I have recently been building an AquaCopter Bullfrog. The goal is to build a waterproof drone that has about 2km range similar to my DJI Phantom 3 Professional. Overall the experiance has been a lot of fun. I started with a couple of used Iris-pluses as donor copters so the equipment is as follows:
1.) MT4006 tiger motors
2.) 14x4.8 3 hole Carbon Fiber Props
3.) 20amp 4 in 1 ESC from 3dr
4.) 2 - 3s 5100 mah Batteries from 3dr
5.) 3dr Telemetry Radio
6.) AuquaCopter Bullfrog Frame
7.) Pixhawk with the latest Flight Controller (running APM on a Mac)
8.) 3dr GPS
9.) 3dr Radio ( That comes with the Iris plus )
The Bullfrog weighs about 2,200 grams fully loaded and gets about 24 minutes of hover time. The MT4006 have plenty of lift and the craft hovers well below 50% throttle.
I have a couple of questions which I am looking for input on:
1.) The copter hovers fine but occasionally in stabilize and lotier, on descent or rapid movements I get into an ocilating spiral of death (OSOD) which is making me rethink the carbon fiber props. I think the problem is related to the PID's not being tuned correctly. I started with the Iris plus pids. I have tried to re-tune but the wind has been to high--2O+ knots (which also contributes to OSOD).
a.) question--is the pid setting the probable cause for the OSOD or is it the max angle ( 45 degrees ) ?
2.) I am looking to add FPV to the drone. I have a blackpearl and the fpv gear that came from 3dr but I think it's not going to have the range and the gopro and gimble will not really work for my waterproof drone. I dont really care about the gimbal but I want a clear picture that transmits at distances up to 2km.
a.) So what is a good camera and transmiter for the copter?
b.) For the ground station, should I keep the Blackpearl ?
c.) What is the best OSD card for a Pixhawk.