Aircraft Performance Data

[ACE-OF-ACES]

Originally Posted by Blackdog_kt

This is a "factory test" thread. You fly, you get the data, you post them here in the format Klem asks.

As someone who has been testing 1C FMs going on 10+ years now I have learned there are two sides to the flight model testing coin

1) the in-game data
2) the real world data

Where one without the other make it pretty useless data.

And mistakes can be made in both!

For example

How many threads have you seen where someone claims there is an error in the FM because 'they' were unable to obtain such and such at such and such altitude? Only to find out later the person making that claim didn't know the difference between IAS and TAS.

How many threads have you seen where someone claims there is an error in the FM because 'they' were unable to obtain such and such at such and such altitude? Only to find out later the person making the claim was comparing the in game plane to the wrong real world data.

With that in mind..

I think before we make any claims about anything we should make an effort to agree upon the real world data we should be comparing the in game planes to. Granted in some cases you will be hard pressed to find the real world data for the exact version of the in game plane, if any. But it just does not make any since to make a claim about how right or wrong the FM is until we can at least agree upon the real world data we are using as the baseline for comparisons

With that said..

I think this thread would be a good place to submit the real world data that matches as closely as it can the in game planes, and leave the test results per test in separate threads devoted to that plane and that test. It would be nice to agree upon a min set of data that should be collected and presented in those individual test, and this thread would/could provide examples of that.

Anyway, just my two cents

[klem]

Apologies to anyone who has downloaded the zip file in the OP. There was an error in it. Please replace with the new one now in the OP.

AoA the objective is to obtain actual performance data of the various aircraft in one place and, where historical data is thought to be appropriate, compare them in the results. Sometimes there will be differences of opinion about which specific aircraft configuration is supposed to be in CoD and it would be nice if 1C would be specific but in many cases it is clear from the aircraft title. There are very few options for historical data for, say, the Hurricane MkI with Rotol CSP running 100 octane and with BCO. The aircraft test in my reference link may not have used a factory fresh aircraft but it would have been up to spec or they wouldn't have used it and it can only be regarded as representative of that aircraft. I expect there were faster and slower ones around. In any case I'm happy to take the only historical British test authority data that has been found (as far as I know). Even without historical data we will at least know for sure what the aircraft is doing in CoD.

The purpose of this post was to draw attention to the zip error. If anyone wants a discussion can they please start a new discussion thread.

[klem]

Climb Tests added to original "Hurricane MkI 100 Octane - Beta Patch v.1.07.18956" post:
http://forum.1cpublishing.eu/showpos...16&postcount=2

Performance is again down.

[klem]

Following some discussion on Spitfire Stability I thought I'd try to measure the hands off stability. I can't be certain that it is correct but we may just have the unstable Spitfire along the lines of the A&AEE (and NACA) findings. I can't vouch that it is a true representation of the condition, I just tried to fly it and see what happened.

Attached is a zip file containing an excel spreadsheet (actually created in Open Office) which is the .csv file output from the test mission but saved in excel format so I could create the chart. A jpg of it is in the attached file and also embedded in this post for easy viewing. The mission file Stability.mis and its Stability.cs script file are also in the zip so if anyone wants to try it, drop those into your My Documents/1C Soft Club/il-2 sturmovik cliffs of dover/missions/ folder.

You will see from the 9000 records of raw data and the fact that I only charted records 4000 onwards that I had a job getting it to settle. I set record 4000 as time zero and charted against time in minutes. I followed the A&AEE method of pilot controlling until steady then releasing the controls. The only adjustment I made was very light and careful aileron adjiustment as it is impossible to fly it hands-off at the A&AEE test rpm of 2580 and full boost (not BCO). Under these conditions it gradually began to oscillate longitudinally.

I charted the RPM, Manifold Pressure (cockpit reading), Altitude and, for us perhaps the most important of all, the Pitch and Speed variations. You can see from about 4.8mins I finally had it settled down and the hands off flying began creating oscillations of pitch and associated speed changes: the descending speed increased until it brought the nose up or it decayed until it brought the nose down. The oscillations are particularly noticeable in the indicated airspeed and Pitch Angles (positive = nose down). The overall progress was a gradual climb but that may be due to my elevator trimming which is quite tricky to get stable with my rotary. Perhaps a minutely lesser trimming would have kept the average altitude generally the same.

Whether or not this truly represents what we are looking for I cannot say. It could just have been bad trimming or indeed instability but I made no elevator inputs at all. Perhaps some of you would like to give it a go.

The mission is included so you can try it yourself. Be sure to edit the file path for the output file in the file Stability.cs You will find it down around line 114, where it reads:
fstring = "E:/CoD_data/BlackBox_Data/" + strfile + "-" + cur_ac.ToString() + ".CSV";

You can see I am using my E; disc. You can edit the disc and path to suit yourself. Use Notepad, Notepad+ or Microsoft Visual C# Express. Dont edit the part from + strfile onwards.

By the way I have now included Elevator trim setting in the output file which was not in my own results. It may be of use, perhaps as a marker for when you finally got it settled. Select a series of records you believe represents the settled test period and chart them.

Edits/Additions:-

EDIT 1: The title of the chart reads 2850rpm, that should read 2580rpm
EDIT 2: Files replaced. Found reason for erratic Pitch curve - wrong data column plotted
One reason why the oscillations are not as frequent as the A&AEE/NACA tests may be that the control column was not truly 'free' as it is held by the joystick springs.
EDIT 3: zip file replaced. Control deflections now included in output file.
EDIT 4: Speed at Altitude chart added. Only a few checks were necessary to tell that it is well below par.

[IvanK]

The Oracle will arrive in this thread shortly

[Crumpp]

To tell you what?

The obvious??

Standing by to be shot down in flames...........

It is a great effort Klem and shows exactly what has been said all along. The basic longitudinal stability and control is not representative of an early mark Spitfire at normal and aft CG.

[Crumpp]

Climb Tests added to original "Hurricane MkI 100 Octane - Beta Patch v.1.07.18956" post:

Hey Klem,

The test's look good.

Try running a test wih CEM turned off. An interesting point was raised in another thread about performance without CEM being improved. Maybe you can spot what is going on when the game controls the engine and what is doing compared with manual controls.