Built as a private venture, the B.4 made its first flight in Sept. 1951 and was intended to be useful for both military and civil roles. The Auster company tried with this peculiar aircraft to create a light cargo variant of their rugged light aircraft family. What took apart the B.4 was its rear pod-shaped fuselage equipped with clamshell doors to ease cargo operations and that funny “quadricycle” undercarriage.
After some modification to the vertical tail surfaces the unique example built appeared at the 1953 Farnborough SBAC Show and was evaluated by the British Army. It had no takers.
Funny looking with the clamshell doors, it was hilarious without them.