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Posted

Hey everyone,

 

I've been playing around some missions involving the elbrus rescue (Maximum extreme and Elbrus rescue version with Mi-8 instead of Huey) and I've encountered some issues in flight.

 

As i try to climb to the top of elbrus (or climbing around the Caucasus), I get these generator failure warnings and my generator/s shuts down, so does autopilot and some other electrical systems which affect my flight. I've tried reading through some Mi8 data and have not really come up on anything pertaining to high altitude flight.

 

I would assume the Mi8 would have an easier time climbing to the top of elbrus versus the huey (which seems easier to climb given i don't get these generator failures). Is it something to do with the rotor RPMS? I know the huey needs some decreasing of collective to maintain proper RPM due to the thinner air, but i'm not sure...

 

Anybody got some tips? I would be forever grateful :) Really love the Hip :)

PINOY PRIDE!!!

 

System Specs: i7-4790, Windows 7 64-Bit, ECS L337 Z87H3-A3X Mobo, HyperX Fury 32Gb, Nvidia Titan (Pascal), TM Warthog and TFRPedals, TrackIR 5

Posted (edited)

The primary factor that you're encountering is the icing on your rotor blades. Due to the environment around the mountain. Ice is building up from the humidity of lower altitudes and as you ascend higher the air becomes much dryer and thus causes the ice to build up. This causes the rotor to work harder adding weight to the rotor blades and draining most of your power. The treatment to this is to engage the de-icer prior to the transition to higher altitudes to at least reduce the effect of icing of the blades.

 

1606.jpg

Edited by Razgriz_37
Posted

It is true what is said above. But also, because of all the anti-ice equipement (wich is electrical) the engines loose a lot of power so, RPM's go down. If the RPM's of your engines go below a certain point (91 or 92% IIRC) the revolutions are too low for the generator to be effective so, automatically it shuts down. And disabling any electrical equipment on your Hip. I did complete the Elbrus mission, only just... It is quite an exciting mission, even tough there is no shooting involved.

Happy Flying! :pilotfly:

Posted

Thank you for the tips guys, I have all the de-icing and stuff on so I guess i'll have to manage my RPM's closely. :)

PINOY PRIDE!!!

 

System Specs: i7-4790, Windows 7 64-Bit, ECS L337 Z87H3-A3X Mobo, HyperX Fury 32Gb, Nvidia Titan (Pascal), TM Warthog and TFRPedals, TrackIR 5

Posted
It is true what is said above. But also, because of all the anti-ice equipement (wich is electrical) the engines loose a lot of power so, RPM's go down. If the RPM's of your engines go below a certain point (91 or 92% IIRC) the revolutions are too low for the generator to be effective so, automatically it shuts down. And disabling any electrical equipment on your Hip. I did complete the Elbrus mission, only just... It is quite an exciting mission, even tough there is no shooting involved.

 

 

Now you can keep on also the stand by generator from AI9V and when main generators fail it switch automatically.

 

Other tips I've heard was to remove all unnecessary loads from electrical buses. You could cut a lot of them. Copilot avionics, lights, bells, whistles . You can cut the left engine generator and stay only with the right one thus easing up the load on the "main engine".

 

As for ice, the main problem I think is not the load as inertia is a double sword, but the modification of the rotor wing profile that can make it unfit for flight and stall.

[sIGPIC][/sIGPIC]

I5 4670k, 32GB, GTX 1070, Thrustmaster TFRP, G940 Throttle extremely modded with Bodnar 0836X and Bu0836A,

Warthog Joystick with F-18 grip, Oculus Rift S - Almost all is made from gifts from friends, the most expensive parts at least

Posted

Rotor RPM is what matters here, not engine RPM, at least not engine RPM directly. Your generators fall offline when your rotor RPM droops below around 88%. Remember that the generators are mounted on the main gearbox, not on the engines. I personally would not bother turning off anything in an attempt to gain power. That's not done in RealLife and it's not helpful in-game in any meaningful way.

Posted
Rotor RPM is what matters here, not engine RPM, at least not engine RPM directly. Your generators fall offline when your rotor RPM droops below around 88%. Remember that the generators are mounted on the main gearbox, not on the engines. I personally would not bother turning off anything in an attempt to gain power. That's not done in RealLife and it's not helpful in-game in any meaningful way.

 

You must be right. I've tried in game and haven't seen much difference from turning loads off or letting them on. Probably just the anti-ice system.

[sIGPIC][/sIGPIC]

I5 4670k, 32GB, GTX 1070, Thrustmaster TFRP, G940 Throttle extremely modded with Bodnar 0836X and Bu0836A,

Warthog Joystick with F-18 grip, Oculus Rift S - Almost all is made from gifts from friends, the most expensive parts at least

Posted

The engine anti-ice system uses bleed air from the engines. That definitely does impact power available. You should see something like 30-50 degree rise in exhaust gas temperature and around 2-3 percent increase in engine RPM when engine anti-ice is turned on.

 

The left engine has manual anti-ice, not automatic, so you could always leave the anti-ice off for that engine and see if it helps...

Posted

You shouldn't be picking up ice in clear air. I'm not sure how DCS models this though.

 

I think the biggest thing to keep in mind is your airpeed. You need to fly at a speed that leaves as much power as possible available for climbing, which is indicated on the chart below where the total power curve is at its lowest.

 

Unfortunately I can't be more helpful and tell you what speed this is for the Mi-8; try difference speeds - not too fast, not too slow.

 

figureg.gif

Posted

Best airspeed for climbing (well, for most available power) is the same for all helicopters, at at least within a very small range. About 70 knots or 130 km/hr.

 

And yes, in real life, if there is no visible moisture, there will be no ice. However, I think that DCS models icing in clear air.

Posted
You shouldn't be picking up ice in clear air. I'm not sure how DCS models this though.

 

DCS doesnt Model Humidity... yet...

 

So the only reference for Icing Conditions are "below 5°"

 

I think someone mentioned they were working on Humidity simulation for 2.0

A.K.A. Timon -117th- in game

Posted

Thanks for the info guys, I tried those Elbrus missions again with the Hip and I've controlled my forward airspeed as well as monitoring engine RPM's (rotor and engine) and i've finally made it to the top and back. The only struggle now is the descent which i tend to overspeed (into RBS..) but i seem to getting it. Just practice and more practice...

 

Now i'm really starting to understand what engine management really is for high altitude heli flights :)

PINOY PRIDE!!!

 

System Specs: i7-4790, Windows 7 64-Bit, ECS L337 Z87H3-A3X Mobo, HyperX Fury 32Gb, Nvidia Titan (Pascal), TM Warthog and TFRPedals, TrackIR 5

Posted

Per the manual:

 

6.12 CLIMB TO ALTITUDE

А. The optimal climb speed is 120 kph in altitudes up to 2000 m; 110 kph in altitudes of 2000 - 4000 m; and 100 kph above 4000 m. Climbs are normally performed in maximum continuous engine power. If required, the climb may be performed in Takeoff power (limited to 6 minutes) as well as power settings below maximum continuous.

  • 3 months later...
Posted

Learning to fly the Mi-8, I'm just running into the same problem. By practicing flight around Elbrus base in Winter, with around 85 percent fuel load and my passenger space filled with soldiers, I can manage to fly without loss of my generators. However, as soon as I land to unload the carried troops, both engines shut down and refuse to restart. Is that part of the same problem? Read about setting engine power, I have no idea, how to do that. Hope you can help another beginner, thanks in advance.

  • 1 month later...
Posted

Icing isn't modeled correctly, There have been issues with the Sabre pitot tube freezing up in clear air. I've flown a Robinson IRL in cold clear air and never saw icing indications.

on

Posted

Make sure that you don't use the dust protectors at altitude either. They will also suck a significant amount of power from your engines.

 

Running the standby generator to prevent power cutout due to low rotor RPM would require keeping the APU on. The APU has a continuous run time limitation of 30 minutes. Your CO would probably have some very specific words for you if you just used it all the time. I'm not sure what happens if you just leave the APU on in the game. I suppose you could get away with it in a pinch.

 

Better to keep rotor RPM up, because low rotor RPM not only robs you of your generators, but much more importantly, lift.

Practice makes perfect.

  • 2 months later...
Posted

Well Hell's bells, I finally have an answer for why my generators fail during less-than-perfect landings I try to make. I was wondering what was causing my generators to fail and it turns out it was my low RPMs on account of suddenly putting in a lot of collective to make sure I didn't smash into the ground.

 

Thanks for the tips guys, this is super useful to newbies like me who don't know why certain things happen sometimes.

 

So when the generators cut out due to insufficient RPM, can you toggle them back on or are they busted?

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