This is a breakdown of m_bergman's excellent 100 scale M47 Patton tank. By separating the tracks, upper and lower hull, it allows you to use minimal support that is easy to remove.
The turret is split also. Lay each piece flat to print.
Monoprice Ultimate / Wanhao D6
Lay each piece flat and use support from Base.
Support % for the hull and tracks can be pretty low (15-20%). However, you may want to use a higher % for the turret top (30-35%) to make sure that it is supported properly.