Great Scott! A ram-air triplane! I'd really love to see the deployment sequence. Or come to that, the packing procedure of one of those... Though I like the idea of parachutes on a truck. Anyone care to take this thing to Bridge Day?
Triplanes only enjoyed a short service life, near the end of the First World War. Sopwith's Triplane was only manufactured during 1917 and was soon replaced by (biplane) Sopwith Camels. Fokker only built DR1 tri-planes between id-1917 and the end of the war. Fokker triplanes were unstable ... er extremely manuverable ... but slower than contemporary biplanes. No tri-planes were manufactured - in significant numbers - after WW1.
The primary disadvantage of biplanes and triplanes is that the high pressure area - below the top wing - interferes with the low pressure area above the lower wing. This interference reduces lift and increases drag, steepening the glide ratio. The only reason early airplanes were biplanes, was that biplanes could be built much lighter than mono-planes.