Hi Sean,

The 26cc engine should be perfectly fine. I have had customers put up to 31cc gas engines (Ryobi's) on them and have tons of fun. The MkII has a short nose and requires nose weight with a glow engine on it, so the extra weight from a gas engine is welcome. The only thing you will probablu have to mod is the firewall. The nose is set up for a horizontal mount for glow engines, (assuming you were going to mount radially) you would need to just lop off the segment off the nose for the horizontal motor plate (mount) and make the firewall from the plywood vertically and add some triangle stock around the inside perimeter for added surface area for your glue bonds. (this may make more sence once you get the plans and manual and see what the nose looks like.

Since I added the ailerons to the new plans as an option, most builders have incorporated them into their planes.

Greg