Yes, the start drive will disengage once the engine started.

Yes a very miniscule amount of clutch bearing negative friction needed to be overcome by the engine. Something like 0.02% losses.

When you shutdown, the engine compression load will reverse drive the system whenever the prop reaches close to TDC- it shows the fluidity of the system.

As of today, many local fliers who came to see the system operating, can't seems to close their mouth while awing.

This cost listed here if i get it machined,

1. Gears x 6 total = USD133
2. Shafts = USD34
3. Shaft brass bushings x 4 = USD40
3. 6061 brackets x 2 = USD92
4. Bearings(high-ends) x 6 = USD48
5. Engine Mods = USD70
6. Special stand-offs x 4 = USD40
7. Motor + ESC = USD80
8. RCEXL ign switch = USD20

The sleepless nights thinking, calculating and producing engineering and 3D drawings are not included in that list...

Looking at it, gee... USD557 almost the cost of the engine itself! But please remember this is a single production, imagine if it is mass produced...