During the manufacture of components of the kit and the construction process by the builder, a lot of drill shavings, rivit heads, etc. wind up being deposited inside tubes of the aircraft. Many of these tubes such as the lift struts, the root tube and others are open at the lower or rear ends of the tubes. Even with diligent efforts by the builder to remove this debris, much will remain in these tubes and when you begin engine break-in and flying, it will eventually work its way down and out of the tubes and through your prop.
There is a very easy method to capture this debris and to prevent it from going through your prop. After the final aircraft assembly and before you begin running the engine, use duct tape or good masking tape and tape over all these tubing ends to cap them up. After 3-4 hours of flying, remove the tape and you will be amazed at how much debris was left and is now stuck on the tape, even if you cleaned the tubes. You can now throw away the tape and leave the tubes open.
In some of the various tubes of the aircraft, due to the way they are constructed and assembled, there is no easy way out of the tube for some small amounts of debris. This is just a situation that you will have to live with. Some of this debris does eventually work it's way out and most of this winds up in the bottom of your aircraft and often gets lodged between the structure and the fabric. You will need to watch for this for a very long time and remove any debris you find. An occasional close inspection to the exterior of the fabric where it joins the structure will often pinpoint this debris as a small bump under the fabric. If possible, you should remove this debris as it can easily work on through the fabric leaving a small torn hole.
Author: George Hurt