Hi Paul,...

I did a review of the Aresti a while back for one of the magazines, and one of the things that I modified on my review piece was the motor mount.

The aluminum one they provide with the plane will work and is adequate, however I felt that being solid aluminum was a bit heavy. I chose to use a Dave Brown fiberglass filled mount for the Saito 72. The first thing I did was to pop their preinstalled blind nuts out and fill the resulting holes with short pieces of hard dowel. If memory serves me, believe it was 3/16 dia dowel (?).

I'm sorry, before the holes are filled you need to find the center between the holes. Yes, there is right thrust built into the firewall, and the "footprint" of the motor mount is offset to the left in order to have the center of the prop fall on buttline center of the plane. In other words,... you need to find the "footprint center" of their aluminum mount so that whatever mount you choose can be offset to the left the same amount. While you are at it, may as well find the thrust line of the footprint so that your mount can be positioned correctly up and down as well.

Once all centerlines from the old mount are found and drawn on the firewall and the holes are plugged, you can install any mount you like. If I remember correctly, the mounting holes for the Dave Brown mount were nowhere near the previous holes, therefore breaking into or slipping into a pre-existing hole was never a problem.

Hope this helps.

Sincerely,
Steve T.