To whom it may concern: For my ongoing pursuit to cross the atlantic with the Got Friends Wilga (for further information and progress update see this thread), I did some extensive testing to optimise the range of the Wilga (80P Version with the Vedeneyev M-14P engine).
It turned out, that she likes it low and slow. High altitudes above 1,000 ft decreased range, same with regimes above 80 KIAS cruising speed. But excessive leaning down to 20% Mixture turned out to be most effective:
(Ranges here are theoretical values with proposed 100% fuel use and no safety margin)
Or if you just stick to the manifold pressure: Go for around 6 mmHG at low altitudes, lean mix and around 80 knots:
You can achieve a range of over 1,000 km (with 10% fuel remaining) when leaning to 20%, maintaining 80 KIAS around 1800 RPM and staying below 1,000 ft. I don’t think that the flight model matches the real world performance in this regard (although it fits the general characteristics of the Vedeneyev M-14P according to its manual) and I am not sure, what prolongued flight with such a flight regime would do to a real enginge, but my challenge is with the simulated bird and this will get me safe through the oceanic legs and the 340 nm across Greenland without a ferry tank!