Elbrus Mission - Question

[Suchacz]

This Mission is the Kobayashi Maru for Huey Pilots.

I managed to take off :music_whistling:

Kobayashi Maru - LOL :lol:

[TurboHog]

Just tried Elbrus Rescue.

 

I don't see any changes in performance at high altitude. I am still able to get there to pick the guys up. Leaving is a different story, but it was like that in the previous version for me. (trying to hop to the ridge full collective and EMER governor, then tumble over the ridge to find out that I still haven't got enough power and crash)

 

Has anyone noticed that the helicopter is shaking violently at cruise speed (as if you're overspeeding). In Elbrus rescue shaking starts at 85kts IAS. Should you get the shaking at cruise speed? Or did I find a bug?

[iFoxRomeo]

TurboHog, that's not a bug. With increasing altitude(and other factors) the VNE decreases.

 

I still don't get the "Emergency Governor". There is no such thing built in the UH-1H.

There is only a GOV(ernor) that can be switched between AUTO(matic) or EMER(gency) position.

So why is the Co-Pilot suggesting it?

To increase RRPM beyond overspeed limits and use the inertia then?

Does the Co-Pilot want to commit suicide?

 

 

Fox

[Hueyman]

TurboHog, that's not a bug. With increasing altitude(and other factors) the VNE decreases.

 

Fox

 

Sorry for that but what you say is false ...

 

 

VNE do not decrease with altitude at all... it is a structural limit that is in function of the True Air Speed ( TAS )... what you read on your airspeed indicator is the IAS ( Indicated Air Speed )... and with density altitude ( pressure decrease etc ), the IAS becomes buch lower that actual TAS ( actual speed in respect of air mass )

 

That explaining, for example, at 15 000 ft, 110 IAS means 135 TAS for example ... for professional pilots, there is a formula which I never use as I'm only PPL and flying generally under FL 065, that allow us to determine the TAS according to temperature off the standard ISA conditions etc etc ...

[TurboHog]

EMER mode on the governor switch - EMER governor for short. What's it you didn't get?

 

About the vibes at cruise speed: If only we could get a changelog I could file a normal bug report without loosely basing it on something I think has changed.

 

Come on BST! Patches come with changelogs!

[Nate--IRL--]

About the vibes at cruise speed: If only we could get a changelog I could file a normal bug report without loosely basing it on something I think has changed.

 

It is either wrong or it is not, changelog or no.

 

Nate

[TurboHog]

It is either wrong or it is not, changelog or no.

 

Nate

 

So what do you think?

[iFoxRomeo]

Sorry for that but what you say is false ...

 

You made me think about it. And in the next days I'll check that carefully. DA, TAS etc. are to be considered, that is correct. But it is more academic than practical, as you only have IAS in the Huey.

And for now my answer is:

 

Check TM 55-1520-210-10 cruise charts chapter 7 page 21 and following.... Too many charts to post here. Not everything that is written in a book is set in stone. But right now it underlines my statement.

 

EMER mode on the governor switch - EMER governor for short. What's it you didn't get?....

 

It implies that the Huey has an additional governor beside the normal governor.

 

Switch governor to emergency function says that you switch inside the governor from normal operation mode to emergency operation mode... Switching function mode within a single governor unit.

 

Switch to emergency governor says that you switch from governor 1(normal operation) to governor 2(emergency operation)... Switching between distinct governor units.

 

I'd say thats a difference. And the Huey has got only one governor unit.

 

Fox

[Hueyman]

You are true when saying it is more academic than practical... but it may produce important differences at some high Flight Levels for sure ...

 

And if you want to plot your nav in flight, using the IAS as a speed reference while flying at 10 000 ft ... the times between all waypoints will be much overestimated as your TAS will be much more than the IAS ... That's why they mainly use GS ( ground speed ) on GPS or such while cruising, so, even better than TAS, it gives the aircraft's speed in respect of the ground, so, no need to calculate wind component etc etc...

 

But yeah, this is off-topic hehe. Just to say that VNE remain the same, but it may be reached much earlier while flying high ... don't think in the real Huey as the higher you are, the weaker the turbine is, so you have hard time trying to get high airspeed in straight flight, but in fighters such Mig 29 etc you really have to watch carefully your charts for not flying over a certain IAS ... at 60 000 ft, things can get really weird, and happen sooner than expected ;-) ( just try to reach the sonic boom at see level and at 35 000 ft, and observe the IAS... you'll see what I mean ... )

 

 

And for the governor, I am not a T-53 expert for sure, so don't know how this one really works... but I do know the P&WC PT6A series engine quite well, and this one has three governors ... while the pilot can only control one : the CSU ( Constant Speed Unit ) that is tasked to manage the oil flow through the prop hub for pitch change, thus trying to reach the pilot-selected prop speed).

 

The 2nd one ( built in the CSU unit ) is the Power turbine governor, that limits the Np to approx 6% above the selected Np in both Alpha and Bêta range ( reverse )

 

The 3rd one is like a fail-safe one, more or less another overspeed gov ...

 

All of that to say the pilot control one Governor, while there is actually, from a mechanical point of view, three govs...

 

Is it the same for our T-53 powered Bell ? I don't know, but it seems pretty logical. When you switch to EMER mode, with max power on ground, collective down, you can't reach the 100% Ng ( N1 ) speed... is there a correlation between collective stick and FCU, to allow a larger max Ng in function of collective position ? I don't know where to find this answer, and didn't read what they said on the provided manual ( my bad ! )

 

Anyway, it isn't possible now to take off again from Elbrus mount... I tried everything, running landing ( low on skids, skiing on the snow with skids to try to reach ETL stage ... smoking hole in the ground ). Even tried to burn as much fuel as I could to make it as light as possible, then try to take-off then descent in autorotation down the FARP ... as this mission is timed ( injured ... ) I failed, but it was manageable ! very hard but manageable

[iFoxRomeo]

Hueyman, we are OT. I´m going to open a separate thread soon to answer you. If time permits maybe tomorrow.

 

Fox

[Nate--IRL--]

So what do you think?

 

No Idea.

 

Nate

[HuggyBear]

AUTO and EMER are two independent parts of the same FCU assembly.

 

In AUTO the FCU controls the amount of fuel fed to the N1 section based on N1, P1, T1 and throttle position.

 

In EMER the FCU controls the amount of fuel fed to the N1 section based on throttle position only.

 

There is an external Droop Compensator cam which applies a slight increase in N1 as collective is increased, this prevents the NR drooping excessively before the Governor can respond and restore the NR.

 

In EMER Gov, full throttle should be able to exceed N1 and EGT limits easily and destroy the engine.

 

- Bear

[heloguy]

Yes, looks like the mission may not be passable at default play in the release build. Will try to test again and fix up for the next update.

 

 

Yeah, just tried this one for the first time. Definitely not too realistic for the poor Huey. It's just not made to go that high. If you look at the -10, the performance charts only go up to 14,000ft PA.

 

It could be completed with the hop method, by letting the emergency governor at full throttle build the rotor up, then max collective while moving toward the edge in order to takeoff, but this would definitely destroy the engine, as my EGT was well over the 625 maximum, and probably close to 760 (didn't notice during my attempt, just that it was in the transient range, which isn't supposed to be used on purpose).

 

So, it could be done in the SIM, just not in IRL. Need a Blackhawk to do it safely, and this would even be a tough mission for that helicopter.

[Nealius]

I think this mission is porked in the current version. The weather is supposed to be bad but it's perfectly clear, and the Huey skin is stuck on the NASA skin no matter what I change it too (and yes, I fixed the skin issue, they work fine in other missions).

[iFoxRomeo]

Hi there. I didn´t open a new thread, so I post here.

 

HuggyBear, i added some points to your post, in red. I hope it´s no problem for you.

 

AUTO and EMER are two independent parts of the same FCU assembly.

You certainly mean N1 Governor and N2 Overspeed Governor are two independent parts of one assembly, right?

 

In AUTO the FCU controls the amount of fuel fed to the N1 section based on N1, P1, T1 and throttle position. up to 6000RPM N2. Then the N2 overspeed governor dictates N1 RPM up to 101,5% N1.

 

In EMER the FCU controls the amount of fuel fed to the N1 section based on throttle position only. Because with GOV SW in EMER position a solenoid valve redirects the fuelflow around the N1 governor and N2 Overspeed governor -thus cancelling both N1 and N2 governors out- to an emergency valve which is directly connected to the throttle.

 

There is an external Droop Compensator cam which applies a slight increase in N1 as collective is increased, this prevents the NR drooping excessively before the Governor can respond and restore the NR.

 

In EMER Gov, full throttle should be able to exceed N1 and EGT limits easily and destroy the engine.

A friend of mine, who was a technical pilot on the Huey, said it should behave the way you said, but he was not absolutely sure, because his last flight with the Huey was 8 years ago.

Interestingly the Huey flight manual TM 55-1520-210-10 from 1988(with latest change from 31. Dec 2002) says in chapter 9 page 1 "Emergency Procedures" that:

 

"The maximum engine torque available for

any ambient condition will be reduced by

6 to 8 PSI when the GOV AUTO/EMER

switch is placed in the EMER position."

 

This should be only possible if the emergency valve is not able to provide enough fuel for N1 to reach structural limit of 101,5% after all. Or am I wrong?

 

I didn´t know this(-6 to -8 PSI) either, and it is not mentioned in my printed flight manual from 2005. So maybe this was changed. Or some operators decided to have a different behavior in that part other than the US Hueys.

 

- Bear

 

 

 

Fox

[Threshor]

I could not take off from the top so after several attempts I moved the waypoints down to the base of the peak just so I could at least play though this one.

[HuggyBear]

G'day Fox,

 

Gov AUTO/EMER and N1/N2 Ospd Gov are just different ways of saying the same thing.

 

Most people are familiar with the switches they see in the cockpit (Gov AUTO/EMER) so it makes it easier to understand in these terms. I'll keep using them. :)

 

In EMER there can be up 10 PSI less Torque available below 4000' PA and up to 10 PSI more Torque available above 4000' PA. This is due to the isolated FCU no longer no longer varying the fuel flow to account for varying P1/T1 (Inlet Air Pressure/Temperature) as altitude increases.

 

Below 4000' PA although there is less Torque available, full throttle is still sufficient to overspeed and damage the N2/NR unless controlled by applying collective to limit the N2/NR.

 

Whether or not N1/EGT limits are exceeded is more interesting. depending on the conditions EGT can be exceeded before an N1 limit is reached and vice versa. Also at low altitudes/temperatures the engine is capable of producing more than 50 PSI Torque so the aircraft/transmission can be damaged without even exceeding an engine limit.

 

Luckily I never felt tempted to wind on full throttle while in EMER so I can't say for sure. :)

 

Cheers,

 

- Bear

Edited September 18, 2013 by HuggyBear
Confused myself with acronyms :)

[armageddon]

Hey guys, i have made some minor adjustments, so that the mission still can be accomplished.

Elbrus Rescue_2.miz

[kontiuka]

I reduced the troop load from 700kg and 800kg to 450kg and 450kg. The mission is still challenging but doable. I still usually bust one or two skids coming off the mountain though. Makes for an interesting landing at the FARP.

[kontiuka]

By the way, does anyone have the weird NASA skin issue in this mission?

[TangoIndiaMike]

Okay Guys, here is the thing I dont understand. The first complain about this mission came in about 4 months ago.

Fixing this issue (reducing the weight of the payload) would take Belsimtek maybe 5 min.

Also many missions of the campaign are not playable because of minor bugs which could be fixed quite easily.

I know its a beta, though I dont understand why they dont fix something as representative as the campaign.

 

Dont get me wrong, I am really enjoying the Huey and the campaign (and the missions aswell).

So thank you Belsimtek for your great work.

 

Ps: My chopper also can´t decide if he wants to be a military or a NASA one.

Edited November 5, 2013 by TangoIndiaMike

[Stevos758]

I just tried twice in the last week. Still crash and burn.

[kontiuka]

Ps: My chopper also can´t decide if he wants to be a military or a NASA one.

Yes, I noticed the same thing (see my post above). I just changed the skin to be a medevac and haven't had any problems since.

[Berniyh]

Love this mission. Run it a few times (sometimes successfully, sometimes not ;)).

 

However, with the newest incarnation with DCS 1.5, I've run into problems. All the flying is going fine. I can take off at the top with manual GOV (just about so).

 

The only issue I'm starting to have is at the very end when I'm taking the second round of soldiers down the mountain. It became very very dark and because the weather was still awful, I really couldn't see a thing.

 

I was going for the night vision and that helped me through the saddle close to the airport, but there I got into some light clouds (which wouldn't have been a problem at day) and really couldn't see a thing, no matter if with night vision or not.

It was just a blind flight. I tried to get into a hover (which is quite hard if you're flying blind) and get closer to the ground, but in the end I blindly crashed into a mountain.

 

Now I wanted to know if this is just on my system due to some graphics setup or if there is a general problem with this mission in DCS 1.5?

 

I'm using a Radeon R9 280X with settings on the High Preset.

 

I sort of doubt that this extremely low visibility is wanted. It was much lower than I would expect from these kind of clouds.

[BackboneOne]

rock on, brother)))