MTK

It started with a very accurately cut, perfectly symmetrical foam core. I had purchased 4 sets of cores from the guy who cut them to my specs back around 2000. The workmanship was exceptional, the best I ever saw. Two sets were built into wings for projects, I sold one and I still had one set remaining. I flew one of the wings in my Temptress for about 10 years. I loved the way the wing flew.

I honeycombed and sheeted the last set of cores a few years ago and just held on to the wing waiting for the right project. The wing was light enough at 10 ounces per panel (honeycombed cores, light wood, carbon veil inside) and super strong. But I've been thinking about getting panels even lighter from discussions with Dean Pappas and Bob Hunt. Bob especially has been talking about built up, 700 square inch wings that weigh in at 7 ounces. He also suggested the "lost foam" technique of building the wings. I tried the technique on a stab for my Delta last year and it worked well. If Bob could build a 700 square Control Line Stunt wing at 7 ounces, why couldn't I build a 500 square panel for Pattern at 6-7 ounces?

The idea of converting the last set of cores into tooling for built up panels was hatched. I proceeded to glass one panel with 2 ounce glass, which produced a good durable surface to sand against. I then cut the 15 stations at 2 1/4" width and sanded the balsa rib relief into each panel. I used a stiff bladed, 14 tooth per inch hack saw for the cutting and more teeth would have been better; the results were good.

If one decides to build tooling in similar fashion as me, he should use heavier foam 2-3 pound stock, and not necessarily sheet the foam. Simply glassing the foam with 2-3 ounce glass is all that's needed. In addition, it won't appreciably change the wing thickness. In my case, adding the extra 1/8" of balsa thickness increased the wing thickness from 11% to 11.5 % which is in the right direction for Pattern wings (I tried very thin, 9 1/2%, wings in my Delta and don't really care for them). Of course, overly thick wings make certain maneuvers more difficult to execute so for current F3A pattern, a thickness of around 11-12% is perfect.