Hi.
I did found the manual with the exact wording but it is for the 2 stroke engine (3.2 HP)[]
If the engine can provide close to 18-20lb then it is enough.
I made some calculations in my mind like if the 3.2 HP engine can provide 30lbs then the 2 HP
should come close to 17 - 18 lbs
I also found in the BF-34EI's manual:
"20 x 6 Mejzlik Carbon Prop:
BF-25F: 1,400 – 6,600 RPM
BF-34F: 1,300 – 7,200 RPM
18 x 8 Bolly Carbon Prop:
BF-25F: 1,400 – 7,300 RPM
BF-34F: 1,300 – 7,800 RPM
Temperature for the above was 15°C, humidity was 20%. Engines were new, with
100 minutes of break-in running. "
Now 20x6 @ 7200 = 17.28 lbs static thrust and 19.64 lbs in flight which sounds realistic.
Thank you as your information about the manual at least provided me with a starting point
of what to expect.
Chris