I have worked out the fuel based on a 61SF powered model I have, the tank in the arrow is about the same, on a normal flight I get 11 mins with this plane, I have calculated that the 61 V standard with 7M carb and pipe presure gives be approx 8-10 mins of flight time.

That is close enough for the first flight.

Once I have proven the plane I normaly just run it to dry and land Dead stick a few times giving me a much better Idea of flight times.

That is all I need to know.

Johnkpap