Controllability and observability are leading factors that need to be considered when designing
a system, and that is applicable for each and every type. In an aircraft system point of view, these
facts can be explicitly described. In an aircraft point of view, controllability and maneuverability
are interrelated, and one can be increased with the expense of their parameter. Accuracy and
precision are the other two factors that can be found in each system and those can be considered
as the main component that can be used to analyze the performance.
PRELIMINARY DESIGN APPROACH TO WING BOX LAYOUT AND STRUCTURAL CONFIGURATIONLahiru Dilshan
This is an assignment that was done to design the basic layout of the aircraft wing and structural configuration. Key aspects of the assignment are to design the structural layout, identify the basic component, identify the structural arrangement
PRELIMINARY DESIGN APPROACH TO WING BOX LAYOUT AND STRUCTURAL CONFIGURATIONLahiru Dilshan
This is an assignment that was done to design the basic layout of the aircraft wing and structural configuration. Key aspects of the assignment are to design the structural layout, identify the basic component, identify the structural arrangement
For Video Lecture of this presentation: https://youtu.be/NAjezfbWh4Y
The topics covered in this session are, drag, categories of drag, drag polar equation and drag polar graph, drag polar derivation, induced drag coefficient.
Attention! "Gate Aerospace Engineering aspirants", A virtual guide for gate aerospace engineering is provided in "Age of Aerospace" blog for helping you meticulously prepare for gate examination. Respective notes of individual subjects are provided as 'Embedded Google Docs' which are frequently updated. This comprehensive guide is intended to efficiently serve as an extensive collection of online resources for "GATE Aerospace Engineering" which can be accessed free of cost. Use the following link to access the study material
https://ageofaerospace.blogspot.com/p/gate-aerospace.html
Structural detailing of fuselage of aeroplane /aircraft.PriyankaKg4
This presentation is about the structural detailing of fuselage of aeroplane .The fuselage or body of the airplane, holds all the pieces together. The pilots sit in the cockpit at the front of the fuselage. Passengers and cargo are carried in the rear of the fuselage. Some aircraft carry fuel in the fuselage; others carry the fuel in the wings.
What are the elements of aircraft performance?
How much thrust do you need?
How fast and how slow can you fly?
#WikiCourses
http://wikicourses.wikispaces.com/Topic+Performance+of+aerospace+vehicles
Longitudinal static stability of boeing 737 max 8Lahiru Dilshan
Recently there were two aircraft crashes, Lion Air and Ethiopian airline crash with 346 people with the flight crew. Ethiopian aircraft incident is currently under investigation and the final report will be published in near future and the Lion Air incident report was published.
Both these aircrafts were in the same type aircraft, Boeing 737 MAX 8, brand new aircraft that introduced very recently for commercial use. There several design modifications and several new systems were included for that aircraft by the designers and manufacturers.
Emergency ejection system in military aircraft reportLahiru Dilshan
Safety is a major concern in the aircraft industry both in commercial and military services. In the fighter jets, there are several unique mechanisms used other than the commercial airliner. Pilots in the fighter jects can abandon the ship in case of an emergency but the other types of aircraft cannot use that kind of mechanism because the passengers are boarded.
IoT Device Intelligence & Real Time Anomaly DetectionBraja Krishna Das
-- Real Time Anomaly Detection
-- IoT Device Intelligence
-- Uni Variate and Multi Variate Anomaly Detection
-- Unsupervised Learning Classification from Anomaly Detection
For Video Lecture of this presentation: https://youtu.be/NAjezfbWh4Y
The topics covered in this session are, drag, categories of drag, drag polar equation and drag polar graph, drag polar derivation, induced drag coefficient.
Attention! "Gate Aerospace Engineering aspirants", A virtual guide for gate aerospace engineering is provided in "Age of Aerospace" blog for helping you meticulously prepare for gate examination. Respective notes of individual subjects are provided as 'Embedded Google Docs' which are frequently updated. This comprehensive guide is intended to efficiently serve as an extensive collection of online resources for "GATE Aerospace Engineering" which can be accessed free of cost. Use the following link to access the study material
https://ageofaerospace.blogspot.com/p/gate-aerospace.html
Structural detailing of fuselage of aeroplane /aircraft.PriyankaKg4
This presentation is about the structural detailing of fuselage of aeroplane .The fuselage or body of the airplane, holds all the pieces together. The pilots sit in the cockpit at the front of the fuselage. Passengers and cargo are carried in the rear of the fuselage. Some aircraft carry fuel in the fuselage; others carry the fuel in the wings.
What are the elements of aircraft performance?
How much thrust do you need?
How fast and how slow can you fly?
#WikiCourses
http://wikicourses.wikispaces.com/Topic+Performance+of+aerospace+vehicles
Longitudinal static stability of boeing 737 max 8Lahiru Dilshan
Recently there were two aircraft crashes, Lion Air and Ethiopian airline crash with 346 people with the flight crew. Ethiopian aircraft incident is currently under investigation and the final report will be published in near future and the Lion Air incident report was published.
Both these aircrafts were in the same type aircraft, Boeing 737 MAX 8, brand new aircraft that introduced very recently for commercial use. There several design modifications and several new systems were included for that aircraft by the designers and manufacturers.
Emergency ejection system in military aircraft reportLahiru Dilshan
Safety is a major concern in the aircraft industry both in commercial and military services. In the fighter jets, there are several unique mechanisms used other than the commercial airliner. Pilots in the fighter jects can abandon the ship in case of an emergency but the other types of aircraft cannot use that kind of mechanism because the passengers are boarded.
IoT Device Intelligence & Real Time Anomaly DetectionBraja Krishna Das
-- Real Time Anomaly Detection
-- IoT Device Intelligence
-- Uni Variate and Multi Variate Anomaly Detection
-- Unsupervised Learning Classification from Anomaly Detection
Availability is a performance criterion for repairable systems that accounts for both the reliability and maintainability properties of a component or system. It is defined as the probability that the system is operating properly when it is requested for use
"Capture" in a lambda expression - C++
A lambda expression is an anonymous, inline function. It is used to create a local function, mainly for passing as an argument to a function call or as a return value.
"Capture" makes variables in the local scope available for use in the body of the lambda expression. By default, variables are captured by value. Variables can be captured by the reference as well. Also, there are syntaxes which allow passing all the local variables and objects into the lambda expression.
What is CAD? What is CAE? and What is CAM? Did you hear about those three terms before? If so, what is the dedicated software, and how do they differ?
The first two letters of each word, "CA" stands for "Computer Aided", which means all three systems are created to help the user to achieve their goals with the power of computers.
In complete words, "D" stands for Design, "E" stands for Engineering and "M" stands for Manufacturing.
Even if you feel all these three terms are similar, that is not. Each one has its objectives.
In geometries, this word is used for shapes that lose their characteristics or that are not generated correctly. Degeneracies can arise due to issues in geometry (parametric) or topology. When parametric space is incompatible with the real world of the geometric model, degeneracy is created. Degeneration can happen not only for edges but also for curves, and faces. Degeneracy is not this kind is not harmful in and of itself. These shapes can be used in Boolean operations, and mesh. Degeneracies that happen after a Boolean operation will cause problems and at that time, we need to be aware of its existence.
Degenerate boundary is an incomplete or zero-area loop, or an incomplete or zero-volume shell.
An operator is a symbol designed to operate on data.
They can be a single symbol, di-graphs, tri-graphs or keywords.
Operators can be classified in different ways.
This is similar to function overloading
The basic meaning of the buffer is a memory block of a computer that acts as a temporary placeholder. Buffer is used in different fields and the most common examples are video streaming and RAM. In programming, a software buffer is denoted by a place that keeps data before the process is started. That will be fast rather than data writing in a direct way. People tend to use “buffer” when data is moving around. The reason is that the data will be temporarily placed in a buffer and move to the final destination afterward. When the receiving data rate is different from the processing data rate, buffers are very useful. You will get to know this while video streaming.
Open CASCADE Technology (OCCT) is a C++ library that is designed for the production of domain-specific CAD/CAM applications. The most important feature of this library is it is free. But the applicability and capacity of this library are huge. Many open-source CAD/CAM products are based on this. With the help of a huge community and development team, developers, users, researchers, and commercial product developers can use it for different industrial applications, research, and many more.
The mechanism is an assembly of machine components (Kinematic Links) designed to obtain the desired motion from an available motion while transmitting appropriate forces and moments.
Four bar linkage is a simple planer mechanism which has four bar shaped members. Usually it has one fixed link and three moving links and four pin joints.
This presentation was prepared to present on behalf of judges of IESL to achieve IESL Industrial Training Award 2020.
Here I included a summary of activities and project experience which performed during the training period.
“Araliya Mushrooms” is a business firm situated in Baddegama, Galle which was founded in 2013. The business started on a small scale with only 2 people and now the firm is expanded within 5 years of time. There are 5 people currently working in the firm. “Araliya mushrooms” firm is the largest mushroom production firm in that region. The main target customers of the business are small scale vegetable vendors.
Computational and experimental investigation of aerodynamics of flapping aero...Lahiru Dilshan
Renewal interest on the exploitation of flapping flight motions to attain high propulsion efficiency of air vehicles is inspired by the aerodynamics of birds’ and insects’ flights. The flapping characteristics can be majorly used to develop micro aerial vehicles (MAV) as this is a lucrative method to generate lift and thrust simultaneously. In this project, the variation of the flow properties and the thrust generation of an airfoil in a flapping (plunging) motion, is evaluated using both computational and experimental methods. The NACA 2412 airfoil was selected for the study and, the computational method was carried out using an inviscid flow model and computational fluid dynamics (CFD) simulations, simultaneously to obtain and compare the variation of properties.
The inviscid model was developed using conformal mapping and potential flow theories, and it is capable of producing results for any arbitrary aerofoil. Steady-state results were compared and validated in both CFD and inviscid flow modelling as the computational framework along with flow visualisation and force sensing as the experimental framework. The validated CFD and inviscid models have been developed to produce a plunging motion to the aerofoil and obtain the variation of drag and lift coefficients with time. The experimental setup was designed to obtain the forces acting on the airfoil, and the flow characteristics were visually observed using a flow visualization technique. The force calculations were done through a developed and optimized load cell arrangement. The developed smoke flow visualisation technique is capable of successfully capturing streamline patterns, flow separation regions. These results were compared along with wake development between computational and experimental models. The Level of agreement and limitations of each method have been discussed in this report.
Experimental and numerical stress analysis of a rectangular wing structureLahiru Dilshan
Structures of an aircraft can be categorised as primary structural components and secondary structure components. Primary structure components are the components which lead to failure of the aircraft if such component is failed during the flight cycle. Secondary components are load sharing components in an aircraft but will not pave the way to catastrophic failure.
Designing aircraft structures should follow several strategies to assure safety. For that, there are three main methods used in designing and maintenance procedures. First one is the safe flight, which an aircraft component has a lifetime. That component is not used beyond that limit and should replace though it is not failed. The fail-safe method is another one that redundant systems or components are there to ensure there is another way to carry the load or do necessary control. The final one is the damage tolerance which measures the current damages are within acceptable limit and carry out the main functions until the next main maintenance process.
To determine the safety of a structure component load distribution, stress and strain variation, deflection can be used as parameters to make sure that component can withstand maximum allowable load with safety factor. There are several techniques used to get accurate results as numerical methods, Finite Element Method (FEM) and experimental methods. In the design process, those three steps are followed in an orderly manner to ensure the safety of an aircraft.
Experimental and numerical stress analysis of a rectangular wing structureLahiru Dilshan
Structures of an aircraft can be categorised as primary structural components and secondary structure components. Primary structure components are the components which lead to failure of the aircraft if such component is failed during the flight cycle. Secondary components are load sharing components in an aircraft but will not pave the way to catastrophic failure.
Designing aircraft structures should follow several strategies to assure safety. For that, there are three main methods used in designing and maintenance procedures. First one is the safe flight, which an aircraft component has a lifetime. That component is not used beyond that limit and should replace though it is not failed. The fail-safe method is another one that redundant systems or components are there to ensure there is another way to carry the load or do necessary control. The final one is the damage tolerance which measures the current damages are within acceptable limit and carry out the main functions until the next main maintenance process.
To determine the safety of a structure component load distribution, stress and strain variation, deflection can be used as parameters to make sure that component can withstand maximum allowable load with safety factor. There are several techniques used to get accurate results as numerical methods, Finite Element Method (FEM) and experimental methods. In the design process, those three steps are followed in an orderly manner to ensure the safety of an aircraft.
Transient three dimensional cfd modelling of ceilng fanLahiru Dilshan
Ceiling fans are used to get thermal comfort, especially in tropical countries. With the increment of the usage of air conditioners, the emission of CO2 is increased. But ceiling fans are a limited solution, that saves much energy compared to air conditioners. Ceiling fans generate a non-uniform velocity profile, so that, there is a non-uniform thermal environment. That non-uniform environment does not imply lower thermal comfort, that will give enough thermal comfort with low energy cost by air velocity. Hence, there will be difficulties of analysing with simple modelling techniques in that environment. So, to predict the performance of the ceiling fan required more accurate models.
The accurate model of a ceiling fan will generate complex geometry that makes difficulties for the simulation process and requires higher computational power. Because of that, there are several methods used to predict the performance of the ceiling fan using mathematical techniques but that will give an estimated value of properties in the surrounding.
General inclusion: flight crew, passengers, munitions, cargo, scientific instruments or experiments, and other equipment aboard.
General Discipline:
Prevention of accidents and incidents
Protection of aircraft occupants
HUMAN FACTOR CONSIDERATIONS IN MILITARY AIRCRAFT MAINTENANCE AND INSPECTIONSLahiru Dilshan
study of how humans behave physically and psychologically in relation to particular environments, products, or services. application of psychological and physiological principles to the engineering and design of products, processes, and systems.
Human factors - Maintenance and inspectionLahiru Dilshan
Maintenance information should be understandable by the technicians and inspectors. Therefore new manuals, job cards and service bulletins should be tested before distribution.
Passengers are more and more demanding in terms of comfort. Therefore thermal comfort inside the cabin is more important.The state of mind, which expresses satisfaction with the thermal environment- ISO 7730
Displays and controls arrangement of military aircraftLahiru Dilshan
In modern-day military aviation, displays are the most
a reliable method of presenting information to the pilots,
with the increment of more sophisticated controls
given to the pilots.
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Student information management system project report ii.pdfKamal Acharya
Our project explains about the student management. This project mainly explains the various actions related to student details. This project shows some ease in adding, editing and deleting the student details. It also provides a less time consuming process for viewing, adding, editing and deleting the marks of the students.
Hybrid optimization of pumped hydro system and solar- Engr. Abdul-Azeez.pdffxintegritypublishin
Advancements in technology unveil a myriad of electrical and electronic breakthroughs geared towards efficiently harnessing limited resources to meet human energy demands. The optimization of hybrid solar PV panels and pumped hydro energy supply systems plays a pivotal role in utilizing natural resources effectively. This initiative not only benefits humanity but also fosters environmental sustainability. The study investigated the design optimization of these hybrid systems, focusing on understanding solar radiation patterns, identifying geographical influences on solar radiation, formulating a mathematical model for system optimization, and determining the optimal configuration of PV panels and pumped hydro storage. Through a comparative analysis approach and eight weeks of data collection, the study addressed key research questions related to solar radiation patterns and optimal system design. The findings highlighted regions with heightened solar radiation levels, showcasing substantial potential for power generation and emphasizing the system's efficiency. Optimizing system design significantly boosted power generation, promoted renewable energy utilization, and enhanced energy storage capacity. The study underscored the benefits of optimizing hybrid solar PV panels and pumped hydro energy supply systems for sustainable energy usage. Optimizing the design of solar PV panels and pumped hydro energy supply systems as examined across diverse climatic conditions in a developing country, not only enhances power generation but also improves the integration of renewable energy sources and boosts energy storage capacities, particularly beneficial for less economically prosperous regions. Additionally, the study provides valuable insights for advancing energy research in economically viable areas. Recommendations included conducting site-specific assessments, utilizing advanced modeling tools, implementing regular maintenance protocols, and enhancing communication among system components.
Industrial Training at Shahjalal Fertilizer Company Limited (SFCL)MdTanvirMahtab2
This presentation is about the working procedure of Shahjalal Fertilizer Company Limited (SFCL). A Govt. owned Company of Bangladesh Chemical Industries Corporation under Ministry of Industries.
Explore the innovative world of trenchless pipe repair with our comprehensive guide, "The Benefits and Techniques of Trenchless Pipe Repair." This document delves into the modern methods of repairing underground pipes without the need for extensive excavation, highlighting the numerous advantages and the latest techniques used in the industry.
Learn about the cost savings, reduced environmental impact, and minimal disruption associated with trenchless technology. Discover detailed explanations of popular techniques such as pipe bursting, cured-in-place pipe (CIPP) lining, and directional drilling. Understand how these methods can be applied to various types of infrastructure, from residential plumbing to large-scale municipal systems.
Ideal for homeowners, contractors, engineers, and anyone interested in modern plumbing solutions, this guide provides valuable insights into why trenchless pipe repair is becoming the preferred choice for pipe rehabilitation. Stay informed about the latest advancements and best practices in the field.
Cosmetic shop management system project report.pdfKamal Acharya
Buying new cosmetic products is difficult. It can even be scary for those who have sensitive skin and are prone to skin trouble. The information needed to alleviate this problem is on the back of each product, but it's thought to interpret those ingredient lists unless you have a background in chemistry.
Instead of buying and hoping for the best, we can use data science to help us predict which products may be good fits for us. It includes various function programs to do the above mentioned tasks.
Data file handling has been effectively used in the program.
The automated cosmetic shop management system should deal with the automation of general workflow and administration process of the shop. The main processes of the system focus on customer's request where the system is able to search the most appropriate products and deliver it to the customers. It should help the employees to quickly identify the list of cosmetic product that have reached the minimum quantity and also keep a track of expired date for each cosmetic product. It should help the employees to find the rack number in which the product is placed.It is also Faster and more efficient way.
Courier management system project report.pdfKamal Acharya
It is now-a-days very important for the people to send or receive articles like imported furniture, electronic items, gifts, business goods and the like. People depend vastly on different transport systems which mostly use the manual way of receiving and delivering the articles. There is no way to track the articles till they are received and there is no way to let the customer know what happened in transit, once he booked some articles. In such a situation, we need a system which completely computerizes the cargo activities including time to time tracking of the articles sent. This need is fulfilled by Courier Management System software which is online software for the cargo management people that enables them to receive the goods from a source and send them to a required destination and track their status from time to time.
Saudi Arabia stands as a titan in the global energy landscape, renowned for its abundant oil and gas resources. It's the largest exporter of petroleum and holds some of the world's most significant reserves. Let's delve into the top 10 oil and gas projects shaping Saudi Arabia's energy future in 2024.
Quality defects in TMT Bars, Possible causes and Potential Solutions.PrashantGoswami42
Maintaining high-quality standards in the production of TMT bars is crucial for ensuring structural integrity in construction. Addressing common defects through careful monitoring, standardized processes, and advanced technology can significantly improve the quality of TMT bars. Continuous training and adherence to quality control measures will also play a pivotal role in minimizing these defects.
2. 1
Abstract
Controllability and observability are leading factors that need to be considered when designing
a system, and that is applicable for each and every type. In an aircraft system point of view, these
facts can be explicitly described. In an aircraft point of view, controllability and maneuverability
are interrelated, and one can be increased with the expense of their parameter. Accuracy and
precision are the other two factors that can be found in each system and those can be considered
as the main component that can be used to analyze the performance.
This report is dedicated to addressing how controllability and observability are used in system
point of view and how the accuracy and precision are essential to the systems. In the later part,
that discusses the relationship between controllability and observability and how these concepts
are used in different aircraft designs and how they are improved in the various aircraft categories.
3. 2
Table of Contents
Abstract............................................................................................................................................1
Table of Contents.............................................................................................................................2
Introduction......................................................................................................................................3
Controllability and Observability ....................................................................................................4
Accuracy and Precision ...................................................................................................................5
Controlled Flight..............................................................................................................................7
Conclusion.......................................................................................................................................9
References......................................................................................................................................10
4. 3
Introduction
Controllability, stability, observability, and maneuverability are different nomenclatures used
in the control system's point of view. Understanding of those terminologies is more critical to
develop more complex systems without considering the type.
Controllability is the response of an aircraft in a steady flight on the pilot control input.
Stability can be described as the tendency of an airplane to return to a trimmed position after
disturbance in an air stream. Maneuverability can be defined as the ability for the aircraft to
commence and sustain maneuvers, its responsiveness, and its performance rate of roll or turn and
pitch rate. But the observability is developed within the control system designing method, and
there are several technical methodologies for that. These factors work in an interrelated and
correlated manner, not as individual and unique features.
When considering the accuracy and precision, these are also correlated facts that need to be
understood and should implement in each system. When the accuracy is high, but the precision is
low or vice versa, the reliability of the system gets low. So, there should be high accuracy and
precision in most of the arrangements. Several technics can follow to increase accuracy and
precision, but there are limitations. In aircraft systems especially control systems, these factors
should be highly considered and clearly identified.
5. 4
Controllability and Observability
The state variable approach is a powerful method to analyze and design of control system.
The state-space analysis is a modern approach that uses in digital computers. Analyze and
designing of systems can be carried out in a linear system, non-linear system, time-invariant
system, varying time system, and multiple inputs and output systems. That state variable approach
is different from the transfer function model as there are several drawbacks such as, the transfer
function is defined under zero initial condition, the transfer function applies to linear time-invariant
systems, transfer function analysis is restricted to a single input and single-output systems. Also,
that does not provide information regarding the internal state of the system. So that controllability
and observability concept has developed.
Controllability concept proved the usefulness of the state variable approach. Mainly, that
indicates, state variable can be controlled to achieve the desired output. In a system, if each state
variable can be found such that those variables can take from a desired initial state to a desired
final stage, that system is said to be a controllable system. Otherwise, the system is uncontrollable.
In other words, a system is said to completely state controllable if it is possible to transfer the state
from an initial state to any other desired state in specified finite time by a control vector.
A system is said to be utterly observable if every state can be identified entirely by the
measurements of the output over a finite time interval. Using the observability test can be used to
find the state variable is observable or measurable. Also, that can be used to solve the problem of
reconstructing unmeasurable state variables from measurable ones in the minimum possible length
of time.
Simply, controllability is concerned with whether one can design control input to steer to
arbitrary values and observability is concerned with whether without knowing the initial state, one
can determine the state of a system given the input and the output.
6. 5
Accuracy and Precision
In a simple definition, accuracy means the closeness of a measured value to a standard or
known value. Accuracy describes systematic errors, a measure of statistical bias. Also, that can be
used to express a combination of both types of observational error.
Precision refers to the closeness of two or more measurements to each other. In other words,
the data set is said to be precise if the values are close to each other when it measures the same
condition. Precision is a description of random errors, a measure of statistical variability.
Figure 1 - Accuracy and Precision
a. Accuracy b. Precision
Figure 2 - Accuracy and Precision - the difference
7. 6
In the scientific world, the accuracy of a measurement is the degree of a quantity to the actual
value of the measurement. Precision relates to reproducibility and repeatability. Precision and
accuracy are two independent properties in measurements. A measurement system can be accurate
or precise or both. Otherwise, those can be not accurate and precise, as well. The measurement
system is said to be valid if both accurate and precise. The comparison between accuracy and
precision is given in Table 1.
Table 1 - Accuracy and Precision - comparison
Basis for comparison Accuracy Precision
Meaning Relates to the level of
difference between the
actual measured value
and absolute value
This refers to the level of
variation that lies in the values
of several measurements under
the same conditions.
Represents Results close to the
standard values
Results how close with one
another
Degree Degree of conformity Degree of reproducibility
Factor Single-factor Multiple factors
Measure of Statistical bias Statistical variability
Concerned with Systematic error Random error
By controlling all the other variables in the system is the primary method to improve accuracy
and precision. Taking measurement multiple times and increasing the number of samples will
remove the random error in the measurements and increase the precision of the results.
8. 7
Controlled Flight
When considering the controlling of an aircraft, the stability and the controllability are vital
concepts. The stability can be categorized into two as static and dynamic. Furthermore, these can
be classified as positive, negative, and neutral stability.
Static stability is the initial tendency of an object to return to its original position after being
disturbed. When the controls are changed and release, the airplane initially moves back to the
original position is the positive static stability. When the aircraft stays where it is after changing
the controls, that shows neutral stability, and when it tends to move further away from the original
position, that means negative stability.
Dynamic stability is there if the aircraft is positively stable. Dynamic stability is the overall
response of an object to its static stability. When an aircraft is disturbed, the overall pattern of
movement becomes progressively smaller, that will be the positive dynamic stability. When it is
in the neutral dynamic stability, the overall pattern of movements is continuously unchanged, if
the airplane is disturbed. If the overall pattern of movements become progressively larger when
the aircraft is disturbed, that shows the negative dynamic stability.
As an aircraft has 3 axes, longitudinal, lateral, and vertical, each axis has its own stability.
Pitch control is responsible for longitudinal stability. The center of gravity and center of lift and
horizontal stabilizer downforce are the facts that need to concern in longitudinal stability, and that
will mostly affect the aircraft loading.
Lateral stability is interrelated with the rolling movement around the longitudinal axis. If
excellent lateral stability will tend to bring the wings to a level flight altitude when one wing is
lower than the other. In general, cases, positive dihedral wings, and high wings provide more
lateral stability. Directional stability is related to the yaw movements, around its vertical axis, and
the airplane’s ability to not be adversely affected by force, creating a yaw type motion. Generally,
sweptback wings, double taper wing arrangements, to a lesser extent, will provide more directional
stability than other wing configurations.
Controllability of an aircraft is the capability of an aircraft to respond to the pilots' control
inputs, and the maneuverability is the quality of the aircraft that can be easily controlled in the
given space region. Also, the airplanes are designed such that, dynamically more stable than the
rotorcrafts because of the sudden maneuverability should be there.
If something is very stable, it is more difficult to change the altitude of that. If an aircraft is
unstable, it’s easier to change its altitude. Based on that, civilian aircraft tend to be very stable,
and fighter jets are more volatile. Commercial aircrafts are easier to control, safe in operation and
9. 8
more comfortable because of the task mentioned above. On the other hand, fighter jets are more
unstable, so most of such aircraft are difficult to handle by pilots. Thus, artificial stability methods
such as computerized controlling are used.
A more suitable example of the fact that discussed above is the BE.2 aircraft. That aircraft
was designed as a two-seater trainer aircraft in 1912. As the purpose is the training pilots, designers
tend to design is a highly stable state. So that the maneuverability is drastically reduced and
controlling response is lagged. Because of that situation, that aircraft was easily outmaneuvered
by the pilots. So, it had to be withdrawn from the frontline service in the war zone because that is
not fit for the air-to-air battles. But that was used in artillery observations and aerial photography
duties.
Like previous sections, controllability is the response of an aircraft in steady flight, on pilot
control inputs. For instance, when the pilot deflects the ailerons, a high resulting roll rate means a
fast response. The stability can be described in the level flight as the tendency of an aircraft
airframe to return to a trimmed position after a disturbance in the air stream. So, there is no need
for interaction from the pilot to get the aircraft to its initial position from the deflected position.
For that, both control deflection and aerodynamic stability should be preserved. As an example, if
the center of gravity (CG) is far aft position, that may not recover the stability whether the inputs
are given. So that there is an issue in slow flights to get back to the stable situation when the CG
is positioned far aft. So that, less stability makes the less controllability of the aircraft at slow
speeds.
10. 9
Conclusion
Controllability, Stability, Maneuverability, and observability are several factors that need to
be considered in the aircraft system design. Those factors need to be considered not only in the
aircraft systems but also in the other control system design. By changing the parameters of the
system, those can be controlled.
Stability and controllability have an inverse relationship as stability can be increased by
expensing the controllability. So that military aircraft are more controllable and less stable. On the
contrary, commercial aircrafts are more stable to ensure comfortability and less controllable.
Accuracy and precision are the other two factors need to be considered when designing the
control system. These two parameters should be in the system together. Otherwise, there will be
several errors, and remedies should be introduced.
11. 10
References
[1] “Stability and Control (Part Two),” 2017. [Online] Available: https://www.fligh-
mechanic.com/stability-and-control/.
[2] “Aircraft Stability (Part One),” 2017. [Online] Available: https://www.fligh-
mechanic.com/aircraft-stability-part-one/.
[3] “Aircraft Stability (Part Two),” 2017. [Online] Available: https://www.fligh-
mechanic.com/aircraft-stability-part-two/.
[4] D.A. Caughey, “Introduction to Aircraft Stability and Control Course Notes,” Sibley School of
Mechanical and Aerospace Engineering, New York, 2011
[5] Surbhi. S. “Difference Between Accuracy and Precision”, Key Differences, 5 January 2018.
[Online] Available: https://keydifferences.com/difference-between-accuracy-and-precision.html.
[Accessed 26 September 2019]
[6] “What is the Difference Between Accuracy and Precision?”, ThoughCo. [Online] Available:
https://www.thoughtco.com/difference-between-accuracy-and-precision-609328. [Accessed 26
September 2019]
[7] Skiba R. “Stability, Controllability and Maneuverability”, volume 16 No 3. 1999