Historical Flight times

I was looking into how long WW1 aircraft could remain in the air. So, I found the website theaerodrome.com which has endurance for each aircraft. I then decided to see how closely WOFF simulates aircraft endurance.

Method of testing: Clear sky, QC flight, 10,000-13,000 ft, 100% fuel, 100% throttle until fuel reaches 0%.

Some results:

Is this something that could be put into a mod? I have always wondered what the flight-time comparisons were but never tested it like this

Good job there, orbyxP!
A fuel consumption mod would be great!

Good find Orbyx and definitely a mod-worthy topic.

Most of the fuel consumption rates in my FM mod files have been set to between about 1.2 and 1.6, depending on engine type and hp amount - those who enjoy flying gas-guzzlers might want to see how quickly the fuel disappears on those. From what I've been able to test, not too (terribly) quickly but definitely a change from the stock value of 1.0. I was tempted to increase the fuel consumption a bit more on some of the types but refrained from doing so - to allow for reasonable endurance times on the types.

A cruder solution is to set max. fuel, if you are flying the FMs on all the types as stock, to about 40 to 45% in the main sim menu - for Germans use about 20% fuel from the summer of '18 for elite units, and 10% fuel for secondary/defense units (to simulate fuel rations). If you are running my tweaked FM files, set fuel to about 80% in the sim menu and you should have a good approximation of the 1.8 to 2.0 values Orbyx has tested, for example, for the Alb. D.I.

Happy flying,
Von S

Yes, that is exactly due to real fuel consumption fix BTW, it was recommendation by OldHat based on his research.

Anyway - good work, orbyxP! We can make mod based on your research. However, we need to test more than 70 planes yet :-(.

Interesting find.
I have never been concerned with running out of fuel in the game (or even come close) but in historical accounts you’ll see it mentioned occasionally. Just figured it was the difference between the real world and the game world - plus the two dozen factors that go into fuel consumption on a real engine.

One problem is making sure flights don't run out of fuel on an assigned mission - obviously in real life they'd make sure it's within the reasonable range but in a sim there's a lot of data that you'd need to process for all the theatre flights just for that 1 item, for 80 aircraft,

Excellent point.
As much as "we" try to simulate historical accuracy there are always limitations in a game environment. Home computers are great at number crunching but they still can't "think."
Sounds like I'll stand pat for now but if anyone is going to experiment I'd be curious how the game engine handles it and how many AI flights in the theater come crashing down.

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I've been adjusting fuel percentage to reflect more accurate flight times for years. And as Jara mentioned above, OldHat did a fair amount of work on this quite a while back when he was putting together his HardCore mod. orby, if you want to take on the task of a mod that would address this permanently across the board that would be great, but if memory serves others have found it was more of job than first imagined. An alternative that would be nice to have, and would most likely be much quicker to create, would be a chart that show's the stock flight times for all the planes in WOFF alongside the real world flight times for each. That way folks could tell at a glance what they should adjust their fuel percentage to before each mission.

Lou

I have set my flight fuel level down to 80% when doing the “Start at Waypoint 1” thing when I am pressed for time but still....

Has anyone ever ran out of fuel in this game or even come close?

Unless you’re really taking some kind of tour, and not following “mission orders and waypoints”, I can’t possibly imagine it. Do some really fly for 2 hours (with mission long complete) with no contacts?
Lack of fuel in this game is not an issue - and one rarely mentioned in historical accounts. Even taking them down to real life numbers wouldn’t be an issue but, as mentioned above, the AI Flights/Campaign Engine may have an issue but even then I wonder.

I, as well as Lou, set the fuel level for ALL flights to 50% before each mission (via ME) and never encounter any problem with AI flights crashing due to lack of juice. Even if there is any problem with some fuel shortage, you will never know, because WOFF does not register an outcome of AI flights (other than player's squad). If you really wish to check the mission outcome - planes either crashed or shot down - run ME after mission and click on Mission Debrief.

Duke, after reading No Parachute I used to set the fuel lower and would make the patrol as long as Lee claimed they were "2+ hours" (using Jara's Mission Editor). I did this for a few days before I couldn't be patient anymore - multiple mission days made it go a lot slower. I've been very close, with some of the other flight mates turning for the nearest airfield while we were already on our way home. Added a nice "will I make it?" feel, but I didn't keep it going. I think I did what Jara did and put the fuel to either 50% or 60%

I will reply to selected points that were raised.

However, I kindly ask @Polovski to see my reply regarding his comment because I feel that it will change the opinion.




A JSGME MOD would overwrite other FM MODS, so another solution would need to be implemented. For example, if JJJ has time to incorporate it into the MultiMOD, that would be ideal. Because then it can cooexist with other FM MODS.




Interesting subject regarding the fuel rations. I think fuel percentages here would work with the modified FM consumption and give interesting results. Will need to test what happens after I've completed the rest of the planes.




Fuel percentage can work, but using 50% for all planes will turn out inaccurate results simply becase there are some planes which do not need adjustments because they are within historical performance. As well as some that require more or less. I believe that changing the FM for each plane would give more accurate results.

Yes, it is a lot of testing.



Even with the MODDED FM, you will have a hard time running out of fuel. See example below.





This will require a two part answer:

1. In QC, the WOFF manager automatically compenstates by adjusting the distance of the flight path based on the amount of fuel consumption.

With a normal MODDED fuel consumption to 1.9 in Alb D1



with an extremely high MODDED fuel consumption to 5.9 in Alb D1



2. In QC and autopilot, the AI will fly between 71 to 85 % throttle, therefore, lower fuel consumption.

Plane: Alb D1
fuelConsumption_frac: 1.9

Flight Time, Range: (100% throttle, no autopilot): 1 hr 30 min, Range 277 km (185 km/hr x 1.5 hrs)

Flight Time, Range: (71-85% throttle, autopilot enabled): 2 hr 11 min, Range 385 km (185 km/hr x 2.11 hrs)

Therefore, it is a safe adjustment to use.




Yes, that is in my plans because I need to make that chart for myself in order to compare stock values and know when to adjust and not adjust.

This subject (like all subjects here as it’s a 10 year old game) was discussed before. Many times.
About the only negative factor I recall was some people thinking it was a “cheat” as, at 50% fuel, the aircraft “manuvers better” but based on the thinking of how these aircraft perform under game load that may be a subject for another day.

As a mod, fine, but as a game change, I think the Dev's have a LOT MORE IMPORTANT things they want to accomplish than this subject (both WOFF and WOTR since they are a small team and limited time).

1. As it stands now ALL PLANES are equal (AI & Player) when it comes to full fuel weight, you start changing it and things start changing in the game.

2. Since all squadrons from all countries are not in the game yet, having AI planes with more fuel (longer flying times) compensates for less planes being up in the air while you are on your mission. Otherwise the AI planes would have to take off and land earlier and with far less impact on your missions (especially for those who like a lot of air to air combat every mission)

For sure thanks Panama Red, yes every single aspect takes huge amounts of time. There's a zillion other things we could be doing that would be far more important.


orby - yes there is some basic adjustment /distance on fuel load, but QC isn't exactly taxing things. Its reduced by a thumb suck though. Go ahead and modify and if you test each aircraft type and with various missions and check AI performance in QC and campaign, dogfighting, in formation, escorting various bombers, take off ,landing and various airfields etc - and all is well then great maybe we can use it.

Don't forget the fuel load reducing affects where the weight is balanced. It can and often does therefore affect aircraft performance, mostly in dogfighting but could affect other things.

As Panama said, there are many other factors in campaign. For example finding replacement squads further away to fill a mission because nearer ones may be unavailable - due to aircraft type not yet available, or squads that don't exist yet and others I can't even remember (WM does all the campaign mission generation code).

Buy yes in theory it's good to do.

Thank you everyone for taking the time to reply to my post. As I said, I won't be making a JSGME mod. However, I will provide a chart for others to use. If JJJ incorporates it into the multimod, then it will eventually be thoroughly tested in all situations when it's active. If not, then at least you'll have a chart when I'm done testing.

Great idea with Multimod, orbyxP. Would it be possible to have two csv tables, one with WOFF's vanilla "fuelConsumption_frac" for each plane and second csv file with modified values?

Thank you JJJ65, I will do that when I have completed testing.

In the meantime, I will share the results for Allied and switch now to German for testing.

Testing method: QC air start (~6 to 10K ft), immediately switch to combat speed (100% throttle) with 100% fuel and running until 0% fuel.

The first test was done by flying each aircraft with default WOFF fuel consumption and recording how long it took before reaching 0% fuel. The second test was done after adjusting the fuel consumption in the xfm in order that each aircraft stays within 5 minutes of its historical flight time (endurance).

The difference is very significant in several cases then being spot on in some.
And the fuel consumption frac is the current game setting?

No, the current game consumption fraction is set to 1.0 for all planes.
@orbyxP - good job

Ah. Right. That was mentioned before.
So the frac number is the recommended change.
Sounds like a plan...

Information link added to MOD section here.

Updated version 2.0 of Multimod including Realistic fuel consumption mod by orbyxP is available here
Thx to orbyxP.

Just a heads up but flight time would be calculated using cruise speed not full throttle so the consumption fraction numbers may need to be higher too. Or is that because you believe testing full on (with its higher use of fuel) then the AI using cruise speed gives them some leeway?
If so the consumption is still not historically accurate though.

Each type would need long campaign missions testing with each type.

@JJJ. Thanks for implementing so quick! Downloaded and installed.

@Polovski. Hopefully there will be enough of the folks here to use the multimod to test like in an open beta. I believe that my values are closer to historical flight times than the default WOFF. I will search for references, but if you take just an example that the Bristol Scout had either 100% throttle or engine off (like in FAQ & Reference section):

Unmodded WOFF is 6 hrs 17 minutes flight time on 100% throttle, while the mod reduces it to 2 hours. I have a feeling that I will find a flight time of 2 hours closer to being historically accurate in the references.

Also, cruise speed will extend the flight time just like in default WOFF due to less fuel consumption, but again, I believe the extended flight times in the MOD will be closer to history.

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Nice bit of work orby, the list alone is very handy and the mod is even better. Keep at the testing, it is much appreciated.

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Dan San Abbott at theaerodrome.com wrote:

Endurance for fighter is based on fuel consumption of the engine at full power at a specific altitude.

Then he goes on to explain...

If you look at the the specification for an engine they give the fuel consumption at so much grams, ounces or lbs per horse power per hour.
For example the 160 Ps (hp) Mercedes D.III data sheets gives the fuel consumption @ 230 grams or 230 / 1000 =.023kg per hour per hour and the oil consumption at 20 grams per Ps(hp)
You are the designer and you want your fighter to have a two hour flight duration at full power, it will require:
Fuel
2hrs x .230kg x 160 ps = 73.6 kg fuel.
Oil
2 hr. x .02 kg x 160 = 6.4 kg. oil generally engineers use 1/10 of the fuel to determine the oil require or in the case 7.2 kg of oil.
The 150 hp Hispano-Suiza Model A engine has a fuel consumption of .52 lbs per hour hour per hp =
150 x .52 = 78 lbs.
Gasoline weighs 7.2 lbs per gallon, 78/ 7.2 = 10.83 gallons or gallons x 4.545 = liters, 10.83 x 4.545 = 49.2 liters per hour.
If the fuel tank capacity is known you can then determine the duration.
The Spad VII DATAFILE on page 24 , gives tha endurance as 1 1/2 hours, by dropping the rpm from 1450 to a cruise rpm of1300 would lower the fuel consumption, horse power and extend the length of duration.

Thank you for these excellent tweaks Orbyx.

Quick question regarding the inclusion of fuel consumption rate into JJJ's multimod ver. 2.0: does it override custom FM tweaks to the xfm files (if custom FMs are installed in JSGME) or only change the fuel consumption rate entry? If necessary, I wlll include Orbyx's fuel consumption numbers in all of my previously tweaked FM files, in a future update (ver. 5.0) of the FM pack. In the meantime, running with a total fuel load of about 70-80% in the main menu in WOFFue/pe, and my FM tweaks, should provide an approximation of Orbyx's fuel consumption tweaks. Great work all round gents' - looking forward to more fuel consumption discoveries.

Von S

Oh great! It’s not enough getting shot at, or bleeding out. Now you also have to worry about running out of fuel even without the tanks being punctured. What’s next? Not being able to do barrel rolls with a full load of bombs? My pilot hates you.

Multimod changes only fuel consumption rate values and does not replace/modify /override custom xfm files. That is the main advantage of Multimod over JSGME mod that replaces entire files..

Mm interesting, sounds good orbyxP - if Dan San explained it so, then that's good info.

Usually changing such things takes long and good testing and mostly there is a reason why some things are as they are, even though they might be historically not correct. Flying under heavy load, no load etc. As Pol said, I believe, longer flights make up for less traffic. If historically there should be 80 squadrons flying for each side, you might only have 10 or so ingame, depending of your setting. And with some of those 10 you still want the chance to meet them. If they are out on patrol, recon etc. only half the time before returning home, chances to meet them might be much less. But as you said, it is like an open beta.

Maybe you should take a look at the Gotha though how that works out for them. Before that it was calculated for them to make London and coming back just with the last drop of fuel. Reducing that might end up with them crashlanding anywhere during their mission, or simply returning back to base halfway, without even coming close to London.

Cheers

WOFF's vanilla Gotha was not able to make return trip to London (max flight time 3Hrs). However, with orbyxP fix it seems quite possible, because it changes fuelConsumptionFraction to 0.59 (almost to one half), so Gotha is less thirsty now (flight time increased to 5 Hrs).

Usually they should make it. Also they become lighter after dropping bombs etc. Of course there are some Gotha airfields farther away from the channel and some closer. Some bombing targets are at the far back of London etc. Also if they have to fight on the trip, that costs time and fuel. But you might be right though, that it's sometimes a bit too close to the last drop. It was made to add the problems and fears of the bombercrews.

I made a testflight with a Gotha-raid to Paris with the new mod. And Paris is closer than London. Still they consumed more than 50% before even reaching the outskirts. So maybe worth to make it 0.50 or something. But it was just one test though.

Sorry, I haven't been paying as much attention as I should and wanted to address this: I have been dropping fuel levels for my whole flight to 70-80% for ages ( seems strange they give me that much power but.. ) I have gotten the low fuel warning from time to time on long escort recon missions...

Thank you for your input. I can certainly test 0.50 on my end and let you know how that turned out.

JJJ made it super simple to try out this historical flight MOD by incorporating it into his multimod. I'm hoping that more pilots try out JJJ's multimod and report back their suggestions like you did. Tweaks can always be done to achieve a good balance between historical flight times and the game's mission objectives.

BTW one thing I forgot to mention, when testing include landing, and forming up on those long missions. Those two can take quite some fuel. So making it back to base with a few % fuel left may not be enough if the airfield is busy.

Flying for one hour on full throttle is still one hour. No more, no less.