Abstract: A bi-propellant rocket engine may include a primary propellant flowing in a central passageway, a secondary propellant flowing in a secondary passageway generally coaxial with central passageway and a pintle tip having a central chamber sidewall coaxial with the primary passageway and surrounding a central chamber, the central chamber sidewall having a first plurality of apertures there through so that some of the primary propellant exits the central chamber transverse to the flow of the secondary propellant in the secondary passageway. The pintle tip may have a secondary chamber sidewall, substantially thicker than the primary chamber sidewall, surrounding a secondary chamber downstream of and in fluid communication with the primary chamber, the secondary chamber sidewall having a second plurality of apertures there through so that some of the primary propellant exits the secondary chamber transverse to the flow of the secondary propellant in the secondary passageway.