Here's what I can do for photos this late in the game. I really should have taken build photos before everything got covered up with electrical tape and zip ties ;) The craft is crude, but I'm really happy with how it flies with modded 2.9.1b firmware. I'm working on 3.0.1, but tonight's weather got in the way of my test flight.
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Ha - This is so old! I started with a Turnigy 9X Tx / Rx set.
You certainly could do that. With mine, I put the center of gravity forward just enough to balance the loss due to the angled rears. When hovering level, I see nearly equal PWM output to all 4 motors.
The last argument only sets the testing order.
void AP_MotorsMatrix::add_motor_raw(int8_t motor_num, float roll_fac, float pitch_fac, float yaw_fac, uint8_t testing_order)
There's a macro that maps motor_num to channel, and by default it's in order.
#define APM2_MOTOR_TO_CHANNEL_MAP CH_1,CH_2,CH_3,CH_4,CH_5,CH_6,CH_7,CH_8
Oh that - the first argument is the output channel (for wiring) and the fifth is the testing order (order they spin if you run the CLI motor test). I figured I'd keep it simple and number them 1-4 clockwise from FR to FL for both the wiring and testing. I'm not really sure why the normal way is crossed...
I should also mention that CW/CCW for my motors ignores the fact that they are upside down in the rear - just refers to the prop direction looking top down.
I might be flying with reversed yaw - Stick left = tail left, not turn left. (the way I learned to play Doom and Quake lol)
The yaw values for the front were intended to help counter the roll caused by the vtail, but also help by torquing in the correct direction. With your numbers, when your rear left increases (+0.5) for yaw, it will also try and roll right, so the front right should try and counter (+ve). You have -0.32 at front right which seems like the wrong direction to me. If you're going to reverse the yaw direction, you might want to also swap all the CW/CCW directions so the torque works in your favor.
I think the right answer would be to remove the frame type parameter and simply make the mix table configurable from within mission planner (i.e. one mix table, populated from eeprom). I'd like to also see a throttle factor added for each motor, but unfortunately the new stability patch code would have to be rewritten to consider it.
I should point out that the tail boom was originally PVC, but it flexed a bit too much in the roll direction, so I replaced it with a piece of carbon tubing - same exact size (and weight) as the PVC, but much more rigid.
When I get a chance, I might reduce the front arm/tailboom lengths to make it more 450 frame size instead of 550 -which could probably do without the carbon.
Thanks Bob,
going to rework my dead-cat quad to VTAIL soon...
Here's a video from a front mounted gopro. There's a yaw spin in there, along with some flips n rolls and even a crash at the end when I got too close to the ground...
DropBox Video
You can download the video to get higher def, but it's mostly just grass blurring by ;)
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