What are components does any Helicopter fuselages have?

Major assemblies of a Single-Rotor Helicopter

CABIN

COCKPIT

COCKPIT DOOR

PASSENGER DOOR

INTEGRAL FUEL TANK

BAGGAGE COMPARTMENT

TAIL CONE

HORIZONTAL STABILIZER

VERTICAL STABILIZER

BATTERY AND ELECTRICAL COMPARTMENT

ENGINE COMPARTMENT

TRANSMISSION COMPARTMENT

FLIGHT CONTROL ENCLOSURE

ELECTRONIC COMPORTMENT

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SCRAMJET Engine

• The wall of Ramjet will tend to fail at the higher temperature around 2500k,
• Like Turbojets, Conventional ramjets are also limited by material problem at high Mach Number.
• When the temperature of the air entering the combustor is too high, during which the fuel injected, it will be decomposed by the higher temperature instead been burned (Fuel will absorb rather than producing energy).
• The engine will become a Drag producing machine instead for a Thrust producing device.
• When the air flow is decrease by the scramjet the relative velocity and kinetic energy both decrease, during that energy required that any missing kinetic energy will reappear as internal energy.
• When the flight Mach number exceeds about 6 led to decelerate the flow to subsonic speeds.

Advantage

• No moving parts easies to manufacture.

• Has less weight and simple design.

• Does not have to carry oxygen tank.

• High seed could be achieved easier, so cheaper access to outer space in the future.

Disadvantage

• Scramjet cannot produce efficient thrust unless achieves high speed, around Mach 5.

• Testing a Scramjet design requires a expensive equipments (hypersonic test chambers and launching vehicles).

• Lack of strength.

 

 

 

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Computational Fluid Dynamics

                The art of replacing the partial differential equations of fluid flow with number, this number is spaced and time to obtain a final numerical description of the complete flow field of interest.

The fluid flow is governed by Three Fundamental Principle:

• Mass is conserved

• F = ma (Newton’s 2 law)

• Energy is conserved

Equation most general form is in PDF

Role of CFD

• Round off errors are compromises to get the accuracy in CFD RESULT.
• To carry out numerical experiments help study the fundamental characteristics of the flow. These numerical are directly analogous to actual laboratory experiments.

Types of fields handled by CFD

• Flow field over the space shuttle

• Flow over wing body

• Unsteady, Oscillating flow through supersonic engine inlets

• Flow field over an automobile

• Flow through supersonic combustion ramjet engine

Flow fields cannot be computed by CFD

• Turbulence model

• Chemically reacting flow

      

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Salient Features Of Scramjet Engine And Its Applications For Hypersonic Vehicles

        The scramejet uses a slightly modified Brayton Cycle to produce power, similar to that used for both the classical ramjet and turbine engine. Where Air is compressed and the  fuel injected, mixed and burned to increase the air, the combustion products are Temperature and Pressure then these combustion products are expanded.

For Turbojet engine Air is mechanically compressed by combustor using a turbine. In principle the ramjet and scramjet works the same. Where the forward motion of the vehicle compresses the air then the Fuel injected into the compressed air and burned. Results the high pressure combustion products expand through the Nozzle. Elevating the surface pressure and moving the vehicle forward.

Parts of Scramjet Engine

Scramjet Engine

        Scramjet is a variation of a Ramjet Engine, It is a type of Air breathing Engine where the combustion takes place in subsonic airflow, Scramjet  is supersonic throughout the entire engine , Scramjet operate more effective at extreme high speed of about Mach 5.

Parts of Scramjet Engine

• Inlet

• Isolator

• Combustor

• Nozzle

 

        The different Part of a Scramjet engine is Inlet, Isolator, Combustor and Nozzle. The scramjet engine must be integrated with the Fuselage of the aircraft, specially the air inlet and the Nozzle. Part of the forebody aircraft fuselarge makes the function of air let compressing the freestream air, and the after body acts as a nozzle expanding the gases for the combustion.

Salient Features of Liquid Propellant Rockets

  

Salient Features of Liquid Propellant Rockets:

                A liquid propellant propulsion system is commonly called rocket engines. It has all the hardware components and propellants necessary for its operations for producing thrust.

Liquid propellant propulsion system

Consists of one or more thrust chambers, one or more tanks to store propellants, a feed mechanism to force the propellants from the tanks into the thrust chamber, power source to furnish the energy for the feed mechanism, suitable plumbing or piping or piping to transfer the liquids,

Has a structure to transmit the thrust force, and control devices to initiate and regulate the propellant flow and thus the thrust.

In some application an engine may also include a thrust vector control system, various instrumentation and residual propellant (trapped in pipes, valves, or wetting tanks).

It does not include hardware for non-propulsive purpose, such as aerodynamic surface, guidance, or navigation equipment, or useful payload such as scientific space exploration package or missile warhead.

Ramjet Engines

 

Ramjet Engines in Fighter Aircraft

            Ramjet Engines is a type of Combustion Engine, comes under the category of Air breathing engine. It is the simplest of all the air breathing engines. It consists of a Diffuser, Combustion chamber and a Nozzle, and ramjets do not need any moving parts such as compressors and consequently no turbine as well.

Major Assemble of Ramjet Engines

• Diffuser

• Combustion Chamber

• Nozzle

• Ramjet Engines mechanism are less complicated jet engine for producing thrust in flying vehicle.

• Ramjet Engines are most efficient when operated at supersonic speeds.

• All the compression is occurs in the intake diffuser section producing rise in the static pressure.

• When the air decelerated from a high mach number to a low subsonic mach number, it results in substantial increase in pressure and temperature so the ramjet does not need Compressor and Turbine.

 

Working

• Ramjet produces power by increasing the momentum of the moving fluid by induction of energy by combustion of fuel, so the momentum of the exhaust jet greater and exceed that of the incoming air on continuous cycle.

• Where the Fuel is burned the high pressure air and the mixture is then expanded to ambient static pressure through a Nozzle System.

• High pressure gas expanded through the Nozzle by converting the low subsonic flow in the combustion chamber into a supersonic jet.

• The combine mixture of air and fuel (supersonic jet) exhausted through the C-D Nozzle.

Working cycle of Ramjet Engines

source:NPTL

Types of Jet Engines used in Aircraft

 

What are the Types of Jet Engines used in Aircraft?

Turbofan Engine

Turboprop Engine

Turbojet Engine

Turboshaft Engine

Ramjet Engine

Scramjet Engine

Unmanned Aerial Vehicles (UAV)

Unmanned Aerial Vehicles (UAV)

                After the Wright brothers worked so hard to put humans in the air by flying machines, now a day’s some aerospace engineers are working hard to take out of the flying machine. UAV Unmanned Aerial Vehicles are the Airplanes that have no humans on board which are operated and flown remotely by pilots.

Israel is the first nation to use UAV in the combat situation arguing that loss of relative inexpensive UAV was better than the loss of a pilot and a multi-million dollar airplane.

UAV are mainly used to carry sensors, target designated and electronic transmitters

 Designed to destroy enemy’s target, UAV are more effective fly at greater range and endurance.

Range – Is the maximum distance an aircraft can fly between takeoff and landing.

Endurance – Is the maximum length of time that an aircraft can spend in cruising flight (level flight).

Engine Mounts

        Engine mount is frame structures that support the engine and connect it to the fuselage. Which are designed to distribute the weight of the engine and distribute torque and vibration generated by the engine, Vibration that originated in the reciprocating engine are transmitted through the engine mount to the airplane structure for such mounts engine must be attached with some sort of rubber bushing between the engine and mount attachment to control these vibration. 

Maximum vibration from the engines are controlled when tightened so that the engines move slightly with respect to the rubber bushing which limits in a torsion during operating condition, But at the same time if the bolt are too tight the mount structure will tend to vibrate along engine which would transmitted to Airplane wing and fuselage structure which would be undesirable. To avoid over tighten of bolts the technicians should always refer to the manufacture’s service before tightening such bolts.

Material Used

Engine Mount should withstand waste heat released from the engine and ability to carry heavy engines at temperature of up to 500 ⁰ C base on the requirement three alloys types are used

Nickel-Based alloys: Can withstand high extreme temperature

Titanium alloys:  half the weight of steel, used in the place where the light weight material is needed

Steel alloys: Use at the place where high strength needed at very low temperature.

Based On Aircraft

Light Aircraft - Engine mounts made of welded-steel tubing or aluminium alloy sheet metal.

Turbine powered Aircraft - Engine mounts made of forged metal bolted to airframe.

Design and Types

Engine mounts vary widely in appearance and Construction, but basic features of construction are same. Each aircraft differs from other, heat released from the engine differs base on this criteria each new engine mount should also be unique and to be designed that engine and its accessories should be easy for inspection and maintenance.

Most aircraft which exactly from same manufacturer of the engine shall uses the same mount.

Types

Dynafocal engine mount

Protects the vibration and motion from the engine to be transmitted to aircraft structure, Fixing is based on the centre of gravity of the engine.

Shape: Ring-like

Bolt Point: Usually Four points

 

Conical mount

Conical mount are attached parallel to the firewalls, easy for installation simple and easy to fix to aircraft.

Bolt Point: Usually Four points

Drawbacks: Vibration and Torque are transmitted through the Frames

 

Bed mount

Bed mount are attached under the crankcase, which totally differs from the other type of mount (Conical mount and Dynafocal engine mount), Designed for perfect fitting of the engine avoid transmit vibration to the structure

Bolt Point: Usually Four points in modern aircraft

Vibration is more Danger to Aircraft leads to failure, Engine Mount Helps to avoid some sort of Vibration to be transmitted to Aircraft Structure.

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Control Surface of airplane

Control Surface of airplane

              Control surface of Aircraft is an aerodynamic device mean by which pilot stabilize aircraft and controls the direction and altitude of an aircraft on flight. Control surface is a movable surface which is lighter in construction has light  spar rod at the front edges to provide strength and rigidity, the spar connect the ribs and covered by the thin skinned sheet. The tabs are attached to the trailing edge of the control surface additional device will be attached based of purpose the control surface is used for transmission of tab loads to the surface.

Sheet Materials used in Control Surface

1. Metal structure                   -        Covered with metal skin
2. Composite Structure          -        Covered with fabric
3. Wooden Structure              -        Covered with Plywood or fabric

Drilling

The hole on the surface made using drain holes to prevent water  trapped inside the structure , which causes the control surface to be thrown out of balance

Jointing

Process involved in jointing the components includes fasteners like adhesive and bonding agents.

Flight Control Surface are sub branched into

• Primary Control Surface
• Secondary Control Surface

Primary Control Surface is designed to provide adequate response to controlling device giving a natural feel.

At low speed control will be smooth and sluggish

At high speed control will become increasingly firm

Responding to speed

At low speed the aircraft respond slow to control applied

At high speed the aircraft respond more rapid (faster) to control applied

Primary Control Surface includes:

Ailerons - (ROLL) Control motion along longitudinal axis.

Elevator - (PITCH) Control rotational motion along lateral axis.

Rudder  - (YAW) Control motion along Vertical axis.

Secondary Control Surface are use to improve the aircraft performance characteristics and to release the excessive control loads applied.

Secondary Control Surface includes:

Wing flaps - Used to increase the Lift and Drag increase while Take off.

Slats - Located on the leading edge of the wings. Creates enough lift at high Angle of attack.

Slots - Span wise gap present at each wing allowing air to flow between the wings, which creates lift thus reduces stall.

Trim tabs - Connect trailing edge to large Control Surface, Used to Stabilize the aircraft.

Balance tabs - Control loads on the control surface is significantly reduced, makes aircraft easy to fly.

Anti-Balance tabs - Maintain the stability in the desire position.

Servo tabs - Small Hinged device to assist the movement of the control surface.

The Combination of this Control Surface of Aircraft helps the pilot in controlling and stressing the aircraft during flight .

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Aircraft Wing Structure

Aircraft Wing Structure

          The Wing, in aeronautics are airfoils attached to each side of the fuselage Wings is the primary lifting surface of the aircraft that support the aircraft in flight, The load acting on the aircraft structure are carried the wing structure. So the design of the wing depends on many facts like lift to weight ratio, rate of climb, size, weight and which aircraft it is used, thought its shape may be widely varied its function remains the same.

Basic features of Wing Constructions

The primary structural parts of the wing are spars, ribs, and stringers.

Spars are also called as wing beams is a main member of the wing structure, it extends from the fuselage to the tip of the wing, all the forces and loads acting on wing are carried and balances by the spars. When the engine or landing gear are mounted on the wing , Spare incorporate structure attached to the components, as spars are designed to have greater bending stress.

Ribs are also called as plain ribs, it’s a chord wise member of the wing structure used to give wing structure it shape, It extends from the leading edge to the trailing edge of the wing It transmits air load from skin to the spars also stabilize the spare against twisting

Stringers are assist to hold shape of wing the span wise called stringers are used. They are attached to the skin usually found fare closed spaced on the upper wing surface, it is used on compression and stiffening of the compression skin to overcome the induced bending loads. But when the wing need of more stiffening where skin is reinforced by panels instead of individual stringers.

Based in this concept, Wing lift the aircraft on air and keeps flying.

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Types of Aircraft Fuselage Structure

Types of Aircraft Fuselage

            The basics of the Aircraft Fuselage was explained in the before posts (https://sabaeroline.blogspot.com/2020/07/aircraft-fuselage-structure.html), Fuselage types would clearly explain in the present post.

    

    In general, fuselage is classified into three major types base on the method by which stress are transmitted to the structure.

There are three most common types of fuselage are:

Truss or Frame Type Fuselage

A truss is a light gauge steel tube assemblage of members forming a frame triangular shape which giver geometric structure to the fuselage. The Primary members of Truss are the four logerons, the longerons are longitudinal member of the fuselage. Lateral bracing are placed at intervals between the longerons. The lateral surface are called as Bulkheads, Space between two bulkheads are called as bays. Lateral and Longitudinal member are made strong stell wires which are design to withstand compression during load applied.

Truss Fuselage are sub-branched into

• Pratt Truss
• Warren Truss

Monocoqne Structure

The word Monocoqne is French word which means “single shell”. In this type the fuselage skin carries all structural stress. The design involves constructing a tube or core which involves no internal structural members which looks like a empty Shell. These types of fuselage are formed by riveting preformed two half together. This Structure carry load effective when the diameter is small. Increasing of the structure diameter depends on the internal cavity.

Semi Monocoqne Structure

It is combination of Truss and Monocoqne type structure together. In Present days Aircraft become large Monocoqne structure not to strong enough. Weight to strength ration is ineffective. Longerons are run length across the monocoqne structure jointing the frame together. Now the Longerons and frame is attached the thin alloy skin shell by rivets and abrasive bonding.

Semi Monocoqne Structure type of fuselage is commonly used both military and commercial aircraft in Modern Days.

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AirCraft Fuselage Structure

Fuselage of Aircraft

    Fuselage is a body of an aircraft to which the wings, tail and Landing Gear units are attached. Spaces from the cockpit cabin, Passenger cabin, Cargo, Controls unit are located inside the fuselage. Design and size of the fuselage varies according to the function to the aircraft. The word fuselage comes from a French word “fusele” means “splindle-shape” Fuselage is a long and vertical spindle hollow tube. The hollow shape design provides maximum strength with minimum weight.

Fuselage are designed to satisfy two major criteria:

• Protect the passengers in the event of crash.

• Efficient in fitting together the wing, tail, landing gear and other control surface in perfect place accomplished with interior space for passenger comfort with minimum frontal area to contour drag for maximum performance.

Fuse large must have a point of attachment for each part such as wings, tail, Landing Gear and Engines to arrange and installed. So that at time of emergency this part can be inspected, removed, repaired and replaced again easily. The fuselage must be very strong at the point of attachment as more loads would be acting on the fuselage and fitted parts during flying and landing.

Outer Design Criteria of Fuselage

Fuselage is the outer shell of the aircraft, the cabin inside are fully pressurized and the pressure inside the aircraft is greater than the pressure outside due to which the fuselage is exposed to different stress, It must be designed with strong durable material. If were any pressure loss occurs. Oxygen levels will drop it can create a dangerous environment to the crew and the passenger inside.

During the time of rotation of the aircraft more torque will be produce fuselage should be designed to withstand this torque force which leads to collapse of the entire structure, as more load will be acting on the outer surface of Fuse large.

Fuselage design base on Aircraft Usage

In fighter jet have a slender and streamline fuselage  to contour drag for maximum performance  and cockpit will only cabin space present large enough only for the controls and pilot. Cockpit is place on the top of the fuselage for ground visualization and the engines and fuel are place at the rear of the fuselage.

In airlines Civil aircraft use to have a wide, long fuselage carry the many number of passenger as well as cargo. The cockpit will have large space and separate desk for passenger cabin and cargo, Cargo space will be located below the passenger cabin and fuel is stored at the wing.

In single engine aircraft the engine is mounted in nose of the fuselage. Cockpit will be place at the top to provide ground visibility.

Fuselage skeleton and skin

Fuselage shielded by a thin sheet of material stiffened by large number of longitudinal stringers running together with transverse frames place between, they carry bending moment, shear force and torsional load which causes axial stresses in the stringers and skin. As shear stress acts on the skin because of the resistance stringers the shear force gets ignored.

(Shear Force: Force acting perpendicular to its longitudinal axis)

Distance between adjacent stringer is usually small due which shear flow in the connecting panel is small.

Material Used

Most airplane uses an Aluminium Fuselage, As Aluminium is strong, corrosive resist to rust and light weight. This characters makes aluminium effect used material for making aircraft component which includes fuselage.

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TYPES OF LANDING GEAR

TYPES OF LANDING GEAR

        The basics of the landing gear was explained in the before posts.(https://sabaeroline.blogspot.com/2020/06/aircraft-landing-gear.html) Landing gear types would clearly explain in the present post. As pilot tries, Not Every Aircraft landing is perfect due to Bad weather conditions, short landing etc., Landing gear play important role at time of rough landing, handles the aircraft smoothly and safely landing without breaking or collapsing the aircraft into pieces. 

TYPES OF LANDING GEAR

There are many types of Landing gear. The types of landing gear used in the aircraft depend on two things design of the aircraft (like military, civil purpose) and its intended use (like Cargo, commercial).There are three main types of landing gears used.

Tail wheel Landing Gear

Tail wheel Landing Gear is also known as Conventional or traditional type landing gear because this was milestone for majority of the aviation history, used in the other legendary fighters of WW2. The main gear are located forward to centre of gravity of flight, which makes the tail to get support  from the third wheel assembled in the tail of the aircraft. In some aircraft skid replaces the third wheel which helps slow the aircraft while landing and provide direction stability in earlier aircraft.

By raising the angle of fuse large when fitted with conventional gear allows to fix long propeller in front of engine for older aircraft, It also provide increase ground clearance of the forward fuse large with is also a advantage in using Conventional Landing Gear.

Directional stability is controlled by different breaking system until the aircraft speed comes under the control of the Rudder. Steerable tail wheel connected to the rudder and rudder pedals by cables. For smooth and easy landing springs fixed for damping.

Tandem landing gear

Most of the aircraft using tandem landing gear are military planes and spy planes. This type of landing gear has a main gear and tail gear aligned on the longitudinal axis of the aircraft. 

The main advantage of Tandem landing gear design reduces drag when deployed they are retractable.

Tricycle-type landing gear

The most common type landing arrangement used in modern aircraft is the Tricycle-type landing gear consist of a nose gear and main gear. Larger and small aircraft today used this gear arrangement.

Benefits

• Allows more forceful application of the breaks without noise created over when Breaking which increases high landing speed.
• Provides better visibility from the flight while landing and ground maneuvering.
• Weights are equally spread over large area and are equally distributer each Gears provide a better safety margin.
• Aircraft centre of gravity lies forward of the main gear, force act on CG point makes the aircraft moving forward avoiding looping which prevents groung-looping.

Landing Gear Design

Depend on the Aircraft usage and operation the landing been designed either Fixed Gear (immovable) Retractable Gear (movable).

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