What would the best style of Rocket stove to make as a 'first try'

Pretty self explanatory question, I guess! I've got my hands on an oil drum, there's a mass of firebricks ready...

What would be a good type/style to build, preferably something that could also be dismantled, since we're just going to build it in the backyard as a tester.

I did just get my hands on a nice ebook on the subject, but it'd be nice to hear suggestions from people with experience, haha.