Warm Head, Cold Heart
All units employ a flat black paint scheme with the cockpit wreathed in fire.
Per FM: Merc (revised), page 75.
Other references:
Hunchback, FM: Mercenaries Revised (plate 7)
Atlas, CM: Mercenaries (p 108)
The Hsien Hotheads’ insignia is a flaming red skull-like mask set on a black shield. Per FM:Mercenaries Revised, page 75.