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DOWNLOADInternational Standard Atmostphere (ISA)
Issue 13, 12 December 2022
By: Anthony O. Ives
The atmosphere has a very important impact on how aircraft perform and hence on how aircraft are designed. The problem with the atmosphere is it changes from day to day as well as seasonal variations. International Standard Atmosphere (ISA) is a typical average atmosphere that you would expect in a moderate climates such as in western europe and parts of north america refered to as ISA conditions. In reality exact ISA conditions are very rarely experienced even in climates where ISA conditions are expected. So ISA conditions are generally used as a baseline and can be adjusted and compensated for depending on the variation from ISA conditions in day to day flight operations.
Issue 12, 28 November 2022
By: Anthony O. Ives
Trigonometry has many applications in engineering, architecture, carpentry and joinery. Trigonometry can be used to determine angles, distances, components of velocities, forces and other vector properties. The trigonometry equations apply to right angle triangles essentially one of the three angles must be 90 degrees however, most triangles that do not have a right angle can usually be split into 2 or more right angle triangles.
Thrust Coefficient and Inflow States
Issue 11, 14 November 2022
By: Anthony O. Ives
Thrust coefficient was introduced in a previous blog article, in that blog article the thrust coefficient was defined in terms of lift coefficient. This article will introduce lift coefficient in terms of rotor blade pitch and rotor inflow which can then be used to give thrust coefficient in terms of rotor blade pitch and rotor inflow. An equation can relate lift coefficient to an airfoil angle of attack (or incidence angle), the origin of this equation will be explained in more detail in a later article but for now we will just use it to understand the influence of inflow on rotor thrust.
Issue 10, 31 October 2022
By: Anthony O. Ives
The most commonly misunderstood formulae in mathematics is those used to calculate circle circumference and area. Circle circumference is distance around the outside of circle. Circumference is very easy to calculate.
The Nature of Exponential Logarithms!
Issue 9, 17 October 2022
By: Anthony O. Ives
Logarithims were briefly introduced in two previous blog articles. Originally logarithms were used for doing arithmetic with large numbers before the introduction of the electronic calculator. Such things as log tables and slide rules were used to do calculations in the way electronic calculators and computers are used today. Flight computers are devices that are used by pilots still today to do calculations which are circular slide rule and make use of logarithmic scales.
Power of little numbers or indices
Issue 8, 3 October 2022
By: Anthony O. Ives
Mathematical notation is just a shorthand way of describing mathematical operations to perform on a quantity or set of quantities to determine another quanitity or set of quantities. The lift coefficent equation is good example of this. The lift coefficent equation describes how lift is related to aircraft velocity, wing area, lift coefficient and air density in shorter more concise, convient, clear way. Try describing the relationship in words and it would be a lot longer and probably very confusing plus not that easy to manipulate if for you want to determine stall velocity is related to lift, etc.
Issue 7, 19 September 2022
By: Anthony O. Ives
Endurance is the maximum time an aircraft can fly for. For most aircraft endurance is important as an aircraft may have to wait to land and need to loiter until a landing slot becomes available. However, some aircraft their specific mission may require them to loiter over a certain location such as surveillance aircraft. For propeller driven aircraft, drag power ratio has the most influence over endurance. Drag power is the amount of engine power required to overcome the aircraft drag.
Issue 6, 5 September 2022
By: Anthony O. Ives
Range is the usually the maximum distance an aircraft is designed to fly. It is important for most aircraft, as generally aircraft are designed to carry a payload a certain distance. The range equation is different for propeller driven aircraft with expendable fuel such as gasoline to that of a battery powered propeller driven aircraft.
Issue 5, 22 August 2022
By: Anthony O. Ives
The stability of an aircraft is really determined by how comfortable and safe the aircraft is to fly. If you have to continuely correct the aircraft so it does not fly of course then it can very tiring and potentially unsafe and very frustrating for the pilot in an overall unpleasant way.
Issue 4, 8 August 2022
By: Anthony O. Ives
Thrust is important in a fixed wing aircraft to overcome drag and move the aircraft forward and generate airflow over its wings. In the case of a rotary wing aircraft or helicopter the thrust provides both forces to overcome drag in forward flight and produce the lifting force to keep the aircraft airborne. Rotors and propellers use the same principle as wings to produce lift.
Issue 3, 1 August 2022
By: Anthony O. Ives
Estimating aircraft wing area is the first thing that allows you to define the rest of the geometry of the aircraft. However, you generally need an estimate of mass to determine your wing area. If you are building functional UAV which has a specific purpose this article makes an intial estimate of aicraft total mass based on your payload, endurance and range requirements.
Issue 2, 25 July 2022
By: Anthony O. Ives
Drag is a force produced as an object moves through a fluid. In order to determine the thrust required to power your aircraft you need to determine drag.
Issue 1, 18 July 2022
By: Anthony O. Ives
Fixed wing aircraft are a good place to start when to learning how to size small remote controlled aircraft. Fixed wing design is also relevant in the design of winged helicopters and tilt rotor aircraft. Fixed wing aircraft are also simpler to build than rotary wing aircraft.
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