution functions of the time moment of the end of each of the work, the delay time of the start of work and the time of the end of all work on the group of aircraft are constructed. Based on the obtained distribution laws, the dependences of the numerical characteristics of random variables — the number of completed work on the aircraft — on the current time were found. The obtained values of the performance indicators allow us to assess the acceptability of the checked rational plan. If, with rational planning of work by a team of a given composition, the guaranteed time to complete work on a group of aircraft is greater than the required value, then the composition of the team will increase. An algorithm has been developed to justify the composition of the minimum number of crews, which can provide training of a group of aircraft with a given reliability for a given time with a random duration of work.

A New Methodology for Aerodynamic Design and Analysis of a Small Scale Blended Wing Body

The blended wing body (BWB) concept is a relatively new concept of an aircraft. The wings and the fuselage blend into one integral structure greatly reduce drag and increases lift thus making it a highly efficient design. The aim of the research was to design a radio controlled small scale BWB aircraft for use over long ranges at low altitudes in order to deliver payloads. The BWB was divided into the center body and the outer wing. Four airfoils, HS522, LA2573A, NACA 25111 and MH78 were analyzed in XFLR5. In consideration of their lift and moment characteristics, NACA 25111 and MH78 were selected for the center body and the wing respectively. The stall speed and wing loading were the primary factors used in determining the area and size of the aircraft which converged to a design having a five feet wingspan. Center of gravity was placed ahead of aerodynamic center to provide static and dynamic stability in pitch. Twist, dihedral and sweep were given to increase stability and controllability. The final design was tested in XFLR5 for stability and in commercial computational fluid dynamic code ANSYS-Fluent for comparison. These simulation results were compared to wind tunnel tests of a 20% scaled down prototype. 3D Panel Method results in XFLR5 were found to be very close to wind tunnel results but CFD results were seen to be not conforming to the wind tunnel results after 10° angle of attack. Thus, CFD was deemed to be unnecessary for designing a plane of this size. Ultimately, a larger test prototype was made out of polystyrene foam and a successful flight was achieved.

Optimization of small aircraft parameters in the initial phase of the project

Conceptual and preliminary designs of future aircraft have become increasingly complex due to the enlargement of the basic criteria for evaluating emerging solutions. In the past, the basic performance characteristics of an airplane were the only selection criteria. Today, more and more emphasis is placed on factors such as impact on the environment, cost-effectiveness, or comfort of travel. The method for optimization of the key parameters of a small aircraft for use in the initial phase of a project is presented in this paper. It takes into account the requirements of aviation safety imposed by the European Union certification specifications CS-23 and requirements of aircraft competitiveness. Requirements and design assumptions were formulated based on the concept of the Small Air Transport system (SATs). The method is based on the multidisciplinary design optimization and covers the basic areas related to the design of aircraft: aerodynamics, aircraft structure, performance and expected operating costs. The objective function is defined as the value of the direct operating cost per passenger-kilometre. An evolutionary algorithm was applied to solve the optimization problem. As an example of the use of this method, the optimization of design parameters of the two classes of aircraft, 9-seater and 19-seater was carried out. The results were compared with the parameters of aircraft, which are in service. Sensitivity analysis of the objective function with respect to selected parameters of the aircraft was also made. The analysis allowed to select the most important parameters responsible for the operational costs.

The International Politics of the F-35 Joint Strike Fighter

There is a good reason why the F-35 Joint Strike Fighter program is so often described as the arms deal of the century. In a report published on the last day of 2010, the Pentagon estimated lifetime operating and sustainment costs for the US F-35 Aeet-then projected at 2,443 units, not counting the prototypes-at US$1.45 trillion.1 Cost analyses of this type are always much-debated: How many units will be sold in total? How does one define lifetime? How reliable will the system be once it enters service? What will be the nature of its deployment? And so on. Beyond dispute is that the F-35 constitutes one of the largest, if not the largest, weapons programs in modem history.The story of the Joint Strike Fighter (JSF) began in 1994, when the United States Congress decided to merge two separate Department of Defense fighter jet research projects. The idea was to produce a fifth generation fighter aircraft for the joint use of the US Air Force (USAF), Navy, and Marine Corps. Preliminary research contracts were divided mainly among McDonnell Douglas, Boeing, Northrop Gmmman, and Lockheed Martin, which subsequently formed teams that also involved other contractors, like Dassault (partnered with Boeing) and BAE (forming a threesome with McDonnell Douglas and Northrop Gmmman). The JSF program was purposely internationalized: a memorandum of understanding was signed by the US and British governments in December 1995, specifying a 90-10 split for co-funding the aircraft's demonstration phase, or, as it was officially known, the Weapons System Concept Demonstration (WSCD) phase.4 In November 1996 the Pentagon selected Lockheed Martin and Boeing as lead contractors; in October 2001 a long and fierce competition to carry out System Development and Demonstration (SDD) was won by the former. The Lockheed demonstrator X-35 turned into the F-35 Lightning II, which carried out its maiden flight in 2006; the two Boeing X-32 prototypes ended up in museums in Ohio and Maryland.The JSF was conceived from the beginning as a multi-role aircraft that would be capable of replacing four or five separate aircraft in use by the US military. To that end, the program gave birth to three different warplanes: the F-35A or the Conventional Take-Off Landing (CTOL) version, which is intended to replace the F-16 Fighting Falcon and A-10 Thunderbolt; the F-35B Short Take-Off and Vertical Landing (STOVL), replacing the AV-8B Harrier II; and the F-35C Carrier Version (CV), taking over from the F/A18 Hornet and possibly the Super Hornet. All three versions completed the critical design reviews and are now in the SDD phase. Low Rate Initial Production (LRIP) aircraft are rolling out from Lockheed Martin's assembly plant in Forth Worth, Texas, and the final Production, Sustainment, and Follow-on Development (PSFD) phase appears to be on the horizon. The US Marine Corps have established an operational squadron of F-35S at their Yuma, Arizona airbase, while instructor pilot training on the initial F-35S set to roll off the assembly line is progressing at a USAF base in Florida.5Globalized industrial partnerships propelled the JSF from the outset, but the multinational collaborative project took shape gradually. Most US allies were not briefed on the JSF until the beginning of the SDD phase, and it is unclear how the US government-specifically the nascent JSF office-decided which governments to engage.4 Canada joined in 1997, turning the US-UK collaboration into a multinational one. At that point, the JSF specified the conditions for different levels or tiers of partnership. Each level was mainly determined by the size of the partner's contribution. Level 1 partners contribute approximately 10 percent to the development of the aircraft. The UK is the only Level 1 partner and has committed $2.2 billion to the program. Level 2 partners, such as Italy and the Netherlands, contribute approximately $1 billion. Level 3 partners-Australia, Canada, Denmark, Norway, and Turkey-contribute $ioo-$2oo million. …

Protecting air transportation: a survey of operations research applications to aviation security

Catastrophic events often illustrate a nation’s preparedness in anticipating and preventing the extreme consequences of an intentional malicious attack. When terrorists hijacked four commercial aircraft for use as guided missiles against the World Trade Center and the Pentagon on September 11, 2001, the world’s population became aware of the human potential to inflict destruction and harm, and the vulnerability of transportation systems against preventing the occurrence of similar disasters. Through research, simulation, and system analysis, procedures may be formulated that limit or eradicate the possibility of future occurrences. Operations research encompasses the optimal allocation of resources subject to constraints, as well as providing techniques that evaluate the performance of security policies. This article provides a survey of operations research activities directed toward analyzing and enhancing the aviation security system, with the intent to be informative and motivate the continual improvement of our nation’s transportation security.

Review of the development of laser fluorosensors for oil spill application

As laser fluorosensors provide their own source of excitation, they are known as active sensors. Being active sensors, laser fluorosensors can be employed around the clock, in daylight or in total darkness. Certain compounds, such as aromatic hydrocarbons, present in petroleum oils absorb ultraviolet laser light and become electronically excited. This excitation is quickly removed by the process of fluorescence emission, primarily in the visible region of the spectrum. By careful choice of the excitation laser wavelength and range-gated detection at selected emission wavelengths, petroleum oils can be detected and classified into three broad categories: light refined, crude or heavy refined. This paper will review the development of laser fluorosensors for oil spill application, with emphasis on system components such as excitation laser source, and detection schemes that allow these unique sensors to be employed for the detection and classification of petroleum oils. There have been a number of laser fluorosensors developed in recent years, many of which are strictly research and development tools. Certain of these fluorosensors have been ship-borne instruments that have been mounted in aircraft for the occasional airborne mission. Other systems are mounted permanently on aircraft for use in either surveillance or spill response roles.

Helicopter loading time study: Hot versus cold

Introduction: Historically our program has used the practice of hot-loading at scenes as a time-saving measure. This practice potentially exposes patients and health care personnel to a variety of risks. Currently no data exist supporting the use of hot-loading as a time-saving technique. We prospectively studied load times and scene times for both hot- and cold-loading methods. Methods: Hot- or cold-loading methods were randomized according to odd or even days of the month for scene runs. Both loading times and total scene times were recorded. An ANOVA was used to compare the times, taking into consideration the aircraft in use (BO 105 or BK 117). Results: A total of 104 flights were entered into the study. For loading time, hot-loading showed a statistically significant difference (F [1, 100] = 112.84, P = 0.000). Means for hot- and cold-loading times are 3.071 and 5.033 minutes, respectively. The interaction effect of aircraft and loading method also was significant (F [1, 100] = 4.637, P = 0.034). The BO 105 (on high skids) was slower to hot-load. In contrast, the BK 117 (additional pretakeoff system checks) was slower to cold-load. The type of aircraft alone showed no effect on loading time. Total scene times were evaluated using the same procedures. A statistically significant difference also was found for the effect of hot-loading on total scene time (F [1, 100] = 11.391, P = 0.001). Means for hot and cold total scene times are 10.54 and 13.615 minutes, respectively. Conclusion: Hot-loading does decrease our program's overall scene times. The clinical significance of this procedure was not evaluated.

Diary of a Disaster: British Aid to Greece, 1940–1941 (review)

144 Reviews Robin Higham, Diary of a Disaster: British Aid to Greece, 1940—1941. Lexington, KY: University of Kentucky Press. 1986. Pp. viii + 261. $27.00. The reasons for the failure of the 1941 British expedition to Greece are generally known, but Robin Higham offers a considerable number of new details from archival sources and personal interviews, and he offers a provocative interpretation. As editor of Military Affairs and author of several publications on British military history, he is well-versed in the subject. Higham places the responsibility for the disaster on Winston Churchill and Anthony Eden. Churchill, he insists, failed to understand and adjust to the importance and need for thorough planning and good administration in the conduct of modern warfare. The author pits an impulsive Churchill against "rational, systematic officers" (p. 24), like General Sir John Dill, Air Chief Marshall, Sir Arthur Longmore, and General Sir Archibald Wavell, and the realistic Greek leaders, head of state, John Metaxas, and his Commander in Chief, General Alexander Papagos. In his determination to find the means to press the reluctant and exhausted Greeks to accept British aid, Churchill is presented as "changing his mind about objectives like a puppy in a fire hydrant factory" (p. 76). This an exaggeration, Higham makes a sound case. When the War Cabinet decided on 5 February 1941 to aid Greece, it did so more on wishful thinking than on hard analysis and good planning. Higham reminds us that the Greeks had less than a three-month supply of ammunition and coal to fuel Greek trains. In spite of British shortages in men and matériel, Churchill convinced himself of "mythical" (p. 84) reserves in Egypt. Further, the British planners neither insured the availability of adequate shipping to move the British expeditionary forces to Greece rapidly, nor did they check the availability of airfields and aircraft for use in Greece. Air Vice Marshall John D'Albiac expected these airfields to be ready at the end of April, which Higham points out "was two months after the Germans were expected to attack! And a month before that the Greeks might well be out of ammunition" (p. 84). But no one, aside from the Greeks, would say no to Churchill, who was determined to have a "great coup" (p. 24). Higham claims that no British officer would stand up to Churchill and tell him that "the Greek armed forces were inadequately equipped, that the British could not reequip them, and Wavell did not have the forces to do the job envisioned" (p. 54). The author argues that Metaxas and Papagos understood these points well and that if Metaxas had lived, he would have refused the British offer. IfDiIl and Wavell were indeed "rational and systematic" officers, Reviews 145 why did they agree to the expedition against their better judgment? Higham dismisses Dill as weak and concentrates on Wavell, who he argues fully understood the domestic and international political pressures on the British Prime Minister to achieve a victory against the Axis. The goal was to create a Balkan front of Greece, Yugoslavia, and Turkey. Wavell believed that preparations and aid to Greece could be a catalyst for the front, but unlike Churchill he never lost sight of his first priority to protect his recent gains in the Western front against Italy. Higham makes a leap of imagination and claims that Wavell believed he could solidify the Balkan front with "a gallant gesture at almost no cost at all" (p. 236). Since he could read the German preparations for the invasion through ULTRA, Higham contends that Wavell intended to time the arrival of the British expeditionary forces to coincide with the German crossing of the Greek frontier from Bulgaria. If the front had crystalized by that time, there would be chance of success against the German attacks. But if the front had not been formed, he would be able to evacuate his force safely and intact to Egypt. The scheme went awry because of bad weather and German delays which pushed the German attack back into April. This interpretation is unlikely to go unchallenged. Although the Greek side is not a major focus of the book, Higham offers a...

Surveillance of oil slicks at sea with US Coast Guard airborne remote sensing equipment

The United States Coast Guard is presently employing high technology state-of-the-art remote sensing equipment on board its medium and long range reconnaissance aircraft for use in many of its missions. One important mission is marine environmental protection. Detecting, identifying, mapping, and documenting oil spills are critical elements in directing and managing effective clean-up operations. Detecting and documenting illegal discharges from vessels and oil platforms are necessary for prosecuting offenders and protecting the environment from further degradation. Airborne remote sensors can greatly enhance environmental mission success. Radar can provide a wide area, rapid search capability. Ultraviolet and infrared line scanners can verify the existence of oil. Microwave radiometers can measure oil thickness and help estimate the volume of oil slicks. Laser fluorosensors can be used to classify the type of oil in a slick and detect neutrally buoyant oil below the sea surface. The US Coast Guard's airborne multi-sensor remote sensing capability has provided greatly improved methods by which to carry out this mission. This paper describes the history and development of the Coast Guard's present operational Airborne Remote Sensing System (‘AIREYE’), discussing its use for ocean oil spill detection and response.

Airplane Travel and Child Safety

As regular airline travelers will readily attest, infants and small children constitute a small but vocal minority of the passengers on commercial flights. Both of the authors have children less than 4 years of age and child restraint safety seats meeting the standards of the National Highway Traffic Safety Administration are routinely used for automobile travel. Use of safety seats has been routinely recommended to families receiving medical care from us. On several occasions, we have attempted to bring these same safety seats on board commercial aircraft for use by our children in seats for which we paid the fare.

Advanced Materials in Future Aircraft Design

As Professor Joad used to say — “It all depends what you mean by…” In this instance it all depends what you mean by future aircraft designs. There are many parameters which must be examined when choosing materials for any specific project, these involve material and manufacturing costs, aircraft performance, material performance and costs to the user such as damage tolerance, maintenance costs etc. The way in which these parameters are interwoven will depend considerably on the type of project being undertaken. A light aircraft for the Tiger Club would require a different mix of criteria to an advanced combat aircraft for the RAF. These in turn would be different from the selection that would be made for a one‐shot vehicle such as a booster rocket. In order to narrow this field we will concentrate on the type of aircraft which is typical of Kingston designs, the small high performance aircraft for use by the Air Forces of the world.

Astronautics and Guided flight Section

The target world like Gaul is divided into three parts, namely:Converted aircraftSpecially developed pilotless dronesTowed targetsand I propose talking about these three types in turn.The only converted manned aircraft in use in the UK is the Meteor U.16. This is a conversion of the Meteor F.8. The main structural change is the extended nose which houses the necessary black boxes, e.g. Autopilot, Control Radio Receiver, Telemetry transmitter, etc. By this means the aircraft can be flown with a pilot in the cockpit in the conventional way for non-firing runs or alternatively as a safety pilot when checking out the drone system.

Helicopters in the Royal Navy

“An historian is a prophet in reverse”.Friedrich Von SchiegelThe advantages to a Navy of an aircraft which can operate from a relatively small deck area are enormous and it is not surprising that the British as a maritime nation were in the forefront of the development of rotary wing aircraft for use at sea. However, the first man to land a rotary wing aircraft on a ship other than an aircraft carrier was an ex-Royal Air Force Officer R. A. C. Brie and the ship was the Italian cruiserFiume.

The Choice between One Engine or Two

THE current discussions to define a multi‐role aircraft for the mid 1970s have been notable for dissension of opinion on the choice between one engine or two. This remarkably basic choice has been with us since pioneer days — Lindbergh's acid comment on the value of two engines was ‘twice the trouble’, while the very fact that there are many aircraft in use of both layouts indicates that there has not been a clear case for choosing cither. Not, that is, until very recently, when statistics on the loss rate of both single and twin‐engined aircraft have confirmed that a definite margin does exist. This is the key to the whole choice between two engines or one, for it is necessary to compare not only the initial costs, but also the maintenance and operating costs, replacement of lost aircraft, and pilot training costs to achieve a realistic comparison on an overall cost basis. As with most cost‐effective arguments a strong danger exists of losing sight of primary objectives in a welter of tenuously related facts. The objectives in the choice between two engines and one is simple; which configuration fulfills an operational requirement at the least overall cost.

Airborne infra-red measurements at the Royal Aircraft Establishment∗

Infra-red radiometric and spectroscopic equipment fitted in a Comet aircraft for use up to 14,000 m altitude is described. Typical results are given as examples of the use of this installation. These include emission from towed pyrotechnic targets, infra-red reflection of sunlight from cloud tops, horizontal transmission measurements and high resolution atmospheric spectra out to 25μ using liquid helium cooled detectors.

Some considerations of optimum weights of fighter aircraft

Over the past ten to fifteen years there has been a tendency for fighter aircraft to grow in size, complexity and cost. This tendency became so marked that there has been a reaction towards reduced weight, greater simplicity and design economy intended to keep down the cost. Of late, both military authorities as well as design experts in many countries have paid considerable attention to philosophy of the light weight strike fighter. There is an opposing point of view which maintains that a fighter cannot be made too Light if it is to have good combat value. There are two major factors involved, namely cost and combat effectiveness. How are these factors to be weighed and an optimum design achieved? The problem is extremely difficult since no simple yardstick has been established to measure combat effectiveness. The armament carried, the electronic aids available for combat and precision navigations, the performance of the aircraft, its handling qualities and versatility of the aircraft for use in different roles during unforeseen exigencies are all factors of critical significance. A slight superiority in one respect or other might mean the difference between victory and defeat. The discussion of the light weight fighter concept has more or less been on a theoretical plane so far. Besides, opinions differ violently as to what exactly is meant when we say that a fighter is of light weight. Should its weight be 6,000lbs. or 18,000lbs.? These are all called light weight fighters by different countries in accordance with their own tactical concepts. The purpose of this paper is to highlight some relevant points and to discuss their technical implications.

The Causes of Noise in Aircraft

THE advantages which arise from the directness and speed of aircraft, and the high record for safety held by Air Lines like Imperial Airways, contribute to the increasing popularity of air travel. With many persons, however, the chief deterrent at present is understood to be the discomfort caused by the noise experienced, and there is no doubt that there are civil aircraft in use to‐day which are excessively noisy. Consequently attention has been directed recently in this and in other countries to suppressing the considerable noise to which passengers in aircraft cabins are usually subjected. The experiments are not yet completed, and it is not possible yet to answer all the questions that may arise. It is thought, however, that the following account of the trend of present results, as judged from recent work in the light of the writer's own experience, may be helpful in indicating the principles involved.

International Aerial Navigation and the Peace Conference

Aërial navigation, owing to the unusual impetus given to it by the Great War, now promises to result in one of the most profound influences affecting the conditions of modern civilization. It is difficult to realize that only twenty years have elapsed since the program of the First Hague Conference proposed “to prohibit the throwing of projectiles or explosives of any kind from balloons, or by any similar means”; and that one of the express causes inducing the nations of the world to agree to the proposal was the undeveloped character of the art of aviation. Although the treaty was short-lived and expired in 1905, the art had so greatly advanced that a complete change of the attitude of many governments had taken place and the renewal of the treaty was out of the question.The opening of the war inaugurated a feverish competition to perfect every possible type of aircraft for use in attack as well as for reconnaissance. The stern demands of military tactics introduced an entirely new phase in the development of aerial navigation.