The all wooden RF6 was the basis for the later T67 Firefly. From Wikipedia - The RF-6 was designed by René Fournier, and first flew on 12 March 1974. An all-wooden construction, it featured a high aspect-ratio wing echoing his earlier motorglider designs. Fournier set up his own factory at Nitray to manufacture the design, but after only around 40 had been built, the exercise proved financially unviable, and he was forced to close down production. In 1981, Fournier sold the development rights of the RF-6B to Slingsby, which renamed it the T67. The earliest examples, the T67A, were virtually identical to the Fournier-built aircraft, but the design was soon revised to replace the wooden structure with one of composite material.