Original:  Martlet 3E The Martlet 3E was a suborbital solid rocket designed to be fired from a smaller, 7-inch (180mm) cannon used in the HARP project.
Revised:  Martlet 3E The Martlet 3E was a solid suborbital rocket designed to be fired from a smaller, 7-inch (180mm) cannon used in the HARP project.
Edit intent: clarity