Western Propeller, Troutdale (TTD).

there was a YouTuber with a Pipistrel who went through the balancing process..
was an interesting video (i had never seen the nuts and bolts of it before)..

https://www.youtube.com/watch?v=DPcDgSMhOtYhttps://www.youtube.com/watch?v=DPcDgSMhOtY

Thanks for the reference, Tacco.