I am in the process of building a 1/20 scale waterline model of a u-boat from a scaled up Fly kit. I'm building it three sections, which fit together to form the completed model (two 4 foot sections and one 3 foot for a total completed length of 11 feet). So far i just have the stern section done but it has been failry smooth sailing thus far. I am very inexperienced at card models, in fact this is the only the third one i have ever attempted, so there has been a lot of seat of the pants learning as i go but i've managed to make it look decent and most importantly be pretty strong. I anticipate this will take a long time to finish as i just plan to work on it bit by bit but it all goes well i hope to make a full hull version of a uboat one day as well in this scale. I'm curious if anyone else has attempted such large enlargements of paper kits and if so, can you point out any pitfalls i may face?