Engine temp

[press]

I`m not sure if this was discussed, but aren`t the engines operating a little bit hot. I monitor engine temp on all my flights and it never drops bellow 880C, but operate at around 950-960C. Usually a TV3-117VM operates at 720-780C, TV3-117MT is 20-30C cooler than VMs. I know the Ka-50 has TV3-117VMA, but it`s hard for me to believe that between these models the difference between engine temp is that high. Also please take note that the engine limiters will start limiting when engine temp reaches 990C.

 

I don`t operate on emergency power, if anyone want's to ask (only 2 Page Ups after engine start up and idle) and usually I fly at ~220km/h, outside temp is ~30C.

[Panzertard]

This thread may be of interest for you:

http://forums.eagle.ru/showthread.php?t=42068

No definitive answer there, but some good related posts.

[RvETito]

Congrats, you seem to have a trained eye ;) EGT/GG RPM is a subject of adjustment IRL via the IGV/VSV. What we have in BS is not incorrect, just the engines are "tuned" with more "open" compressors.

[press]

Although I have an engineers degree in helicopters I work on Boeing 737, but my father works on Mi-8/17. I browsed his manuals and spoke with him about engine temperature during normal operations of TV3-117VM. From when I started BS for the first time I`ve noticed that the engines are a little bit hot. Is there a way to cool them down, to make them operate at 7-800C?

[RvETito]

I'm affraid that requires hardcoding. As I said the EGT is a subject of adjustment via the IGV/VSV mehcanism i.e. you adjust the air mass flow through the compressor at given RPM. The very same manual you quote says that for the TV3-117VM (it's the same for the VMA) the maximum measured allowed EGT per mode are as follow:

 

- idle - 780'C

- 2nd cruise - 870'C

- 1st cruise - 910'C

- maximum continous (nominal)- 955'C

- take-off - 990'C

- emergency (2.5min power for VMA)- 990'C

 

While for the paramaters given in the main chart are for operation of the engine on test bench in ISA conditions, without taking into account the exhaust nozzle, the dust protectors and the engine bleed system for anti-ice and other helicopter needs it says:

 

- idle - 780'C max (usualy not defined, only RPM)

- 2nd cruise - 770'C

- 1st cruise - 815'C

- maximum continous (nominal)- 855'C

- take-off - 890'C

- emergency (2.5min power for VMA)- 920'C

 

So there are many factors that could affect those numbers and in service we always try to reach maximum EGT for the given RPM (power mode) because this is what gives output shaft power. I can tell you the difference- we had one Ka-32 (VMA engines) with very 'closed' compressor (VSV), it easily hit 100-101 % compressor RPM but could never reach EGT more than 920-930'C and the EEG was limitng it's power by gas-generator RPM. Another helicopter with exactly the same engines did 950-960'C at 99% Ngg and the difference in the abilities of the two identical helicopters to lift their load in equal conditions was obvious.

 

So what you see in BS is the perfect case - RPM limit almost coincides with the EGT limit i.e. you get maximum engine hp ouput.

 

You can tune the EGT by adjusting the VSV mechanism IRL and it's a common practice for some operators to increase their engines' service life. They reduce their power, making them colder in favor of longer TBO.

[mvsgas]

Maybe, it could be your ambient temp affecting your engine temp like in RL?

 

I set map temp to -17C (0F)

 

and got 83% RPM and 605 EGT (FTIT) sitting in the runway

 

with 48C (120F),

 

I got the results I would expect, higher RPM and EGT

Edited August 25, 2009 by mvsgas

[Tbag]

Very interesting information here! :thumbup:

 

I'd really like if such information could be kept in a wiki or the like.

[press]

I'm affraid that requires hardcoding. As I said the EGT is a subject of adjustment via the IGV/VSV mehcanism i.e. you adjust the air mass flow through the compressor at given RPM. The very same manual you quote says that for the TV3-117VM (it's the same for the VMA) the maximum measured allowed EGT per mode are as follow:

 

- idle - 780'C

- 2nd cruise - 870'C

- 1st cruise - 910'C

- maximum continous (nominal)- 955'C

- take-off - 990'C

- emergency (2.5min power for VMA)- 990'C

 

While for the paramaters given in the main chart are for operation of the engine on test bench in ISA conditions, without taking into account the exhaust nozzle, the dust protectors and the engine bleed system for anti-ice and other helicopter needs it says:

 

- idle - 780'C max (usualy not defined, only RPM)

- 2nd cruise - 770'C

- 1st cruise - 815'C

- maximum continous (nominal)- 855'C

- take-off - 890'C

- emergency (2.5min power for VMA)- 920'C

 

So there are many factors that could affect those numbers and in service we always try to reach maximum EGT for the given RPM (power mode) because this is what gives output shaft power. I can tell you the difference- we had one Ka-32 (VMA engines) with very 'closed' compressor (VSV), it easily hit 100-101 % compressor RPM but could never reach EGT more than 920-930'C and the EEG was limitng it's power by gas-generator RPM. Another helicopter with exactly the same engines did 950-960'C at 99% Ngg and the difference in the abilities of the two identical helicopters to lift their load in equal conditions was obvious.

 

So what you see in BS is the perfect case - RPM limit almost coincides with the EGT limit i.e. you get maximum engine hp ouput.

 

You can tune the EGT by adjusting the VSV mechanism IRL and it's a common practice for some operators to increase their engines' service life. They reduce their power, making them colder in favor of longer TBO.

 

I understand perfectly. By any chance do you know what is the file with the engine parameters? :D

 

Recently I`ve flown with two different Mi-17s. One is a VIP version and one is cargo. Both of them have engines set for heavy lifting. OAT was +30C, wind calm. The VIP helo had 11 pax (this helicopter has 3 armchairs and a couch for 8 people, fridge, microwave oven, WC, air-conditioning - the empty weight is quite heavy), and the cargo helo (standard 1 bench + 915L extra fuel tank) ~15 pax. On both flights in both helicopters I`ve looked at the engine parameters. Idle temp ~620C, at a cruise speed of 150km/h, at 100m AGL, weight conditions from above the engine temperature in both helicopters were ~720C. During take off and landings the engine temp reached ~820C. I`ve inserted "~" sign because both engines don`t operate identical, there was a difference of ~40C between left engine temp and right one.

 

@mvsgas: I usually fly at 25-30C, or at what temp is set the mission/campaign.

[wickedpenguin]

I'd just like to make an "aside" of sorts. When so many other games and sims are having serious issues (Rise of Flight, I'm looking at you), I'm thrilled that we can play a simulator whose only problems are minor technical niggles like an engine running "a little hot".

[RvETito]

I understand perfectly. By any chance do you know what is the file with the engine parameters? :D

 

Recently I`ve flown with two different Mi-17s. One is a VIP version and one is cargo. Both of them have engines set for heavy lifting. OAT was +30C, wind calm. The VIP helo had 11 pax (this helicopter has 3 armchairs and a couch for 8 people, fridge, microwave oven, WC, air-conditioning - the empty weight is quite heavy), and the cargo helo (standard 1 bench + 915L extra fuel tank) ~15 pax. On both flights in both helicopters I`ve looked at the engine parameters. Idle temp ~620C, at a cruise speed of 150km/h, at 100m AGL, weight conditions from above the engine temperature in both helicopters were ~720C. During take off and landings the engine temp reached ~820C. I`ve inserted "~" sign because both engines don`t operate identical, there was a difference of ~40C between left engine temp and right one.

 

@mvsgas: I usually fly at 25-30C, or at what temp is set the mission/campaign.

 

Sounds like reasonable numbers for the conditions you describe.

[Yo-Yo]

The EGT is defined by the power the engine produces. Knowing air mass flow, compressor pressure ratio, turbines pressure ratio and their eficiency one can determine the EGT for certain power. The second parameter to check is SFC that determines fuel flow for certain power ratings. It is the first and second ways to estimate the model.

 

And the third way is :)