The F4B (USN) was initially based off of the Boeing Model 99, and the P-12 (USAAC) began as the Boeing Model 102. The Boeing Model 100 was the production civilian and export version. All were based on the same basic root design, but had numerous differences between them, especially as there were also significant differences between different production models of the P-12 and between different production models of the F4B.
The Boeing Model 100 is where my heart really lies the deepest of all. Only 7 were ever manufactured, and these were originally built for notable pilots such as Howard Hughes, Art Goebel, Tex Rankin, and Paul Mantz, as well as for a few foreign governments. The Paul Mantz example survives today, owned by Kermit Weeks, and it is very, very close to completion of a lengthy restoration to fly again, by Roy Rehm, who in addition to restoring the Model 100, has been building 7 other exact reproductions of the Model 100/P-12/F4B types - two of these, a P-12 and F4B, are also owned by Kermit Weeks, while the rest are owned by other individuals.
According to Ed Maloney (who rescued one of the last survivors many decades ago, a P-12E, for his "Planes of Fame Air Museum"), the P-12/F4B was always described by its pilots as being one of the most maneuverable airplanes ever built and a dream to fly - it was exceptionally fast for its day and extremely maneuverable. The P-12 and F4B were the first single seat fighters capable of executing all fighting maneuvers while still being fully loaded, including outside loops. It was very sturdy, stable, easy to take off and land, easy to recover from a spin, and just had wonderful handling characteristics - so much so, that both Army and Navy pilots loved to put it through its paces just for the pure enjoyment of flying.
This is my kind of heaven on earth:
https://www.youtube.com/watch?v=Oq5HhAvPP78
