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jf1981 05-06-2011 09:41 AM

IAS - TAS correction
 
Hi

I'm looking forward how to have TAS out of IAS. Based on manual informations or sharts, I have for example our ot 180 mph at 10,000 ft an estimated TAS of 210 mph.

This turns out to be quite underestimated. When I travel, I record times much less than expected for a given distance.

For example, I expected a little bit more than 10 minutes travelling time between Gatwick and Holam airfields at 180 IAS 10,000 ft. It took 8 minutes.

I can't see the true figure since the full screen mode does'nt show TAS either !

Any idea about this error ?

Regards

Viper2000 05-06-2011 09:48 AM

Wind?

jf1981 05-06-2011 10:20 AM

Quote:

Originally Posted by Viper2000 (Post 279265)
Wind?

I'll do further trials to check this.

Remo 05-06-2011 11:56 AM

Quote:

Originally Posted by jf1981 (Post 279272)
I'll do further trials to check this.

Try running the same route in both directions..

The average should cancel out wind (only roughly though)

jf1981 05-06-2011 12:44 PM

It's not wind. I get roughly same flight time in both directions at level namely Milestone-Gatwick 12 mins at boost 1 lb/sqft and 10,000 ft level, 190 IAS which is about 35 miles.

I guess my initial figure was quite wrong due to error in translation of IAS to TAS during climbing.

Must be my fault. I'll have to sort this out later.

Latest figure seems quite correct, I don't think there was a lot of wind on that map given they have simulated wind in the game.

Regards

1.JaVA_Platypus 05-06-2011 06:09 PM

180mph IAS on 10.000 Feet should be 216 Mph. But indeed, if you are descending or ascending, the TAS will be diffrent. And for Dead reckoning navigation, you should use Ground Speed. So wind direction and speed should be calculated as well.

TAS increases by 2% for every 1000 Feet. This is a rule of thumb wich can be used for speeds below 400km/h 248Mph or 216Kts.

When done properly, Dead reckonging can give immense satisfaction! If only we could get the level autopilot to work in COD....

Vengeanze 05-06-2011 07:04 PM

Wasn't it so that in IL-2 you could see TAS in wonderwoman view (or whatever that view is called)??

jf1981 05-06-2011 09:29 PM

Quote:

Originally Posted by Vengeanze (Post 279585)
Wasn't it so that in IL-2 you could see TAS in wonderwoman view (or whatever that view is called)??

Used to, but when I checked, I found that i's a copy of the IAS.

Vengeanze 05-06-2011 09:40 PM

Quote:

Originally Posted by jf1981 (Post 279656)
Used to, but when I checked, I found that i's a copy of the IAS.

Easily fixed.
1. Install a copy of IL-2 and Clod each on your comp
2. Launch IL-2, grab a Yak and fly straight west max speed for the channel and voilá, you've got an IL-2 Yak in CloD.

Peril 05-07-2011 11:35 AM

So, are you all 100% sure the map is correct to scale?

Simple town and map position errors have already been corrected in latest beta so they do exist.

jf1981 05-09-2011 05:56 PM

Quote:

Originally Posted by Peril (Post 279863)
So, are you all 100% sure the map is correct to scale?

Simple town and map position errors have already been corrected in latest beta so they do exist.

It 'apparently' is or should be.

It in fact seems to be when I crossed check that, but I was not measuring so accurately however.


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