To make it even faster, connect the opposite tick of the rapid clock to the dispenser as well so you get 2x the dispensing action.
Although I think the signals are sent faster than a dispenser can fire anyways, but works great if you just use 2 dispensers (one on each output). Also works great with speeding up command blocks for pre-1.7 minecraft. 1.7+ minecraft you can just use setblock redstone_block/air clocks or falling sand/redstone block clocks. If you have access to command blocks, this is the fastest easiest clock to make.
Although I think the signals are sent faster than a dispenser can fire anyways, but works great if you just use 2 dispensers (one on each output). Also works great with speeding up command blocks for pre-1.7 minecraft. 1.7+ minecraft you can just use setblock redstone_block/air clocks or falling sand/redstone block clocks. If you have access to command blocks, this is the fastest easiest clock to make.
summon FallingSand ~ ~1 ~ {Block:minecraft:redstone_block}
With a firework summoning command block you get tons of rockets.
http://forum.feed-the-beast.com/threads/1-7-10-purgatory-mod-pack-v0-2-0-hqm-tech-quests-rf-beta-release-10-6.52413/