reported Huey's new performance profile discussion

[Tim_Fragmagnet]

It needs another rework.
 

 

For the points marked as "level flight impossible", I am unsure if it is realistic or not, it is very possible the real aircraft produced enough power that full forward cyclic could not maintain level flight. However data for flight over the Vne of 125knots, let alone over 50PSI is hard to come by, and usually for the UH-1H with the old blades.

 

Overall the huey has more available power, however at low speeds the performance discrepancy is not good. You go from requiring far too much power to requiring far too little power. 


However, the engine profile doesn't seem to take altitude into account.




As for the engine profile itself, it is still underpowered at high power settings.

The new profile produces 50PSI (1158shp) at 101% N1
The real huey produces 50PSI (1158shp) at 96-98% N1


However the EGT profile has improved significantly.
 


The hover performance is not great, however. It requires too much power at every weight.

Here is a more advanced profiling of the hover performance.

The new WIP fuel consumption is far better than it was, but it's still using too much fuel at higher power settings, however it is reaching what could be considered "close enough", but could still use another tweak.

 

 

The rate of climb is messed up too.

Edited July 5, 2023 by Tim_Fragmagnet

[Tim_Fragmagnet]

@P61 Let's reconvene shall we.

 

The fuel consumption is unacceptable.
The achievable true airspeeds at different altitudes are way too high, and are unacceptable.
The power requirement for hovering is unacceptable.
At high power settings we still underperform fairly significantly. It is better than it was before, but 6500lbs performing like 8500lbs while within the officially stated Vne is still not acceptable.

Edited May 18, 2023 by Tim_Fragmagnet

[Japo32]

In this update, if we turn off the governor, the RPMs go high. That is right, so we move the throttle down to maintain the green arc. Once we have those RPM stabilized. Without touching the throttle, if we raise the collective, RPMs should go down (without governor) but they rise!!! totally the opposite.

Is that something is happening to you?

Here there is a video in spanish of a Friend that tested today and he is very frustrated because he loves the UH1H so much, and see this wrong is bad for all of us that expect something near perfection with the time the Huey has already among us. Hope if there is a bug here, can be solved soon. Thanks!

 

Edited May 19, 2023 by Japo32

[dsc106]

I came to see what other people thought of the engine update. Not a real pilot let alone a Huey pilot, but have years of experience flying it. Having a hard time keeping nose down now, or high collective and level flight. Need lots of left pedal for take-off. Landings feel different.

It's screwing with my muscle memory. If this is an improvement that is more realistic I will take it, but are we sure this is correct?? I am not sure how to feel... maybe this is a "I don't like change" symptom, but since Huey is my main I will be upset if they went and changed it for the worse and it takes months to fix it now.

Is it really suppose to feel this powerful?

[Tim_Fragmagnet]

1 hour ago, dsc106 said:

I came to see what other people thought of the engine update. Not a real pilot let alone a Huey pilot, but have years of experience flying it. Having a hard time keeping nose down now, or high collective and level flight. Need lots of left pedal for take-off. Landings feel different.

It's screwing with my muscle memory. If this is an improvement that is more realistic I will take it, but are we sure this is correct?? I am not sure how to feel... maybe this is a "I don't like change" symptom, but since Huey is my main I will be upset if they went and changed it for the worse and it takes months to fix it now.

Is it really suppose to feel this powerful?

So what's currently happening is that low speeds and hovering take far too much power, thus an unrealistically large amount of left pedal.
As you speed up into translational flight, you require less and less power, thus less and less left pedal, that is correct. However it is overly exaggerated in the new model.

Something to note is that the tail rotor has always been messed up in this module. As seen here, 

It's hard to quantify if this is an improvement or not, in some ways yes, it is better, however in others it is significantly worse.

As for if it's supposed to feel this powerful. If you check the charts, we're actually still lacking power at the high end. It's supposed to be even more powerful than this.

In terms of keeping the nose down at high power settings and low weights, it's possible that the real aircraft had this issue as well, but it is difficult to find data on this, as the Vne for the huey was 125knots as a safety precaution to keep pilots from accelerating into retreating blade stall, so recorded performance data generally ends there. Another limit is the transmission limit of 50PSI of torque, it can operate above that limit at risk of damage, but once again, finding recorded performance data at that range is very rare.

Edited May 19, 2023 by Tim_Fragmagnet

[hamid]

I just updated DCS
I found a big problem In new UH-1H engine modeling
it is true that if we close throttle to flight idle position , N2 ( free turbine) reduce and separate from rotor RPM ,
But
in DCS when we increase collective while throttle is in flight idle , engine work again ! and we can not complete autorotation . In real at this time N2 remain at last position when we use collective in autorotation ( Governor does not work) .

Edited May 19, 2023 by hamid

[dsc106]

Thanks for the detailed reply. 

While I have no real world helicopter (let alone Huey) experience, I do feel frustrated at the half-baked change. Huey is my main, I love flying it. And it’s screwed up all my hard earned muscle memory and if it’s in error, knowing ED it could take months to fix…

Maybe how hard I need to keep the cyclic pushed forward at speed is normal, then. But the whole package feels wonky now and I don’t want to relearn if it’s wrong and going to change again.

The amount of power produced at half collective and high weight loads also seems odd. I don’t understand the specifics as well as you but I’m thankful for your input! Hoping this gets sorted.

[Japo32]

I have fear that this will remain for years, as ED sometimes leave the issues for years without touching in some cases. Can we have the option in DCS extra menus to select old engine model? at least until all is solved. Of course in Multiplayer it could be forced to new model.

Edited May 19, 2023 by Japo32

[BIGNEWY]

Folks keep the feedback constructive, we appreciate the testing and data, allow us time to take it all in. 

The fuel consumption has already been brought up internally and we will be checking it. 

 

please always include track replays from your tests

thank you

[Japo32]

@BIGNEWYYes.. it happens me as well. Here is the track to let you check it out. Please.

As seen when the Governor is off the RPM rises. That is OK. But when I stabilize them lowering the throttle, When I raise the collective RPMs should go down as the blades are more angle into the wind so more resistance, and with same ammount of fuel, RPM should drop. But they do rise, that is the opposite they should do. Here it is the track.

UH1HWithoutGovernorIssue.trk

Edited May 19, 2023 by Japo32

[BIGNEWY]

threads merged

@Japo32 we will take a look, I am currently busy however with todays newsletter. 

thanks

[MoleUK]

41 minutes ago, dsc106 said:

I second the idea to get a checkbox in special settings to use legacy engine model on the Huey until this is sorted. I love to fly this regularity and am concerned to practice muscle memory when the specs clearly aren’t right yet.

Regarding performance, I noticed I was able to keep the engine torque well above red line for at a minute or so while flying around with no ill effects or warnings. The EGT was in green I believe. Is this normal? Anyone else? 

You can definitely redline and beyond the torque without a problem atm. I have no idea if it's accurate or not. I have hit 160 knots fairly easy in a moderate dive, others have hit much higher speeds. Doesn't fall apart unless you start doing hard turns.

I suspect a lot of people won't like the new FM (And that's what it feels like, not just an engine overhaul) when it's running light or unarmed. When it's heavy it feels closer to the old Huey with some new oddities like losing a lot of rudder authority (consuming fuel at 2x or 3x the rate it feels likeit maybe should) and a weird hover transition area for landing in particular.

When it's light something feels very off. It wants to go UP. Almost get some Gazelle tingles when it's light. But, again, i'm only judging that by other FM's and the previous huey FM, not any RL experience etc.

Edited May 19, 2023 by MoleUK

[BIGNEWY]

folks please dont get into a back and forth about open beta and stable its not helpful in bug reports. 

We are looking at the data and found some things we would like to tweak, so please be patient while we work on it. 

thank you

[hamid]

12 hours ago, hamid said:

I just updated DCS
I found a big problem In new UH-1H engine modeling
it is true that if we close throttle to flight idle position , N2 ( free turbine) reduce and separate from rotor RPM ,
But
in DCS when we increase collective while throttle is in flight idle , engine work again ! and we can not complete autorotation . In real at this time N2 remain at last position when we use collective in autorotation ( Governor does not work) .

 

@BIGNEWYPlease check this

[Volator]

On 5/18/2023 at 3:31 PM, Tim_Fragmagnet said:

You go from requiring far too much power to requiring far too little power

Just did the first flight with the Huey, and this were my exact observations. I was going at 107 kts at 30 psi torque (old model gave me around 90 kts, which was very close to the performance a German Army Huey pilot once told me), while hovering IGE at the same weight required 40 psi, muuuuch more than before the patch. Because of this you also need much more left pedal on take-off. These are some serious changes.

On the bright side, the stupidly excessive wobble on start-up is gone!

Edited May 20, 2023 by Volator

[Tim_Fragmagnet]

I realized I should probably cite my sources.

null

You'll notice the operator's manual is not included.

That is because the data within the operator's manual is derived from documents like these.
The data in the operator's manual is superseded by these documents in regards to absolute performance profiling.

I HIGHLY recommend reading Helicopter Drive System Load Analysis, absolute thriller.

 

 

Edit: looks like I forgot one.

 

 

Page 21? Absolutely R I V E T I N G.

Edited May 20, 2023 by Tim_Fragmagnet

[Revhed]

To add to this discussion - There also seems to be some unusual behavior introduced with the RPM governor & Droop compensator functions. I was flying in the Multi Thread version after applying 2.8.5.40170 open beta patch.

The Governor RPM Control Switch only seems to affect rotor RPM (up or down) while on the ground. 

The Droop compensator logic seems to function very differently. These are the steps to reproduce the unusual behavior: Reduce throttle to idle. Allow blade RPM to reduce to a stable (low) speed. Raise collective (rapidly advancing to maximum deflection) and the Rotor RPM increase seems magical. The Heli will lift off and you can fly around with the throttle remaining at idle. The rotor acceleration is significantly faster than if you just advanced the throttle. Is this behavior realistic? Previously the Rotor RPM would decrease further, and the Heli would remain on the ground.

It seems like the interaction between the governor, droop compensation and engine power are all mixed up.

And I've also noticed the excessive fuel burn. I think it's so dramatic that it won't be possible to complete some of the longer campaign missions. It's like there's an afterburner installed on the turbine!

[Mike145]

On 5/19/2023 at 11:47 PM, Volator said:

Just did the first flight with the Huey, and this were my exact observations. I was going at 107 kts at 30 psi torque (old model gave me around 90 kts, which was very close to the performance a German Army Huey pilot once told me), while hovering IGE at the same weight required 40 psi, muuuuch more than before the patch. Because of this you also need much more left pedal on take-off. These are some serious changes.

On the bright side, the stupidly excessive wobble on start-up is gone!

 

I`d just like to say these are my findings as well.  Where I was achieving a hover by 30psi, now 40+ and when you get to transition, you go UP fast.

[GremlinIV]

Initially i thought this update was just so the engine indicators, dials and gauges, showed correctly towards IRL, but i took her up for a flight and well...........................

All of the comments i concur... for the purposes of feedback - (and as always these are MY experiences, a ham-fisted pilot that knows nothing about helicopters)

 

1. More left pedal and cyclic for IGE hover required or round you go.

2. Fuel consumption is through the roof....

3. Climb climb climb if you dont get that collective off, then its down down, holding level was just weirdly feeling like a knife edge.

4. Previously when i hit the afterburner stop on my Warthog it was 90ktswith 40% fuel slick, now its pushing 140+kts and still wants to climb.

5.  Had to redo all my axis for roll/pitch/yaw, did they do the same they did with the apache and increase the axis thingemmy bobs.

6. You need to swing the Pedals ALL the way left from right off centre when you hit 100kts+ so assume tail rotor still not fixed.

7. Cyclic can be trimmed forward to the stops and still up she goes.

 

I had been training someone in the Huey so we can move onto the Apache.  I have had to put off the apache cos it is £$%^%$, and right now the Huey is also £$%$%^&.

No changes to the F-18 though right? RIGHT??? - i hope not....

Caveat: Not a real pilot, but even i can feel these changes are NOT right, of course there can be many reasons for them.  So whats going on guys?

Edited May 21, 2023 by GremlinIV

[Tim_Fragmagnet]

I have done another performance test, and will compile the graph into the main post.

 

 

 

Our huey is generating too much lift at high power settings. 
This is likely because the drag of the module is so high that to try and improve the accuracy of the speed vs torque metric, the amount of lift generated per horsepower was cranked up.

However when doing the rate of climb test, you fly at 60knots TAS, where drag is not much of a factor, just lift.

Really, you should just be able to match the rate of climb performance to the real thing by adjusting lift per torque, and then adjusting drag to make the speed vs torque metric more accurate.

However I'm not a developer, and have only been researching this aircraft's real performance for a year. You guys have worked with it for a decade, I'm sure you know more than I do.

 

 

To do this test yourself, create a mission with no wind, and set the weather to 15C    29.92inHg

Then on a huey, remove the external hardpoints, add the IR suppressor, max out the fuel, and then with a mission trigger, add 119kg of internal cargo to match the 7700lbs test weight.

 

Then fly the huey at 60knots true airspeed at different torque settings.

Edited May 23, 2023 by Tim_Fragmagnet

[Tim_Fragmagnet]

I have done a full profiling of the hover performance, and will compile the results into the main post.

It's not even close.

Edited May 23, 2023 by Tim_Fragmagnet

[BIGNEWY]

tim can you also include the track replays from your tests. 

thanks

[Tim_Fragmagnet]

I don't personally trust the track system for data collection but if you have a use for it, so be it.

They aren't the most stable hovers but they're good enough due to how the torque model works.
If you need better hovers, I'm sure you have professionals that can do it better than I can.

7500lbs 2ft,5ft,OGE Hover.trk

8500lbs 2ft,5ft,OGE Hover.trk

9500lbs 2ft,5ft,OGE Hover.trk

12000lbs 2ft,5ft Hover.trk

13500lbs 2ft Hover.trk

 

 

And I'll do one even better.

Huey Test 15C 29.92inHg.miz

 

Here is the mission used to run the tests. ANYONE who wants to run these tests to double check me, feel free.

There is a trigger to adjust the internal cargo of the huey in kg to achieve the desired weights. The mission defaults to a weight of just over 6500lbs via fuel alone.
For weights over those which fuel alone can reach, maximum fuel should bring the aircraft to a total weight of 7438lbs, take whatever your desired weight is, subtract 7438 from it, convert it to kg. then apply it to the trigger.

There is no wind and it is at a temperature of 15C and pressure of 29.92inHg (it is unsure if DCS is accurate enough to model 29.921255347142inHg but the difference should be negligable)

These are ISA conditions, the exact same conditions used for the IRL huey performance profiling.

In short, the only relevant variables are the pilot, and the performance of the aircraft.

Edited May 23, 2023 by Tim_Fragmagnet

[BIGNEWY]

35 minutes ago, Tim_Fragmagnet said:

I don't personally trust the track system for data collection but if you have a use for it, so be it.

for debug purposes they are fine and required for bug reports. I will pass them to the team. 

thanks

[MilesD]

It's great to see all of this detailed user feedback. Many of us truly appreciate all of your effort in gathering, compiling, evaluating and submitting the flight data to assist ED to improve the UH1's FM. 

It's also great to see ED (BigNewy) right in here coordinating, consolidating, and forwarding the appropriate information to make our Huey better.

Thanks Guys!!!