Radio Controlled FPV Helicopter

This aircraft is an Align T-Rex 450 V2 helicopter clone (HK450V2) with a lot of avionics for FPV flight. This is the first version which I tested in flight, and it contained the following equipment:

Helicopter body:
- HK 450 V2 carbon fiber chassis
- 325mm carbon fiber rotor blades
- Turnigy Sentry 40A ESC
- Turnigy 450/500 3500kV Motor (11T Pinion)
- 3x MD922 Servos for CCPM, MKS DS460 for tail rotor
- OrangeRx R610 6 channel 2.4GHz receiver + OrangeRx R100 satellite receiver

Additional equipment:
- Eagle Tree Logger V3
- Eagle Tree OSD Pro
- Eagle Tree GPS Module
- 1/3-inch SONY CCD Video Camera (PAL)
- 1.2Ghz 500mW Video Transmitter
- Flymentor stabilization system

Ground equipment:
- Spectrum DX6i radio
- Video receiver
- Fat Shark video goggles

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I flew this helicopter a few times and it proved to be rather difficult to control in this configuration. First, the 450 size helicopter was noticeably overloaded with this much equipment on it and felt rather dodgy in flight. It climbed well with a strong battery and could maintain stable hovers, but I doubt it could autorotate. Actually the main problem was the camera field of view which was too narrow. The 1/3" camera with a built in 3.6mm lens has around 60 degrees field of view, which is too narrow for comfortable flight and maneuvering around objects. I installed Flymentor so that I can level the helicopter in case of a video feed dropout or similar emergency. However Flymentor did not perform reliably, the memorized horizontal position during initialization could not be kept stable every time. I suppose that the reason for this was the thermal drift or improper calibration of the cheap Flymentor MEMS gyro.

The previous experience led me to modify the configuration, I removed the Flymentor completely and replaced the old camera with the GoPro HD Hero 2. This camera has 170 degrees field of view and can record high quality HD video in parallel with the composite output required for FPV flight. However this addition required me to completely change the placement of components on the helicopter, and I did not finish this work yet. I'll post some photographs later when I get it finished.