Spit IIA Speed in game test

[Ernst]

Originally Posted by 5./JG27.Farber

You doing it wrong. At 100m's I get 460 Km/H IAS at 1.3 Ata and at 5km's I get 420 Km/H at 1.3 Ata...

I have tracks if you want them.

I would like the tracks not because i do not believe But because i would like to learn... Its possible to maintain 460 km/h when coming out of dive but when accelerating in level flight i cannot build more than 430.

[IvanK]

Exccellent graph Klem

[klem]

Originally Posted by 5./JG27.Farber

We both take off and he'll say 2000m's and Ill say what? we are are at 2200. Read from the needle.

Specsavers?

Seriously, that's weird. Even if he had set field elevation, typically 995mb, thats only about 150 feet/50m difference from the default 1000mb. 992 would be about 240ft/80m.

[Crumpp]

Seriously, that's weird.

YES and pretty much invalidates the ability to test any kind of performance without a stable atmospheric model.

[Crumpp]

Even if he had set field elevation, typically 995mb, thats only about 150 feet/50m difference from the default 1000mb. 992 would be about 240ft/80m.

It should be easy to confirm the atmospheric model.

1. Go to a known airport like London Biggen Hill. The field elevation at EGKB is 599 ft.

2. Set your altimeter to field elevation (599 ft) and your altimeter setting should read 992mb when converted. If it does not read the setting and record the temperature.

[CWMV]

Originally Posted by Ernst

I would like the tracks not because i do not believe But because i would like to learn... Its possible to maintain 460 km/h when coming out of dive but when accelerating in level flight i cannot build more than 430.

I get the same figures, ie 460kph in level flight(no diving into it), more with boost.
Trim is your friend, and keep the ball centered.

[klem]

Originally Posted by Crumpp

It should be easy to confirm the atmospheric model.

1. Go to a known airport like London Biggin Hill. The field elevation at EGKB is 599 ft.

2. Set your altimeter to field elevation (599 ft) and your altimeter setting should read 992mb when converted. If it does not read the setting and record the temperature.

Temperature is if course important. btw Biggin alt may vary according to spawn point. On my server its true height (pos.z) is 180.77m/593.1 feet at the runway intersections and at the central 'airfield' symbol position in FMB but is listed as 587 feet in the info IvanK posted from the FMB.

In the ATAG server I find 992Mb is almost correct on the safe side but I've never seen Biggin in use on the patched server.

In my Channel test map for my own server I get Tangmere scripted out as 45 feet and temperature 16.9 deg C. Atimeter setting of 996mb gives altimeter reading of 59.08 feet and 995mb gives 31.36 feet (altimeter figures actually captured by scripting but gauge reading is correct as far as the human eye can tell).

At Manston it is scripted out as 150.2 feet and 16.7 degrees C. Alt setting of 996 gives altimeter reading of 167.24 feet and 995mb gives 139.74.

So, on that mission map I would set 995 to give me a safety margin for very low flying.

Now between airfield, a 0.2 degree C change over 145.2 feet altitude change = 1.377 deg C per 1000 feet. Standard rate is ~1.98 degrees C / 1000 ft but my only usng 1 decimal place for temp and a non-standard day pressure could be the cause of that anomaly as, say, 16.949 (Tangmere 16.9) minus 16.551 (Manston 16.6) would take us to 2.74 degrees / 1000. The real figure is somewhere in between so very likely 1.98.

My point is that I'm guessing the atmosphere across the map is consistent and without weather pattern although why it would be different in my server (Multiplayer, Server, Create Server) and the ATAG server I can't say UNLESS ATAG's Mission Parameters aren't standard (does Flow affect this?). I did try different mission start times to see if there is a generic 'day' weather pattern operating changing temperature and pressure over time but the temperature and required baro settings didn't alter between 7 a.m., 12 noon and 9:00 pm.

OK, just some more spare time rambling to indicate we don't have a standard day and we don't know why it changes between servers. Or why Farber's wingman's altimeter reads different to his by 200m

[klem]

I have been asked for the mission and script files I used for my tests. I'm attaching them plus a version of the output .csv file saved into Excel where I summarised some records for the chart and added a few calculations plus some conversion factors and odd formula memos at the top. If you want to save your output as excel then just copy/paste any .csv file data into it. The mission punches up some data on screen and even more data in the output file. Coders can play with he .cs file and add or change whatever they like.

First, how to use the files. Drop the .mis and .cs files into your /1C Soft club/il-2 sturmovik cliffs of dover/Missions/ folder where it is esy to find when you later run Multiplayer.... Server... and create the server ("OK")

Open the Performance.cs file with notepad and search for //FILEPATH
1. Set the filename for output file by editing the part in quotation marks
strfile = "Performance";
e.g. you can see that I have used the name of this mission (Performance.mis) and script file (Performance.cs) without the .mis or .cs extension. The name of the aircraft you test will be added automatically to the filename thus creating separate files for each aircraft tested,
e.g. Performance-SpitfireMkIIa.csv

2. Edit the output file path to your choice by editing in the following the first part in quotation marks (not the "-" or ".CSV" part)
fstring = "E:/CoD_data/BlackBox_Data/" + strfile + "-" + cur_ac.ToString() + ".CSV";

Be sure to create the folders you need in Explorer or the file output will fail!
Also be sure to close the .csv file before you run further tests or the mission cannot write ti the file.

Typical result for the above is a .csv file as follows:
"E:/CoD_data/BlackBox_Data/Performance-SpitfireIIa.CSV"

If you create your own mission you can still use the script. Just copy it and give it exactly the same name as your mission file, e.g.
MyMission.mis needs file MyMission.cs
Don't forget to edit the filename as 1. above to, say "MyMission" to get you MyMission-SpitfireMkIIa.csv

More about the script and output:-

Deep breath and one piece at a time....

The .cs file is a bit untidy with various rem'd out lines I didn't use in the end. Also it comes with a bit of advice...

The whole thing comes from data inside the game, the various C# 'References' parameters. You don't really need to go there but note the following.......

I could not make head or tail of the parameters Z_VelocityIAS or Z_VelocityTAS which I output as WIAS and WTAS. I took these to be IAS and TAS values from within the game parameters but they don't make sense. If anyone can shed any light, fine, but I didn't use these and I calculated the TAS, see below. I left them in the file in case anyone knows them.


G_z is from Z_Overload and is in fact what we would call G value plus 1, so instead I took G values from: parameter part.ParameterTypes.Z_Overload, n
where n is for fore and aft or left and right or up and down. In the output file these are titled Acc_for_aft, Acc_lft_rgt, Acc_up_down (the G value used to measure G-cutout). For those that want to know....
Acc_for_aft = cur_Plane.getParameter(part.ParameterTypes.Z_Overl oad, 0);
Acc_lft_rgt = cur_Plane.getParameter(part.ParameterTypes.Z_Overl oad, 1);
Acc_up_down = cur_Plane.getParameter(part.ParameterTypes.Z_Overl oad, 2);
All most of you need to know is that Acc_up_down is the vertical G value I used to measure G-cutout in another similar test setup.

Ht_m and Ht_ft are calculated from the parameter pos.z and taken as the True altitude. This is the target value when you want to set the Altimeter accurately.

TrueROCms and TrueROCfpm was my attempt to cross check the ROC gauge reading by calculating movement from positional shift but that didn't work out. I was too lazy to remove it. Ignore these.

I think everything else is self-explanatory.

So Finally, how did I create the chart? Well my flying wasn't too sharp as I couldn't easily trim the Spitfire (IMHO its an unrealistic b*tch to be frank) so I had to filter out that mass of data to where the height was the required height +/- 50 feet and the tightest range of Rate of Climb, on one set as high as about +/- 30 fpm (I have left the filter set up for the sea level figures at 0 - 50 feet). Then I looked for a decent set of consecutive records that indicated reasonably consistent flying and took one of those records as data for the chart. These were in any case good within a couple of mph. You'll see I have copied those to the bottom of the spreadsheet. I also added calculations for True Airspeed based on formulae in my earlier post and highlighted in green at the top of the Excel sheet (along with some other junk). For this I had to assume the cockpit indicator IAS value was correct (I scripted it out as IAS). This is because I couldn't find a TAS parameter inside the game.

[IvanK]

Thankyou.

[5./JG27.Farber]

Originally Posted by Ernst

I would like the tracks not because i do not believe But because i would like to learn... Its possible to maintain 460 km/h when coming out of dive but when accelerating in level flight i cannot build more than 430.

PM me you email address and I will send you the tracks.

Or you can try 09:30 pitch and 1.3 Ata, line up the slip slide with rudder (ball - move towards it) and aileron (needle), make sure you are not ascending or decending with the altimeter. You wont be able to go straight to 09:30 pitch you will have to work the pitch down to it keeping the U/pm in the 1900 to 2350 range. Practice Practice Practice!