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View Full Version : Determination of need to correct IAS or not before TAS.



M_Gunz
07-19-2007, 04:58 AM
We still don't know from Oleg how realistic the IAS pitots are modeled.
I'm not like to blow it off simply because of how realistic The Ball is modeled which by Oleg
to me in earlier email goes down to details of the ball size and material, the tube and the
fluid used --by country and manufacturer-- differs per plane. Hard to believe that the slip
ball is modeled to such detail rather than simply moving by slip data and yet IAS is by data
alone.

Oleg may reply to question sent and may not. If he does then maybe this "issue" becomes decided
without any "this therefore that" form of rhetoric-reasoning. I hate making declarations based
on guesswork and wish-fitting.

Viper has written about comparing between planes but I am thinking that determining from game
may only require one and would like to know if this following may be a good way:

I read that as speed increases over about 210mph that even modern planes start needing IAS
correction from compression. By modern I don't mean something with super-instruments but
rather what many GA planes made in the last 40 or so years have which is not far cry from
pitot and guage in WWII military AC.

So possibly to run the same long straight sea level course at largely different speeds and
check time? Something passing over two concrete airports on Crimea map? Question arises
to me if using waypoints and game autopilot that can be checked with devicelink to monitor
IAS and 'compliance to flight regimin' would suffice? Would 'the cheatin AI' fake IAS?

M_Gunz
07-19-2007, 04:58 AM
We still don't know from Oleg how realistic the IAS pitots are modeled.
I'm not like to blow it off simply because of how realistic The Ball is modeled which by Oleg
to me in earlier email goes down to details of the ball size and material, the tube and the
fluid used --by country and manufacturer-- differs per plane. Hard to believe that the slip
ball is modeled to such detail rather than simply moving by slip data and yet IAS is by data
alone.

Oleg may reply to question sent and may not. If he does then maybe this "issue" becomes decided
without any "this therefore that" form of rhetoric-reasoning. I hate making declarations based
on guesswork and wish-fitting.

Viper has written about comparing between planes but I am thinking that determining from game
may only require one and would like to know if this following may be a good way:

I read that as speed increases over about 210mph that even modern planes start needing IAS
correction from compression. By modern I don't mean something with super-instruments but
rather what many GA planes made in the last 40 or so years have which is not far cry from
pitot and guage in WWII military AC.

So possibly to run the same long straight sea level course at largely different speeds and
check time? Something passing over two concrete airports on Crimea map? Question arises
to me if using waypoints and game autopilot that can be checked with devicelink to monitor
IAS and 'compliance to flight regimin' would suffice? Would 'the cheatin AI' fake IAS?

BBB_Hyperion
07-19-2007, 07:16 AM
The ai will try to hold the speed given when possible . Only at the start it there is a problem but the longer the distance waypoints that factor can be hold lim ->0 . I got pretty good results for fuel usage on fw190 , p38 but that was based on fuel consumption per hour . Main problem is IAS Devicelink gauge data or corrected IAS. Does the gauge show cas or not. For lower speeds the difference is so little that it doesn't matter but for compression effects it should mach 0.6-7. Gauge delay maybe an issue as well. We all know the famous dive tests which were results of gauge delay, so indication of airspeed was too high cause airdensity changed quicker as the gauge could handle. Don't know if that is modeled ,maybe it is cause the climb indicator is delayed as well.

M_Gunz
07-19-2007, 03:00 PM
From reading at sites like this: Aerospace.org (http://aerospaceweb.org/question/instruments/q0251.shtml)

I get this idea that correction for pitot compression begins at or before 200kts.

Position of the pitot and shape of the plane have loads to do with it but in simulation a
simple table is all that is needed to get the same basic results on the guage itself.

I think that if I don't hear back soon then I will try FMB and 4 point waypath at 320kph
and then whatever speeds I can get the autopilot to fly with overheats toggled off.
If the mission calls for 800kph during the run the I guess to find out how fast is possible.

What matters to me is IAS shown between far apart points and time only. By the charts, if
there is a difference it should not be tiny.

BTW, good to see you Hyperion! Did I once give you data from dive tracks years ago?
I remember the conclusions were not so satisfying for whoever I did that due to start
conditions just for one problem and not going further.

Viper2005_
07-19-2007, 03:13 PM
You'll find this autopilot rather more useful than the standard game autopilot for test purposes:

http://www.acompletewasteofspace.com/modules.php?name=F...le=viewtopic&t=13359 (http://www.acompletewasteofspace.com/modules.php?name=Forums&file=viewtopic&t=13359)

M_Gunz
07-19-2007, 04:21 PM
Why?

EDIT:Add -- can I set it to run waypoints? I don't think so!