A “hybrid” inflator having an extended filling capacity is disclosed. This inflator is designed to deploy an inflatable curtain airbag. The inflator will have an inner chamber that is connected to an outer chamber by a bleed hole. The inner chamber has a first supply of gas and a pyrotechnic material. This first supply of gas is sufficient to inflate an inflatable curtain after ignition of the pyrotechnic material. The outer chamber has a second supply of gas. The second supply of gas bleeds out of the outer chamber through the inner chamber and into the inflatable curtain. The inflatable curtain may be initially filled by the first supply of gas in the inner chamber while the second supply of gas slowly bleeds out of the inflator into the curtain to maintain the curtain at a desired pressure sufficient to provide impact protection to the vehicle occupant.