G and its real meaning

[jalbert]

Anyone care to help me out with the relationship between accelerations (lateral and vertical)and other parameters with which your average joe may be more familiar?
For example what sort of v/s would equate to a 2.0g touchdown?Or put a high speed RTO in g terms.I appreciate that the relationship is not a linear one but anything on this type of stuff would be welcome.Checkboard - you may be the man.
Thanks in advance y'all.

[EchoTango]

Acceleration is the rate of change of velocity.

Gravity gives an acceleration of 32 ft/sec/sec

An aircraft doing 150kt (no wind) on a 3 degree glideslope has a vertical velocity of 13.3 ft/second.

The formula we need is

v squared = u squared + 2as
where u is initial velocity
v is final velocity
a is acceleration
s is distance travelled between u and v

We have u=13.3, v=0

All the vertical deceleration occurs in compression of the oleos and tyres. Say a movement of 3 feet. Assume the load/deflection curve is uniform over that 3 feet, and oleos do not hit limits.

Then a = u squared / 2s = 13.3* 13.3 / (2 * 3) = 29.5 = 29.5/32g = .92 extra gs

Note the effect of the v squared

If you can at the last moment halve the vertical speed to say 6.6 ft/sec while the oleos are deflecting, you get only 0.23 extra g.