Unique wing-folding mechanism, developed by Leroy Grumman, permitted compact storage on carriers. Hellcat rugged, reasonably fast, easily maintained, and stable gunnery platform. Established air supremacy in the Pacific and was most important shipboard fighter of WWII. Its appearance summer 43 changed disastrous situation virtually overnight when it became first carrier-based fighter to threaten the Zero. Highlight of its operational career was probably Battle of the Phillipine Sea ("Marianas Turkey Shoot") 19-20 Jun 44 when Hellcats completely smashed Japanese attack on first day of battle, accounting for bulk of 346 aircraft destroyed. Overall kill ratio was highest of all Navy fighters, 19:1; 4,947 (of a total of 6,477) Japanese combat aircraft were destroyed by carrier-based F6Fs (An additional 208 kills scored by shore-based F6Fs). Top-scoring Navy ace, CDR David S. McCampbell, scored all his 34 victories in his F6F after late-May 44.