Was the MKX11 the only one with the nose blister?
I am building a 1/5 spit and the plans show the cannons to be 7/8 of an inch at the leading edge. but the plans also shows to make them out of 3/4 sq balsa. That's pretty tough to do. I emailed MR Scale the answer I got GO WITH WHAT THE PLANS SHOWS. Not much help. I made them 7/8 and they seam a little big. What is the right size for 1/5 Spits? Thanks Rich

Rich, the cannons on the 1/5.3 scale Taylor design are just slightly under 7/8" at their widest point. I would say that 7/8" on your 1/5 Platt bird is in the ball park. The blister on the top of the Mk.XII cowl is unique to that variant. I'm not certain but I think the blister is related to the Coffman cartridge type starter.

Thanks Chad. I did find a MKIV with a clip wing in one of my books. I will leave the blister off for right now untill I deside which model Spit I want to chose.