Wing Tip Bows

10/16/2005

The aileron build process has alot of starting and stopping, due to glue-curing waiting time in between processes. Therefore, I jumped over to have a go at the laminated bow tips. I had purchased 1/8 x 3/4 spruce from Aircraft Spruce a couple of weeks ago, so the material was here ready to go.

The jig was made as per the diagram below, which I came across at the EAA.org website in the 'members only' area. To draw the semi-circle, I simply used a thin piece of timber just over 21 inches long, cut a V at one end to locate the pencil, and a nail at the other end, set at 21 inches - basically a huge compass. For the 3/4 inch inner line, I filed a small V 3/4 inch down from the 21 inch outer line, rested a pencil in there, and drew the arc.

All 6 pieces of 1/8 x 3/4 were glued together flat on the bench, then while still wet, were place into the jig. The gap between the outer and inner blocks was not 3/4, but 7/8. This extra room gives you an easier chance in getting the 6 pieces in the jig all at the same time. I then tapped in wedges to force the tip bow to the outer blocks.

One mistake I made was to not make the base of the jig deep enough. The base really needs to go past the semi-circle line by 5 inches or so. This would have enabled me to have had another former block each side. To work-around this, you can see in the bottome picture to the left is a long piece of ply...i nailed 2 blocks underneath this ply spaced 41 7/8 apart [I know that's a touch narrower than the plans, but I figured there would be a little natural spring-back]. Then forced the bow between the blocks.