The page is in Japanese, but the model is straight forward and easy to build. Scroll down the page until you see "Sopwith F.1
Camel" right below that is the link to the model, it is in Japanese but
it says PDF in the file name. This is a small model, the whole thing
fits on one sheet of paper, but it is well worth the time. You should
put some extra effort into detailing the model, put some bend in the
wings, add in the wing wires, etc. for a great model.
Here are some Reference Pages on the Sopwith Camel:
http://www.cbrnp.com/profiles/quarter1/barkers-camel.htm
http://sped2work.tripod.com/camel.html
http://www.airmuseumsuk.org/museum/IWMLondon/800/pages/193%20Sopwith%20Camel%202F1.htm
Bonus Model - Snoopy as the World War I Flying Ace
http://www.chthulhu.com/models/ace.html
There are two versions of the model, the image above is from version 1, version 2 is in yellow with an air corp logo on the dog house.