The First World War was the reason of advanced science of flight and necessitated bigger planes and it then changed the aircraft from a killing and maiming hobby for the rich to a killing and maiming war machine. By the records Russky Vitaz was the first four engine aircraft developed at that time and after many more improvements Igor Sikorsky’s Ilya Murometz was the monster plane. But Ilya Murometz failed to begin as a beast of the skies; rather originally designed as a luxurious passenger liner featuring electric lighting, heat, a bathroom, and even a glass floor, the bomber must have been amusing as well as terrifying to its wealthy passengers. The K-7 was a gigantic elliptical wing of extremely thick airfoil (span 53m, area 452m2) with two triangle section tailbooms, carrying tailfin and tailplane with control mechanics. The wing had almost strait center (width 6m, length 10m, height 2.33m) where rooms for payload and people was arranged. Elliptical consoles with 14 fuel tanks were attached to the centroplane. The center was covered with duralumin, consoles with fabric. There were no such a thick tubes to comply with requirements of central spar so it was made of two parallel tubes. The rest of wings frame also was made of welded steel tubes.
There is more different huge airplanes, but there is explanations for few of them. Enjoy!

Page 1 <> Page 2