If the DragonFly flies as a Tricopter, could a Septacopter be made also?

[MadH00ter]

Hi Folks,
Just a quick question... I have a Tricopter, and am thinking about making a PentaCopter/DragonFly. And was just curious if it would be possible to make a SeptaCopter, 3 motors per side acting as one (1 motor inverted like the DragonFly). So just add the back motors in opposite locations, on the same side, as the front motors and use not a Y connector, but a 3 to one connector to control each side and still have the tail rotor? See pic if still confused about this concept...



Thanks,
MadH00ter

 

[JayArr]

I only have limited knowledge about tricopters, but as far as I understand it with the dragonfly is that you just chain the 2 left motors to the same input from the flight controller. If so, it would be possible and relatively easy (in theory) to add another motor to the same input.
A potential problem could be the available space for another rotor on each side though. There might also be some issues with the handling I suppose. It'll be interesting to see, since I couldn't find any attempts to make such a thing.

 

[Flat4]

I believe Josh mentioned he had the the motors facing downward linked to the same channel, which was just throttle. I think the key to the dragonfly config is that the two center motors (the ones facing down) are positioned right at the CG of the copter, thus just providing pure lift, with no pitch or roll control. All while the standard three tricopter motors provide your pitch, roll, and yaw control.

I would think for this same configuration to be used in a pentacopter style would require your center 4 motors to be right on the CG, and used as pure lift motors like the dragonfly. I can't see why it couldn't be done, I just think a bit of work on the geometry of your frame would be needed.

As JayArr mentioned, I think finding the space to fit those two extra motors on each side on the CG may be a bit tricky.

 

[BankNYank!]

Going from tricopter to pentacopter is fairly easy because of the fact that the two additional motors are on the aircraft cg. The two additional motors are connected to the same output on the flight controller as the two front motors (left and right respectively). Because the two additional motors sit on the aircraft's cg they do not interfere with the tilt control of the aircraft which keeps everything balanced according to the flight controller. The roll of the aircraft will be more sensitive but that can be adjusted in the flight controller.

The issue with a septa copter would be that the two additional motors (when compared to the pentacopter) would not be over the aircraft cg and therefore would cause adverse affects on the crafts ability to maintain flight. Not to say it isn't possible just saying that it would be more challeging than just plugging in a couple 'Y' servo cables to the flight controller.

Another option and one that would give you even more lift would be to mount the two additional motors on the top of the boom that is at the aircrafts cg in the pentacopter configuration in the same format as used on a Y-6 layout. This would give you a septa copter with (I'm predicting) amazing lift characteristics and technically it would be a septacopter. Of course the main issue would be getting the motors far enough apart so the props don't hit each other.

This is all of course my opinion in relation to my understanding of multirotor flight but I hope it helps!