I took another break while Ron fit the cowl. The instructions include a diagram for making a template for the DA150 Exhaust Pipes. Find some stiff paper or card board for this and with the engine in place, and the muffs temporarily bolted on, line the holes up with the template over the exhaust, and securly tape one edge to the bottom of the fuselage. You do a similar process to transfer the cowl mounting screws from the mounting blocks (That are installed, drilled with T-Nuts!), to the engine cowl. The instructions give great guidance on this with good pictures. Now you can remove the muffs and mark and drill the mounting holes in the cowl, and mark the Exhaust holes.
Ron went on to assemble the Receiver tray and the Tank mount while I trimmed the cowl. Something I have always wanted to try was to create a sort of Louvre for cooling exhaust rather then a big hole. This can be risky! If I made a mistake, I would have to replace the
Cowl!!!I have worked with composites professionally for 20 years... so it is my advice to trim the cowl as indicated in the instruction manual... But this is what I did......
I used a structured tooth tungston carbide bit to cut the perimeter of where the "Louvres" should be. Then I placed a piece of 3/32 inch balsa sheet under the tab, heated it locally with a heat gun and folded the tab up while it was hot. Then quickly, I cooled it with a squirt bottle of water. Sort of a Thermo-Forming process... you usually only get one shot at this!