by dmitrynizh » Wed Apr 21, 2010 6:34 pm
You can use 9g there just fine, but they are a bit overkill as 5g have proven to be perfectly enough for TW742's ailerons. I glued mine in, and then covered with tape: , but if you cut EPS carefully so that the servos fit snag, then tape is enough, especially if you cover the walls of each servo "bay" with fibertape (let fibers be aligned horizontally, this will reinforce the walls) and then cover each servo with fibertape as well. I use this on all my 10-20oz foam planes including zagi-like delta wings.
To cut clean servo bays, make a template and then cut many, not just two, parallel cuts with a sharp X-acto blade and then again at 90 degrees. Have a mark or a piece of tape on your blade to control the depth of each cut. After that, you will get very clean and snag bay with flat bottom. Another method is to use a hot wire cutter to carve out the bay (more advanced).
You also might consider running a few lines of fibertape alone both sides of the wing and also covering the whole wing with 2mil packing tape as I did. You can skip this, it is not at all required, but if you do, it will be much stronger with a weight increase which is less than what many expect from 2mil tape.