I recently picked up an L-39 in MS Flight Sim 2020, and loved the look of the throttle in cockpit. It in fact looks a lot like the KG12 throttle handle VKB has been teasing for literally over a year now.
I decided to make my own.
Print it in the orientation shown in the screenshot, with the cylinder end with the longest mount arm down. I used 0.3mm layers to print it, so it was faster. There really is no reason to use 0.2mm layers, it gives no advantage. Print it with auto supports, and it should print perfectly. You will need to spend some time cleaning out the actual mount holes, but otherwise should be very easy to clean up.
I printed mine in PLA, though you could easily print it in PETG or ABS too.
When mounted, keep in mind that the taller side encroaches a little on the adjacent throttle lever. If there is no lever to that side, no problem. Otherwise you may need to lower that lever handle to clear it. Mine is setup with the prop control beside and below the throttle handle. Handle is 96mm wide in total, and quite comfortable to use.
UPDATE: Check out the multi-part MK2 here: https://thangs.com/Darkstar77/VKB%20NXT%20THQ%20KG12%20Throttle%20Grip%20MK2-53569
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