When I was a kid, I always used to think, is there a need of clutch ? what does it do exactly ? & as a kid I was able to imagine the working of brakes & how does the speed increase but I was never able to understand clutches ! It was truly a satisfying moment for me when I was completely able to understand clutches. So here it is, today we’ll see everything you need to know about Clutches ! more “How car clutches work ? | Parts, function & types !”
Very few are lucky enough to take a ride in a Chopper & I am happy to be one of them ! Anyway, helicopters are indeed one of the most interesting machines from which I know so far. Subjects like flight mechanics & helicopter dynamics are not for weak hearted ones; they are seriously challenging to study ! Well keeping those complex calculations, equations & relations aside, lets at least know how helicopters work, fly & are steered ! more “How do helicopters fly, work & turn (Animation) ?”
Missiles – pretty cool uhh.. but what makes them so cool ? Well, the best thing is you could launch a weapon thousands of miles away. This leaves no reason why the military of every nation won’t keenly research on it.
The word missile comes from the Latin verb mittere, which means – “to send” ! Basically, a missile is a self-propelled guided munition system. The first missiles were developed by Nazi Germany in WWII. These were simply radio controlled by the operator & were only built in small numbers.
So here we will be looking into the main systems of a missile i.e guidance system, flight controlling, propulsion & about warheads. Lets get to the first one –
How are missiles guided to their target ?
Missiles can be guided & targeted in a number of ways. The most common method is using some form of radiation such as infrared, laser beams, radio waves. The radiation may be emerging out of an engine or radio waves from a radar station. In case of fighter jets, the missile follows the heat signatures of the engine or the heat released through the nozzle & in case of radar, the missiles follow the radar waves itself(an echo; return signal). These methods are called fire-&-forget as they don’t need any further assistance or guidance to follow their target. A human operator can also steer the missile by using his computer. Another method is to guide the missiles using visible light. One can imagine this as a person flying a RC helicopter of drone.
How do missiles change their directions OR how does the flight system of missiles work ?
To steer or maneuver the missile, the flight system uses the information from the guidance system & accordingly adjusts its thrust & other components. One way of maneuvering is thrust vectoring. Trust Vector Control(TVC) is the ability of an aircraft to manipulate the direction of it’s thrust through nozzle. Therefore TVC are also used to change the direction of missiles. Other way of guiding missiles is through aerodynamics i.e by adjusting wings & fins(tail). Some missiles are also equipped with gyroscopes which are powered by batteries & sometimes help the missile to tilt rapidly.
Source:YouTube; Credits: documentariesfootage
How are missiles propelled ?
Here comes the engine section 😉 . Missiles generally use rocket & jet engines for their propulsion. As missiles often have multiple engine stages, they use rocket engines for OR a rocket booster for launching(as more energy is required to overcome gravity & its own weight in the beginning) & later jet engine is used for further flight. Either solid type of fuel or liquid propellant (for larger missiles) is used to run the rocket engine & generally turbojet engines are used for the 2nd stage for flight.
Missiles generally have one or more explosive warheads. The warheads of a missile provide its primary destructive power (many missiles have extensive secondary destructive power due tTo the high kinetic energy of the weapon and unburnt fuel that may be on board). Other types of warheads include nuclear weapons, chemical or radiological weapons. Warheadless missiles are often used for testing and training purposes.[Source]
Fact for the day :-
The Dongfeng-41, is a Chinese nuclear solid-fueled road-mobile balistic missile in the flight test stage of development. It is believed to be one of the most powerful missile in the world having an operational range of 12,000-15,000 kms & a speed of Mach 25(30,626 km/h; 19,030 mph; 8.5073 km/s) 😮.
Damn…these guys build these high-military class-shit & fly as well as control them at such high speed, whereas I’m having difficulty even to imagine that speed 🙁 !!! Hats off to them.
Rotary Gnome engines were widely used in aviation before & during WW I ! Besides aviation, Gnome engines were also used in some early motorcycles & aircrafts. So lets see what are & how do rotary engines(gnome engines) work ? more “How do Rotary engines(Gnome engines) work ?”
Nothing much to give introduction on Radial engines except that they were widely used during World War II. More efficiency & power were the greatest needs of that time. Having many advantages over the rotary engines used in World War I, radial engines proved to be great for aircrafts.
Radial engines :-
Radial engines are Internal Combustion Engines same alike the piston-cylinder arrangement except one change – the piston in the cylinders radiate(oscillate/reciprocate) outward from the central crankcase(like the rims of a tire). Radial engines are also called “Star engines” as they resemble the shape of a star when viewed from the front side. The radial configuration was very commonly used for aircraft engines before the gas turbine engines came into existence.
History :- C. M. Manly constructed a water cooled 5 cylinder radial engine in 1901 – a conversion of rotary engine for an Aerodrome aircraft. The machine was unsuccessful, but the Manly-Balzer engine(later in 1903) pointed the way to high power, low weight aircraft engines.
Piston– The piston is used to transfer the expanding force of gases to mechanical rotation of crankshaft via a connecting rod. The piston is able to do this because it is secured tightly within cylinder using piston rings to minimize the clearance between cylinder and piston ! Crankshaft – A crankshaft is a part which is able to convert the reciprocating motion to rotational motion. Connecting rod – A connecting rod transfers motion from a piston to crankshaft which acts as a lever arm. Inlet & Outlet valves – It allows to enter fresh air with fuel & to exit the spent air-fuel mixture from the cylinder. Articulating rod assembly – The assembly joins all the connecting rods of pistons with a single part as the cylinders are coplanar (discussed later). Spark Plug– A spark plug delivers electric current to the combustion chamber which ignites the air-fuel mixture leading to abrupt expansion of gas.
Radial engines work like any other 4 stroke engines. They both have similar parts but their construction & design are different. Each cylinder has an intake, compression, power & exhaust stroke. If you consider the above engine consisting 5 cylinders, numbering the top as 1 & going clockwise, then the firing order is 1-3-5-2-4 & again 1 ! Nothing complicated to understand, the firing order & opening/closing of valves are such adjusted that the ongoing power stroke directly helps compress the next cylinder to fire, making the motion more uniform.
Why odd number of cylinders ? For smoother operation of the engine, consistent power should be produced. For producing consisting power, odd number of cylinders are used so that every other piston firing order can be achieved. If an even number of cylinders were used, an equally timed firing cycle would not be feasible.[Source]
How do inlet & outlet valves open & close at that particular times of strokes ? Unlike the engines used in cars & bikes, the axes of the cylinders are coplanar, hence the typical camshaft cannot be used for controlling the inlet & outlet valves nor the same crankshaft could be use to deliver the power. Instead the pistons are connected to the crankshaft with a master-and-articulating-rod assembly. I know it is quite difficult to imagine especially which we’ve never heard of, so I’ve included an animation 🙂 !
Radial engines generally use poppet valves which are overhead the cylinders. These valves are driven by the push rods- which are controlled by the cam plate which rotates in opposite direction than of the crankshaft. The cam is made to spin slow with the help of a geared mechanism.
Smoother operations :- Radial engines are great at producing consistent power(contribution of each piston) as discussed earlier. This consistency helps the engine to run smoother.
Tougher & easier maintainence :- All thanks to simple design which makes it less vulnerable to damage as well as it makes much more easier for maintenance workers during routine check-up.
Cost :- Radial engines’ parts, repair costs, & maintainence costs are inexpensive. A cheaper option is welcomed blindfoldedly in a expensive field of work.
Drag :- As the cylinders are clearly exposed to the airflow during flight, drag increases considerably.
Visiblity :- The pilot may experience visibility problems, due to huge single engines located near the nose of aircrafts.
Installation :- It is more difficult to ensure adequate cooling air in a buried engine installation.
Gas turbines OR popularly known as jet engines stole the market as they were much more powerful, efficient & light weight than radial engines. To know more about gas turbines/jet engines, read one of my previous articles in which I have explained in detail about working of jet engines ! I have also written a post on types of jet engines (it’s pretty cool…you should give it a try 😉 )
The first jet engine successfully flew in August, 1939. Hans von Ohain of Germany was the designer of the first operational jet engine, though credit for the invention of the jet engine went to Great Britain’s Frank Whittle. Whittle, who registered a patent for the turbojet engine in 1930, received that recognition but did not perform a flight test until 1941. Its been more than 75 years, there has been continuous development in jet engines & has a significant increase in their efficiency. There are many types of jet engines depending on their construction & power they can deliver. Todays jet engines are able to produce so much of thrust that airplanes could fly at speeds multiple times the speed of sound ! more “Types of Jet Propulsion Engines (animations)!”