High Quality Content by WIKIPEDIA articles! The Grumman XTSF was a proposed twin-engine torpedo scout aircraft, designed by Grumman for the United States Navy towards the end of World War II. Based on the design of the F7F Tigercat fighter, enlarged and with the addition of a bomb bay, the XTSF was deemed too large for carrier operations, and the project was cancelled before any aircraft were built. Instead, the Navy chose to order the single-engine XTB3F, which became the successful AF Guardian.