gabriel pagliarani wrote:About hydraulic fluid I have some doubts about ricin oil, that it was used mainly as lubricant mixed directly to fuel in the attempt to save piston wearing and avoiding sudden grips. This kind of oil was just used on GP 2 strokes engines of bikes before new synthetic lubricants during '70s.
I know but for example Finnish Air Force History by Keskinen and Stenman says that the hydraulics oil used in FIAT G.50 was really ricin oil. Ricin oil jams (<- note again!
) at about -15 to -20 degrees C. In hot conditions it was not a problem and G.50 was developed for hot conditions. The use of ricin oil was a great surprise to Finns and I think Italian and Finnish mechanics solved these problems eventually together. Italians were led by (Eng.)Capt. Luigi Pelli (It is a funny coincidence but his last name could be also Finnish one
gabriel pagliarani wrote:Hydraulic fluid for changing angle to the blades of propeller was hydraulical oil featuring extremely low compressibility (very similar to actual DOT brake fluids) At that time those hydraulical fluids had an high % content of water, therefore could be easily frozen at -20°C.
Ricin oil is just similar. I think in this case water was not the problem.
gabriel pagliarani wrote:Soviets had the same problem but they solved by mean of animal oil (from wales?). In Italy there was no kind of such oil. And what about Morane Saulniers? Those planes had to be filled with the same fluids of G-50 plus glycholethanol for the cooling system.
MS didn't suffer from any freezing problems in Finland so the they didn't have same fluids. Or maybe the French had more experince in operating in extreme coldness?