Contra rotating Propellers (Unit 3) OS H60 Golden Head. spur gear drive "Rolls Royce Griffon" style.

★Will you be honest for the third time through repeated trial and error? . After learning from the data from Units 1 and 2, we decided to use an all-gear drive system this time, and I can't wait for the actual test propeller to arrive. ★As it was an amateur design that prioritized sturdiness as a practical flight goal, the unit weight is high, so the rough engine size is 5 to 6 kg, and I would like a thrust ratio of at least 0.8, but what about a dream? It looks like it will be a pretty tough goal to reach vertical rise...(^^;