I was reading this comment about the Pendulum rocket fallacy under this answer and looked at the picture (below) as I've seen it (or similar) in science books all my life, and I realized that I don't understand how that thing works. I do understand that the engine is near the top, and at least one of the propellant tanks is at the bottom, but does that large "cage" that Goddard is holding on to stay on the ground? The equivalent of the "rocket body" is only the two vertical rods - held at their midpoints? When launched, did it just slide freely through those those U-shaped holders?
And what is the stuff at the bottom - ground level? Is it just holding the rocket from tipping?
And finally, did Goddard really not have the "Use of basic Newtonian mechanics"? Or is it really that the point of this configuration was to first demonstrate and study successful launch and engine function under acceleration in flight, and once that was off the ground, the study of in-flight stability* could be done with next generation designs?
above: Cropped details of a photo of Goddard and Rocket originally from NASA and described as "Dr. Robert H. Goddard and a liquid oxygen-gasoline rocket at Auburn, Massachusetts. 8 March 1926 (according to National Air and Space Museum)"