View Full Version : Speed trials disappoint

06-15-2005, 10:47 AM
I can't help but notice one thing. I tried a couple of planes to see how fast they can go, using the figures in the "view objects" menu as a giude.

Now, the Bf-109K-4 is listed as capable of 710km/h at 6000m, yet I pushed it in the sim almost to the point of engine damage and didn't even get 500km/h out of it. Same story with the Mustang.

This is very strange.

06-15-2005, 10:54 AM
You did account for the display showing Inidcated Airspeed and convert it to the True Airspeed didn't you?

Or, you could turn the cockpit off and see the TAS in that view...

06-15-2005, 10:55 AM
I`m not a test freak like some here, but usually this because you`re not flying in correct test conditions or you`ve mixed up the readings, probably TAS to IAS. The sim wouldn`t say one thing but make something else happen.

I`m sure others will point you right.

06-15-2005, 10:58 AM
I took the readings off the speed bar. And the discrepency betwen TAS and IAS would not be 200km/h !!!!!!

also, what are "correct test conditions"?

06-15-2005, 11:10 AM
Originally posted by Vlad381:
I took the readings off the speed bar. And the discrepency betwen TAS and IAS would not be 200km/h !!!!!! Yes.

If you're using TAS figures, make sure you have your TAS.

also, what are "correct test conditions"? Noon, Crimea, perfect weather.

06-15-2005, 11:18 AM
Originally posted by Vlad381:
I took the readings off the speed bar. And the discrepency betwen TAS and IAS would not be 200km/h !!!!!!

also, what are "correct test conditions"?

Yes it would... On the altitudes above 5000-6000 meters (where max speesd are usually reached). Take a look at ClnlSandersLite's IAS/TAS conversion chart here:


I'm not a dedicated tester, but I know that the game models influence of many atmospheric conditions on planes performance, and one of the maps was chosen as a "benchmark map" for all tests. It's the Crimea one, but I don't know what "benchmark" time and weather settings are.

Cheers - Art

P.S. - when You allow no-cockpit view, the Ctrl-F1 colour speedbar shows the TAS, the red speedbar in cockpit shows IAS only.

06-15-2005, 11:23 AM
The difference of IAS and TAS is actually somewhere in that range. At 20'000 feet (~6000m), 500 IAS is 700 TAS.

06-15-2005, 11:37 AM
Right - have to use the cockpit off configuration - even at low alt there is quite a difference.
I was testing the corsair awhile ago and thought it was slow on the deck - but with pit off the readings were spot on

06-15-2005, 12:20 PM
[QUOTE]Originally posted by Vlad381:
I took the readings off the speed bar. And the discrepency betwen TAS and IAS would not be 200km/h !!!!!!


It`s funny when people act like you get real upset and indignant because something in their view cannot possibly be. You just end up showing how little you actually know.

I`ve seen this before. You really should make sure you know what you`re talking about before you start using multiple exclamations.

06-15-2005, 12:22 PM
Test conditions must:

1. clean configuration..
2. 25% fuel
3. empty ammo
4. Crimea map
5. trimmed f0r level flight
6. cockpit off
7. make sure you have the right supercharger, boost settings

I think youll find Oleg does a pretty good job on top speeds.. I tested the mustang and it ok...The one plane that was really low was the 3.04 P38L was 20-30 khp off.

06-15-2005, 12:31 PM
True that...if you think something is way out of wak...then suspect your test methods or interpretations. Face it fresh out of the factory aircraft are capable of reach POH performance numbers but once out in the field those performance levels quickly vanish as wear and tear on skin and powerplant.

I fly what they give me there is no other show in town. We have been flying this series now for how many years you end up just flying the airplanes the best way you can warts and all. Aaaah but what fun it is!


06-15-2005, 12:47 PM
all right all right, thanks guys for correcting me. I have realised my error and will try again. I know now how much of a fool I lloked making that statement http://forums.ubi.com/images/smilies/35.gif


PS one thing stands, byt IAS the Bf109 K is faster than the P-51, just http://forums.ubi.com/images/smilies/25.gif

06-15-2005, 01:56 PM
hey there.

Just did some tests with the cockpit off so I can see the TAS. Whoo. All going as it should.

Now I also understand why I can never level-bomb anything accurately. http://forums.ubi.com/images/smilies/1072.gif

One last question, is there any quick way you can work out TAS in "full switch" mode?

06-15-2005, 02:02 PM
Memorizing the chart.

06-15-2005, 02:39 PM
Originally posted by Vlad381:
I took the readings off the speed bar. And the discrepency betwen TAS and IAS would not be 200km/h !!!!!!


Dont worry mate you're not the only one who has ever confused IAS and TAS.

06-15-2005, 03:42 PM
Yes, flight simming can bee a learning experience. http://forums.ubi.com/images/smilies/25.gif

Skoshi Tiger
06-15-2005, 10:21 PM
You have to rember that the indicated airspeed is actually measuring the presure of the air that is being forced into the pitot tube compared to the static air at that altitude.

It uses a modified type of barometer to measure the pressure. The airspeed indicator is calibrated to a standard sea level air density.

Air density is determined by the pressure and temperature of the air (I'm not sure what standards they used in WWII but now its 1013.25hPa at 15C)

Which means that TAS and IAS are only equal to each other if your flying at 0 feet, the current air presure is 1013.25 hPa and its 15C. Any variations in those variables and there will be a difference.

For each 1000 feet of altitude the temerature drops about 2C and the presure drops at about 1hPa every 30 feet or so. So the ISA and TAS is rarely the same.

06-16-2005, 03:31 AM
Now it's my turn to show my ignorance! http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

Would top speed be tested with WEP or just full throttle?

Skoshi Tiger
06-17-2005, 12:22 AM
"top Speed" would be with WEP. Being very retentive, aeronautical engineers have a lot of differnt Maximum speeds. Nowadays they are given a V code. A few of them are

Va €" design manoeuvring speed
Vb €" the design speed for maximum gust intensity ( **** the crosswind component!)
Vno €" maximum structural cruise speed
Vne €" never exceed speed (' Your wings fall off http://forums.ubi.com/groupee_common/emoticons/icon_eek.gif ')

If your interested heres a useful link on speeds is


06-17-2005, 01:04 AM

and play the bloody game http://forums.ubi.com/groupee_common/emoticons/icon_mad.gif