I put a little glass on top & bottom, both ARF & kit. Sometimes the ARF's show it, sometimes there's a belly pan that hides it. Here's why I do it.

A friend bought a stick type plane kitted in Illinois called the "Corvette." The kit was built, covered and flown by an experienced builder before he lost eyesight and sold all his stuff.

The friend proceeded to put about 150 flights on this plane, practicing pattern maneuvers & inverted flight, and learning to do rolling circles. One day he was doing rolling circles and a wing half fluttered away, leaving the plane to augur in. We found the parts and examined them on a picnic table at the field, and found no joiner. There was no spar element between the halves of the wing. The two halves had been butt-joined in the middle and 'glassed top & bottom. The wing held together all that time with nothing bracing it in the middle except that 2" strip of fiberglas, epoxied to the center.

I figure with a joiner, that plane would probably last longer than me!

Dave Olson