Tu-154B Systems
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Stabilizer
TU-154 is equipped with electrically controlled movable stabilizer. Rearrange of stabilizer allows you to save the desired efficiency of elevator in the landing mode, and allowed to expand the range of operating CoG positions.
Stabilizer can operate in automatic mode. In this mode, the stabilizer move to desired position simultaneously with the deploying flap, depending on the situation of stabilizer handle 302. Handle has three positions: P-S-Z (front-center-rear). The required position is selected, depending on position of center of gravity (CoG), % of MAC. When centering least 28% selected "P", from 28% to 35% - the "S", more than 35% - the "Z".
In reality, the crew determines the CoG by aircraft loading before takeoff, and by elevator/stabilizer position gauge (309) before landing. To determine the desired position of the stabilizer, you should check the balancing of PB in horizontal flight at an altitude range, with the usual speed of 400 km / h. If a thin needle 309 is located in the green sector - centering the front and stabilizer handle is installed in the "P". If the orange - CoG is a rear, a "W". The arrow in the black sector - CoG is the average, "S".
In this model, CoG position can be viewed by clicking the mouse at the center of the device 309. A string tips with show landing parameters - CoG, Vref etc.
In addition to the automatic mode, the stabilizer can be operated manually. To do this, open the lid 301, the automatic control of stabilizer will stop. There is a toggle switch under lid, by pressing it you can control the electric stabilizer. The position of the stabilizer is controlled by a thick needle 309, when the electric lights up scoreboard 313.
Wing Mechanization
Mechanization of the wing are flaps, slats and spoilers. In this model, mechanization is implemented simplistically, in particular, as well as in the PT are not modeled by a separate slats control. Slats are moved along with flaps.
Flaps are controlled by hydraulic systems 1 and 2? and it's depend of pressure of hydrosystems. Position of resettable stabilizer is depend by position of flaps if the stabilizert set to combined mode, as default.
Flaps are controlled by the crane 451. In this model, valve 451 is controlled by the mouse, you can also use the standard commands for the simulator extend/retract flaps. For this purpose, use a couple of buttons on the joystick.
Flaps are 4 fixed points: removed 15, 28 and 45 degrees. Landing flaps position - 45, in some cases - 28. Take-off should be made with the flaps in position 28 or 15 degrees.
In the process of retract and extend of flaps light green boards 314, 315. Flap position can be tracked using the device 310.
Gear and Brakes
The Gear, like the flaps, operate by hydraulic systems. In this model, the gear extend depends on the pressure in the hydraulic system 1. Operate by hydraulic systems 2 and 3 are not implemented, due to the lack of failures in sim.
There is a crane 452 for gear control, you can use standart shortcuts (g and G). In reality, the management of the gear harder than done in the model. Perhaps in the next release will be realized the logic of "crane chassis in neutral."
Position of the gear is controlled by the lighting board 311. When the gear has extend, burn three green lights. Then gear has retracted - all lights extinguished. In the process of retracting and extending of the gear, burning three red lights. A sound alarm and placards "Extend gear!, at the top of the device 311.
In this model, in this version, all three gear strut are produced simultaneously, and locking of strut impossible. Also not implemented "hang" the front strut when you try to extend the gear at speeds exceeding 400 km / h. Modeling this situation postponed.
Steering of front wheel depends on the pressure in the hydraulic system 1, and combined with the management of the rudder. You'll need to include steering of the front wheel (447) and choose limit to turn (448): 10 degrees (takeoff and landing), or 63 degrees (taxi).
The model has certain drawbacks: not modeled mode free orientation front wheel, ie, when you turn off 447, the front wheel is still manageable. Unfortunately, the JSBSim FDM does not provide a ready free-oriented wheel. Of course, it is possible to calculate the means of the same JSBSim, and perhaps this will be a priority for further development of the model. Free-oriented wheel is essential for correct simulation of landing on the drift ...
Visual model of gears performed with a high level of detail is required to pay serious attention to the animation. To implement the movement details of each strut is more than thirty animations, and an auxiliary support Nasal. Gear strut is a good example of the capacity of the simulator in the animation of complex movements.
The brakes are dependent on the pressure in the hydraulic system 1. As in reality, the plane could not brake if there is no pressure in the hydraulic system. Perhaps the parking brake should be independent of hydrosystem - in fact there are no stops under the wheels in flightgear:)
As in reality, the model may differential brake. But the main bogies rotation not modeled ...
Due to the lack of failures, the emergency brake is not engaged. In this version of the model, the brakes will not decline. Nor is overheating.
Spoilers
The aircraft is equipped with outer, middle and inner spoiler sections. Inner sections are only used after landing, outer section - together with the ailerons to improve the manageability of roll. Middle section used for all the allowable range of speeds and at any altitude, if necessary to accelerate the descent of aircraft.
Spoilers use of hydraulic systems 1. To manage spoilers, use the handle on the center console to the left of the throttle levers. In this model, the middle section control buttons j, k, inner - are retract automatically when the reverse engaged and gears has compression, as well as on a real airplane. Forced internal spoilers extend is not implemented.
Spoilers position, for middle sections can be monitored on the handle on the center console. In addition, when you open the spoilers locks, light yellow placards 316 - 319.
Reverser
Engines 1 and 3 equipped by reversers. When the reverse engaged, the special nozzle flaps overlap and direct jet stream forward, up and down.
To simulate the reverser used to ability of FDM JSBSim. It's allows you to reject smooth vector of thrust that enables relatively realistically simulate reversal, and separately for each engine.
In this model, control of reverser can produce by joystick throttle handle. Conveniently, if the axis of "throttle" provided some intrmediaty lock for throttle handle. When you move the handle to lock, initially included a small reverse - the leaf removed from the lock and turn to the reverse position. Upon further movement of the handle thru lock position, engines went to full reverse. Reverse position and locks controlled by boards 579 G, N for the flight engineer panel.
In the model, for the proper control of reverser by joystick, you need to specify a threshold response. The threshold is defined by two variables: / fdm/jsbsim/fcs/revers-1-limit and / fdm/jsbsim/fcs/revers-2-limit. One sets the threshold of a small reverse inclusion, the second - full. By default, the threshold is set at a small reverse 0.1 (10% progress in full throttle handle movement), the threshold of inclusion of full reverse - 0.04 (4%). Change default values for your joystick, you can editing the tu154-set.xml file, see line 378.
If your joystick focus is not equipped lock for idle thrust, or you do not want to use the administration of the reverser by throttle handle, you can disable this behavior by setting / fdm / jsbsim / fcs / revers-by-joy to 0, by editing the line in the set-file. In this case, the possibility of including reverse by pressing F2.
Electrical
Electrical model is rather simplistic. There is a bus, sources, consumers, all this as it works, and allows you to give a very simplistic view of the electrical system of real aircraft. But since this version is not intended to create procedural simulator, to simulate all electrical systems not too sure. However, the potential that lies in the code electrical permits if they wish to make a model with any necessary degree of reliability.
TU-154 uses:
Bus 27 V DC
Bus of three-phase 220 V 400 Hz AC
Bus of 36 400 Hz AC
Power sources are used:
Three alternators, engines given by
Alternator driven by APU
Airfield source direct and alternating current RAP
Batteries
Converters
Emergency converter
For power on aircraft, you should:
Connect the battery to the DC bus (sw 569). Batteries must be connected to the bus during the whole flight.
Turn on converters (565, 567)
Include RAP (sw 552 down), if the aircraft is on the airport and the RAP is available. In this model, RAP is always available.
Include generator APU (sw 552 up), if the APU is running.
Include engine generators (switches up 561-563, sw. 552 in middle position), if the engines are running.
You can observe bus parameters by devices 501-503, 504-507 multiposition switch, 553-556, 564. In this version, these devices do not work very reliably.
Fuel
Fig. . Fuel tanks TU-154B.
In this model, the fuel system include:
Fuel tanks
Electric pumps
Valves, fuel pipes, cutoff valves, etc.
Portioner
Automatic Flow control system
Automatic alignment system
Fuel meters and flowmeters
The fuel system of any airliner - is a fairly complex set. Tu-154 is no exception, and to properly manage the model should have some idea of how to set up the system. The model implemented the so-called "modified fuel system", which was applied in a series of aircraft N 508.
Fuel is stored in six tanks: four tanks in the wings, and two - in fuselage. The main fuel is in the wing tanks, the tank 1 in fuselage - consumables, and the tank 4 - ballast, used to shift forward CoG. Tanks contents:
Tanks 2 - 9500 kg per tank
Tanks 3 - 5425 kg per tank
Tank 4 - 6600 kg
Tank 1 - 3300 kg
Fuel pumps are installed in tanks 3 - 3 pumps, in 2 tanks - 2 pumps, in the tank 4 - 2 pumps, and in the consumable tank 1 - 6 pumps. Pumps tanks 2,3,4 feed fuel to tank 1, from which four pumps feed fuel to engines. Also, from the first tank a separate pump is supplied APU. In addition, a separate pump feeding a DC, to provide fuel when the engines and all generators and dropouts 220 W electrical power.
For consumable tank installed portioner - device, overlapping flow of fuel from fuel pipes, if the service tank full. Portioner cyclically bypass fuel to consumable tank from tanks 2,3,4. The appliance can be seen on the fluctuations of the arrows fuelmeter of consumable tank 1.
To ensure the correct sequence of fuel consumption, the system provides automatic flow control. Automatic controls the transfer pump, and thus makes the consumation of fuel in the specified program to ensure optimal CoG parameters. In case of refusal or disable the automatic flow, it is possible to manage the transfer pump manually using switches on the fuel system panel of flight engineer.
The consumation of fuel can be made not equally from right and left groups of tanks, or can be made unsymmetrical filling. There is an automatic fuel alignment system for correct the inequalities fuel in groups of tanks. Automatic monitoring equality of fuel tanks in groups, and in case of uneven consumation, turn off the transfer pump on the side, where the spent fuel more. On disconnecting the pump signal yellow lamp on the fuel system panel.
In a system capable of pumping fuel from the 3-tanks in the 2 nd and 4 th in 2 nd. This is done to ensure optimum alignment after landing the aircraft, or if the next flight, 4-th tank is not filled.
Monitoring the quantity of fuel in each tank and control the total amount of fuel on board is determined by the fuel meters. In addition, the system equipped flowmeters that measure the instantaneous fuel consumption of engines (521-523). By integrating this information, an additional flow meter (530) continuously calculates the current balance of fuel. Before the flight, this device must manually set the amount of fuel filled.
The procedure for launching the fuel system:
Turn fuel meters and flowmeter. Expose the amount of fuel on the device 530, at the bottom of the device is mouse zone. The amount of fuel can be viewed on the device 531, the arrow "C"
Turn the automatic flow control system (5018), and automatic alignment system (5016). Turn on the automatic mode of fuel consumption (5019). Lamp "automatic flow does not work" (5004) should shut off.
Turn the 4 pump of consumable tank (5012). Should the green lamp kindle (5011). The lamp is lit - the pump is working.
Turn cutoff valves 5014, should kindle green lamps 5013. Now, the fuel enters the engine, turns off placards "P fuel" (579-C).
Turn the pumps of tank 4 (5009) and the pumps tanks 2 and 3 (580, 581, 5007, 5008). In automatic mode, these pumps are controlled by automatic flow control, to include their needs in order to ensure fuel engines at the time of denial automatic.
Depending on the number of filled fuel consumption will be:
From tanks, 2 to consume to the balance of 3700 kg in each tank. Lights yellow lamp (5001) and the green lamp tanks pumps (585, 589, 586, 590).
Of the tanks 2 and 3, to complete consume fuel from tank 2. Lit the lamp (5001, 5002) and the green lamp of tanks 3 pumps (584, 588, 592, 587, 591, 595) and 2 (585, 589, 586, 590).
After tank 2 will empty, lamps 5001, 585, 589, 586, 590 are off. At this point in the tank 3 is about 1725 + -250 kg. Fuel consumed from tanks 3.
In the case of uneven develop appropriate group of pumps will be switched off automatic alignment, and light yellow lamp (582, 583, 593, 594).
After tank 3 will empty, lamps 5002, 584, 588, 592, 587, 591, 595 are off. Flow switch to the tank 4, light on lamps 5010 and 5003.
After tank 4 will empty, lamps 5010 and 5003 are off, consumption will be made from the tank 1. After consume tank 1 to the balance of 2500 kg, light boards "Ostatok 2500" (Rest 2500 kG) and insert siren.
Engines and APU
There are three NK-8-2U engines on Tu-154B. It's a turbojet, 105 kN thrust takeoff. To start the engine and provide power to an aircraft there is APU TSA-6A.
In the simulation engine, focused on the reliability of high-altitude and high speed characteristics, and modes of behavior in the engine close to the tolerance. If the provision of performance came down to creative thinking about scheduling a "Practical aerodynamics" by Ligum, the fuel automatic had to simulate separately. As in the real engine of the model is applied full-traction method cutoff of fuel at takeoff mode at negative temperatures. But the jump in the draft closing bypass valves have not yet received.
APU - this additional engine, operating for the generator. In addition to providing electrical power from the APU selection of hot air to start the engine, and the aircraft climate control. In this model, APU - is another engine of another type of thrust close to zero. The simulator does not distinguish between the engine and APU, and therefore in-flight APU disabled tachometer shows non-zero rpm, as if his turbine was in the air stream.
In this model, the engine can be run only from APU. Starting in the air is possible, but not yet implemented. Also, no system failures, and the engine never fails, even if the virtual pilot not in compliance with restrictions on takeoff regime. Engine gauges show not a clear values, and if there will be willing to accurately simulate the temperature of the oil and bearings, vibration, and other "stop the T-gas" - welcome aboard!
To start the APU must be:
Turn on the power system of APU (570). Open APU door will be on (577-F).
"Run-cold" switch (571) - in the up position.
Insert the APU fuel pump (572). If the expense is the fuel tank, turn on the placard "P fuel" (577-G) and "Ready to Run"(577-H) will on.
Click "Start" (574). Green lamp automatic APU (577-J) start will on, on the tachometer (508) will increase speed.
After the APU stay to work mode, light board (577-I), and (577-J) off. APU is running, you can turn a generator on bus.
To turn off the APU, you need to click "Stop" (575), and after turbine shutdown - shut down the switches 570, 571, 572.
To start the engine you need:
Move throttle levers in the idle position.
Prepare the fuel system.
Start the APU.
Open air bleed valve of hot air from the APU. Translate into the top position toggle switch 573 and hold it until shut off board "ready to start"(577-H).
Include turbine exhaust termometers (515-517) switches 5030-5032. Thermometers to verify serviceability by clicking on the buttons 5033-5035.
Open the lid panel start engine 5038.
Set a toggle switch "Run-Off" to "Run" (577-A).
Set a toggle switch "Start - Cold" to "Start" (577-B). Cold start modeled, but not without glitches. In this version using the "cold start" is not recommended.
At temperatures below-5C, insert tumbler "heating ignition device (577-C). In this version of the engine will start at any position of the heating.
Select a engine by Choose a multiposition switch (577-D).
Open the cutoff cranes by moving the levers in the front position. Cutoff cranes are on the left side of the throttle levers, the left side of the flight engineer panel.
Click on "Run" (577-E). If all the preparatory operations are performed correctly, the green lamp lights up "PDA works" (577-G), will grow up (control of tachometer 512-514). When the engine go to idle rpm, may briefly light up the lamp "Dangerous turnovers starter" (5036).
If necessary, suspend the launch, click on "Ending Start (577-F).
After engine ashieved idle rpm and "PDA works" (577-G) will off, then the switch (577-D) following the engine and repeat the starting procedure.
After all engines will running, put a switch (577-D) in the neutral position, turn off the tumblers "Run-off" (577-A) and heating ignition device (577-C). Tumbler "Running - Cold" (577-B) leave in the "Run". Close the door panel run.
After all engines ashieved idle rpm, connect generators (561-563) to bus.
Hydraulic
Tu-154 has three completely independent hydraulic system. Hydrosystems supplied work (with a triple redundant) boosters - hydraulic powered units for elevator, rudder and ailerons, and actuators ABSU RA-56. In addition, further supplied:
From the first hydraulic works:
Flaps, the first channel
Gear, the main system
Braking wheels, the main system and parking
Spoilers, inner and outer sections
Charging Hydroaccumulator emergency braking
From the second hydraulic works:
Flaps, the second channel
Gear, emergency systems
Front wheel steering
From the third hydraulic works:
Gear, emergency backup system
Each hydraulic system has a two-plunger pump, creating pressure. On engine 2, there are two hydraulic pump, on the left and right engines - one by one, and two additional pumping stations with electrical power from the AC.
The first hydraulic system uses:
Pump left engine
Pump center engine
The second hydraulic system:
Pump center engine
Pumping Station 1
The third hydraulic system:
Pump right engine
Pumping station 2
In each of the hydraulic system includes Hydroaccumulator - Specialty balloon filled with nitrogen, acting as the storage of energy. In addition to the three Hydroaccumulator within the system, there is an additional Hydroaccumulator used only for emergency braking. Before the flight, emergency hydroaccumulator should be charging from hydrosystem 1.
You can connect the hydraulic system 1 and 2 through the electrically controlled valve. In normal operation, this feature is used to charge the hydraulic system 1 of the hydraulic pump 2, or before starting the engine for brake on, or after turn off the engine 2 after landing.
Hydrosystem themselves quite complex, and their interaction with customers at times recalls the puzzle. However, management of hydrosystems is quite simple. Governance:
Three switces under the cover 339 includes booster - hydraulic steering surfaces
Nine switches 540 - 548 include hydropower of aggregates of RA-56, three independent channels for each unit
Sw. 5028, 5029 include pumping stations 1 and 2
Sw. 5027 connect hydrosystem 1 to 2.
Button 5026 charges Hydroaccumulator emergency braking of the hydraulic system 1
Manometers 532-535, 125-128, lamps 5021-5024 and 121-124 are used to control the pressure
Indicator of level of fluid 536, 537, and buttons 5025 allow a rapid control the amount of fluid in the systems.
In this model, hydrosystems, except for the inclusion of boosters and RA-56 actuators, not required a crew maintenance. Pressure in the system appears after start of engines, and continues until the engines are running. As in the real plane, with the engine stops in the air pressure in the system creates a rotation of the compressor air flow. The degree of accuracy of modeling this situation is questionable.
Hydraulic model is quite complicated, and not even only because of the branched structure. Calculation of pressure in the hydrosystem, ie, computation of amount of energy stored in the gas spring of hydroaccumulator requires some mathematical support. All mathematics hydraulic cheat means JSBSim. Perhaps, on the theme of modeling the hydrosystem will write a separate article.
