The vane is another critical part because it is responsible for transmitting energy from the expanding gases to the rotor.
The above photo is from Radian and the vane was made from M2 Tool Steel. I chuckled when I first seen this part.
When you examine the original patent Jim had the vane tips has sharp points that made following the constant velocity
cams mathematically possible.
It is when the transitions where added Jim realized the complexity of the relationship between the cam and the vane.
By adding the transition area it meant rounding off the vane tip. All this led to a fantastic multi dimensional math
By adding the slots on the top and on the ends of the vane John's engineers are adding even more unneccesary complexity
- not to mention weight.
I can see why they did that because the trick is to have enough contact pressure to seal in the expanding gases.
I had a different solution where the contact pressure can be increased during compression and power strokes but reduced
during intake and exhaust strokes.