Aircraft Seating and G-Forces??

[JA Yawd Bwoy]

I have heard this from fellow people as well, but is it just me (and them) or whenever you happen to sit behind the wing of an airliner/plane you experience far more G-Forces than if you sit infront of the wing or close to the cockpit? It is something that I have experimented with and I find it true all the time.

[SeanD]

I suppose if the engine is mounted to the wing you may experience a little more of a pull than push feeling if your seated behind the wings.

[tgrayson]

Originally Posted by JA Yawd Bwoy

I have heard this from fellow people as well, but is it just me (and them) or whenever you happen to sit behind the wing of an airliner/plane you experience far more G-Forces than if you sit infront of the wing or close to the cockpit? It is something that I have experimented with and I find it true all the time.

I'm hesitant to rely on superficial impressions, because you'd have to be in both places at once to fairly compare the forces. If you're sitting in the rear, how do you know what you would have felt had you been up front?

That said, if you're talking about responses to turbulence, the person in the rear may experience some rotational forces as the airplane pivots nose down in response to updrafts that would tend to magnify the g-forces. The reverse for those sitting up front. How significant? Dunno.

And there may be some aeroelasticity issues, depending on how much fuselage is behind the wing compared to in front.

[JA Yawd Bwoy]

Originally Posted by tgrayson

I'm hesitant to rely on superficial impressions, because you'd have to be in both places at once to fairly compare the forces. If you're sitting in the rear, how do you know what you would have felt had you been up front?

That said, if you're talking about responses to turbulence, the person in the rear may experience some rotational forces as the airplane pivots nose down in response to updrafts that would tend to magnify the g-forces. The reverse for those sitting up front. How significant? Dunno.

And there may be some aeroelasticity issues, depending on how much fuselage is behind the wing compared to in front.

Why would you have to be at both places at once? If you sit behind the wing one leg, and infront the other four times, I think that is plenty proof!

[SoCalAprch]

I'm pretty sure its the same or else the plane would bend. The G forces are distributed evenly throughout the vessel.

[Hacker15e]

G is just Newtonian physics in action. If the airplane is all in one piece and flying along, it has the same inertia at every location. The airplane *does* bend during flight...but it shouldn't feel any different at one part of the jet than another.

You may feel slightly less G sitting in front of the mains during rotation, or maybe slightly less if you're sitting at the tail, but we're talking about 10ths of Gs here; barely perceptible.

[BobDDuck]

Originally Posted by JA Yawd Bwoy

Why would you have to be at both places at once? If you sit behind the wing one leg, and infront the other four times, I think that is plenty proof!

How do you know that the airplane is doing the exact same thing both times. If you are looking for an answer, you need to control all the variables other then the one you are looking for. You may sit at the wing and experience X during the first flight and sit up front and experience Y during the second and conclude that sitting up front = more "Gs". What you don't know is that during the first flight the plane pitched up D degrees and the second time it pitched up D+n degrees.

That's the problem with Mythbusters.

[JA Yawd Bwoy]

So basscally yall are sayin I have issues?

[tgrayson]

Originally Posted by JA Yawd Bwoy

Why would you have to be at both places at once? If you sit behind the wing one leg, and infront the other four times, I think that is plenty proof!

Conditions are never the same. Without a g-meter, I'm skeptical of the data.

[tgrayson]

Originally Posted by JA Yawd Bwoy

So basscally yall are sayin I have issues?

Not necessarily, just that you lack objective data. And we haven't come up with a plausible mechanism that would explain your subjective impressions. Doesn't mean that you're wrong.

[Minuteman]

Well, up front you have g-money, g-dogg, and g-strings. In back you have g-funk, g-unit, g-fizzle, g-muffins, and G-Dubya. So all else being equal, you have more G's at the back.



In terms of ride quality, I would expect it mostly depends on where a seat is in relation to the center of gravity (CG). When the aircraft has a non-zero pitch rate the people farthest from the center of rotation (usually the CG) will experience the most displacement and, since the aircraft is essentially a rigid structure, the highest accelerations for the same angular velocity (pitch rate).

The CG is usually around the 1/5 to 1/3 point on the MAC of a wing. On an MD80 that puts it around row 20 out of 30 (so the people in Row 1 are farthest from the CG.) Conversely, on something like an Electra, that has a whole lot of fuselage behind the wing, I would expect the people at the back to have the wild ride.

As an aside, g loading is often a big hurdle for high-speed trains and terrain-following aircraft. As you travel faster, you have less time to change your elevation (to stay on/close-to the ground), so you have to accelerate up and down at higher magnitudes. But those are g forces that affect the entire vehicle pretty much uniformly (if some parts didn't experience the same accelerations as the rest of the vehicle, they would eventually stop being a part of that vehicle).

[Superfly7XAF]

This is an interesting question. At first I thought it was just you, but after physically thinking about it, you might be on to something. Just my opinion but it seems like when taking off the pilots (in the front) would experience a more gradual and "easy" rotation from level upwards as the nose slowly lifts off the ground, whereas at the same time the passengers in the back would rotate if anything the opposite direction of the trajectory of the plane (in other words slightly dip before being pulled back up while taking off).

So looking at thinks from a profile prospective taking off the pilots would move linearlly then gradaully rise up very smoothly, being that their at the front of the plane. However people in the back would be level then move slightly down then suddenly up. This jerk might give you slightly more Gs and the sensation you're talking about.

Just my .02

[JA Yawd Bwoy]

Originally Posted by Superfly7XAF

This is an interesting question. At first I thought it was just you, but after physically thinking about it, you might be on to something. Just my opinion but it seems like when taking off the pilots (in the front) would experience a more gradual and "easy" rotation from level upwards as the nose slowly lifts off the ground, whereas at the same time the passengers in the back would rotate if anything the opposite direction of the trajectory of the plane (in other words slightly dip before being pulled back up while taking off).

So looking at thinks from a profile prospective taking off the pilots would move linearlly then gradaully rise up very smoothly, being that their at the front of the plane. However people in the back would be level then move slightly down then suddenly up. This jerk might give you slightly more Gs and the sensation you're talking about.

Just my .02

Exactly the answer I was looking for! Thank you sooo much! I am soo sitting from the wings foward from now on!

[Superfly7XAF]

Just to add to what I said above, If you drew out a profile of the position of people in the front vs the people in the back you'd see two curves. The people in the front would have a much larger radius of rotation (if that makes sense) b/c they'd get off the ground first, if only slightly. Whereas the people in the back would travel straighter longer and then change direction in a shorter period of time giving it a shorter radius of rotation (if that makes sense). A slower change in direction would yield less G force than the faster change which takes place at the back. It would be like pushing someone up who was already jumping vs. someone who was standing still or falling. (if that makes sense)

[JA Yawd Bwoy]

Originally Posted by Superfly7XAF

Just to add to what I said above, If you drew out a profile of the position of people in the front vs the people in the back you'd see two curves. The people in the front would have a much larger radius of rotation (if that makes sense) b/c they'd get off the ground first, if only slightly. Whereas the people in the back would travel straighter longer and then change direction in a shorter period of time giving it a shorter radius of rotation (if that makes sense). A slower change in direction would yield less G force than the faster change which takes place at the back. It would be like pushing someone up who was already jumping vs. someone who was standing still or falling. (if that makes sense)

Makes sense to me! Thanks again!