After many years of procrastinating I'm finally building a Phase 5. Designed in 1978 this model is often considered to be Chris Foss's (CF) best slope model. It was never available as a kit so the only way to get one is to build it yourself. CF is still selling the plans if you fancy one.
The Phase 5 plan calls for a built up wing but I'm deviating from the plan and making one from foam with a balsa skin. A snow day today meant I could make a start. CF does not specify what sections are used for the root or the tip so a bit of guesswork and internet trawling resulted in the semi-symmetrical E374 for the root, modified a little to make it thinner. The tip is fully symmetrical and is between NACA 0010 and 0011. It's actually 10.67% thick so maybe it's NACA 0010.67?