The twisted Cartesian model for the double path space fibration Tornike Kadeishvili and Samson Saneblidze 55R05, 55P35, 55U05, 52B05, 05A18, 05A19 math.AT/0210224 A. Razmadze Mathematical Institute Georgian Academy of Sciences M. Aleksidze st., 1 380093 Tbilisi, Georgia kade@rmi.acnet.ge A. Razmadze Mathematical Institute Georgian Academy of Sciences M. Aleksidze st., 1 380093 Tbilisi, Georgia sane@rmi.acnet.ge The paper introduces the notion of a truncating twisting function from a cubical set to a permutahedral set and the corresponding notion of twisted Cartesian product of these sets. The latter becomes a permutocubical set that models in particular the path space fibration on a loop space. The chain complex of this twisted Cartesian product in fact is a comultiplicative twisted tensor product of cubical chains of base and permutahedral chains of fibre. This construction is formalized as a theory of twisted tensor products for Hirsch algebras.