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EAV-9 "Colibri" VTOL [BG]

EAV-9 "Colibri" (Hummingbird) is a high-performance, easy-to-fly, RTG-powered bicopter exploration drone. It’s designed to operate in Kerbin, Laythe and Eve atmosphere with unlimited flight time, conducting experiments and scouting for interesting locations for future missions. Also suitable for stunt flying around KSC.

Stock + Breaking Ground DLC. 46 parts, root part is the QBE core.

- Compact design (1.3 x 1.9 x 1.9 m, 0.9 t) with full suite of repeatable surface science instruments
- Near-perfect CoM balance for satisfying flight characteristics
- Maximum horizontal speed ~50 m/s, operational ceiling ~8 km (on Kerbin)
- Self-sufficient on two RTGs even with maximum rotor RPM
- Self-rescue with differential thrust in case of rollover, see video
- Thrust level for hovering exactly on 2/3 throttle scale - intuitive control (on Kerbin and Laythe. Varies on Eve.)

- Stage to start motors
- Engage SAS
- Throttle up to 2/3 to lift off
- Use Z and X for sudden controls if necessary
- Refer to video for self-rescue technique in case of rollover
- I recommend enabling the “no crash damage” and “unbreakable joints” cheats during practice to save some time. Crashes will happen anyway. With these cheats, you can try again in 5 seconds instead of perhaps 30.

- Although this craft is IMO easy to fly, multicopters do require some practice to fly at will. A soft landing (<4 m/s) is especially challenging. But after one or two successful flights, the real fun begins.
- It’s possible to disable the tiny internal reaction wheel (0.5 kNm) and rely on the blades for flight control, but I find the result not satisfying. Flying with the reaction wheel, on the other hand, feels pretty smooth and realistic, so I decided to keep it this way.
- It requires relay network to operate on Laythe or Eve.
- For science transmission, land the craft on a safe place, enable allow partial transmission function of the antenna - there is no way (and no need) for it to carry enough EC to transmit all data at once. Use time-wrap to speed up the process.
- Unfortunately, grip pads cannot completely stop it from slowly slipping on slopes, not even with extreme friction and maximum downward thrust (~3 Gees). Therefore, using the scanning arm requires some ad-hoc creativity.
- It’s more fun to fly on Kerbin and Laythe, less so on Eve. It may require enabling pitch/yaw/roll control of the blades and messing around with blade pitch/control authority for better result. Eve is not a good place to fly things on. Eve is not a good place.

Wish you enjoy and happy landings!