TAS, IAS, et al...

[Guest deleted@50488]

Anyway in IL2 to display these airspeeds ?

 

I once had the idea that the HUD could commute between IAS and TAS, but I'm not sure nor have any idea how to ? Is there a keyboard shortcut for that ?

 

What about pitot error, due to simple sideslip factors, but also position errors, compressibility errors ?

 

I do not notice any significant variation in my readings when, for instance, I use a pronounced sideslip for landing.

[Finkeren]

Having the HUD being able to show TAS would be really useful and would make speed tests much less labor intensive to conduct.

 

Can’t be too difficult to do either. The sim obviously “knows” what the TAS of a given plane is and actually has to do a calculation to convert it to the IAS shown on our instruments.

[-=PHX=-SuperEtendard]

The HUD displays IAS only and cant be changed IIRC. Also the altitude in the HUD is to the ground, for actual ASL altitude you need to use the plane's indicator (calibrated to standard atmosphere).


For my speed tests I use this TAS calculator: http://indoavis.co.id/main/tas.html which is really good since it also includes temperature as a parameter. I took the temperatures at different altitudes in the Autumn maps with the Bf 110 and Pe-2 up to 9k they are these:


0 m: 15°C

1000 m: 9°C

2000 m: 1°C

3000 m: -2°C

4000 m: -10°C

5000 m: -17°C

6000 m: -22°C   

7000 m: -30°C  

8000 m: -38°C  

9000 m: -43°C 

I compared the calculator with a real report featuring both measured IAS and calculated TAS and it was almost a perfect match, at most a 3 km/h difference, which could be explained by changing the temperatures by a couple of degrees in certain cases. But I'm with the doubt of using the temperatures I measured or these "corrected" ones... because I don't know if the difference is in my own judgement of the plane instruments (not the most precise, there are markings each 10°C intervals), or if the game has some slightly off temperature numbers.

For the calculator you need to use feet as altitude, in meters it doesn't take into account the conversion, for the other parameters you can use the option you like the most. Altimeter setting would be 1013.25 hPa or 29.92 inches as we are measuring altitude above sea level. Even though it says "knots or mph" in the speed section you can use kmh as well.