As certified by ATC # 311 on April 7, 1930, the RNF was a typical example of three seat open biplanes that dominated the market at the time. It looked like what it was, a scaled down version of the Waco Ten series. Although in reality it was only about 5.5% smaller and 6.5% lighter than the Ten, the RNF with a 110 horse power Warner Scarab engine managed to out perform the earlier plane by a margin of at least 10% in every aspect while at the same time delivering reduced operating costs and with a significant improvement in reliability. The plane was an instant hit and its popularity only increased when a later certificate revision allowed the installation of the upgraded 125 horse power Scarab.
Within days, in an attempt to produce an even more economical variation, the company certified the Waco KNF, same airframe with a 100 horse power Kinner K-5, and before the summer was over the INF, powered by the 125 horse power Kinner B-5, joined the team.