Airfoils are the shape of wing cross section that results in aerodynamic efficiency. Each airfoil gives different flight characteristic as some are good for lift, some are good for fast flying with lesser drag force depends on the purpose of designed purposes.
Airfoils have numerous designs in general but the basic airfoil that is commonly used in the trainer plane is the flat bottom type. This design is developed for the plane that needs more lift and stable flight, the trainer plane is a good sample of this kind. However an aerobatic plane needs agile movement so as to snap into the desired fettle so the symmetrical airfoils are superb for this reason. In a supersonic airplane the airfoil is very complex and also very thin to reach maximum speed of the plane.
For RC flyer we need to have fundamental knowledge of airfoil in order to determine the type of plane we are flying. With a closer look on the wing’s airfoil we know the reason the plane is made for, and how to handle it in the air. Studying airfoils is relatively study of the lift which incurs more things in concern. So knowing airfoil is to find the right wing for plane but knowing lift is further topic we must cover to get the full story related to airfoil.
Lift is the most important part of flying so we seem to ravish extensive mankind energy to figure out how to build the lift force. As a fixed wing airplane we get into fundamental of lift that can be generated through these determinations.
1) Speed: Some time nominated by letter “V” or velocity. Lift can be built up on the wind speed that flows through the wing both from the engine and the wind itself – natural wind for the glider in this instance. For this reason the more the engine is accelerated the speed or velocity will be increased the more lift will be built up on the wing. A trainer airplane needs some speed to maintain itself in the air however a supersonic jet needs more speed to stay in the air – these are the matters of airfoil and wing size. In conclusion speed is one crucial factor that affects the lift.
2) Angle of attack: This is the wing angle that penetrates the wind. Some flyer might not interest in this point but it is in fact a factor that bears identical lift to the airplane. The picture is explaining how the lift can be increased in relation to the angle that is applied. In many plane the angle of attack is preset on the wing as typically known as Wing Incident.
3) Wing area: The wing area plays significant roll in the lift which is similar to the bird that is big bird has larger wing area than small bird. So the lift must be variable to the wing area that is calculated on wing loading. The carrier plane needs bigger wing area than a trainer plane as shown in the below picture. So wing loading is very important to get correct design to the airplane and is immensely affected the control of the RC plane in general. On the RC plane kits we must pay attention also to the wing area and wing loading as this will gives a hint of how it will behave in the air.
4) Airfoils : This was explained in the initial part of the story but it is less known to many as the flyer are not all the builder therefore we are not likely to get involve in the magic behind this thread. In short airfoil is the cross section area of the wing which is developed into various designs in accordance to the purpose of airplane usage.
This picture gives more detail on the airfoils which is a fundamental to the wing design. As RC builder it is an interesting issue but in reality the common use of the airfoils is not many – Clark Y is one of the popular airfoil among the RC builder.
The theory behind the Airfoils
Bernoulli is a famous scientist and the founder of fluid dynamics theory which is known as Bernoulli’s principle states that for an non viscosity flow of a nonconducting fluid, an increase in the speed of the fluid occurs simultaneously with a decrease in pressure or a decrease in he fluid‘s potential energy. Please see below picture for more understanding of his theory.
From Bernoulli theory this illustration shows the relationship between velocity and pressure that facilitates the lift under the airfoil design. On the upper part of the wing the pressure is less than the lower part’s so lift is generated according to the rule. This is a common issue to the RC builder but for the newbie in this hobby I hope it is helpful for you.
So the combination of Airfoils and the Angle of attack are the key factors for Lift. The Airfoils are not fully understood without the concept of lift so these two variants must be determined in a good respect in a wing design.