Spit IIA Speed in game test

[klem]

Originally Posted by ATAG_Snapper

I've also found a pronounced difference in FM for the Spitfire IIa between offline and online. The two FM's are the same at SL, but I found the IIa's online FM takes a remarkable departure from the offline FM as altitude increases.

Snapper, try adjusting the Altimeter barometric setting in both cases at the same field until it reads zero feet or as near as you can get. Is it the same baro setting in each case or are you seeing different atmospheric conditions?

In my own created server and in ATAG I find the correct setting 'on line' for Tangmere (which is about 39feet) is 995mb. Based on that I set 995 at Manston and get 140 feet in both servers. IOn off-line single mission Free Flight over England after landing Manston I have to set 996 to get 140 feet. So different types of 'day' perhaps?

[ATAG_Snapper]

Maybe that's it, Klem.

Except, the Ia's FM's agree very closely under the exact same test conditions offline vs online. The IIa's FM's do not.

[5./JG27.Farber]

Me and my wingman often have 200m's defference staring from the same field on our altimeters.

[klem]

Originally Posted by 5./JG27.Farber

Me and my wingman often have 200m's defference staring from the same field on our altimeters.

??!!

Both have same baro setting?
Reading from the tooltip or the gauge needle?
Tooltips are to nearest 100 feet in RAF planes so one a/c at 90 feet and one at 105 feet will read 0 and 100 respectively.

Or the 109s are porked and next time I will run from a 109 at 25 feet and see what happens behind me

[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.

[IvanK]

Easiest way to set accurate QNH is set the Altimeter to the field elevation. Field elevation can be found in FMB. Attached file has every airfield's elevation in the Sim all obtained from FMB.

A 1mb error should only result in 30ft/10m error.

I do believe the default maps have some diurnal variation in both Temperature and pressure. I too have seen 992mb as the setting on ATAG at some times and 995mb at other times.

[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.

[5./JG27.Farber]

Originally Posted by klem

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.

Im talking about the 109. Maybe its different.