Well, British anti-zeppelin fighter, again...
In 1915, bomber zeppelins of Germany bothered all the UK, and in the company of N.P.Billing was designed a large fighter plane that was wanted to wait and ambush zeppelins in heights and attack them from above. The type P.B.29E crashed during tests and was replaced by the P.B.31E, similar but improved type (one of the designers was R.J.Mitchell, later designer of famous WW2 fighter Spitfire). The plane with five-member crew was equipped by two gunposts, headlight in front of hull and even bed , because the plane was assumed to fly even about 18 hours without landing. It was extremely slow, though (about 120 km/h) and also its rising took a long time, so it looked obvious that zeppelines could easily escape and the plane was not able to intercept them. They found out soon that all the conception of such a fighters was mistake. The only built prototype was tested in 1917 at Eastchurch navy base and in the summer of the same year was canceled.