Generator failure

[LtMacGowan]

Sometimes i get warning generator 2 failure, warning generator 1 failure but can find no warning lights and it doesnt seem to effect flight performance. What is it, what causes it, should i be concerned, and what remedies it?

[Rogue Trooper]

Usually it is caused by the rotors slowing down too much for the generator to reliably Generate high voltages, It can be caused by too much collective (blades angle is too high and changed too quickly) or during a real tight manoeuvre.

 

The engines governor will increase power output to the rotors automatically in order to keep the blades turning fast enough to generate power but there is a delay.

[Art-J]

^ What Trooper said. In Mi-8 generators are mounted not on engines, but on the rotor gearbox. The rotor RPM at which they cut out is about 90-91% If I recall correctly, so not much margin to play with. Be smooth with collective input , especially when flying heavy or very high.

[Cibit]

I am surprised by you not finding any changes with the flight characteristics as the pitch and yaw channel disengages when the generators fail. At least when it happens to me, generally evading ground fire or practicing emergency situations. But as said above if its happening in normal flight regimes then modify your collective inputs, its a very powerful beast and needs a gentle hand:)

[gospadin]

Specifically, I think you're not allowed to change the blade pitch by more than about 2 degrees per second. More than that will cause your generators to fail/reset or overspeed your rotor.

[ebabil]

while playing corder canpaign, i landed on a high place near mountains. i embarked troops and then i got generator failure alert , couldn't take off.

this helicopter is designed to be operated at high altitudes and at cold of Russia right? how is that happening every single time? should we drive mi8 just only batumi sea side?

 

i sometimes manage to take of somehow but after that point, helicopter doesn't act normal. over reacting to every cyclic and collective input. may be it loses hydraulics?

[NeilWillis]

Altitude affects all helicopters - you were probably over weight for the conditions. No design can defy the laws of physics unfortunately. The EPR (Engine Pressure Ratio) indicator is very useful for assessing performance before unsticking. Comparison of sea level and high altitude numbers will show some eye opening limitations.

 

The record height for a helicopter is just 42,500 ft, and around 25,000 ft is considered the ceiling for turbine power. A hover take off at anything like that altitude is going to tax any power plant, and reduce the payload to virtually nothing.

 

The Hip may perform better than most, but to be fair, I haven't really explored that area of the flight envelope in DCS World. The ragged edges are naturally going to be the most difficult to simulate with any realism I guess.

 

What were the numbers in your case ebabil? Maybe it is time for me to have a play with that too.

[ebabil]

be honest i didin't notice the weight. it is a campaign mission.

i landed with full 2 sets of rockets. then embarked some troops. helicopter refused to hover. i managed to fly rolling down the montain. after a while i had to land to pick some other troops and helicopter didin't take off in no circumstances. lost my front wheel, crushed into a building. game over.

 

generators stopped and started again again again.

but flight controls never recovered. it flew like brick right after the first generator failure alert.

[AlphaOneSix]

The autopilot kicks off when the generators fail, and the autopilot does not come back on again until you push the button to turn it back on.

[ebabil]

which one ? i don't use autopilot , just manual flight

[AlphaOneSix]

Pitch/roll channel

 

Hydraulics have nothing to do with the generators.

[MAD-MM]

Your Generators disconnect when Rotor Speed is dropping down do overstress of to much Blade angel and disconnection of the Pitch Roll channel because of the Genartor Failure

I play also the Mission and it is possible, was starting with Engine dust Protection they consume even more Engine Power. Take a advice from me, bring the ECL Lever left of your Collective from Auto to Take Off Power, and start with not overstress the Engines in hoverconditon with Ground Effect, afterwards dont Try to climb even more try to bring your MI-8 in foward movement that produce more lift and you can climb gently away.

Edited January 12, 2017 by MAD-MM

[Pocket Sized]

which one ? i don't use autopilot , just manual flight

 

Just so you know, the autopilot doesn't interfere with manual flying at all. It provides dampening to make her fly even better, in fact. You just turn it on and after that you don't need to touch it.

[AOG]

It's not really an autopilot. It's a Stability Augmentation System sometimes abbreviated as SAS. It acts like a low pass filter. The pilot commands are fed through but transients get dampened out.

 

AOG

[Rogue Trooper]

The MI-8 deals with Altitude superbly, the finest machine we got in DCS at the mo.

 

Switch the engines to high power mode, a rolling take off is preferable, I have rolled over a cliff before to help generate air speed over those blades... a do or die situation you could say.

 

Increase collective slowly and be clean on the pedals; not too much as it will blead power from the engines. Indeed, allow her to yaw with the engine torque to free engine power for lift.

 

Landing "over weight" in a short confined space, HOT AND HIGH, is fabulous in this machine..... love those wheel breaks!

Edited January 15, 2017 by Rogue Trooper

[Hermit713]

The autopilot kicks off when the generators fail, and the autopilot does not come back on again until you push the button to turn it back on.

 

 

Yeah what he said

[Neon67]

is there an indicator somewhere in the cockpit to know at which point the generator will deactivate ?

 

I struggle sometimes to know my power limit, I just do it with my ears

[Pocket Sized]

is there an indicator somewhere in the cockpit to know at which point the generator will deactivate ?

 

I struggle sometimes to know my power limit, I just do it with my ears

 

The main rotor RPM. For safety I keep it above 90% at all times.

 

When the gen actually dies there is an audible "tick" as the inverters reset, also if you have the fans on they will shut off with the generators.

[AlphaOneSix]

The book says that the generators will fall offline at 88% rotor rpm. But like mentioned above, you want to keep it higher. By the book, your rotor rpm should never fall below 92%.

 

I've had the generators kick offline during a flight one time, and it was a very unpleasant experience. Everything got real dark and the pilots got real quiet. I don't think our passengers knew what was going on, though.

[msalama]

generators kick offline during a flight one time

 

But aren't you the engineer, and if so, what did you do? Apologies if I've misunderstood your position though.

[AlphaOneSix]

We don't fly with a flight engineer. We fly with two pilots up front, and two crew chiefs in the doors*, in the "American-style".

 

Anyway, we took off from an unimproved site with a load of passengers in the back, and the aircraft initially took off at about 99% N1 on the engines and then once we tried to start flying it started sinking (i.e. engines were at the max of 101% and the rotor was drooping anyway). Well the pilots couldn't really lower the collective much or else we were going to impact the terrain (but hey we were going kind of slow anyway, below ETL) so the rotor drooped below 88% (I think maybe 86-87%) and then we finally mushed through ETL, the aircraft started flying better, and the rotor came back up, at which time just about everything came back on by itself, except the AP of course.

 

*All of our aircraft are Mi-17V-5 or Mi-172 with ramps in the back instead of clamshells, and doors on both sides.

 

EDIT: Sorry, I still didn't make it clear, I'm a crew chief/mechanic. My company does not have flight engineers at all, the pilots perform all flight engineer duties in flight.

Edited January 20, 2017 by AlphaOneSix

[Rogue Trooper]

How are you finding this old bird Alphaonesix?

[msalama]

Roger that. Thanks for the explanation and the story. Sounds like you were in a bind there :unsure:

[AlphaOneSix]

How are you finding this old bird Alphaonesix?

 

I like it. I mean you can tell right away that Russian helicopters have a very different design philosophy from Western helicopters, but it's great at what it's designed to do.

[Rogue Trooper]

Helps you blend in somewhat I guess....

 

How would you say the philosophy is different?... rougher?