58

That is crazy. DON'T just rely on an person who's new to airplanes and only training is 5 minutes of showing them what to do, who may or may not react correctly when it springs to life, as the only thing preventing the plane from heading off somewhere while you try to dive clear. Don't. Do. It. Tie the tail. To something. Anything. Use the passenger and ...


43

The sound you're hearing is the APU (Auxiliary Power Unit) running. Turbine (jet) engines turn at a much higher RPM than reciprocating engines. This means that an electric starter motor would have to be bigger and heavier in order to produce enough torque to get the engine moving fast enough. The bigger the engine, the bigger the starter (and the batteries ...


37

The means of starting most turbine engines is high pressure bleed air. This bleed source typically comes from an APU but may also come from an already running engine (crossbleed start) or an external huffer cart. In some airplanes the start is completely FADEC controlled and need only be initiated and monitored by the flight crew, and in other airplanes ...


35

When you have the thrust levers of, say, a 747 all the way back to idle, the airplane still has enough power to move. In fact, you will have to use the brakes to keep it from taxiing too fast. If you didn't use the brakes, it would finally accelerate to somewhere around 45 knots or so, far too fast for taxiing, but much too slow to take off. At the idle ...


33

Radial engines - especially older large-bore designs like you find in WWII era warbirds - can suffer from a phenomenon known as hydraulic lock. Basically while the engine is off and cooling some oil from the crankcase seeps past the piston rings in the lower cylinders, and collects there. When you try to turn the engine over with this oil in the cylinder ...


28

No, it is perfectly normal to operate without any fuel in the center tank. Until your fuel load is over about 17,000 lbs, the center tank should be empty. That’s enough for about 2 hours of flying, plus reserves. If your simulator requires fuel in the center tank in order to start the engines, it isn’t accurately replicating the real aircraft.


28

(airliners.net) Be sure to turn on the appropriate pumps on the lower-left of the overhead panel. The APU can start without them via suction. Otherwise, it's a simulator problem. Also see: Why are fuel tanks in the wings filled first, and why are they used last?


26

When you shut down a radial the unscavenged oil in the case (oil coating the surfaces that didn't get pumped back to the reservoir tank) runs down and seeps past the rings of the cylinders directly below and to each side at the bottom. In theory, it can create an hydraulic lock if there is enough oil collected in a cylinder, that happens to be on its ...


24

It's a Jet Fuel Starter (JFS) system, used by the F-16 and other jet fighters. On-board compressed air (called Stored Energy System) is released onto a turbine, which starts a small gas turbine engine, which then mechanically engages with the engine's gearbox to spin it. F-22 calls it Auxiliary Power Generation System. On the F-16 the JFS allows two bursts/...


23

Modern jet transport category aircraft have APUs and they will be running if no engines are. Batteries on jets do not work very long with all electrical buses energized and the first thing you do after turning the batteries on is seeing that they are working correctly and then starting the APU (assuming no GPU is hooked up, if there is a GPU then starting ...


22

I’ll second John K’s answer. Do not attempt to hand prop an airplane without receiving professional instruction on how to do it safely. It is a real easy way to get seriously injured or killed, as this idiot almost found out. It should also involve two competently trained people, one to do the hand propping, and the ...


21

You may be expecting the rotor to spin up in lock-sync with the engine. That's not quite what happens on a turbine helicopter. Turbine helicopter engines (turboshaft engines) have a turbojet engine inside them that makes thrust. This engine has a shaft of its own - so that its compressor blades are connected to its own turbine blades. The turbojet's ...


18

Perusing the A380 Training Guide, Edition 01, 01 Sep 2008, Section 5 - Engine Starts, Subsections 5.8.6 (Engine Start Valve Stuck Closed), 5.8.6 Engine Start Valve Stuck Closed ECAM actions – ENGINE MASTER OFF. Check MEL, and in conjunction with, advise LAE of situation in preparation for Start Valve Manual Operation. For Start Valve Manual ...


17

If you would like to know about jet engines, please read @casey's answer. It's very detailed and good. There are some turbine engines which are started a different way. We are talking about turboprop or turboshaft engines. A famous example is the PT6 turbine, delivering power to many small turbine-powered propeller airplanes like Beachcraft's King Air ...


16

They are all harder to start in the cold, fuel injected engines included, and need an over-rich mixture for starting. The rich mixture is required because a lean one is harder for a spark to light off if the fuel/air charge is cold. Now, it's still cold outside after the engine warms up, so the air charge is still cold, initially, but on a warm engine it ...


15

You sure can! In reality the engines in modern prop planes are not all that different (in some cases even identical) to the engines of the hand crank days. The reason many older planes were hand crank was simply to save the weight toll of a starter motor and battery to drive the system. Some older aircraft have no active electronics (the piper cub comes to ...


14

I have no desire to dispute what a fellow retired 747 captain said, so I'm wondering if there was some miscommunication between you and the captain. Or perhaps his definition of catastrophic is different than mine. My understanding of catastrophic would preclude any attempt to restart the engine. During my time on the 747 I had three engine failures. One ...


14

It is oil. When the engine is cold, the piston rings don't quite seal the cylinder and oil leaks past and pools in the bottom cylinders. If the engine is started with oil above the pistons (looking from the centre), severe damage can occur as oil is not compressible, causing an hydraulic lock, and the piston can be prevented from rising all the way to the ...


12

If so, how do you do it safely without cutting your hands off or being pulled in by the propeller? The short answer is "very carefully." A longer answer, and the way my father taught me to do it (but not necessarily how others might do it) when I was in my early teens was as follows: Stand close enough to the propeller disk so that you're not leaning ...


12

The isolation valve in Open or Auto ensures that the Auxiliary Power Unit (APU) bleed air reaches the engine number 2 starter. Engine number 2 start Exhaust Gas Temperatures (EGT) are generally higher. http://www.lt-vacc.org/images/mesti/Boeing%20737-300-400-500%20Operations%20Manual.pdf Engine number 2 is started first because it's on the opposite side of ...


12

Rotor bowing is not unique to this generation of engines. It was an issue with the early IAE V2500. I remember initially they would have somebody manually rotate the fan some time after shutdown. This engine still has a longer start motoring period over the comparable CFM. The root cause is simply making the shafts thinner, increasing their flexibility. ...


11

(Source) Image shows how the shaft is connected to the gearbox. The engine shaft is connected to an accessory gearbox. The spinning shaft spins the gearbox, which drives the generator, the engine-driven fuel pump, and other accessories. The same gearbox can be spun using high-pressure air—from the APU or a start-cart. This high-pressure air spins a turbine ...


10

Excellent answers so far. There are a couple other ways in which a jet engine can be started. The F-16 has the engine connected to a gearbox with a special, high-speed-balanced shaft. There is a clutch where the shaft connects to the gearbox. Also attached to the gearbox is a smaller turbine known as a Jet Fuel Starter (JFS), approximately the size of a ...


10

Airliners usually push back from the gate and then start their engines when well clear. If the aircraft has an unserviceable APU, a ground based power supply must be used at the gate for the start. Permission(coordination) is required so that their are no hazards for ground crew and vehicles in the gate area. After one engine is started at the gate, the ...


9

I guess now it is my turn to add exotic ways to start a jet engine. The Jumo 004 of the Me-262 and Ar-234 had a small piston engine in the central spike which was electrically started, but also could be hand-started by a mechanic. Did you ever note the hole in the middle of the spike, and the ring stuck in it (see the left picture below)? The ring was ...


9

In the real aircraft that checklist item would mean bringing the thrust lever of the engine to be started up out of cutoff and to the idle position. This would be accomplished by physically moving the thrust lever forward slightly out of the cutoff detent. However, in the computer flight sim for which the linked checklist provides guidance, the cutoff ...


9

The main reason behind this capability is that the Boeing 787 starts its engines entirely on electrical power generated by the APU's VFSG (Variable Frequency Starter Generators) vs relying on APU bleed air to start the engines. Thus there isn't the typical drop in pneumatic pressure caused by the pneumatic starters on regular jetliners. See 787 No-Bleed ...


9

Carburetors don't work as well in cold conditions because they themselves tend to cool the air as it flows through the Venturi tube, compounding the issue of cold intake air and cold fuel. From Wikipedia: When the engine is cold, fuel vaporizes less readily and tends to condense on the walls of the intake manifold, starving the cylinders of fuel and ...


9

The procedure you seem to refer to isn't hand starting. It's done on radial engines, with ignition off and valves locked open, to clear oil that may have settled in the lower cylinders (by seeping past the piston rings while the engine was standing) and prevent a hydraulic lock that could bend a piston rod or otherwise break things (at the absolute minimum, ...


8

It can take from a few seconds to eternity. If the core cools down, the engine might lock up. Windmilling starts are only possible if the aircraft is flying fast and low enough. It will assist the startup process, but needs additional help from the starter or bleed air, typically below 300 knots and above 20,000 ft. Details vary from type to type. If ...


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