Improved tail motor mount.

The base is now 3mm thick, the horn is also thicker - stronger, and the nut hole has been enlarged to accept an easier to find 4-40 nut. This doesn't leave a lot of 'meat' around the nut, so I put very-VERY small dabs of gel CA on each side, before pressing the nut into place. This will add strength, and also make the nut a part of the piece, so if cracking does occur, it shouldn't just fall apart. Enjoy!