German bombing of English cities started in 1915 and immediately posed a problem, since air-to-air combat was in its infancy. There was an outcry to Do Something, but what could be done?
"Then we saw the Zeppelin above us, just ahead, amid a gleaming of clouds: high up, like a bright golden finger, quite small (...) Then there was flashes near the ground – and the shaking noise. It was like Milton — then there was war in heaven. (...) I cannot get over it, that the moon is not Queen of the sky by night, and the stars the lesser lights. It seems the Zeppelin is in the zenith of the night, golden like a moon, having taken control of the sky; and the bursting shells are the lesser lights." -D.H. Lawrence
"Hey, go get shot by a Maxim gun because there's not much we can do about the bombs" isn't much of a morale boost, but in those early days it was extremely difficult to down a zeppelin.
The German airships operated at 9,000 feet or more, and the most common British biplane in the home islands, the B.E.2a, took nearly an hour to get to that altitude. Once there, it had barely a 10mph advantage over the zeppelins, making for impossible stern chases unless it had been vectored right into the path of its target.
Further, the zeppelin was protected by defensive gun positions in its gondolas.
One solution suggested was for a plane that would patrol at altitude, like a destroyer picket looking for intruding enemy ships.
Meet the Supermarine Nighthawk...
No faster than the B.E.2a, and taking an equally interminable time to climb to altitude, it was supposed to (at least according to the design brief) have the endurance to orbit up there for nine hours or more.
In the nose was a steerable searchlight, powered by a separate gasoline genset, maybe the first airborne auxiliary power unit. Above the top wing was a gunner with a 37mm recoilless gun with which to engage targets.
It failed to live up to performance expectations and the engines were terrifically unreliable and, by the time it finally flew in 1917, there were conventional fighters like the SE.5a which had the speed and altitude to intercept zeppelins conventionally. Besides, the slow and obsolescent B.E.2's had already been successfully shooting down the dirigibles by using an upward-firing Lewis gun loaded with incendiary ammo.
It sure did look steampunk, though.
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