Quoted from sheahan2:
Installed a 12v adjustable speed fan with heatsink to the Left Flipper (number 1), nothing on the right flipper (number 2) and had Ambient temperature as a reference (number 3). After 45 minutes of play I peaked at around 170 deg F on the right flipper and just under 90 deg F on the left flipper.
I could barely hit the left ramp after 45 minutes. Heatsink fans is a huge improvement! I'm going to be making a set of these for every machine!
Flipper fade is real. Your result is a little lower than the testing done in March on the newer code for the Tibetan Breeze cooling kit, and higher than the testing done on last year's code. A player's style of play has a lot to do with how hot the coils get and how fast. A trap player will get them hotter faster.
One tip if you're DIYing it, though. I wouldn't recommend a heat sink on the actual coil body. If that coil wrapper under the heat sink gets crunchy over time and is breached, metal heat sink against metal coil windings would not be good. A fan pushing enough CFM over the coil body doesn't need a heat sink anyway. If the fan is physically on the heatsink which is on the coil, vibration over time may kill the fan - another negative for that approach. That's the kind of problem I had with the old V1 Tibetan Breeze kits before I redesigned them, although that was slightly different since the fan bracket was perpendicular to the coil, so it took more of the force.
Here's the temp graph of a stock, uncooled R&M for all three flippers over time with March 2021 code. In my experience, the threshold of perceptible fade for most people is around 140F, but if you're really dialed into it, you could tell around 130F when the shot timings change but you can still make them.
Rick and Morty Stock Flipper Temps-sml (resized).jpg