One target used by Britain to train her air gunners is a model airplane running on wires. As the plane, suspended on a roller, is drawn past the gunner, he pulls the trigger of a camera gun at the instant the model enters the field which, in actual flight, would be the effective range of his gun. This sort of target practice speeds up training in the use of the service sights with which gunners must be familiar. It is usually done in the open, but if weather is bad the target an be converted for indoor use.