1-because it adapt with high pressure.2-means use less force to generate bigger force.3-from principle of pascal’s said, when force is applied in close system, pressure exerted is always the same at any point of container.4-used different types of hydraulic fluids depend on which part of system involve.
-which parts in used of hydraulic system especially in aircraft?-
-there are 3 type of flight control which consist -passenger stair we can adjust the height of stairs by using hydraulic system-which control surface generate bigger forces.
-types of aircraft that going to discuss and compare with are
1-DA-40 is a light aircraft which fully cable control system.2-means that not have hydraulic system for their control surface except for landing gear.
1-A simple mechanical cable operated system as you will find on aircraft such as the DA-40. 2-The cables in some light aircraft are replaced by rods. 3-The control column can be moved by raising and lowering the elevator
1-due to have best performance of such aircraft, retractable landing gear does not practicle for light aircraft2-
5-hydraulic system is weight enough and not suitable for light aircraft6-due to low in weight compare to airplane, therefore less pressure required to control.
-example of cable control system of control surface
Piston pump used to operate high pressure aircraft
1-Most military planes using 4000 psi systems (although some new military aircraft have made the move to 5000 psi)……which equivalent to 27579.0282-is used to overcome huge of pressure in hydraulic system.4-Hydraulic fluid exposed with high pressure require4-hydraulic pump
piston pump because only 5000 psi and below pressure capacity is needed
Vane pump because only 2000 psi and below pressure capacity is needed
2-as a backup system3-Three independent sub-systems designated System A, System B, and standby, deliver hydraulic fluid at a pressure of 3025 psi (209 bar) especially
Devices operated by hydraulic system in aircraft
DEVICES OPERATED BY HYDRAULIC SYSTEM IN AIRCRAFT LECTURER’S NAME: DR.SOFIAN MOHDGroup Members: 1) AMIRUL IMAN BIN HASRI AD110155 2) JASWANT SINGH BAL AD110177 3) AMAL IQMAL BIN ADNAN AD110189
AIRCRAFT HYDRAULIC SYSTEM A crucial component to operate modern aircraft (mainly for large commercial airplane). Helps to ease the work of controlling an aircraft without concerning on sloppiness. Create large/unlimited force by exerting minimal strength on control system (compared with other fully mechanical operated aircraft)
Landing gear• Uses tricycle landing gear• Fixed landing gear which does not require any hydraulic systemBraking system• Disc brake system which similar to other land vehicle• Hydraulic fluid : Mil-H-83282• Type of hydraulic pump : Vane pumpGear steering, Cargo door, Passenger door*Similar to commercial airplane and light aircraft*
Cable or high steel rod used as flight control. Low cost. Cable is strong enough to flight control. Cable is made from strong and high tension string. If hydraulic used, might be not efficient for the performance of DA-40 because strength to weight ratio is really important to make an aircraft fly. Sometimes light aircraft is equipped with hydraulic system, if then, the pressure used of that such aircraft is around 1000psi and below. Mineral-base Fluid MIL-H-5606
Boosted control system This is a simplified boost system. When the pilot moves the column, tension in the cable or rod also opens a valve letting pressure from a hydraulic or pneumatic pump expand a slave cylinder that assists moving the control. The control column can be moved by raising and lowering the elevator but a considerably more force is required.Booster Assemblies The booster system is designed so that the pilot has a normal feel of control forces when hydraulic pressure is available to the booster cylinders. Hydraulic flight control boosters operated by both hydraulic systems are incorporated in each of the three surface control system.
Landing gear• Similar landing gear with a commercialaircraft, which is tricycle landing gear.• Slight difference in type of hydraulicsystem used to generate power tooperate the landing gear, due to jetfighter flexibility and speed inperformance.•Hydraulic fluid : Exxon Hyjet V (Type V)•Type of hydraulic pump : Piston pump
F-22 Raptor (Military Aircraft) Hydraulic system with more than 4000psi. Thick hose The hydraulic system includes four 72 gallon-per-minute pumps and two independent 4,000 psi systems. Large power pump and accumulator. It exposed with high speed so require more energy. Sometimes require large reservoir. Hydraulic fluid used is such type of Synthetic Fluid MIL-H-83282. Non-petroleum base hydraulic fluid for use in high performance piston engine and turbine powered aircraft.
Utility systemLanding gear Previously , cable system was introduce in the early days to operate landing gear system. Due to lack in efficiency, hydraulic system was widely use these days. An easy working principle, with a push of button ,the landing gears can be set to radial movement of gears that is powered up by hydraulic system to steady state of take-off or during/after landing. Fluid used for this hydraulic system is :Skydrol 5 Hydraulic pump used in this part of system is : Piston pump
Brakes Use to reduce aircraft speed on ground Fully functional with hydraulic system (conventional brake drum is no longer in use) Fluid used : Exxon type 4 Type of hydraulic pump used : Vane pump
Gear steering, Cargo door, Passenger door Fully functional with hydraulic system Fluid used :Exxon type 4 Type of hydraulic pump : Vane pump
Braking system• Used to reduce airplane speed ,no means ofcable• Fully functional hydraulic system•Hydraulic fluid : Exxon Hyjet V (Type V)•Type of hydraulic pump : Piston pumpGear steering, Cargo door, Passenger door*Similar to commercial airplane and light aircraft*
Empennage hydraulic system -Empennage need hydraulic system because of the efficiency of system compared to cable or steed rod connected to empennage. -The fluid that used for empennage hydraulic system is DTD585. This fluid is most suitable for this system because of the pump use for this hydraulic not required large force compared to other. -That fluid also cannot expands due to high temperature. -The pump used for this hydraulic is really small than in aileron part.
Boeing 737 Most commercial airliners planes using in range 3000 to 4000 psi systems (although some new military aircraft have made the move to 5000 psi) of hydraulic system. Therefore , piston pump is used to control hydraulic fluid flow through Boeing 737 hydraulic system Synthetic based fluid is used to run the system which is Exxon type 4