Let's make winglets!

02/19/10

In the summer of 2004 an anonymous friend -Pete- suggested that my plane would fly better with winglets. He also offered to make some (!) I accepted his generous offer because I was quite curious about the potential performance and handling benefits, and also because I wanted to see how one would go about making winglets.

In a nutshell, the process was to start with a suitably designed winglet, make negative molds of it, and produce a customised version according to the specific needs of my wing.

The Open Jantar does not come with winglets, and they are not available, as far as I know, for retrofitting. The Nimbus II, being essentially the same platform, was the obvious place to start. So these are basically modified Nimbus II winglets. The modifications were twofold: We "laid them down" a bit since my wing flexes significantly more than the rigid Nimbus carbon wing, and we had to build up the interface since the molds we had fitted a narrower tip.

My wing has a split at the 20.4m span to accommodate either terminations or extension and we chose to use that as the installation point for the winglets.

I did not get a chance to use them very much in 2004, but in the summer of 2005 I used them extensively and I can confidently say that they do improve both handling (in the form of quicker roll response) and performance. Not to mention the fact that they look wicked cool.

I have not quantified the performance gain, but it is evident in the fact that on long final glides (between 20 & 40 miles) with equal wing-loading and without modifying the polar in the flight computer, I frequently find myself ending above glide slope when flying with the winglets versus being right on, or slightly below glide slope when flying without them.

Here are some pictures of the interesting fabrication process.