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General Forums => Aircraft and Vehicles => Topic started by: Batz on May 21, 2004, 09:29:06 PM

Title: Converting MP into ata and lbs
Post by: Batz on May 21, 2004, 09:29:06 PM

I need a math lesson :)

How is it done?

Title: Converting MP into ata and lbs
Post by: Pei on May 21, 2004, 09:43:33 PM

http://www.hitechcreations.com/forums/showthread.php?s=&threadid=66658

1.0 ata  =  1 Atmosphere = 14.7 inches/Hg = 0lbs boost IIRC

Title: Converting MP into ata and lbs
Post by: BPNZ on May 21, 2004, 10:12:49 PM

Hi Guys,

Ah, not quite.

1 ata = 1kg/cm^2 = 14.2 lbs/in^2 = 28.96 inHg
An ata is NOT 1 atmosphere :aok

There is a program 500k that is brilliant for conversions like speed pressure, nearly everything:

convert.exe (http://www.joshmadison.com/software/convert/)

This should make things easier.

It confused me for a while too :D

Brian

Title: Converting MP into ata and lbs
Post by: Batz on May 21, 2004, 11:02:54 PM

Thanks!!!

Title: Converting MP into ata and lbs
Post by: HoHun on May 22, 2004, 01:57:19 PM

Hi Batz,

All conversions should be done via the international system.

The international unit of pressure is 1 Pa = 1 N / m^2.

1 ata = 98.0665 kPa
1 psi = 6.89476 kPa
1 mm Hg = 133.322 Pa
1 in Hg = 3.3863788 kPa

Since psi are often provided as pressure relative to the standard atmosphere, for a correct conversion you need to add/subtract the standard sea level atmospheric pressure:

P = 101.325 kPa

(Note the difference to the technical atmosphere ata is based on.)

Regards,

Henning (HoHun)

Title: Converting MP into ata and lbs
Post by: Pyro on May 22, 2004, 03:42:00 PM

Quote

Originally posted by BPNZ
1 ata = 1kg/cm^2 = 14.2 lbs/in^2 = 28.96 inHg
An ata is NOT 1 atmosphere :aok

That's embarrassing.  I always assumed 1 ata was 1 atmosphere.

Here's an online script for converting various pressure units.  Unfortunately, it does not have an entry for ata.

http://www.masterplumbers.com/utilities/converter/pressure.asp

Title: Converting MP into ata and lbs
Post by: flakbait on May 23, 2004, 07:21:31 AM

Boy are you off BPNZ. One ATA is one atmosphere (29.92" Hg or 760mm Hg) and it can be readily converted into PSI, InHG or anything else you want without any math what-so-ever.

http://www.pawprint.net/vv/

Converts anything to anything or from anything (confused yet?). Volume, pressure, mass flow, strength, temperature, flow molar, area, charge, absorbed dose, current, data, data transfer, image resolution, currency, telecom, and a mess of other stuff! Best part: it's free.



-----------------------
Flakbait [Delta6]
Delta Six's Flight School (http://www.wa-net.com/~delta6)
Put the P-61B in Aces High
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Title: Converting MP into ata and lbs
Post by: butch2k on May 23, 2004, 07:55:55 AM

ata as defined by German sources is not equivalent to one atm !
It's indeed equivalent to 28.96 inHg as BPNZ underlined earlier in this thread.

Title: Converting MP into ata and lbs
Post by: GScholz on May 23, 2004, 08:08:05 AM

Actually you're both wrong ... but only by a few decimal points.


1 ATA = 1.033 Kg/cm2

1 bar = 1.0193 Kg/cm2

Title: Converting MP into ata and lbs
Post by: HoHun on May 23, 2004, 02:03:12 PM

Hi Scholz,

>1 ATA = 1.033 Kg/cm2
>1 bar = 1.0193 Kg/cm2

Both wrong :-)

1 ata = 1 kp/cm^2 - note: 1 kilopond (obsolete) = 1 kg force (even more obsolete), assuming standard gravity

1 bar = 100 kPa = ca. 1.0197 kp/cm^2

(You should always refer to the original SI definitions for accurate conversions.)

Regards,

Henning (HoHun)

Title: Converting MP into ata and lbs
Post by: HoHun on May 23, 2004, 02:06:16 PM

Hi Flakbait,

>One ATA is one atmosphere (29.92" Hg or 760mm Hg) and it can be readily converted into PSI, InHG or anything else you want without any math what-so-ever.

Actually, ata and atü are based on the "technical" atmosphere of 1 kp/cm^2, while atm refers to the "physical" atmosphere of the international standard pressure P = 101.325 kPa.

Math is still required :-)

Regards,

Henning (HoHun)

Title: Converting MP into ata and lbs
Post by: B17Skull12 on May 23, 2004, 03:43:58 PM

<---confused:confused:

This high school physics?
or college pyhsics?

Title: Converting MP into ata and lbs
Post by: gwshaw on May 23, 2004, 09:43:40 PM

PSI > Hg

(PSI * 2.04) + 29.92

(+25 PSI * 2.04) + 29.92 = 80.92 in Hg

As already mentioned, the Germans didn't use quite the same standard atmosphere as the US & GB.

You can just multiply ATA * 28.96 to convert ATA to in Hg, or divide in Hg by 28.96 to convert to ATA.

80.92 / 28.96 = 2.79 ATA

It is probably possible to go straight between PSI & ATA, but I just use in Hg as an intermediary.

Greg Shaw

Title: Converting MP into ata and lbs
Post by: flakbait on May 23, 2004, 11:12:24 PM

Quote

Originally posted by HoHun
Hi Flakbait,

>One ATA is one atmosphere (29.92" Hg or 760mm Hg) and it can be readily converted into PSI, InHG or anything else you want without any math what-so-ever.

Actually, ata and atü are based on the "technical" atmosphere of 1 kp/cm^2, while atm refers to the "physical" atmosphere of the international standard pressure P = 101.325 kPa.

Math is still required :-)

Regards,

Henning (HoHun)

If you use the program I posted it ain't! :D That program converts everything for you; guaranteed migraine prevention! It does include the ATA conversion factor (listed as kg/cm^2 or 28.959 inHg) in case anyone is wondering.



-----------------------
Flakbait [Delta6]
Delta Six's Flight School (http://www.wa-net.com/~delta6)
Put the P-61B in Aces High
(http://www.wa-net.com/~delta6/sig/life_modem.gif)

Title: Converting MP into ata and lbs
Post by: HoHun on May 24, 2004, 12:24:05 AM

Hi Flakbait,

>If you use the program I posted it ain't! :D

Then don't use it. It gives wrong results.

Regards,

Henning (HoHun)

Title: Converting MP into ata and lbs
Post by: LLv34_Camouflage on May 24, 2004, 05:03:06 AM

Quote

Originally posted by B17Skull12
<---confused:confused:

This high school physics?
or college pyhsics?

Unit conversions are generally taught on the first physics course. IIRC, for me that was on 8th or 9th grade, junior high school.

Camo

Title: Converting MP into ata and lbs
Post by: capt. apathy on May 24, 2004, 05:11:23 AM

Quote

Originally posted by B17Skull12
<---confused:confused:

This high school physics?
or college pyhsics?

judging from the fact that most seem to have a different answer, I'd have to say bar-room physics.