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[Dimlee]

I have to say that this exercise was an eye-opening one for me.
I believed earlier that ranges of aircraft were more or less "historical" here. Apparently, they were not - at least of some a/c of 1942-1943 we tested.

I did similar tests before but just for a small selection of twin-engine equipment such as Bf 110 including the Dackelbauch variant, Ar 234, Pe-2. But I paid more attention to the time, not the range and didn't notice any major issues.

Maybe I'll run another series of range tests for a wider selection, also in Ultrapack.

[SAS~Storebror]

Quick sanity check.
P-47C fuel capacity is 202 Imp.Gal (source: http://www.wwiiaircraftperformance.org/p-47/p-47c-afdu.html).
That's 918.31 litres.
With a specific weight of 0.71kg/ltr for grade 130 fuel, we get exactly 652kg of fuel for the P-47C.

Cross check with P-47C-5.fmd:

Code: [Select]

[Mass]
  Empty 4490.92
  TakeOff 5125.78
  Oil 97.52
  Fuel 830.07
Too much fuel onboard the "C" Jug. To be precise, it's roughly 10kg more than a "D" Jug could carry internally.
Conclusion: The "Fuel" parameter in "P-47C-5.fmd" needs to be adjusted to "652.0".

I figured out that the P-47C here in BAT needs to be set to 71% fuel load to be the real range it would of had in real life.

830.07kg x 0.71 would be 589.35kg, that'd be too little.
However, this might be the result of an error in the R-2800's specific fuel consumption.
Theoretically, the factor would be 0.79.
Taking your test results for granted, the fuel consumption is off by factor 1.1063.
That would mean we would need to add the following lines to the "[R-2800-21]" of "PW_R-2800_Series.emd":

Code: [Select]

FuelConsumptionP0 0.4425
FuelConsumptionP05 0.2655
FuelConsumptionP1 0.3098
FuelConsumptionPMAX 0.3319

Mike

[Vampire_pilot]

Yes, this is how it's done *properly*.

A rework of thousands of FMs and thousands of emd files, based on data yet to be determined or created. So, who wants the job (and get called out for "errors" afterwards)?

For each modpack individually. buttons are not interchangeable between UP and BAT for example.

Since, sometimes fmds are not interchangeable for other parameters, namely if one modpack has touched the CoG of the 3d model at some point in the last ten years and the other has not. Not even as simple as "just align that then" - because this messes up the cockpits too and they'd have to be fixed again.  I have been there and done that on the 11th hour before a release more than once and I loath this.

Oh. And that would just be fuel consumption and range.
Have we talked about "wrong" altitude performance and speeds yet? Or FMs that do not "feel" right?

[SAS~Storebror]

True that.
Even more, I just figured out that for whatever reason, the Duxford tactical trials clearly state 202 imp gal total capacity, whereas T.O. 01-65BC-1 (the P-47 B/C/D/G Pilot's Manual) specify a capacity of 305 US gal all across the set.
That would change a lot.
We would now need 819.73kg of fuel (not that much off the 830.07 set in the fmd), and this would mean the FuelConsumption params in emd would need to be:

Code: [Select]

FuelConsumptionP0 0.5564
FuelConsumptionP05 0.3338
FuelConsumptionP1 0.3895
FuelConsumptionPMAX 0.4173
Quite a difference.
Who's to judge which set is right?
Who tells the Duxford guys they were all wrong? Or the people from Farmingdale, Evansville and Buffalo that they were too dumb to get their fuel capacity right?


Mike

[Vampire_pilot]

A gem of almost 14 years ago

https://www.sas1946.com/main/index.php/topic,9735.msg104497.html#msg104497

[Wing Walker]

Who knew it would be so interesting to just make an accurate "Pre-P-51" escort mission...

Combat Radius:
5mins Fuel Warm up and takeoff--climb to 25,000ft--5mins at combat power--15mins at military power ----return at 25,000ft-- cruise at 25,000ft-- fuel reserve of 30mins at cruise power.

The 71% fuel I came up with was through testing going by the max range (1046Km) and the definition I found in a military document of "Combat Radius"

Yes, this is how it's done *properly*.

A rework of thousands of FMs and thousands of emd files, based on data yet to be determined or created. So, who wants the job (and get called out for "errors" afterwards)?

I'm sure no one is going to edit all a/c in BAT.  I only went down this rabbit hole because I had an interest in the P-47.

I found when doing the research for historical accurate mission making, things are not always spelled out for you in black and white and single source.

You have to take in all the information and put together the reality of the picture yourself.  For instance the whole range issue seemed to be mixed up between no drop tanks and the 200gallon one, and only one mention in a report saying there was no combat worthy one in 1942 for the '47. 

I'm not sure the same person to "edit" all this would be the same person that would like to research it all.

Quite a difference.
Who's to judge which set is right?

Also 202 ImpGal is 242.59 Gallons...  I think I remember seeing that wondering if they meant the 200gal drop tank since others sources seemed to report the max range as it would be with it.

I believed earlier that ranges of aircraft were more or less "historical" here.

Me too, I assumed the basics like combat range would be easy to set up.  Though it seems some FM's have been developed with a lot more attention than others.

Maybe it has to do with not all maps are 1:1 scale so it would of been hard to measure.


Some sources I saved:

http://www.wwiiaircraftperformance.org/p-47/p-47c-tactical-inc2.jpg
http://www.wwiiaircraftperformance.org/p-47/p-47c-tactical-charts.pdf
I thought this source was really good. Its an actual military documents that reports pretty much exactly what I was trying to find, that never happens.

 http://www.wwiiaircraftperformance.org/p-47/p-47c-tactical-trials.html
This is the same source as SAS~Storebror that also have the images of the above documents in it.

https://forum.axishistory.com/viewtopic.php?t=148000
This was just a forum I was looking at for possible overlapping info to confirm things.

https://www.368thfightergroup.com/P-47-2.html
This has some good snippits of stats.  Mentions the 200gal tank like it were normal.  I didn't realize something was wrong with the info until building the mission to Berlin.

https://www.joebaugher.com/usaf_fighters/p47_3.html
This one also mentions the 1250mile range with the 200gal tank, but doesn't specify when it was developed or that is wasn't "combat capable".

Of course the one source I found that mentioned that there was no fuel tank until "a year later" which would of been March '43 didn't get bookmarked or is hidden is something.

[Wing Walker]

Tried out "fuel consumption" vs "weight"...


The load out of the a/c affects speed (and therefore range), but not fuel consumption.

Again I tested with the P-47C with the default load and a heavier load with it set to 10% fuel to get the run time until 0% fuel.

The heavier load 14,326Lbs was: 500lbs bomb + rockets + extra ammo flew for  about 11mins until the, fuel hit 0% keeping a speed of about 263mph.

The lighter load 12,878Lbs(default), at a speed of 279mph lasted for 11mins also, but was faster.

So running for the same time, giving more range because of the speed.