In fact, back then this meant very little to me, but this is the very first "proof of concept" test to determine that a bi-state valve with modulating dutycycle could actually be used to proportionally control a fluid flow, and here the effect is allready "somewhat visible": It can be seen that as soon as the solenoid goes silent in the full open position, immediately the flow smoothes out and the liquid surface in the cup calms down.


In hindsight, I am pretty convinced that had I done this test outdoors in moderate windy conditions, the 100% open valve would still allow me to aim the stream from some height into the bucket, but the modulating valve combined with the wind would have made a big mess with droplets all over the place

As said, back then it meant little to me, and althoug I absolutely DID observe the nozzle pattern change in the running Veoc's intake, since it was glow, and I was not even busy with gasoline conversions back then, I never made the connection to "better evaporation".
In fact, the solenoid was put aside about 2 years before the first fixed wing gasser conversion, and it took me another two years of messing about with modifying carburettors, before I remembered I still had that Stihl thingy somewhere.
It was only then, and not even immediately but after several weeks of running the solenoid in an actual plane, that I started noticing those differences and had to figure out a way to explain them. Initially, I was fairly baffled to be honest, because I would never have guessed that stock spraybars would be so bad at atomising and evaporating fuel. After all, the average glow engine has an intake-air velocity of somewhere in the order of magnitude of 60 to 100 mph (displacement x RPM / throat cross section).

Very fascinating stuff, this...