I built up this latest version the night before the Motherboard shoot for the Blast. I'd been told we'd be flying in an enormous construction space, so I brought it along to maiden. I was so confident flying it with 35 degree mounts I didn't think it an indoor maiden would be a problem.

Our space turned out to be a lot smaller than expected, but I wanted to try the steeper motor mounts so badly I gave it a go anyway. As soon as it lifted off it shook so violently I cut power and let it drop. What I didn't realize was that yaw authority increases with motor angle (more horizontal thrust, more yaw force), and now it was now so responsive it had violent yaw oscillations. It was eventually tamed with some outdoor tuning.

As I flew it more I found a strange and interesting flight characteristic: it accelerates forward with just throttle, no need to drop the nose, almost like a plane. Most of all it was just freakin' FAST, always taking off with a mind of its own. At times it felt like it needed more pitch I, as it had a tendency to drop its nose a few degrees and settle there. It wasn't an aggressive correction like auto leveling, more of a feeling that the craft had an angle it wanted to fly at. After some experimenting I figured out what was going on.

A Quick Diversion into FFhysics

Here's a simple schematic of an ideal Thrust A Tail configuration. Front and rear motors and props are identical, the rear motor is tilted at 60 degrees so that it has half the thrust of the front motor (cosine 60 = .5). CG is located 1/3 of the way back so that the rear motors have twice the leverage and half the lift. This configuration is very similar to a tricopter, with similar CG location, with the two rear motors taking the place of a tricopter's single rear motor.