Our dimensions are(I believe): 3/4´´and 1´´ of the cylinders, the inside gap is 1.5 mm between outer wall of inner cylinder and inner wall of outer cylinder.
Pretty much seems like anything is working, we tried running 55 V input and got about 2 Amps of current with 50% square wave duty cycle. That means about 55 W input. I believe with more cylinders we will get much better efficiency. We have no measuring equipment for efficiency yet but we will get it, I am sure we can get OU but with coating I believe it will be much better. So many more things to do...
The rubber material is called EPDM 1722, 2 mm thickness... So we push it in between the pipes, very amateur style but works....
