Jump to content

A10C engine model


AstroEma

Recommended Posts

The link in your post takes the user to a controlled document, the dissemination of which is restricted by US federal law.

 

Just because some knucklehead accidentally forgot to password protect the download link on a US Government computer system, doesn't mean its okay to possess or distribute the document in violation of the distribution statement which is clearly visible on the front cover.

 

Hahaha watch out guys we've got OSI here.

[sIGPIC][/sIGPIC]

EtherealN: I will promptly perform a sex change and offer my hand in marriage to whomever
Link to comment
Share on other sites

Bug thread closed, so I'm sure this won't last long but:

 

TO 1A-10C-2-71JG-2, Maximum Power Engine Trim (ITT)

 

CAUTION

Do not exceed 5 minutes at MAX power setting, or allow TEMP (ITT) to exceed 860°C on TF34 CDD display window (ITT) or 865°C on cockpit indicator. If limit is exceeded, refer

to Overtemperature Chart.

 

Step 5 "Slowly advance throttle lever to max NG RPM. Retard throttle to 775° C ITT"

 

And

 

Each aircraft/element will accelerate to 200 KIAS. Climb speed will be 200 KIAS and power setting will be 800 degrees ITT unless specifically briefed otherwise.

 

Max we can reach in the sim is 750 but here are two examples, real USAF documentation, that states we should be able to reach higher. Ideal rate of climb (sorry can't share that document) is rated at 775 to 800 ITT.

Link to comment
Share on other sites

  • ED Team

Ok guys, I am going to open this again. Dont make me regret this, and/or allow anyone on the ED Team to give me a "I told you" comment.

 

First, I wont discuss the forum moderation of any specific users, if you want to discuss how the rules are applied, feel free to PM my and I would be happy to go over any questions you have.

 

Now the engines.

 

I understand that documents showing some of the maximums and ranges of the ITT were listed here. And I understand how you guys are trying to make heads or tails of why DCS runs differently. I am not going to profess to being an FM engineer or someone that works on A-10 engines (most I have done is a '69 Chevrolet 350, not really helpful here :) ).

 

So this is all how I understand it.

 

ED builds their FM based on a specific set of data in order to make things like an engine run like the engine would, or as close to it as possible in a consumer based simulation. In order to code that, they need more than just 1 or 2 specific numbers. You cant say, for example, the maximum number for ITT is X, and expect ED's model to always get there. ED will build its model of the engine, and it should fall somewhere in the range of specs. They cant take a number and somehow plug it in and change how the model works. I know some FMs worked like that in the past, where you could plug in maximum numbers and that is what you got. ED's FMs are more complex than that.

 

Now when ED modelled this engine, they had certain documents, documents specific not only to the A-10, but the engines as well. Like the software suit, they probably arent the same engines currently running in the A-10C tomorrow in the real world. As such, not every document you can dig up might match DCS. If someone that works on an A-10C currently, wants to send all classified data they have access to, to Moscow for ED to update their engine model, by all means do that, I would assume they would have to share a room with Snowden, but hey, we would have a more accurate model right? ED had limits on what they could model with the A-10C with their agreements they made, that limited them based on what access they had to documentation. We live with that on certain systems, the engines might not be any different.

 

Any Engine ED puts in any aircraft in DCS is a fresh, out of the box, never been used before piece of equipment. Its not been run on a bunch of missions, its not had any wear and tear, its not dirty, nor does it have any damage that might affect any number of things in the operation of that engine. Its a clean, fresh install every time you load that aircraft. This will have an effect on anything. How that effects ITT for example could very well explain some of the lower numbers we are seeing. Not saying that is what is happening, again, I am neither a FM engineer nor a A-10 engine builder. This is something to keep in mind.

 

Lastly, I understand there is some functionality not currently available, that you can basically override limitations set and allow greater ITT numbers. While it would be nice to have everything modelled, I am not sure this warrants ED dropping work on things like the Hornet to go back and make sure we can do this. It doesnt sound that helpful to me, least in the sense that its blocking me from enjoying the sim. This is never been reported before (I did check and couldnt find a report anyways), so I assume not too many other people are screaming at their PCs begging for a little more out of their ITT numbers for that mission they are on.

 

Now I dont mind trying to discuss this further, but lets keep the discussion civil and mature. ED doesnt feel like this needs to be addressed right now, either because of priority levels or lack of actual complete documentation (no a flight manual cant really be used to model an engine, its ok for checking that model later though if its the same engine).

 

Hope this helps a little guys.

  • Like 1

64Sig.png
Forum RulesMy YouTube • My Discord - NineLine#0440• **How to Report a Bug**

1146563203_makefg(6).png.82dab0a01be3a361522f3fff75916ba4.png  80141746_makefg(1).png.6fa028f2fe35222644e87c786da1fabb.png  28661714_makefg(2).png.b3816386a8f83b0cceab6cb43ae2477e.png  389390805_makefg(3).png.bca83a238dd2aaf235ea3ce2873b55bc.png  216757889_makefg(4).png.35cb826069cdae5c1a164a94deaff377.png  1359338181_makefg(5).png.e6135dea01fa097e5d841ee5fb3c2dc5.png

Link to comment
Share on other sites

Glad to see this re-opened, right move IMO.

 

What you wrote is very understandable, I for one never thought that a complex FM could be tweaked in a minute to match a certain number.

 

With that said, it seems that ITT is quite an important number, and we're seeing a ~ 100ºC difference between the RL aircraft, and what we have in DCS, which translates into lower thrust to weight ratio, with all connected consequences that you can imagine.

 

Now, there are indeed different priorities for different people. Someone thinks the A-10 is old, and ED should concentrate on newer things.

I am a hardcore fan of the A-10C, as many others here I suspect, and I'd like to have this issue fixed. The fact it wasn't reported doesn't really mean it's not an issue, IMO it just means that most of us are not so lucky to be working on / flying A-10Cs for a living, and therefore if you don't know about something, then you can't say if it's correct or not. Give an A-10 that reaches Mach 2 to my girlfriend, and she'll be perfectly happy :P

 

So I'd still like to make a case for modifying the FM in order to:

 

- Meet or get closer to RL performance, and make this a more accurate simulation.

- Allow us to more closely simulate RL procedures

- Show that ED really keeps an eye on all their modules, and updates/fixes things to maintain the status of best an most accurate FMs on the market.

 

 

Let's try to be practical here:

 

- What engine are we simulating in DCS A-10C?

- Is it the same engine used by the A-10s described in the official documents?

 

IF YES

 

> If the provided evidence isn't enough to work on, how can we help ED find the required information, and what should we be looking for?

 

 

Do you think this is an acceptable course of action?

Windows 10 - Intel i7 7700K 4.2 Ghz (no OC) - Asus Strix GTX 1080 8Gb - 16GB DDR4 (3000 MHz) - SSD 500GB + WD Black FZEX 1TB 6Gb/s

Link to comment
Share on other sites

I took this picture yesterday, reaching almost 800. Whats wrong with it? Snoopy said it couldn't reach 750.

is there any kind of condition that I need to pay attention?

 

QhUkqHy.jpg

 

 

Max we can reach in the sim is 750 but here are two examples, real USAF documentation, that states we should be able to reach higher. Ideal rate of climb (sorry can't share that document) is rated at 775 to 800 ITT.


Edited by Vitormouraa
  • Like 1
Link to comment
Share on other sites

  • ED Team
I took this picture yesterday, reaching almost 800. Whats wrong with it? Snoopy said it couldn't reach 750.

is there any kind of condition that I need to pay attention?

image

 

Thanks for the picture, I plan to try running through it myself, once my gaming machine is back in once piece (the wife went nuts in Ikea and I have been in Ikea hell ever since) I wanted to see for myself what it could do.

64Sig.png
Forum RulesMy YouTube • My Discord - NineLine#0440• **How to Report a Bug**

1146563203_makefg(6).png.82dab0a01be3a361522f3fff75916ba4.png  80141746_makefg(1).png.6fa028f2fe35222644e87c786da1fabb.png  28661714_makefg(2).png.b3816386a8f83b0cceab6cb43ae2477e.png  389390805_makefg(3).png.bca83a238dd2aaf235ea3ce2873b55bc.png  216757889_makefg(4).png.35cb826069cdae5c1a164a94deaff377.png  1359338181_makefg(5).png.e6135dea01fa097e5d841ee5fb3c2dc5.png

Link to comment
Share on other sites

  • ED Team
From this conversation with a real A-10C pilot, he felt the DCS A-10 engines are indeed underpowered. I know it's not as helpful as raw data/numbers, but I feel it vindicates that we're on the right track with this discussion.

 

As I said though, without hard data to build an FM on that really doesnt help. Do engines currently operating in the A-10 now produce more power than older ones? This version we have isnt the current version being operated by the USAF.... and as Snoopy stated at one point, he had documents he couldnt share... so really cant upgrade the engines on the A-10 without getting the documents to do so.

 

Its really what I am trying to get across... we have an accurate modelled older engine. For a new engine we need full new docs that probably the public simply cant get, much like software suites...

64Sig.png
Forum RulesMy YouTube • My Discord - NineLine#0440• **How to Report a Bug**

1146563203_makefg(6).png.82dab0a01be3a361522f3fff75916ba4.png  80141746_makefg(1).png.6fa028f2fe35222644e87c786da1fabb.png  28661714_makefg(2).png.b3816386a8f83b0cceab6cb43ae2477e.png  389390805_makefg(3).png.bca83a238dd2aaf235ea3ce2873b55bc.png  216757889_makefg(4).png.35cb826069cdae5c1a164a94deaff377.png  1359338181_makefg(5).png.e6135dea01fa097e5d841ee5fb3c2dc5.png

Link to comment
Share on other sites

  • ED Team
From this conversation with a real A-10C pilot, he felt the DCS A-10 engines are indeed underpowered. I know it's not as helpful as raw data/numbers, but I feel it vindicates that we're on the right track with this discussion.

 

The DCS A-10 engines give the same maximal thrust as they should regarding the manufacturer's specs.

A-10 in DCS performs exactly as it is specified in the performance charts in the manual.

Maximal AoA, lift are exactly as they specified in the very specific official book... even the conversion from true AoA to the units at the gauge is authentic.

 

Very often pilots look at their muscle memory regarding the performance at not to the flight parameters... it's sad, but it is a very well known fact.

 

So, if you can perform accurate tests of the A-10 in DCS and then compare it to the corresponding charts in the manual, this discussion would have sense. Otherwise, it's not more than ambient air disturbing.

Ніщо так сильно не ранить мозок, як уламки скла від розбитих рожевих окулярів

There is nothing so hurtful for the brain as splinters of broken rose-coloured spectacles.

Ничто так сильно не ранит мозг, как осколки стекла от разбитых розовых очков (С) Me

Link to comment
Share on other sites

  • ED Team
If we knew or could get some feedback as to what information is needed to adjust the engine model, it would help a lot. I'm sure even if not all the data is available a lot of it can be inferred through secondary means and be in the right ballpark.

 

But we arent seeing the discrepancies that are being reported at this point, clearly the picture posted above shows the ITT higher than what someone claimed wasnt possible in DCS. This leads me to believe it needs to be properly tested before we run to it needing any sort of fix.

 

ED has a complete set of docs on the engine. It might be a little older than what is currently in the field, but again... same as software suite and other things...

64Sig.png
Forum RulesMy YouTube • My Discord - NineLine#0440• **How to Report a Bug**

1146563203_makefg(6).png.82dab0a01be3a361522f3fff75916ba4.png  80141746_makefg(1).png.6fa028f2fe35222644e87c786da1fabb.png  28661714_makefg(2).png.b3816386a8f83b0cceab6cb43ae2477e.png  389390805_makefg(3).png.bca83a238dd2aaf235ea3ce2873b55bc.png  216757889_makefg(4).png.35cb826069cdae5c1a164a94deaff377.png  1359338181_makefg(5).png.e6135dea01fa097e5d841ee5fb3c2dc5.png

Link to comment
Share on other sites

I'll do some tests comparing the numbers that can really be achieved (according to available real life procedures and documents) with the simulation and report back.

 

Perhaps we can work out a test procedure here so we can test the performance under different conditions? I think maybe the personal impression is different bacause in DCSW we often fly under different conditions and with other loadouts/fuel loads, or whatever parameters there might be, compared to real life.

 

EDIT: IIRC one example might be tanking. A while ago I read some source that had numbers on speeds and altitudes used by USAF tankers when refueling A-10C, and I found it was almost impossible to even join on the tanker at those altitudes and speeds (which were described as normal) because at that altitude I couldn't fly that fast in the sim. The tanker just escaped.

Those tests were cut short by the tanker-accelerating-bug so I never got anywhere. But if we can dig up such numbers those could give us hints.

 

Thanks for re-opening, Sithspawn.


Edited by Aginor
Link to comment
Share on other sites

  • ED Team
I'll do some tests comparing the numbers that can really be achieved (according to available real life procedures and documents) with the simulation and report back.

 

Perhaps we can work out a test procedure here so we can test the performance under different conditions? I think maybe the personal impression is different bacause in DCSW we often fly under different conditions and with other loadouts/fuel loads, or whatever parameters there might be, compared to real life.

 

EDIT: IIRC one example might be tanking. A while ago I read some source that had numbers on speeds and altitudes used by USAF tankers when refueling A-10C, and I found it was almost impossible to even join on the tanker at those altitudes and speeds (which were described as normal) because at that altitude I couldn't fly that fast in the sim. The tanker just escaped.

Those tests were cut short by the tanker-accelerating-bug so I never got anywhere. But if we can dig up such numbers those could give us hints.

 

Thanks for re-opening, Sithspawn.

 

Probably TAS/IAS mixing?

Ніщо так сильно не ранить мозок, як уламки скла від розбитих рожевих окулярів

There is nothing so hurtful for the brain as splinters of broken rose-coloured spectacles.

Ничто так сильно не ранит мозг, как осколки стекла от разбитых розовых очков (С) Me

Link to comment
Share on other sites

I dug up the maximum thrust maximum speed level flight chart from the A-10A manual which cites its source as flight tests from 1982.

 

For a point of comparison I started DCS A-10C in the black sea air start map, climbed to angels 20, and turned so the wind is at my back, dropped all ordinances, and went full throttle and let it fly. I got to 242 IAS knots.

 

According to the chart, at 40k lbs, at 20k feet altitude, drag index 0, I should be getting around 270 IAS knots, with a range of 250 to 285 depending on temperature variance.

 

I concede I am not an expert in these matters, so with all likelihood I am not doing the measurements correctly.

 

I would appreciate any guidance for how to preform the tests accurately so we can compare results to the flight data properly.

Link to comment
Share on other sites

@Yo-Yo:

That was my first thought too, but as far as I remember it the numbers were not matching the difference at that altitude (at least not in the "normal atmosphere" my real life IAS/TAS chart uses).

I will have to repeat that test now and see.

 

Are there any peculiarities in the DCSW atmosphere simulations that I should keep in mind, or does it behave reasonably close to reality?

 

EDIT@Raistlen007: Those are not applicable I think, the A-10C is heavier. Might still be a starting point.


Edited by Aginor
Link to comment
Share on other sites

I think I agree that the difference in aerodynamics are probably marginal enough to not cause more than, let's say ten knots, difference.

 

I'd still prefer numbers specifically for the A-10C if we want to be as precise as possible to find out whether something is really wrong or not.

 

EDIT: Oh, and @ED, specifically Yo-Yo: Would you prefer tests to be done in 2.0 or in 1.5.4? Are there differences in the A-10C flight model and/or the sim's atmosperic model?

Link to comment
Share on other sites

I dug up the maximum thrust maximum speed level flight chart from the A-10A manual which cites its source as flight tests from 1982.

 

For a point of comparison I started DCS A-10C in the black sea air start map, climbed to angels 20, and turned so the wind is at my back, dropped all ordinances, and went full throttle and let it fly. I got to 242 IAS knots.

 

According to the chart, at 40k lbs, at 20k feet altitude, drag index 0, I should be getting around 270 IAS knots, with a range of 250 to 285 depending on temperature variance.

 

I concede I am not an expert in these matters, so with all likelihood I am not doing the measurements correctly.

 

I would appreciate any guidance for how to preform the tests accurately so we can compare results to the flight data properly.

 

 

Why not just start the mission without stores so you wont have to drop them and the pylons..?

Windows 10 Pro, Ryzen 2700X @ 4.6Ghz, 32GB DDR4-3200 GSkill (F4-3200C16D-16GTZR x2),

ASRock X470 Taichi Ultimate, XFX RX6800XT Merc 310 (RX-68XTALFD9)

3x ASUS VS248HP + Oculus HMD, Thrustmaster Warthog HOTAS + MFDs

Link to comment
Share on other sites

  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...