I built my own Quadcopter following this online build
Turnigy H.A.L. frame
Turnigy D2830-11 1000kV motors
Slow-Fly 9x4.7 props
Zippy compact 4000mah 3S 25C battery
QBrain 4x25A ESC
APM2.6 with power module. ESCs calibrated, apm autotuned, running arducopter 3.1.
All-up weight is 3.3lbs (1.54kg).
eCalc says that I should hover at 71% throttle and that is consistent with my experience. I've attached the eCalc page of my exact build to this post.
After tuning my apm2.6, all flight modes tested so far work very well (stabilize, alt hold, loiter, RTL, acro). I hover at half stick in acro mode, so I should have plenty of power to maneuver vertically. However, if I descend at any reasonably speed (70cm/sec or more), my props lose serious amounts of lift making it very difficult to stop the descent and avoid a hard landing.
Here is a video of my testing the quad and demonstrating the behavior that I believe is vortex ring state (settling with power) which perfectly describes my flight symptoms. Maybe I'm just falling too quickly and expect too zippy of a response from my quad. But there have been times when I'm sure that VRS prevented me from stopping a descent. Is there a way to alleviate VRS symptoms on my quad? It can carry more weight, it usually carries 10.7 more ounces of gimbal and video transmitter weight.
My quad has climbing power, but loses lift when it descends faster than a snail's pace. Would larger props help? Any advice is appreciated.