To drop bombs, first you must have them loaded in the hangar screen. Once you have the bombs on board, you can use the backspace key to cycle through your different secondary weapons. You will see the ammo counter change to reflect what you have selected. It will show the ammount of fuel in an external tank as well. Use backspace to select the ordinance or tank you want to drop, then hit "b" or your secondary trigger to release that ordinance. Be sure to backspace back to your 2nd bank of guns for Air to Air fighting when you are done.
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Lephturn - Chief Trainer
A member of The Flying Pigs
http://www.flyingpigs.com "A pig is a jolly companion, Boar, sow, barrow, or gilt --
A pig is a pal, who'll boost your morale, Though mountains may topple and tilt.
When they've blackballed, bamboozled, and burned you, When they've turned on you, Tory and Whig,
Though you may be thrown over by Tabby and Rover, You'll never go wrong with a pig, a pig,
You'll never go wrong with a pig!" -- Thomas Pynchon, "Gravity's Rainbow"