Is this what you are after???
From the RAF Flight Information Handbook:
Chinook HC Mk2:
AUW/MTWA/OWE = 50044lbs - 22700kgs
Tyre Pressure in PSI = 87
Rigid pavement subgrades:
High = 11
Med = 11
Low = 12
Ultra Low = 12
Flexible Pavement subgrades:
High = 8
Med = 10
Low = 12
Ultra Low = 13
Given that they land in fields/car parks I guess you wouldn't need too much LCG.
Cheers