I think so. At the apex of the loop gravity balances centrifugal force, Fg = Fc, when going the minimal speed necessary to get through the loop. Fg = m g, Fc = m v^2 / r. So mass m drops out of the equation.

You just have to go fast enough. The minimum speed keeping you from falling out of a circular loop is sqrt(gr), with gravitational acceleration g and loop radius r. 10m radius requires 36km/h, which might be suitable for a Jetski. Larger ships need bigger loops to physically fit, and consequently larger speeds. It’s quite surprising, but a monstrous 100m radius loop needs less than 120km/h.

IIRC, the first model ate mosfets for breakfast because the photo resistor is way too slow going from illuminated to dark. That leaves the mosfet in a fairly high resistance state for an extended amount of time during which it dissipates a lot of power. You should add some kind of Schmitt trigger inverter that buffers the resistive divider and gives you a clean narrow edge to drive the mosfet gate. A 74HC14 together with a 7805 voltage regulator should give you enough output voltage to drive the mosfet. These chips cost less than a single replacement mosfet and you can drive 6 coils with them.

Isn’t that the same for Reddit or Lemmy? The content creators and mods don’t see a penny either. Operationally, a social network probably requires a lot more compute power and somewhat more bandwidth compared to a site that serves mostly static content. But I don’t see why small donations shouldn’t cover that. The cost per user seems moderate, otherwise few people could afford to run an instance with 1000s of users without charging them.