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If it is the model aero engine I found a short video clip off - it isn't really a valve less design - just a rotary valve => nothing new.Or is it something different that we haven't seen yet ?
Can't really see but it looks similar to the 'Cross Rotary Valve' .https://www.bing.com/images/search?q=cross%20rotary%20valve&qs=n&form=QBIRMH&sp=-1&pq=cross%20rotary%20valve&sc=1-18&sk=&cvid=E41476CEA8704E6EA53793089C609D4AThere have been models made with this arrangement I'm pretty sure. ( Pascoe ?? )The (one of ) other design (s) is the 'Aspin Valve'A description of these are in that book I gave you Jo. 'Valve Mechanisms for High Speed Engines' Back now to sulking .. Still no proper bacon in the shop I'm not thriving. Damn sure I'm running short of some essential micro nutrients Dave
Those oring just prevent leakage to the outside, mainly leakage to the intake. The seal in question is simply a very small clearance between the rotary valve and head. In production engines this is achieved with silicon aluminum head and chromed valve of brass/bronze. The expansion rates of these material allows a small clearance over a wide range of temperatures. Rotary valves need to be quite large to compete with poppet valves in terms of power.The Aspin valve is a very specific design. The only model engine to use it was the Webra T4-.91 The other Webra T-4 (40, 60, 80) used the Cross type. HP VT series are not Aspin, but are a rotary type.