Performance planning charts? Tutorial?

[WildBillKelsoe]

Hi again,

I'm looking for tutorial on how to calculate the following:

1- torque available

2- hover power required and hover ceiling

3- drag

4- climb/descent

5- idle fuel flow and fuel flow vs torque

6- level acceleration vs coordinated climb charts

 

Now before you jump in by shooting a TM55-1520-210-10, I have it, but most graphs are undlear to me, and don't know if they apply to this module under current configuration. I wanted the charts used by Belsimtek for their module if any.

[iFoxRomeo]

Hi again,

I'm looking for tutorial on how to calculate the following:

1- torque available

2- hover power required and hover ceiling

3- drag

4- climb/descent

5- idle fuel flow and fuel flow vs torque

6- level acceleration vs coordinated climb charts

 

Now before you jump in by shooting a TM55-1520-210-10, I have it, but most graphs are undlear to me, and don't know if they apply to this module under current configuration. I wanted the charts used by Belsimtek for their module if any.

There is always a description in the TM55 preceeding the charts. Read the method.

 

Unfortunately the DCS Huey does have different engine parameters. Especially torque available and EGT don´t fit.

 

Fox

Edited May 2, 2015 by iFoxRomeo
picture added

[WildBillKelsoe]

Thanks for your reply. I suspected so, maybe devs could shed some material this way?

[sondo214]

And I thought that only the limmits where not implemented. I did not know that even the readings are false...

 

Tell me about a completed Huey module then...

 

Pfff

[DSPALLASVI]

And I thought that only the limmits where not implemented. I did not know that even the readings are false...

 

Tell me about a completed Huey module then...

 

Pfff

My thoughts exactly!:blink:

[sondo214]

I really did not expect that... Now I am truly dissapointed... I discontinue my flying till these are fixed...

[iFoxRomeo]

I really did not expect that... Now I am truly dissapointed... I discontinue my flying till these are fixed...

That´s why I don´t want to post anymore in the bugs section. I don´t want to discourage anyone of flying any DCS module. Sorry if I did that.

 

There are bugs, there are problems, there are wrong values, but it is still a enjoyable module. And I still hope to see improvements when DCS 2 gets released. I´d accept and welcome a Huey 2.0 and Mi-8 2.0.

 

Sondo, I think we are somehow victims of our own expectations, maybe fed by marketing.

This is not a professional full flight simulator. Even those have their flaws.

 

I was at a point where I didn´t want to fly any helicopter in DCS anymore.

But now I just reduced my expectations for a 50$ software. It is still the best Huey simulation for this price for a home PC.

 

You have to ask youself: Do I really expect the feature set and detail depth of a multimillion full flight simulator brought to a home PC for only 50$?

 

Fox

[sondo214]

I don't know...If you put it that way... What upsets me most are not it's flaws but the fact that BSD has stopped working on it, so I cannot see any potential in fixing them...

[Weta43]

Unfortunately the DCS Huey does have different engine parameters. Especially torque available and EGT don´t fit

Presumably you have some other charts to check agianst that cause you to say this & are not basing your statement on the chart you posted ?

I'm no expert on this, but the heading on that chart indicates it's giving advice on maximum torque available for 30 miutes continuous operation under those conditions, not providing instantaneous or short term absolute limits - in other words IRL these could be exceeded for short periods, but doing so risks damage(otherwise you wouldn't need the "30 minutes operation" caveat).

It appears to be a 'do not exceed' advisory - like the red line on the RPM guage on your car. It doesn't mean it won't do more revs - it's just not a good idea to do so if you want the engine to keep running for a period of time..

If that's the case, the numbers are not reflections of the short term capabilities of the system, and the only way to check them against the sim would be to run a series of tests where you exceed them for 30 minutes, and see if you get an increased failure rate (except that some of the causes of the failures aren't modelled, so you don't need to use that chart in DCS except in so far as you want to apply real life discipline on yourself - like watching your EGT ).

The fact that at a given altitude and temperature, the maximum available torque in the sim is not the figure shown on the chart is not an indication that the sim's maximum short term available torque is incorrect, only that this isn't what the chart is about (, and that the damage modelling in SIM is incomplete).

 

At least that's how it looks to me...

 

(& I'm not saying the SIM's figures are gospel, just that that chart isn't the one to use to check them.)

[WildBillKelsoe]

Are there any ways to extract or see raw data? Maybe we can make our own charts?

[iFoxRomeo]

Presumably you have some other charts to check agianst that cause you to say this & are not basing your statement on the chart you posted ?

 

Yes, I do have additional charts. I didn´t base my statement on this chart alone. It was a general statement.

 

I'm no expert on this, but the heading on that chart indicates it's giving advice on maximum torque available for 30 miutes continuous operation under those conditions, not providing instantaneous or short term absolute limits - in other words IRL these could be exceeded for short periods, but doing so risks damage(otherwise you wouldn't need the "30 minutes operation" caveat).

 

The 30 minute limit is solely based on the EGT, from 610°C to 625°C and only for the mission. That means, once you accumulated 30 minutes of total time within 610°C-625°C range during one flight, you may not use it anymore untill you shut down the engine. "30 minutes continuous" might be irritating for one or the other. You don´t say continuous to a time restricted limit. Its either 30 minutes or continuous.

No, instantaneuous exeeding of these limits is not allowed. Once you do so, you have to write it on the report sheet and depending on the duration and value, the intensity of maintenance will be determined.

 

It appears to be a 'do not exceed' advisory - like the red line on the RPM guage on your car. It doesn't mean it won't do more revs - it's just not a good idea to do so if you want the engine to keep running for a period of time..

Good example with the car. If you exceed the red line in your car, you could get a instant piston rod failure. Or the lubrication could fail, leading to a piston seizure. Or nothing happens. But safe operation is only below the red mark. And if the engine fails, unlike in your car, you can´t just pull over to the roadside. You fall out of the sky. This 30 minute limit is a yellow area, where you can operate under certain conditions for a short duration of time.

 

If that's the case, the numbers are not reflections of the short term capabilities of the system, and the only way to check them against the sim would be to run a series of tests where you exceed them for 30 minutes, and see if you get an increased failure rate (except that some of the causes of the failures aren't modelled, so you don't need to use that chart in DCS except in so far as you want to apply real life discipline on yourself - like watching your EGT ).

 

As I said before. The EGT values are off in the DCS Huey.

With these charts you can instantly check the engine. If a value, taken from the chart, doesn´t correspond to the measured value in the helicopter, something´s wrong with the helicopter. No tests needed for a failure. Thats a different story.

 

The fact that at a given altitude and temperature, the maximum available torque in the sim is not the figure shown on the chart is not an indication that the sim's maximum short term available torque is incorrect, only that this isn't what the chart is about (, and that the damage modelling in SIM is incomplete).

 

Well, the charts in a flight manual are something you can rely on in real life. If your helicopter is properly maintained, you can rely on these charts and you will get almost identical results, always, provided the environmental conditions are the same as in the chart.

 

There is no maximum short term torque in the UH-1H. It is always 50psi for the main gear box as maximum. Up to that value you can use any torque the engine produces.

 

At least that's how it looks to me...

 

(& I'm not saying the SIM's figures are gospel, just that that chart isn't the one to use to check them.)

 

See the following text:

 

Yes, this chart can be used to check the DCS Huey, because:

 

 

"Realistic modelling of the UH-1H instruments, weapons, engine, radios, fuel, electrical, and hydraulic systems."

 

Thats a quote from the DCS homepage.

Unlike the comparative/relative "most realistic...experience" for the flight physics, the engine modeling is described as realistic, in absolute terms. So it has to withstand the comparison to the real Huey´s engine.

 

ED and BST themselves set the bar so high.

 

 

We are totally drifting from what WildBill wanted to know, but you asked for it.

 

Fox

Edited May 4, 2015 by iFoxRomeo
picture was faulty

[Weta43]

We are totally drifting from what WildBill wanted to know, but you asked for it.

Perhaps we are – not sure what you mean by ‘you asked for it’ though...

Especially as your reply essentially confirms what I was saying, but I’ll have one more attempt at getting my point across & then call it quits.

You say :

Yes, this chart can be used to check the DCS Huey, because: "Realistic modelling of the UH-1H instruments, weapons, engine, radios, fuel, electrical, and hydraulic systems."

But you also say:

Good example with the car. If you exceed the red line in your car, you could get a instant piston rod failure. Or the lubrication could fail, leading to a piston seizure. Or nothing happens.

Meaning it’s an entirely realistic possibility that the observed effects (during the flight) of exceeding the guidelines on that chart are that:

nothing happens.

So if one of the realistic possible outcomes of exceeding the guidelines on that chart is that nothing happens, having nothing happen when you exceed the chart’s parameters in DCS IS one of many realistic possible outcomes. The problem is not that it happens sometime, rather that it happens always, which you can only discover through repeated testing.

the only way to check them against the sim would be to run a series of tests where you exceed them for 30 minutes, and see if you get an increased failure rate

 

Anyway .. I guess the point you meant to make was that there are issues with the torque indications in SIM which would mean that complying with the chart you provided resulted in lower available performance than could be expected IRL (but you can’t tell that from this chart).

As an interim tool for in SIM use, from reading others’ analysis comparing the observe torque in sim with expected torque, I roughly calc that if WildBill were to add 12.4% to the quoted torque figures on the chart (or multiply the observed readings by 0.89), he’d be getting performance constraints +/- 2psi from expected IRL across most operating regimes (?).

 

Not ideal, but a suggestion till it gets fixed...

[Chic]

Weta43,

Thanks for weighing in here.

Acknowledgment of this issue lends hope.

[iFoxRomeo]

Perhaps we are – not sure what you mean by ‘you asked for it’ though...

 

WildBill wanted to know how to calculate the performance of the Huey with the help of the performance charts.

 

"Hi again,

I'm looking for tutorial on how to calculate the following:

1- torque available

2- hover power required and hover ceiling..."

 

Then I answered him by posting the 30minute torque available chart with my annotations, to provide him a guideline, how he can calculate the performance. I took the values that are given by the flight manual itself as an example. Neither WildBill nor I talked about exceeding limitations. Just performance calculation in general.

And then you started with exceeding the limitations. That´s why I said "you asked for it".

...

Especially as your reply essentially confirms what I was saying, but I’ll have one more attempt at getting my point across & then call it quits.

 

Well you can see it that way, that I "essentially" confirmed your post, but thats only half the truth. With every small increment of exceeding a limit, you increase the overall failure probability, exponentially.

 

Throwing in your opinion without accepting a discussion won´t help finding the truth.

 

Meaning it’s an entirely realistic possibility that the observed effects (during the flight) of exceeding the guidelines on that chart are that: "nothing happens"

It is realistic that nothing happens, when you exceed the limits by 1% for a blink of a moment.

But its completely unrealistic that you can pull the collective all the way up to the mechanical stop and have the EGT around 800°C for a long long time. After one hour, I stopped this test. Nothing happened, no failures.

 

So if one of the realistic possible outcomes of exceeding the guidelines on that chart is that nothing happens, having nothing happen when you exceed the chart’s parameters in DCS IS one of many realistic possible outcomes. The problem is not that it happens sometime, rather that it happens always, which you can only discover through repeated testing.

That chart I posted does only tell you the maximum torque the engine is capable to produce under certain environmental conditions.

 

I have the impression that you don´t understand what it means to exceed a mechanical/structural limit. It´s not: Oh I exceeded a limit, now let´s throw the dices to see what might happen. You cannot say that the possibilities have equal probability. This isn´t a lottery.

 

It does never happen anything at all in the DCS Huey. I never had engine chip, mgb chip, main rotor failure or engine failure because of exceeding a limit/limits. Nothing.

 

Anyway .. I guess the point you meant to make was that there are issues with the torque indications in SIM which would mean that complying with the chart you provided resulted in lower available performance than could be expected IRL (but you can’t tell that from this chart).

As an interim tool for in SIM use, from reading others’ analysis comparing the observe torque in sim with expected torque, I roughly calc that if WildBill were to add 12.4% to the quoted torque figures on the chart (or multiply the observed readings by 0.89), he’d be getting performance constraints +/- 2psi from expected IRL across most operating regimes (?).

 

Not ideal, but a suggestion till it gets fixed...

These torque figures are only examples from the flight manual. They are not from WildBill or me. They are just examples, how one can calculate the torque available. Both the calibrated and the indicated torque.

 

Yes your right, I said that the engine values have "issues".

They have issues, because ED/BST set the bar so high with the "realistic modeling of the UH-1H engine".

 

 

Fox

[msalama]

Nothing happened, no failures.

 

+1

 

Did the same thing just now, flew around with my EGT in the red for an hour or so. Nothing. No failures whatsoever.

 

And ditto with the engine and gearbox oil temps too, BTW. You can drive around with everything in the red forever and nothing happens. Quite a glaring omission in a sim claiming to be realistic if you ask me.

 

And this chopper isn't even a beta anymore :huh: Has anyone tested the Hip, BTW? Or the jets for that matter?

[WildBillKelsoe]

Sometimes I pinch myself because it is whats available. To be honest, I fly DCS modules just to relive most of the books I read by real folk who did fly the real thing.

[Guest]

Sorry to revive such an old thread but:

 

DCS UH-1H

Engine EGT limits were implemented

Fine tuning of the engine and hover modelling was done, discrepancy with real chart now not exceeding 2.7%.

 

 

Is this suppossed to address all of the issues discussed here?

[PeroperoDokkiri]

I am curious too. Anyone?

[Guest]

I did a test and using the max torque available chart I got a very wrong outcome.

 

0 ft pressure altitude, 20°C=max torque 44lbs

 

At 44lbs the huey's engine exploaded after 4 minutes...........

[Guest]

Ok it seems that DCS is ignoring outside temperature.

 

Look at this. https://forums.eagle.ru/showthread.php?t=199483

[BaD CrC]

Interesting Piston85.

 

Would be curious to know the position of BST and what has been implemented exactly. We are having a lot of engine fires here in BSD since the implementation of this EGT limits and I am a bit surprised sometimes.