An aspirated-type high-expansion foam generator comprising: a nozzle manifold having at least one header (224, 230) configured to receive a foam solution; at least one nozzle assembly attached to the nozzle manifold, each nozzle assembly having, a nozzle configured to discharge the foam solution, and a nozzle insert disposed within the nozzle; and a foam generator assembly disposed adjacent the nozzle manifold, the foam generator assembly including, a body portion having an inlet to receive the foam solution from the at least one nozzle assembly, a first and a second foam generating portion each having a tapered configuration, the foam generating portions comprising at least one surface (122a, 124a) with a plurality of holes for facilitating the generation of foam; wherein the first foam generating portion has a base of the first foam generating portion being connected to an outlet of the body portion such that a portion of the foam solution exiting the body portion impinges on an interior surface of the first foam generating portion, characterized in that the second foam generating portion has a base of the second foam generating portion being connected to an apex of the first foam generating portion, and wherein the second foam generating portion protrudes into an interior of the first foam generating portion, wherein a ratio of a largest inlet dimension (D1, D2, D3, D4, D5) of the foam generator assembly to a length of the foam generator assembly is 0.50 or less; and each nozzle insert includes swirl vanes (266, 276) to create a swirl pattern in a flow of the foam solution, the swirl vanes splitting a flow path of the foam solution through the respective nozzle into at least two curvilinear paths that have solid surfaces, wherein each curvilinear path includes a crossover path (261a, 261b) that transitions the respective flow path from a downstream side (266a, 276a) of a swirl vane to an upstream side (266b, 276b) of another swirl vane, the crossover path defined by a non-sharp transition member in the nozzle insert. a nozzle manifold having at least one header (224, 230) configured to receive a foam solution; at least one nozzle assembly attached to the nozzle manifold, each nozzle assembly having, a nozzle configured to discharge the foam solution, and a nozzle insert disposed within the nozzle; and a nozzle configured to discharge the foam solution, and a nozzle insert disposed within the nozzle; and a foam generator assembly disposed adjacent the nozzle manifold, the foam generator assembly including, a body portion having an inlet to receive the foam solution from the at least one nozzle assembly, a first and a second foam generating portion each having a tapered configuration, the foam generating portions comprising at least one surface (122a, 124a) with a plurality of holes for facilitating the generation of foam; wherein a body portion having an inlet to receive the foam solution from the at least one nozzle assembly, a first and a second foam generating portion each having a tapered configuration, the foam generating portions comprising at least one surface (122a, 124a) with a plurality of holes for facilitating the generation of foam; wherein the first foam generating portion has a base of the first foam generating portion being connected to an outlet of the body portion such that a portion of the foam solution exiting the body portion impinges on an interior surface of the first foam generating portion, characterized in that the second foam generating portion has a base of the second foam generating portion being connected to an apex of the first foam generating portion, and wherein the second foam generating portion protrudes into an interior of the first foam generating portion, wherein a ratio of a largest inlet dimension (D1, D2, D3, D4, D5) of the foam generator assembly to a length of the foam generator assembly is 0.50 or less; and each nozzle insert includes swirl vanes (266, 276) to create a swirl pattern in a flow of the foam solution, the swirl vanes splitting a flow path of the foam solution through the respective nozzle into at least two curvilinear paths that have solid surfaces, wherein each curvilinear path includes a crossover path (261a, 261b) that transitions the respective flow path from a downstream side (266a, 276a) of a swirl vane to an upstream side (266b, 276b) of another swirl vane, the crossover path defined by a non-sharp transition member in the nozzle insert.