Engine Governor Switch Question

[-Nighthawk-]

Hey,

I'm in the process of learning all of the different engine functions and I was just wondering what the left and right engine governor switches do (turn them on during startup)

 

I've been doing some research but can't find a clear answer.

 

cheers

[mvsgas]

AFAIK they are the FADEC for KA-50 engine. Basically you control blade pitch with the collective and engine governor control engine RPM based on torque requirement from the main rotor. Many aircraft have to option to turn the FADEC control to back up or turn them off for emergencies. Keep in mind I do not work on helos so I could be wrong.

[AlphaOneSix]

Yeah, no FADEC on the Ka-50. In fact, no digital fuel control at all. Even the newest engine of the family, the VK-2500, does not have a FADEC, but it at least has an electronic fuel control. The TV3-117 fuel control is purely hydromechanical, and receives N1 and N2 speed information through gears and flex shafts.

 

The engine governor monitors three parameters: N1 (gas generator turbine) speed, N2 (free turbine) speed, and EGT (exhaust gas temperature).

 

In the event of an N1 or N2 overspeed (around 107% for N1 and around 118% for N2), the governor will send a signal to an emergency fuel shutoff actuator and shut off fuel to the engine. These overspeeds will only happen if something very, very wrong happens in the engine. As a pilot, there is nothing you can do to cause those overspeeds (at least not to the extent required to cause engine shutdown).

 

The last parameter monitored, EGT, is handled a little differently (and is the only one your likely to notice during flight). In this case, the governor works in conjunction with a temperature controller to reduce the amount of fuel going into the combustion chamber when the engine reaches a certain preset temperature. This is done in order to prevent an overtemp of the engine. In other words, as you pull in more and more power, at some point, the governor and the temperature controller are going to adjust the fuel flow to not give you all the power you're asking for. This is accompanied by the ENG PWR LIMIT lights. When those lights come on, the aircraft is telling you that you're essentially out of power.

 

EDIT: This information is also in the flight manual on page 2-85.

[-Nighthawk-]

Thanks for the explanation,

so basically it's just a safety thing for the engine to prevent overspeed, high temperatures, fuel flow etc.?

 

(want to know more about aircraft engines for the game and I'm planning on becoming an aircraft engineer) :)

[Focha]

Alpha does that mean (in simulation) that if you turn off the two engine governors you will not have that engine protection when your ask for more engine power? Eventually the lights will go yellow but there is no way of controlling the EGT, leading to a engine failure, right?

 

I guess, for example, in Bell 206 the governor will control the engine RPM by controlling the fuel that goes to the engine but what I understand from your post is that on Ka-50 the governor only controls the excess of power and not the need of it, don't know if you understand my question very clearly, but in Ka-50 it seems it only controls the limit and not the addiction.

 

Best regards and thank you for the tech info.

[AlphaOneSix]

Alpha does that mean (in simulation) that if you turn off the two engine governors you will not have that engine protection when your ask for more engine power? Eventually the lights will go yellow but there is no way of controlling the EGT, leading to a engine failure, right?

 

I am pretty sure that you won't even get the yellow warning lights if you leave the governor off, but I can't remember for sure. You can break the engines very quickly that way (overtemp, that is...have not tried it in the game, though...would be a good experiment).

 

I guess, for example, in Bell 206 the governor will control the engine RPM by controlling the fuel that goes to the engine but what I understand from your post is that on Ka-50 the governor only controls the excess of power and not the need of it

 

Correct, on the Ka-50, the governor is a limiting and shutoff device only. The fuel control on the engine itself handles fuel scheduling for the engine. That is, you increase pitch in the blades with the collective, so the rotor slows down. The fuel control gets an N2 indication from a flex shaft, and it knows that the rotor is slowing down, so it schedules more fuel to increase your N1 to keep your N2 stable. The fuel control is a hydromechanical unit mounted on the engine itself. The governors (one for each engine) are electronic boxes mounted elsewhere in the airframe and receive electric signals from a tachometer generator (for N1), a set of speed transducers (for N2), and a thermocouple harness (for PTIT).

 

You can fly just fine without the governors on, you just won't have PTIT limiting or overspeed protection. Or more specifically, YOU (the pilot) become the governor, and you have to be careful not to pull too much power to get into an overtemp situation.

[mvsgas]

Cool Alpha61, so it actually uses N2 to control engine Speed? (Engine Fuel control) I figured it had a specific sensor for the power turbines...What are the turbines that send power to the gearbox, what are they called I mean?

[AlphaOneSix]

Cool Alpha61, so it actually uses N2 to control engine Speed? (Engine Fuel control) I figured it had a specific sensor for the power turbines...What are the turbines that send power to the gearbox, what are they called I mean?

 

The Russians refer to the turbines in the hot section as the "gas generator" (N1, the one that drives the compressor, sometimes called the compressor turbine) and the "free" turbine (N2, drives the gearbox, sometimes called the power turbine).

 

The N2 input is just one of several parameters used by the fuel control to determine how much fuel to send into the engine. The N2 input comes from a flex shaft directly off of the free turbine shaft. The N1 input comes from the accessory gearbox on the engine (since the accessory gearbox is driven by the compressor shaft, it's the same as your N1). The engines also synchronize with each other using air pressure (bleed air from the combustion section), so that if one starts putting out more power than the other, the other will pick up the pace a bit. There are a couple of other things, but all in all, it's a pretty ingenious fuel control, considering it was developed in the late 1960's.

[mvsgas]

Where could I find more info on the engine? Is there more stuff in the forums? Probably I seen this question before. What I was looking for was how many stages of compression, is it a high bypass, how many HPT and/or LPT. How many ignitors. See, for me working on fighters, N1 is the first stage of compression or lo pressure compressor (PW-220 and GE-110 is the first 3 stages) and N2 is the second stage or high pressure compressor (the rest of the stages before the combusted chamber). We also have two sets of turbines, HPT to drive N2 and LPT to drive N1. I thought helo engines had 3 sets of turbines. Thanks man.

[AlphaOneSix]

The attached photo is from http://brigadyr.net/ which has lots of great pictures of military equipment.

 

Anyway, from the picture you should be able to see that the TV3-117 has 12 compressor stages, followed by the combustion chamber (green) followed by the two-stage gas generator turbine, and then finally the two-stage free turbine. You can also pretty clearly see the flex shaft that comes off of the free turbine shaft that goes to the fuel control, which is on top of the engine.

 

There is no high/low pressure turbine, specifically. There is just the two gas generator disks that power all 12 compressor disks. Or maybe to be more helpful, what you consider HPT drives the entire compressor section, and what you would consider LPT is what drives the main gearbox.

 

There is no bypass at all.

[Focha]

Thank you Alpha for the great information and knowledge.

 

Best regards to you.

[mvsgas]

The attached photo is from http://brigadyr.net/ which has lots of great pictures of military equipment.

 

Anyway, from the picture you should be able to see that the TV3-117 has 12 compressor stages, followed by the combustion chamber (green) followed by the two-stage gas generator turbine, and then finally the two-stage free turbine. You can also pretty clearly see the flex shaft that comes off of the free turbine shaft that goes to the fuel control, which is on top of the engine.

 

There is no high/low pressure turbine, specifically. There is just the two gas generator disks that power all 12 compressor disks. Or maybe to be more helpful, what you consider HPT drives the entire compressor section, and what you would consider LPT is what drives the main gearbox.

 

There is no bypass at all.

Thanks man, very cool..Sorry I am a big geek when it come to aircraft stuff.

I can also see 4 stages of what it look like to me to be CIVV/IGV. Looks like no bypass air, I wander how the keep the turbine from melting, wow. Gearbox on top, that just look weird to me. I do not see any FOHE or oil air coolers, very interesting man. Thanks, my experience with jet engine is so limited is cool to see other engines and their differences.

Sorry -Nighthawk-, I am not trying to hijack your thread man.

[press]

Thanks man, very cool..Sorry I am a big geek when it come to aircraft stuff.

I can also see 4 stages of what it look like to me to be CIVV/IGV. Looks like no bypass air, I wander how the keep the turbine from melting, wow. Gearbox on top, that just look weird to me. I do not see any FOHE or oil air coolers, very interesting man. Thanks, my experience with jet engine is so limited is cool to see other engines and their differences.

Sorry -Nighthawk-, I am not trying to hijack your thread man.

 

Not every member of this forum is an aircraft engineer (see the CIVV/IGV or FOHE). I can start also (I`m an aicraft engineer also) and no one will understand a thing. :smartass:

 

Gearbox is on top of the engine for easy access. Remember, that these engines (different variant) are used on the Mi-17/24 or Ka-32 which have the engines installed on top of the fuselage.

[Yo-Yo]

Where could I find more info on the engine? Is there more stuff in the forums? Probably I seen this question before. What I was looking for was how many stages of compression, is it a high bypass, how many HPT and/or LPT. How many ignitors. See, for me working on fighters, N1 is the first stage of compression or lo pressure compressor (PW-220 and GE-110 is the first 3 stages) and N2 is the second stage or high pressure compressor (the rest of the stages before the combusted chamber). We also have two sets of turbines, HPT to drive N2 and LPT to drive N1. I thought helo engines had 3 sets of turbines. Thanks man.

 

 

I know at least one engine of four turbines. It is D-136 derived from D-36 turbofan triple-schaft gas generator.

[amalahama]

Yeah, and Trent XWB has 9 turbines! (triple shaft too)

 

Regards!

[AlphaOneSix]

The gearbox on top of the engine is the accessory gearbox, and runs the fuel control, one of the two oil pumps, RPM tachometer, and fuel pump. The air starter also mounts to the accessory gearbox for starting the engine. The gearbox portion is only the darker gray piece at the top left of the photo. The larger, more silver thing behind it is the fuel control. There are oil coolers, but they do not mount on the engine. They are completely separate (back by the APU on the Ka-50) and oil is piped to them from the engines and main gearbox. There are 5 stages of variable guide vanes. You can probably melt things in the engine if you don't have the governors on. With the governors operating, your max EGT is about 990C.

[-Nighthawk-]

This is all gibberish for me, hopefully I'll understand it one day :P

[Skypat]

did you notice that EGS TEST switch is bugged ?

when the EGS TEST switch is clicked in CT-1 (up) position, you can't move it anymore in down position (CT-2)

 

best regards

Skypat

[mvsgas]

press

Not every member of this forum is an aircraft engineer (see the CIVV/IGV or FOHE). I can start also (I`m an aircraft engineer also) and no one will understand a thing.

Sorry press I do not follow what you are saying, Who is and aircraft engineer? I never said I was an engineer, I am just a bad mechanic.

 

Yo-Yo

I know at least one engine of four turbines. It is D-136 derived from D-36 turbofan triple-schaft gas generator.

Thanks, I know some engine with several turbines, I just never seen the inside of a helicopter engine, I did not know how it look like. To me that engine looks like the core of the engines I have worked on (N2), I appreciate all the info.

 

-Nighthawk-

This is all gibberish for me, hopefully I'll understand it one day

Sorry guys, I do not mean to start talking in code. CIVV stands for Compressor Inlet Variable Vanes, IGV stand for Inlet Guide Vanes. This things help control airflow to the compressor blades to help minimize if not prevent compressor stalls and to improve airflow for compression.

FOHE stand for Fuel oil heat exchanger, one of many devises used to cool the oil.

 

Skypat

did you notice that EGS TEST switch is bugged ?

when the EGS TEST switch is clicked in CT-1 (up) position, you can't move it anymore in down position (CT-2)

best regards

Skypat

I have been looking for a EGS Test Switch but can not find it, did you mean the КОНТР. ЭРД СТ-1 – РАБОТА – СТ-2” (EEG PT-1 Test – Operation – EEG PT-2 Test)?

P.S. I went to the game and tried this switch and it work as advertise in the manual page 2-85 and 2-86. I place switch КОНТР. ЭРД ТК – РАБОТА” (EEG GG Test – Operation) to test (ТК) and then moved КОНТР. ЭРД СТ-1 – РАБОТА – СТ-2” (EEG PT-1 Test – Operation – EEG PT-2 Test) to СТ-1 and СТ-2 whit all the required light and voice warning. Did you try left clicking with the mouse to go up to CT-1 and right clicking to go down to CT-2?

 

AlphaOneSix

Our gearbox is the same way, but on the bottom. We just call it a gearbox module with the Main fuel control, fuel pumps, oil pumps and other component that engine module together. At any rate thank you very much for the information.

Edited April 15, 2009 by mvsgas

[Skypat]

P.S. I went to the game and tried this switch and it work as advertise in the manual page 2-85 and 2-86. I place switch КОНТР. ЭРД ТК – РАБОТА” (EEG GG Test – Operation) to test (ТК) and then moved КОНТР. ЭРД СТ-1 – РАБОТА – СТ-2” (EEG PT-1 Test – Operation – EEG PT-2 Test) to СТ-1 and СТ-2 whit all the required light and voice warning. Did you try left clicking with the mouse to go up to CT-1 and right clicking to go down to CT-2?

 

hello

thanks it works

best regards

Skypat