WOFF FM Thread

[Bucksnort]

In an effort to keep the peace on the official WOFF forum and still be able to talk about alternative flight models and share ideas I thought I would have a go at starting a WOFF FM thread here in neurtal territory on CombatAce. 

 

FM arguments are never resolved, so the intent of this thread is to fiddle around with the FM's and get them the way each of us wants them, share and compare notes and hopefully have fun 

So here is the first effort.  This is an Albatros D.V FM created by Hellshade with data from Elephant and Jim F. Miller.  It makes only two changes to the WOFF Albatros D.V flight model.  It reduces the weight from 680 kg to 620 kg and the horsepower from 180 to 170.  According to JFM at least 742 of the 900 Albatros D.V's were built at this weight and horsepower.

 

The one change to Hellshade's original file that I made was to pair it down to just the .xfm files and make it JSGME ready.  Simply download this file and install it using JSGME from your Mods folder under the OBDWW1 Over Flanders Fields folder.  If you don't like the FM, then simply uninstall it using JSGME and you're back to the stock WOFF FM.

 

Bucksnort

Alb DV 620kg 170hp.zip

[+elephant]

Here is another FM revision for the D.Va this time, made by gavagai, from RoF Forums:

 

 

 

You can try this Albatros D.Va in quick combat mode. If you like it I think you can figure out how to use it for the campaign, too.

You'll see that the yaw behavior is more realistic, the roll rate is decreased, and it is unstable in the pitch axis. That's my best approximation of what I know about the real aircraft.

Other fixes for things that were obviously wrong:

empty and loaded weight
lower wing dihedral
CLmax
aspect ratio

The rate of climb is way too good at low altitude, but that is true for all scouts in WOFF, so it is not my fault.

 

I have prepared gavagai's Mod to be used not only in QC, in easy to enable JSGME format.

 

Alb D.Va 680kg 190hp_gavagai.7z

 

Please download again, I have revised  the file due to folder naming error (D.V instead of D.Va)

if you got the original file it will change the D.V FM...

Edited March 3, 2014 by elephant

[Olham]

Good point, Buck.
I wonder what you guys will come up with, but keep your attention to the fact,
that the FMs and AI abilities, their actions, responses, overall behaviour,
are like a "three-dimensional grid" where one thing is connected to another.

So I believe to understand from recent posts, that there may be good reasons,
why a specific aircraft has a WRONG weight - maybe the whole interaction and
desired overall FM could only be achieved this way?
After all, they have "knitted" this complex interactive Monster-AI over four years
to get it all right.
Watch not only your own craft; make sure to check, what your comrades can or
cannot do with their crates now - it won't help you much, if you must win the
war single-handedly.

Me, I am the total Albatros-Lover, and I was surprised and disappointed to find
my favourite bird changed so much, compared to OFF.
But then it was very unbelieveable in OFF, and I'm getting to a point, where
I feel it is much more believeable in WOFF.

I will see after some time, if there are still points I'd like to see changed,
or if I will learn to fly these birds again, like I did before in OFF.
In OFF I always broke my lower wings in the beginning, and I was cursing the
devs (you may remember that, Pol...) for "building such crappy Albatros".
In the end, I was perfectly able to take up fights even against the nemesis,
the Sopwith Camel - and win most of them.

However - maybe there is always room for slight improvements - so I wish you
all good luck for the tweaking. Me, I'd never dare to touch the digits.

 

 

PS: Buck, is your mod only for QC, or for campaigns too?

[+gavagai]

Regarding FM changes, you can do a lot to the FMs and the AI will still fly fine.  The warnings against doing this seem like a bit of a red herring.

 

Now, for horse power, changing it does nothing (same is true of RPM).  Aircraft performance in WOFF seems to be a function of the max sea level airspeed, the weight, and the LDmax (lift/drag). "170hp" is just a generic designation for the Mercedes D.III power output in the Albatros D.III or D.V.  Primary sources indicate 175 PS @1450 rpm, with the max rpm in level flight at around 1500 rpm.

 

Now, regarding weight, there is a Windsock document that has the OAW Albatros D.Va coming in at over 950kg.  We also have a primary source that says 914.5kg.  So, I went with the primary source for my WOFF FM.  That same Windsock document doesn't convert correctly between metric and imperial units, fwiw.  They say 5km = 15250ft.

 

The other big difference you can feel in the FM I made is the rudder response.  No more hockey skids to the point of flying sideways through the air.  I also reduced the roll rate slightly to feel more like the Rise of Flight Albatros D.III.  Every account I have read of the Albatros describes mediocre roll performance, and with all the subjectivity that comes along with it, it seemed appropriate to make that change.

 

Incidentally, the WOFF FM leaves out the 2 degrees of lower wing dihedral in the Albatros V strutters.  I was very surprised that they missed this.

 

-------------------

 

Now, having argued myself silly at the Rise of Flight forums over the Albatros airspeed, it is great that I can finally tinker with the FM in a WW1 flight sim.  However, WOFF is not free of the same problems.  Just like Rise of Flight, the Entente rotary scouts are pretty fast.  118.5mph for the Camel, 110mph for the Nieuport 17, 116mph for the Nieuport 24, etc.  As Pat Wilson says, FMs will never be perfect, but they shouldn't be obviously wrong.  The idea is to make the relative performance of the aircraft credible.  So, one of the first things I did was to slow down the rotary scouts (including the Dr1, ahem).  For example, all of the more detailed sources have a max airspeed of about 107mph for the Nieuport 24, but there is one figure out there that says 116mph and WOFF went with that one.  That ends of skewing the whole balance in 1917 when your Albatros is slower than 116mph.

Edited March 1, 2014 by gavagai

[Olham]

Gavagai, those weights for Albatros D.Va are not their empty weights.

I have a clear photo of Albatros D.Va Serial-No. 7098/17 (the well-known "Gisi"), which was

from the last production batch ordered October 1917.

 

It's weight table reads:

 

Leergewicht: 680kg (empty weight)

Nutzlast: 235kg         (live load)

Gesammtgew: 915kg [strange they wrote it with two "m" - may be an old form of German]

 

There were also OAW-built Albatros D.Va (Ostdeutsche Albatros-Werke).

A weight-table in a historical photo I found a "WingnutWings", reads:

 

Leergewicht: 717kg (empty weight)

Nutzlast: 220kg        (live load)

Gesamtgew: 937kg

 

I think it is most safe to go after weight tables shown in historical photos, where we also see

the serial number of the plane, so we can say, which production batch it was.

Any researcher - even the good ones - make mistakes; I much prefer a first-hand source.

 

 

PS/Edit:

There were Albatros D.Va with 200 hp, which might have been those heavy weights.

Unfortunately I don't have any data for those - neither prod. nr. nor weight tables.

Edited March 1, 2014 by Olham

[+gavagai]

When did I say they were empty weights?  That would be ridiculous.

 

What I'm explaining is the loaded weight I selected for my Albatros D.Va FM when all of the component weights are added together.

[+elephant]

 

 

According to JFM at least 742 of the 900 Albatros D.V's were built at this weight and horsepower.

 

Jim was trying to make a raw example...

It is my feeling that every D.V left the factory with the 620kg/170 hp specs,

marked in 2 row weights table on the port fuselage.

Here is another pic that narrows down Jim's count more:

 Albatros D.V 4640/17 (the last one left the factory being D.4702/17)

 

 

The words "Zulassige Belastung" (denoting a 2 row table) partialy and barely visible between the anemometer and the V strut.

 

The D.V's that were retrofitted with the D.Va improvements were given new weights tables ala D.Va style (3 row)

Here is Ernst Udet's D.4476/17 with the old style two row weights table scrubbed off...

in order to receive a new revised one, due to uprate?

 

 

Here is an older D.2359/17, captured in March 1918, with a later style 3 row weights table and retrofited braces.

 

 

​IMHO, the introduction of D.V uprated in WOFF is not quite historical, souldn't be before October November '17.

 

 

 

[+gavagai]

Well, it doesn't matter elephant, because changing the horsepower in the FM file does nothing.  You can enter "0" for the horsepower and you get the same FM.

[+elephant]

When did I say they were empty weights?  That would be ridiculous.

 

What I'm explaining is the loaded weight I selected for my Albatros D.Va FM when all of the component weights are added together.

 

It seems from the net weight of the D.Va in WOFF that the chose to portray the OAW variant.

600 of them were made from Sept/Oct '17.

The had additional lower wing reinforcements that raised their net weight to 717 kg.

To counter that they had to reduce the fuel tank capacity by 15kg.

 

 

They should have slightly reduced range, is it the case in WOFF?

 

As Olham noted above, the greater number of D.Va-s were made by Johannisthal (1062) had net weight of 680kg.

 

The engines upgraded to Mercedes D.III aü  (the ü was for "über", meaning "overcompressed")

did not add any weight to the plane so no change expected to the weights table.

Well, it doesn't matter elephant, because changing the horsepower in the FM file does nothing.  You can enter "0" for the horsepower and you get the same FM.

 

I was refering to the historical horsepower of the D.V (Mercedes D.III engine) not the FM...

[+gavagai]

Well, they didn't increase the wing strength to match that weight, then.  All of the Albatros scouts have the same max-g in WOFF.

 

I don't believe your claim that they were delivered with the D.IIIau engine.  According to Dave Watts at theaerodrome deliveries of that engine did not begin in number until June 1918.

 

On the other hand, the regular Mercedes D.IIIa produced more power than its usual designation.  The British rated an engine from a captured D.Va at around 188hp @1500rpm, and the engine revved to over 1550rpm in level flight (at least 190hp).

[+elephant]

I said that the upgraded engines to D.IIIau didn't add any weight, not that any Albatros was ever delivered from factory with such engine.    

[+gavagai]

Oh, sorry then.

[+elephant]

ERRATUM!

Please, download gavagai's FM tweak again, I have revised  the file due to folder naming error (D.V instead of D.Va)

if you got the original file it will change the D.V FM...

 

Sorry!

[Slick Wilhelm]

Hi guys,

 

What are you using to look at the FM data in WOFF? What software program would I need to be able to do the same? 

 

Does anyone else feel that there's something wrong with the Alb. D.III FM, specifically the "insty stall" when initiating a left hand bank/ turn?

 

I haven't had the opportunity to fly the D.V as modeled by OBD, so I have no comments on that(yet). 

Edited March 1, 2014 by Slick Wilhelm

[Olham]

Hey, elephant, nice to see you joined in.

You have your facts together MUCH more orderly and precise than I ever will.

I am curious what you guys will come up with.

 

Wilhelm, I did not see the "instant stall" on the last D.III trips.

I may have had them in the beginning, not sure (derfinitely on the D.V though),

but I don't pull the stick so suddenly back anymore, and then the craft behaves

rather nicely.

We must not forget: not only may the WOFF Albies be "cut down" to more realism -

also a Sopwith Tripe, which I fought, could not do the crazy things they used to do

back in OFF. Had I treated my D.III even more careful, I could have shot him down

(but I didn't and so my wings broke - Mmuahahahahaaa!!!)

Edited March 1, 2014 by Olham

[Hellshade]

I'd be interested if there's any way to add the more "bumpy" feel of flying into WOFF that exists in RoF.    Is that possible?

[+elephant]

 

What are you using to look at the FM data in WOFF? What software program would I need to be able to do the same?

 

 

You can open them with Notepad.

 

I'd be interested if there's any way to add the more "bumpy" feel of flying into WOFF that exists in RoF.    Is that possible?

 

gavagai, has made a deeper investigation of WOFF FMs.

in RoF Forum he claimed that (RoF feel) can be achieved at some point and noticed that the FMs in WOFF were deliberately  made "easy".

It would have been a huge task though...

[+gavagai]

The bumpy feel is turbulence in Rise of Flight.  The initial release of WOFF had pretty strong turbulence, but it was toned down after a few patches.

 

What can be done is to make the WOFF scouts behave more like real aircraft.  However, I never received any feedback on my work.  Elephant, have you actually tried my D.Va?  Did you like it or not?

[+elephant]

I haven't flown any sim for some time now...

[+gavagai]

Well, there you go.  I have received zero feedback so far, so not much reason to work on the additional aircraft except for my own pleasure.

[rjw]

Hello Folks, May I chime in here.

 

I have read all the threads here with interest as well as the one on simhq on the FM issue.

 

I have tried Hellshades mod to the xfm and also the stock xfm from WOFF. I flew both in QC with the DV against 2 Pups and recorded video of the performance. The video of the Hellshade xfm is up on that site and the video of the stock xfm is currently uploading to YouTube and will be posted in that thread shortly. Once that upload completes I will log  back in here and post both of them here for your perusal. Keep in mind I am a newbie flyer of the DV so please don't look for Hellshade's quality.

 

Keep up the investigative work, it can only add to our knowledge base and assessment of things as they are in WOFF. I would like to think that we all have the same POSITIVE interest at heart with respect to WOFF. It is a great sim and can only get better if we are all open minded.

 

Best Regards to all

[Olham]

Well, there you go.  I have received zero feedback so far, so not much reason to work on the additional aircraft except for my own pleasure.

 

You shouldn't say that, gavagai - this thread only started today, and has already two pages.

Me, I just had no time for testing yet - give the people some time, I'd say.

Edited March 1, 2014 by Olham

[rjw]

Hi Folks;

Ok, I have gone back to the stock xfm for the DV and recorded a video of a combat with 2 Pups in QC.

For the sake of comparison I am posting the original video of the same scenario that I took in QC using the modified xfm for the DV, followed by the video of a combat session in QC with the stock xfm.

My impression is that there is little difference and if there is, it is very marginal. I am now inclined to lean in favour of Polovski's comment that my first impression "Could be a placebo.. our new XFM uses setting intelligently. What is in a text file is not the whole story. RexH says "both calculations are based on propRPM times propMOI. So there is no need to adjust for inline engine differences."

I am no expert flyer of the DV but I can say that my approach to handling it is consistent across both video's. What does stand out (but is not evident in the videos) is that during the course of learning this craft I discovered that forward speed is everything and that when trying to turn when the speed is low caused bad things to happen. Keep the speed up well from stall and make those turns with gentle progression. quick snappy moves makes the DV unhappy and you also.

Video with Hellshade's modified xfm:

 

http://www.youtube.com/watch?v=0Q4D5VYsdWk

 

video with stock WOFF xfm:

 

http://www.youtube.com/watch?v=l2e05DVpsXo

 

Best Regards

 

[Slick Wilhelm]

You can open them with Notepad.

 

LOL, my bad. I didn't realize they were just flat files. 

[Olham]

I discovered that forward speed is everything and that when trying to turn when the speed is low caused bad things to happen.

Yes, that sounds alright - the rather heavy craft (compared to canvas planes) is an energy fighter,

and "energy" means "forward speed". All your moves in a fight must be so, that you constantly

regain any lost energy; after a climb, the next turn will go better, if you dive before turning.

A nimble little turnfighter may be able to "hang on it's wings" a bit longer before it stalled -

the Albs need energy.

 

Thank you for testing, Robert.

I just had no time yet; could only make one campaign flight 20 minutes ago, and that was with a D.III.

What you report doesn't sound to me like there is an issue, or that the FM needed to be modified.

As I just realised again in a fight against two SPADs - the strongest "factor" for how it all goes sits

in the cockpit. Can I have a mod that makes me an 'instant ace', please?

Edited March 1, 2014 by Olham