Endo-Composite Structure is an experimental chassis technology developed by the Lyran Alliance in 3067 By mixing and matching standard and Endo-Steel components, Lyran engineers created a BattleMech skeleton that weighed 75% of a standard chassis but was only half as bulky as a traditional Endo-Steel system. This provides the 'Mech with more tonnage and frees enough room to keep a good weapons load. More importantly unlike the Composite Internal Structure developed by the Federated Suns, the Endo-Composite structure resists damage as effectively as a standard chassis.
Though developed by the Lyrans, the Word of Blake did have access to the technology when they took over Hesperus II and Coventry. The Lyrans were able to get the technology to Clan Wolf-in-Exile however, and they created their first Endo-Composite skeleton in 3073.
An Endo-Composite structure can only be mounted in BattleMechs. It weighs 75% of a standard chassis, rounded up to the nearest half ton. Though less bulky than a traditional Endo-Steel structure it still takes up critical spaces. An Inner Sphere Endo-Composite structure occupies 7 critical slots, while the Clan equivalent occupies 4 slots. These slots are allocated like standard Endo-Steel critical slots and treated identically.
To find the cost of an Endo Composite Structure, multiply the total tonnage of the skeleton by 3,200. The resulting number is the cost of the skeleton in C-Bills.
- Tactical Operations, p. 342, "Endo-Composite Structure"
- Tactical Operations, p. 411, "Heavy Weapons And Equipment Construction Data"