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View Full Version : IVV vs landing G value


kuobin
23rd Apr 2007, 04:22
Hello gentelmans:
Is there any way or table to convert Inatant Vertical Velocity(IVV) to landing G value,
One company's ACMS provide printout function for their crew to see how is their landing but three is no G value,THey give you IVV one second before touchdown insted.
but G value is good reference if hard landing happens,ground engineer also need this to decide if any specific check has to be carry out...
Any idle about this? thanks!!:ooh:

cwatters
23rd Apr 2007, 07:50
I'm not a pro pilot but know basic physics.. You can only compute acceleration from velocity by knowing the stopping distance/displacement (or stopping time). In this case the distance is the vertical distance. If you assume the displacement is the ammount by which the UC legs are compressed during the initial contact/bounce then I guess you might be able to calculate something if you have that data. It's unlikely to be accurate though.
g=(V^2)/2s
where s is the displacement
Might be easier to use a table based on past data where you have both the speed and the resulting g to compare with. Weight will probably be a factor as well. I wouldn't fire anyone based on this calculation :-)

EDIT: This assumes that the UC leg is a spring and doesn't "bottom out". In practice they probably have shock absorbers which will complicate things no end.