TheSonntag
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How Many G's Are Usually Pulled In A Civil Flight?

Fri Oct 14, 2005 9:08 am

When a civil airplane takes off and does not have to do maneuvers like avoiding collisions or avoiding colliding with mountains, how many G's are usually pulled in a "normal" flight. I guess its not very much, of course, but still I always feel as a passenger that I sometimes get lighter or heavier...

So how much is it usually, and what are limits that are used in flights with passengers?

Michael
 
SlamClick
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RE: How Many G's Are Usually Pulled In A Civil Flight?

Fri Oct 14, 2005 9:17 am

For reference autopilots are commonly set to "quarter-G" pitch changes. That seems similar to what us corn-fed autopilots might do. So, say with no turbulence from 0.75 to 1.25G in a routine flight.

With turbulence that pilots would call moderate and passengers would call severe, maybe from 0.5 to 1.5G

That's about my guess.
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Starlionblue
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RE: How Many G's Are Usually Pulled In A Civil Flight?

Fri Oct 14, 2005 10:33 pm

SlamClick has given operational limits. Airframe limits are of course much higher.

For the 340-300:
Flight maneouvering load acceleration limits:
- clean configuration: +2.5 g to -1.0 g.
- flaps and/or slats extended: +2.0 g to 0 g.
Hard landing limits: More than +2.0 g or sink rate in excess of 10 ft/s (600 ft/min)
Source: http://www.sasflightops.com/

Obviously the plane would hold up to more, but you can see that you will never "pull Gs" as a pax.

Fighter pilots will pull 7 or 9 (in some planes) Gs as a matter of routine, but those pilots are used to it. For the untrained, 3-4 Gs is A LOT. I've experienced 5 once and I almost blacked out despite clenching and breathing properly.
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
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Jetlagged
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RE: How Many G's Are Usually Pulled In A Civil Flight?

Fri Oct 14, 2005 11:06 pm

In a turn, typical maximum bank angle is 30 degrees, which for a level co-ordinated turn is approximately 1.15 g.
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PhilSquares
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RE: How Many G's Are Usually Pulled In A Civil Flight?

Fri Oct 14, 2005 11:10 pm

During a normal flight the "G" forces are really kept to a minimum. You most like experience more during the takeoff and landing than you do in flight.

For example a 30 degree bank turn, straight and level unaccelerated flight will produce 1.2 "G's", a 45 degree turn is 1.4 and a 60 degree is 2.0. Just as a point of interest a 9 g turn will result from a 84degree turn. Note, all are straight and level, unaccelerated flight.

So, you can see, excluding turbulence, the G force shouldn't be more than 1.2 G's.
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Pyrex
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RE: How Many G's Are Usually Pulled In A Civil Flight?

Sat Oct 15, 2005 12:29 am

I once pulled 1.8 g (several times) on an A300 doing parabolic flights (Zero-G) and I can tell you it is a strange feeling on such a large plane. I thought it would be easier to move (it isn't that much compared to fighter jets or extreme rollercoasters) but it wasn't.

I don't know the operational limits of the plane but if they are anything like Starlionblue's figures we were awfully close...
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TheSonntag
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RE: How Many G's Are Usually Pulled In A Civil Flight?

Sat Oct 15, 2005 1:33 am

Ok thanks for your input... I really think 9Gs would not be good for me  Wink

Space Aircraft have 3gs for 20minutes, right?
 
Newark777
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RE: How Many G's Are Usually Pulled In A Civil Flight?

Sat Oct 15, 2005 1:42 am

Just as a comparison, those amusement park rides that spin you around and pin you against the wall, they only go up to about 2G's.

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Pyrex
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RE: How Many G's Are Usually Pulled In A Civil Flight?

Sat Oct 15, 2005 2:02 am

I thought the large roller-coasters went as high as 4-5 g (not continuous, obviously, just for brief moments). Thanks for the correction.

Quoting TheSonntag (Reply 6):
Space Aircraft have 3gs for 20minutes, right?

What do you mean by space aircraft? Space Shuttle and the like?
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SuperD
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RE: How Many G's Are Usually Pulled In A Civil Flight?

Sat Oct 15, 2005 2:40 am

Quoting Pyrex (Reply 8):
I thought the large roller-coasters went as high as 4-5 g

The highest Gs pulled on rollercoasters are somewhere between 5-6 Gs, but that's only for a nanosecond.

On a typical civilian flight, my vote is with:

Quoting SlamClick (Reply 1):
with no turbulence from 0.75 to 1.25G in a routine flight.


[Edited 2005-10-14 19:47:28]
 
TheSonntag
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RE: How Many G's Are Usually Pulled In A Civil Flight?

Sat Oct 15, 2005 5:15 am

Quoting Pyrex (Reply 8):

What do you mean by space aircraft? Space Shuttle and the like?

Yes, Space Shuttle, Saturn V, Soyus and craft like that
 
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Starlionblue
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RE: How Many G's Are Usually Pulled In A Civil Flight?

Sat Oct 15, 2005 7:31 am

Quoting Newark777 (Reply 7):
Just as a comparison, those amusement park rides that spin you around and pin you against the wall, they only go up to about 2G's.



Quoting Pyrex (Reply 8):
I thought the large roller-coasters went as high as 4-5 g (not continuous, obviously, just for brief moments). Thanks for the correction.



Quoting SuperD (Reply 9):

The highest Gs pulled on rollercoasters are somewhere between 5-6 Gs, but that's only for a nanosecond.

Exactly. About 2 sustained. About 5-6 momentaneous.
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jwenting
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RE: How Many G's Are Usually Pulled In A Civil Flight?

Sat Oct 15, 2005 3:36 pm

Space Shuttle flight profiles are designed to not go over 3G continuous (maybe during turning maneouvres they go up a bit higher for a few seconds).

Saturn rockets went a lot higher. Not sure how much, but 6+G was likely the norm rather than the exception.
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zvezda
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RE: How Many G's Are Usually Pulled In A Civil Flight?

Fri Oct 21, 2005 8:20 pm

Quoting Starlionblue (Reply 2):
For the 340-300:
Flight maneouvering load acceleration limits:
- clean configuration: +2.5 g to -1.0 g.
- flaps and/or slats extended: +2.0 g to 0 g.
Hard landing limits: More than +2.0 g or sink rate in excess of 10 ft/s (600 ft/min)
Source: http://www.sasflightops.com/

Obviously the plane would hold up to more, but you can see that you will never "pull Gs" as a pax.



Quoting PhilSquares (Reply 4):
For example a 30 degree bank turn, straight and level unaccelerated flight will produce 1.2 "G's", a 45 degree turn is 1.4 and a 60 degree is 2.0. Just as a point of interest a 9 g turn will result from a 84degree turn. Note, all are straight and level, unaccelerated flight.

I participated in the acceptance flight testing of an A319. We pulled +2.5g, -1.0g, and executed one 60 degree turn in each direction. I was in the left cockpit jumpseat at the time. I wouldn't mind doing it again.  Smile

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