Ben Beyer also said his turned 5600 but at 5000ft above sea level and with a Bisson with the curled tips still on so I would say that
Its not a tuning issue as they are tuned perfectly.
seems a bit suspect.
Bottom line is mine yanks a Wild Hare Ultimate off the ground and goes vertical out of sight and it is way more power than my ZDZ60 ever had, in fact I had a Brison 4.2 that couldnt turn the same prop with as much authority.