Where can I find this transonic prop airfoil? I am interested in identifying this prop airfoil due to its uncommon high .92% efficiency (the best metal props are closer to 83-87%). I have done an exhaustive search for it. It is labeled "NACA RML 9 G 06a". I do not know where I originally got this plot and therefore have no way to know what "ref 3" is.

It does not appear to be a airfoil number and a google search doe not return any "NACA RML" however I have a library of about 2000 "NACA RM" which refers to NACA Research Memos; perhaps the additional "L" means "Letter(s)".

I can find NACA reports starting with "RM G-10" but no G-9. I have also searched for derivatives of "06a" in an airfoil number. I would appreciate any assistance in identifying this airfoil.
The label you seek is not an airfoil, it is a research memorandum produced at Langley. (RM Lxxxx) The subject airfoil is NACA 4-(5)(08)-03 and the maximum efficiency from the test as reported in the conclusion was 88% at m0.71, partway down the curve where compressibility effects become adverse.