Algodoo

Sweet, simple, and monstrously powerful.
Gone back to Short-stroke springs, with very positive results. The revvage doesn't fluctuate at all on this one, but it takes a mule kick to start it up.
Will sit at a comfortable 361.28 rad/s.
[= 3450 rpm]

Attatched to my 10m scale gear box, but instead of having 6 gears, actually has 12.
6 low-speed, 6 high-speed.

Tap Q for anti-clockwise output,
Tap A for clockwise output,
Press Z to halt the engine.

Low-speed gear set is cluctched on G, and high-speed on F.
The engine doesn't give a hoot if absolutely everything in the gear system is engaged, but the output does; be sure to either be in G or F, not both at the same time. Same applies for each gear, which are toggled on 1 - 6.
Deselect the current gear before changing.

Output disc is either the orange or blue one; orange is only there for when I churn very high revs through the gear system.

Simulation frequency is on 230 Hz; best results ensue any scene you plonk this into is at 230 Hz aswell.
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There's a free copy of the engine itself, which you can use instead of my gearbox, if you wish.

This is the engine used in my Triaros, albeit, the ration between G and F has been decreased in that version.