toh! un motore che non conoscevo ...

[rednose]

... Si è giusto come uno di noi diceva prima, anche a me sembra capire che non ci sono valvole solo luci come nel 2t

La parte rognosa mi sembra come detto da qlk prima la tenuta della testa - che io comprendo essere fissa con sotto i cilindri a revolver. Nello FAQ dice

The Duke sliding seal arrangement is analogous in function to a ported 2-stroke or Wankel engine port sealing, allowing similar technologies to be applied.* The Duke uses sliding metallic seals operating on an oil film. Materials used are those found in production road vehicles.* The V3i engine has seals which are of a simple design and operate at modest contact stress and sliding velocities. Oil film calculations conducted support good nominal lubricating film thickness.
All V3i gasoline and Jet A1 testing to date (March 2012) has been completed with a single set of prototype seals which remain in good condition.* These seals will be reassembled into an engine for further testing without modification or repair.

Duke challenges in seal development are much less than in a 2-stroke or in the Wankel engine due to lower sliding velocity and a flat monoplane sealing surface (Wankel has 3 seal faces, 1 curved, that meet at a corner, seals). *So far, our sliding seal challenges are proving to be modest in reality

Non mi va di tradurre ma tanto sappiamo tutti l'inglese giusto? :-) :-) :-) :-)