ORIGINAL: doxilia
Thanks for posting that Terry. Iremembered a thread of that nature but I wasn't sure what to look for.
John, that RX crankcase looks sweet! I didn't know OS made a RE Heli engine. I'll have to look up the vintage.
I'm actually wondering how well that crankcase might convert a 61 RF and/or RFHanno... If it worked, it would make a great backup for a Hanno.
What struck me about the liners was the thinner head shim on F. Did Nelson stroke out that VF? If memory serves me, the V series were short stroke engines compared to the FSR/RSR and then the SF/RF series. My 25 VFcertainly is a short stroke but then it is a DFengine (28K rpm anyone...

)
David.
David,
OS made both RF (LS) and RF-N (short stroke=VF.61 P/L/crank) heli engines. I have examples of each.
and Johnkpap,
Aside exhaust piston won't work in a rear exhaust case.
Terry in LP
edit to change...rear exhaust 'liner' to case.