This is a Mid / High power rocket made from a PDF someone posted on a rocket forum:

http://www.rocketryforum.com/showthread.php?59964-Offering-up-a-Scratch-Design

There are two fincans, one for a 54mm motor, and one for a 38mm motor.

I had to add a significant amount of weight to the nosecone to get the balance right with either configuration.

Launched successfully with a Gorilla Rocket Motors H225 Black Lightning: http://www.gorillarocketmotors.com/reloads.html