Switchblade is a small or miniature loitering munition developed by AeroVironment. It is mostly used by the United States army and also used in the Russian – Ukrainian war. Switchblades can be carried by the army by using a backpack. Switchblade gets launched from a tube and then flies to the target where it detonates by using an explosive warhead. There are two variants of Switchblade 300 and 600. 

Switchblade loiter munition

Switchblade is used for long range targets. It has the capability of identifying, tracking and engaging the targets as well as to follow a pre-programmed line of path. Switchblade 300 is designed to destroy light armored vehicles and can also be made to retarget en-route. It is very small and does not produce noise and does not have any heat signature which makes it very difficult to identify and  intercept. 

Switchblade 600 is similar to 300 and it is portable and can be set up in 10 minutes. It can fly up to 40 km in 20 minutes and after that loiter for next 20 minutes giving it a maximum range of 80 km. It can strike a target at  a speed of 185 km/h. Its GPS system provides situational awareness, information collection, object and target recognition. It is propelled by an electric battery and a propeller located at the back. It has a two tandem piercing warhead and can also destroy tanks with reactive armour. 

So, a Switchblade 600 can destroy a tank. It has two warheads. The first one destroys the reactive armour which is meant in the tank to counteract RPG or missiles and the second warhead destroys the tank. 

Since the Switchblades work on GPS for its location and navigation, it can be jammed and its operation can be disrupted. Also it has a range of only 40 km and an endurance of 20 minutes. Also for utilizing its long range capabilities of 80 km it requires two antennas to be deployed in the field for relaying command from one operator to another through data link.

Switchblade launch from a tube

Loitering munition as the name suggests is a munition which loiters on any target and then makes a hit. This was first tested or used in 1944 by the Japanese special attack unit of military aviators. This type of suicide aircrafts are also called Kamikaze and this is a Japenese word with its literal meaning as divine or spirit wind. 

This warcraft  is a combination between UCAV and missile. On seeing at a first glance we can infer that it is a cruise missile having wings. This type of weaponry system falls in between the above two categories. It is similar to the cruise missile but has the capability to loiter on any target for a considerable amount of time. Unlike UCAV it has inbuilt warhead. 

Loitering munition examples are IAI Harpy, skyStriker, Warmate, Switchblade, Trinetra, Nagastra, Raytheon Coyote. 

Switchblade loitering munition

These type of suicide drones were first made in 1980s  but the term loitering munition was not used. From the 2000s these types of drones were made to have extra capabilities, there were improvements in design as well as some advanced technologies were added. 

Loitering munitions are used by both Russia and Ukraine at present and have found success in disrupting the armed forces. 

Lancet loitering munition

These type of drones can be countermeasured  by making cages of chain link fencing, wire mesh and wooden logs around the target which confuses it. Inflatable decoys and wooden vehicles can also be used to confuse these drones. These drones can also be shootout by rifles. Electronic warfare systems can also be used to stop the drone by jamming the GPS and radio links. A slat armor can also be used around vehicles as these drones have a less powerful warhead.

Aerodynamics is the study of flow of air over any object. It is the study of dynamics of air. Any object which undergoes any motion has an aerodynamic effect in it. We can harness the power of air through aerodynamics. In general aerodynamics has a degrading feature which is called drag. 

Drag opposes the motion of the object or the vehicle. So, there will be more consumption of fuel by the engine in order to overcome this drag. The amount of drag increases with the speed. So car designers need to design cars in such a way that there should be a minimum effect of drag. There is also one effect of aerodynamic forces, which is lift. For the aircraft lift is useful, as it makes the aircraft fly in the sky. However, for the case of a car, it is not useful. The air which is blowing beneath the car can uplift the vehicle when the car is moving at a very high speed.

Air flow over car

So, with respect to a car we need to see both lift and drag. Nowadays cars are designed which are of aerodynamic design. Aerodynamic design means the car is designed to overcome both lift and drag forces or to utilize it for the enhancement of car performance. Cars are now made of streamlined shape. By streamline means there is a smooth flow of air over the car body. When there is a smooth flow of air and no restriction to it, then there is a very less creation of drag force. We have cars with door handles and wipers as well as flush headlights and glasses designed in such a way that it provides least resistance to the flow of air. So now in a car there is more concentration on its design with every detail. Similarly bumpers with spoilers are provided in order to channelize the flow of air beneath the car and create a downforce such that the car does not leave the ground at a very high speed. Similarly a rear wing is also present in racing cars in order to create a downward force at high speeds. These are adjustable which means it can move up and down in order to adjust and create the required downforce. 

Smooth car design

Earlier designs of the cars used to have a blunt body. A blunt body can create a huge amount of drag.  At lower maximum speed of cars this does not create a significant amount of drag, however at  high speed it can create substantial amount of drag and can affect the performance of cars. 

So this is how aerodynamics work on a car.

Aerodynamics is the study of dynamics of air. When there is a flow of air over any object, then there is a creation of lift force as well as drag force. These two forces are a result of pressure differences which are created due to flow of air over the top and bottom surface of the body and also due to shear stress on the surface of the body. However, a major contribution is of forces which are created due to pressure difference. These forces are normal and perpendicular to the flow direction. 

The force which is perpendicular to the flow direction is lift force. The force which is parallel to the air flow is drag force. Lift force and drag force are both related to a coefficient, which plays a major role in calculation of these two forces. These coefficients are called lift coefficient and drag coefficient. 

Lift and drag forces are proportional to the surface area, density and velocity of air. Formula to calculate the lift coefficient is 

\[{c_l} = \frac{L}{{q_\infty }S}\]

and to calculate drag coefficient is 

\[c_d =\frac{D}{{q_\infty }S}\]

 Lift force makes any object fly. It uplifts the object from the ground. Drag force opposes the motion of the object. In order to overcome this drag force there needs to be some counteracting force. The engine of the vehicles as well as of the aircraft opposes the drag force and makes the vehicle as well as aircraft move forward. Similarly lift is balanced by weight. Lift is a good force for aircrafts and helicopters, however it is a degrading force for racing cars and vehicles.

There are different types of drag force like induced drag, pressure drag and skin friction drag and drag at supersonic speed which is wave drag.  We can also calculate these drags.

Coefficient of Induced drag can be calculated as 

\[ C_{D,i}=\frac{C_{L}^{2}}{\pi e AR}\]

Coefficient of lift at supersonic speed and wave drag coefficient can be calculated as, 

\[c_{l}=\frac{4\alpha }{\sqrt{M_{\infty}^{2}-1}}\]

\[c_{d}=\frac{4\alpha ^{2}}{\sqrt{M_{\infty}^{2}-1}}\]

this is with respect to a  flat plate at  supersonic speed. 

Aerodynamics is the study of flow of air over any object and the flow of air over any object can generate forces. These forces are lift and drag. Lift is the force which tries to lift any object from the ground. Drag opposes the forward motion. Lift can be considered as a supporting force for aircrafts and degrading force for vehicles, particularly racing vehicles, whereas drag can be considered as a degrading force for both aircrafts and vehicles. Sometimes drag is useful to reduce greater speed in a racing vehicle.  

We are using wind tunnels in order  to test or visualize airflow and measure aerodynamic forces. These forces are measured using various probes which are placed at different points in the wind tunnel. The probes can also be put on objects in order to measure the forces. 

Wind tunnel Test

Nowadays in order to measure aerodynamic forces there are uses of pressure sensors and force sensors. These sensors provide more accurate readings. After getting the readings, we can use it to measure coefficient of lift as well as coefficient of drag. These coefficients are used in order to measure the lift as well as the drag force. 

Aerodynamics can also be measured by the use of computational fluid dynamics or CFD. There are many simulation software which can predict near accurate aerodynamic results using CFD. These are more cost efficient and less time consuming than carrying out wind tunnel tests. 

Aerodynamics can also be measured in real life, like while using our own vehicle and measuring the drag force using some devices. These are not accurate and can differ on different situations, like weather condition, traffic and condition of the track or road.

Sails are mainly used with boats.  Sails are curved and it is designed in such a way that it creates a region of high pressure and low pressure around it. Sails can be compared with the wings of any airplane. On any wing there is a creation of high pressure on the bottom surface and low pressure on the upper surface. So, the upper portion of the wing is at a lower pressure and the bottom surface is at high pressure. The wing is designed in such a way that the flow of air over the top surface is at a higher speed and the flow of air at the bottom surface is at lower speed, this creates a region of lower pressure on the top surface and a region of higher pressure on the bottom surface, resulting in a net upward force of lift. 

Sail on a boat

Similarly on the sail there is a lower pressure on the front side and a higher pressure on the back side due to its curved design.  The flow of air on its front side is at a higher speed creating a low pressure region and the flow of air behind the sail is at a lower speed creating a high pressure region. This difference in pressure creates a net forward force like the lift of the aircraft. 

This is how a sail works. So, we can say that the working of the sail in the  boat  is an analogy to the working of the wing on an aircraft.

Aerodynamics is the study of flow of air over any object. When an air flows over any object there is creation of forces over it such as lift and drag. These forces are created due to pressure differences over the top and bottom surfaces.  

One of the methods to learn aerodynamics is by simply visualizing. Aerodynamics can be learnt by seeing the flow of air over our car, or any other vehicles, while riding a bike, or by driving and just sitting in our cars. 

When we ride any bike we have flow of air over our body, which in general gives some resistance to the flow of air. This is also aerodynamics. We can reduce the air resistance by tilting our body forward. When we are in a car and put our hand outside we also see the flow of air and feel resistance to it. These are the cases of aerodynamics. If we slightly bend our palm to the direction of flow of air then there is less drag. However, these methods should not be done at a  high speed of the car, otherwise it can cause injury.   

Airflow over hand

Use of aerodynamics is also in aircraft. We see aircrafts and helicopters. Aircrafts are the perfect example for the use of aerodynamics. Wings of the aircraft generate lift, which is the main source of force for uplifting the aircraft from the ground and flying in the sky. Similarly, helicopters use aerodynamics through the use of its rotor and blades in order to lift up and fly forward into the sky. Rockets and spacecraft also use aerodynamics.

Racing formula cars use streamlined bodies in order to move faster and reduce drag to a significant amount. Cricket balls are a fine example of aerodynamics. We can swing any ball by the use of seam. 

Racing car aerodynamics

In our home we can make a small wind tunnel in order to study the flow behavior over any object. Similarly, wool tufts and fan can be used to visualize the flow of air. In the present day, we can use modern technologies like computers in order to study aerodynamics with the use of computational fluid dynamics or (CFD). These are very cost efficient and are also used by many industries.

Aerodynamics is the study of flow of air over an object and  its associated different flow characteristics. Aerodynamics create lift and drag. We can study the flow of air over any surface like a sphere, a ball, car and aircrafts. Study of aerodynamics helps us to understand the different types of forces created and its effect on objects. 

In order to study aerodynamics, in industry or for commercial purposes wind tunnels are used. There are huge wind tunnels which are generally used for testing aerodynamics of objects for a speed flow between low subsonic to hypersonic. For all these purposes different types of wind tunnel are used. However all these wind tunnels are very costly and take a huge amount of time to manufacture or build. 

We can also take simple techniques in order to make or replicate the wind tunnel. These types of techniques are not as accurate as the wind tunnel testing but can give a fair result from which we can deduce our hypothesis and correlate our speculation. Some of these techniques are like using fan and wool tufts, using water and ink, small replicas of a wind tunnel, using smoke and others. We can also use the softwares in order to simulate the aerodynamic behaviors. 

Ball in a Wind tunnel

Using fan and wool tufts can give us a fair amount of idea about the direction and behavior of air flow over the object. We can also simulate by using water and dyes or using ink  in order to get similar behavior. With the use of fan and smoke we will also have a fair idea about the behavior of flow over any object. 

Nowadays with the advancement of computation technologies we have many softwares which can do our simulation faster and more accurately then the wind tunnel test and at a lower cost. Computational fluid dynamics is the field which is used now in industry as well as we can also use it in our home through the use of computers. The results of CFD are more accurate and can simulate real world scenarios. It has highly reduced the cost as well as time which is otherwise generally taken by wind tunnel testing.