I am going to continue this thread and use it to document my experiences with the smooth cowl on a Model IV-1200 with a ROTAX 912UL installation. I hope that others who have, or are considering, feel free to add and comment.

It is NOT a straight forward installation. I had problems with the top cowl which are documented in another thread. That solved, I am now trying to get the oil tank installed.

After installing the firewall, and re-installing the engine mount and engine, the instructions say to slip it into the box inserted in the firewall... but like Bill (mr. Bill) stated above and shows with an excellent photograph, it does NOT happen that way. Maybe with a sledge hammer, but certainly not with anything less!

My opening is actually slightly greater in height than called for, as I tried to not have to cut the tank! I am at 9 5/8" when the opening is called for to be 9 1/2". It be any taller, as the cross tubes above and below limit that height.

I removed the engine mount and engine again, attached the oil tank losely in the mounts and the engine mount, and tried to install that as a unit. No way... a failed idea. Can't get the engine mount close to the firewall... the oil tank stops it short.

So I toss it out to the forum, before I go off and try and find some firm to cut about 1/2 inch out of the oil tank and weld it back together, has anyone actually installed one in the Model IV-1200 smooth cowl WITHOUT the cutting and welding of the oil tank? If you did, HOW??!!!

I hope that this is the last serious challenge in this install! I want to go fly it!! Cheers!