 However, both the RB.106 and J67 were cancelled during the Arrow's design phase, too far into the program to select the Olympus.Orenda Engines quickly responded with the PS.13 Iroquois design.In overall design terms, the PS.13 was similar to the RB.106, using a "two-spool" layout with low-pressure and high-pressure sections of the compressor for added efficiency.