RE: Fully ducted Kyosho F-86 videos
The following chart compares the benchmark rk720 with the kyosho rotor.
The os 15 cvr is included from dyno results obtained from nitro rc.com
the kyosho fan is 44% efficient. The rk720 is 58% efficient.
Even that being said, the kress fan will allow the os 15 to get to 24k or so, yielding nearly 3.8 lb.
this being compared to the 27.1k and 3.4lb obtained by the kyosho fan due to it's lower fan loading and lower efficiency.