CLASSIFICATION OF AIRCRAFT
HELICOPTER is a rotary wing plane by which raise is produced by its rotor blades. They’ll take off and land with out the necessity for runway. They’ll hover within the air or maneuver in any route in a 360-degree house. In the present day, helicopter makes use of embody transportation of individuals and cargo, army makes use of, development, firefighting, search and rescue, tourism, medical transport, legislation enforcement, agriculture, information and media, and aerial remark.
When the blades rotate relative to the air the particular airfoil form will generate raise power and make them fly.
The blades derive rotation from an engine extra particularly a turbo shaft engine. The compressor sucks the air in and pressurizes it gasoline is burned on this pressurized and sizzling air. The recent exhaust leaves the combustion chamber passes by a sequence of turbine phases and make them flip. There are two Units of generators one turbine set turns the compressor and the opposite set turns the helicopters rotor shaft.
Jet Engines of Airplanes are used to generate thrust power nonetheless the first operate of the helicopters jet engine is to show the rotor shaft.
When the helicopter is at an angle the Pressure produced by the blade just isn’t vertical. The horizontal element of this Pressure will make the helicopter transfer within the desired Route. The vertical element of the Blade Pressure will Steadiness the gravitational power.
The raise produced by an airfoil varies with the angle of assault. Usually, the higher the angle of assault the extra the raise.
The raise forces appearing on the blades can be totally different on this case. The variations within the raise forces will lead to a torque that may flip the helicopter. Thus, the blades should carry on altering angle of assault in order that at one specific location the angle of assault is all the time the identical. Such complicated of the blades is achieved by a swash plate mechanism.
The underside Swash plate doesn’t spin, however it may transfer and tilt. A high swash plate is fitted on the underside swash plate By way of a bearing. So, the highest Swash plate can inherit all of the movement of Backside Swash plate whereas on the identical time it may rotate independently. High swash Plate is hooked up to the rotor Shaft with the Helpance of a driver. So, the highest swash plate will all the time transfer with the blades.
The blades are linked to the highest swashplate with the Helpance of management Rods. The attention-grabbing factor about this association is that simply by tilting the underside swashplate we will obtain the various Angle Criterion of the blades.
Meaning with this swashplate tilt we are going to all the time have the ability to keep a optimistic angle of assault on the rear and a adverse angle on the entrance portion of the rotor disk.
In brief Swashplate tilting backwards produces a torque. This type of management is named cyclic pitch.
What occurs in actuality is the helicopter will flip sideward. By making use of torque in a single route to a rotating object the article turns in several route. This impact is named gyroscopic precession.
If we simply raise the underside swashplate with out tilting it, the angle of assault of all three blades will range by the identical quantity. Because of this the helicopter raise Pressure would be the identical in all three blades and the helicopter can transfer up or down with none tilt. Such blade management is named collective pitch.
Helicopter wants tail rotor for efficient operation. With out the tail rotor the helicopter fuselage would have spun. This is because of a consequence of Newton’s third legislation of movement.
The rotor will get the power of rotation through a bevel gear linked to the engine. Bevel gear Transmits Pressure to the rotor bevel gear nonetheless in line with Newton’s third legislation of movement, the Rotor bevel gear ought to Transmit an equal and reverse Pressure to the engine bevel gear. This response Pressure will make the entire helicopter flip reverse to the blade rotation alongside the helicopter centre of gravity.
The operate of the tail rotor is to stop such helicopter rotation by producing a power on the tail. By correctly adjusting pitch angle of the tail rotor Blades the Pilot can simply manipulate the tail rotor power. With the Helpance of the tail rotor Yaw movement of the helicopter will also be achieved.
LOOMING BAY
It’s a bay by which all helicopter wires or we are able to say loom (bunch of wires) are repaired. When the helicopters come for the servicing or overhauling all of the looms are indifferent from the helicopter and ship to the looming bay. Right here first the plane involves the plane division and right here the helicopter is disassembled, and the respective elements are despatched to their division for repairing or overhauling. So, within the looming bay all looms are repaired just like the insulation of wire is checked, if the insulation of wires are lower than 20 mega oms then the wires are changed, But when the insulation of the wire is greater than 20 mega oms then they’re repaired. For instance, sealing materials are inserted, they’re correctly insulated, they’re made fireproof. These checks are carried out with the Helpance of following issues: –
Circuit Diagram
Fireproof materials fluoroplastics is used it may stand up to as much as 400 diploma Celsius.
Sealing materials Vgo-I is used
Automated harner loom testing machine (it checks the isolation).
So, as we all know that close to engine the temperature could be very excessive and the wires close to the engine must be excessive temperature resistance so shielding wire PTFE (polytetrafluoroethylene) is used. These wires can resist excessive temperature in addition to low temperatures (-60 to 200 diploma Celsius).
Additionally, some pink tapes are used to restore the wires, these tapes have a property that they persist with itself solely and doesn’t persist with some other materials.
Determine 1 wire looms
STRUCTURAL REPAIR BAY
BLADES
Helicopter blades are of two sorts one is foremost rotor blade and second one is tail rotor blade. Blades performs an necessary position in producing the raise and carrying the entire weight of the helicopter so, blades needs to be robust sufficient to take the load of the plane and bear all stresses which act over it that’s the reason the principle rotor blade are made by becoming a member of small-small blades collectively. All these small blades are having honeycomb construction from inside in order that load could be distributed, and the load of the blade doesn’t exceed. The principle benefit of any such blade is that they are often repaired simply. If there may be some crack or deformation over the blade, then we dont have to vary the entire blade simply we now have to vary the small blade which obtained broken. So, this save money and time each.
Whereas tail rotor blades come within the set of three and we can’t restore the blade if, one blade obtained broken and can’t be repaired then we now have to vary the entire set of blades, this we are able to say the disadvantages of the tail rotor blade. Additionally, one necessary characteristic is added to the blade is that a mild is fitted on the ends of each blades so that in evening flight the world could be seen that’s coated by the blades whereas rotating.
One other characteristic is added that a steel strip is joined in entrance of the blade in order that ice formation could be prevented when the helicopter is flying at an space the place temperature is low with the Helpance of electrical provide on these steel strips.
Determine 1 foremost rotor blades
TAIL ROTOR ASSEMBLY
Tail rotor meeting is a spot the place tail rotor is repaired. It obtained absolutely dissembled right here after which checked for damages and areas for enchancment after which they’re fastened. On MI 17 helicopters the tail rotor has 3 blades and all three blades have marking and you need to observe it like first blade has pink color marking equally second blade has inexperienced and third one has blue color marking and these blades needs to be fitted of their precise positions. You can’t match pink marking blade in second or third place you need to place it in first place.
Some extra precautions are taken for a security these are: –
The distinction between the peak of blades shouldn’t be exceed by ±5 millimetre.
Distinction in blade angle (each minimal and most) shouldn’t be greater than 10 (1/6 diploma).
Normally MI 17 tail rotor meeting takes 500-man hours to finish the duty or 33 days.
FIRE PROTECTION SYSTEM
Fireplace safety system could be very essential system for an plane. It must be lively all time and in case of fireside it ought to work. One of these system will help to protected in emergency conditions.
The hearth safety system utilized in MI 17 helicopters has an working voltage of 24 to 36 milli volts.
This technique is fitted elsewhere and displays the temperature, if the temperature rises from the restricted worth then it signifies within the cockpit with pink mild and a few sound. This technique consists of 6 plates which displays temperature as much as 150 diploma Celsius and 1 extra plate as much as 200 diploma Celsius. And on this Freon gasoline is used as hearth extinguisher. Additionally, hand co2 extinguishers are additionally utilized in case there may be some system failure or small hearth is taken place. This technique measures each 2-degree Celsius rise in temperature.
INSPECTION AND REPAIRING METHOD
BRINELL HARDNESS TEST
This methodology is usually used for measuring the hardness of a steel or alloy. On this methodology a ball form indenter is pressed beneath a load into the specimen. Because of the load the fabric deforms, and this deformation is measured, and hardness of the fabric is set. Now a days that is finished digitally means you dont have to look at or measure the deformation with the Helpance of computer systems it’s proven on display digitally.
Determine 2 Brinell hardness check
SAND BLASTING
Sand blasting is a way to make the fabric floor tough earlier than it’s despatched for casting. This methodology helps to coat the fabric simply over it. In sand blasting methodology a mix of sand and steel is used. The fabric is stored contained in the chamber and the machine is began, contained in the chamber a turbulence is created because of which the sand and steel particles bombard to the fabric floor which makes it tough.
Determine 3 Sand blasting machine
THERMAL SPRAY MACHINE
This machine is used for the coating of the supplies. On this course of temperature can attain as much as 3000? F. on this course of acetylene and oxygen gasoline is used and imparted on the fabric. This system is principally used for the rotable elements. When the will temperature is reached over the fabric then an alloy rod is inserted from the again and it will get sucked inside and will get coated over the fabric.
Determine four Thermal spray unit
ROBOTIC PLASMA SPRAY
As we all know that plasma spray is the approach by which the new spray is sprayed over the fabric which softens the fabric and the powder is sprayed with which will get coated over the fabric. The same course of is completed within the robotic plasma methodology, however the one distinction is that it’s finished with the Helpance of robotic arm. And it’s finished in a closed room as a result of the temperature reaches very excessive and a few quantity of radiation can be there. All the pieces is completed with the Helpance of computer systems. This methodology could be very efficient now a days and saves a lot of time. The specimen is positioned on the desk as proven within the determine and every little thing is completed by robotic arm.
Determine 5 Robotic plasma spray
NDT TECHNIQUES
RED DYE INSPECTION METHOD
Because the identify counsel that a pink dye is used to examine the cracks or defects. This system is used for no ferrous supplies.
FLUORESCENT PARTICLE INSPECTION
This system can be used for the nonferrous supplies to detect the defects and cracks.
MAGNETIC PARTICLE TESTING (MPT)
This system is used for the ferrous supplies. This system is used for crack detection. The next steps are adopted on this approach: –
First the fabric is magnetized with the Helpance of magnets.
Because of the magnetization magnetic particles are deposited over the crack (if there) and if there is no such thing as a crack then no particle can be deposited.
Now a magnetic ink is sprayed over the fabric.
Ultimately UV rays are put over the fabric and if the cracks are their then they’ll glow. And we are able to say that crack is there.
Determine 6 Magnetic particle testing
RED DYE INSPECTION METHOD
Because the identify counsel that a pink dye is used to examine the cracks or defects. This system is used for no ferrous supplies.
FLUORESCENT PARTICLE INSPECTION
This system can be used for the nonferrous supplies to detect the defects and cracks.
ENGINE DIVISION
Within the engine division we had been glad to see three foremost engine of various aircrafts first is MI-Eight helicopter second is MI-17 helicopter and the third one is An-32 plane.
These all three have totally different engine fitted inside them.
MI-Eight Helicopter —– TV-2 engine
MI-17 Helicopter —– TV-3 engine
AN-32 plane —– AI-20 engine
Totally different engines have totally different specs given beneath: –
TV-2 ENGINE
Its weight is 332.5±2% (in kgs)
It has a 10-stage axial compressor
Turbine– 2 stage compressor turbine and a pair of stage free turbine
TV-3 ENGINE
Its weight is 285±5.7 (in kgs)
It has 12 stage axial compressor.
Turbine– 2 stage compressor turbine and a pair of stage free turbine.
AI-20 ENGINE
Its weight is 1040±2 (in kgs)
It has a 10-stage axial compressor
Combustion chamber annular sort
Turbine3 stage response turbine
Additionally, in AN-32 plane TG-16M (auxiliary energy unit) is used. It’s a gasoline turbine APU. It’s used for the beginning of AN-32 plane. It offers 20-60 volts variable DC at 1000 amps.
Its most use top is 3.5 kms.
ENGINE OVERHAULING PROCESS
SELF SEALING TANKS
In MI-17 helicopters some particular sorts of gasoline tanks are used, these have a property that they seal itself when there may be some harm or gap within the tanks. These tanks are particularly made so that in warfare situation if any bullet hits the tank then as a substitute of leaking of gasoline or burning of gasoline it should seal the outlet or harm and no such incidence will happen.
These tanks are made with the Helpance of following gadgets: –
Cotton canvas
They initially cowl the tank
Cellous rubber
This rubber has a property to heal itself. After cotton canvas 2 layers of cellous rubber is used to make it safer.
Glass fabric
After this a layer of glass fabric is used. It has a property that it’s fireproof so, in case of leakage of gasoline it is not going to catch hearth ever in touch with sparks or hearth.
Fireproof paint
On the final 2 layers of fireproof paint is completed in order that there aren’t any probabilities of harm even when the spark is initiated because of bullets or some artillery harm.
Determine SEQ Determine * ARABIC 7 Self-sealing tank
HYDRAULIC OIL AND ITS COOLING
In MI-17 helicopters there’s a hydraulic tank of 15 liters which carries the hydraulic oil in order that the hydraulic system will work correctly. There may be additionally a drainage tank of 3 liters in order that the gasoline which will get wasted will deposited within the drainage tank. The hydraulic oil which is used for MI-17 helicopters is OM-15. This hydraulic oil can be utilized as much as 110 levels Celsius, after that temperature the oil begins shedding its properties.
For the cooling of the hydraulic oil radiator is used. When the temperature of the hydraulic oil reaches the 65 levels Celsius then the oil begin flowing by the radiator. The method of oil flowing by the radiator has a unique mechanism, the mechanism is given beneath:-
When the oil temperature reaches 65 levels Celsius a valve will develop.
Now this expanded valve stops the direct movement of the oil and the oil passes by the radiator.
The valve which get closed is as a result of growth of the spring which is fitted beside the valve, when the temperature reaches 65 levels Celsius the spring obtained thermal growth and the valve get closed. The utmost growth within the spring is 5mili meters.
Now the oil will go by the radiator and get cooled and can attain to the will system