At that precise moment--and this was the first warning he had that there were Huns about--he heard a ferocious rattle of machine-gun fire, and got a glimpse of streaking flame and smoke from the tracer bullets whipping past him. The Huns, three of them and all fast fighting scouts, had seen him coming, had probably watched him drop back out of place in the Flight, had kept carefully between him and the sun so that his glances round and back had failed to spot them in the glare, and had then dived headlong on him, firing as they came. They were coming down on him from astern and on his right side, or, as the Navals would put it, on his starboard quarter, and they were perhaps a hundred to a hundred and fifty yards off when Ricky first looked round and saw them. His first and most natural impulse was to get clear of the bullets that were spitting round and over him, and in two swift motions he had opened his engine full out and thrust his nose a little down and was off full pelt. Promptly the three astern swung a little, opened out as they wheeled, dropped their noses, and came after Ricky, still a little above him, and so fairly astern that only the centre one could keep a sustained accurate fire on him. (A scout's gun being fixed and shooting between the blades of the propeller--gun and engine being synchronised so as to allow the bullet to pass out as the blade is clear of the muzzle--means that the machine itself must be aimed at the target for the bullets to hit, and the two outer machines of the three could only so aim their machines by pointing their noses to converge on the centre one--a risky manœuvre with machines travelling at somewhere about a hundred miles an hour.) But the fire of that centre one was too horribly close for endurance, and Ricky knew that although his being end-on made him the smaller target, it also made his machine the more vulnerable to a raking shot which, piercing him fore and aft, could not well fail to hit petrol tank, or engine, or some other vital spot. He could do nothing in the way of shooting back, because, being a single-seater scout himself, his two guns were trained one to shoot straight forward through the propeller, the other, mounted on the top plane on a curved mount which allowed the gun to be grasped by the handle above his head and pulled back and down, to shoot from direct ahead to straight up. Neither could shoot backward.