​The cost of F-35As in the eighth production lot is $94.8 million each, the system program office announced last Friday. We reported that this makes the cost comparable to that of some fourth generation fighters. Several readers have noted, however, that the cost quoted does not include the F135 engine. Pratt & Whitney, maker of the F135, declines to state the unit cost of its engines, for competitive reasons. The contract awarded to Pratt & Whitney in October for F135 engines was $1.052 billion for 48 of the motors, which would yield a unit cost of about $22 million each; however, a P&W spokesman noted that the contract also included other things, such as engineering work and spares. At the gross figure, however, an F-35A with engine would cost about $116 million. That tracks with the Lot 7 price, provided by the F-35 SPO, of about $112 million for an F-35, engine included. In 2008, Boeing received a $2.3 billion contract from the Republic of Korea for 21 F-15K fighters. That contract, too, included things other than simply the aircraft. However, at the gross value, the unit cost works out to $109 million, or $120 million in inflation-adjusted dollars. The F-35 SPO is aiming for a base-year 2010 unit cost of F-35As in the $80-$85 million range, which would make the F-35 comparable not only to F-15s but to less expensive aircraft such as the F-16.