XY-8 Build

[Bartman]

I've been working on a new frame for a quad that is a little bit different than the standard x or + layout. The design has 120 degrees across the front and rear motors leaving 60 degrees on each side between the motors. The goal for my build is a coaxial quad using the eight Robbe Roxxy motors that came with my original MK Okto II kit with 10" props but any 110 to 120 W motors would do. Emowillcox is also building himself one (with the DJI WKM control system) but he's using four Avroto motors with 12" props.
So far I've got the frame plates cut (Thanks Windhorny!) and I'm now getting started cutting the arms and ordering small parts like motor mounts from HK.
The hole pattern is for a full Mikrokopter electronics stack.
I've got a camera mount that I've been working on and it will be adapted to fit right onto the bottom of the XY quad and lightened up a bit for smaller cameras in the GoPro to Sony NEX range.
That's it for now. More pics as it comes together.
View attachment 1182

Bartman

 

[Droider]

The design has 120 degrees across the front and rear motors leaving 60 degrees on each side between the motors

Whats the thinking behind this Bart?

Dave

 

[Emowillcox]

I think the plan is to have a better field of view for the camera with out the arms getting in the way.

 

[Bartman]

Whats the thinking behind this Bart?

Dave

like Mike said, to get the benefit of a Y-6 which has the props a bit farther out to the sides, to get the better survivability of an 8, to see if the MikroKopter FC can handle the asymmetry of the motors/arms.
if i can get my components in place i should have it flying sometime next weekend or next week.

 

[Bartman]

if it flies well, i can make frame plates available for sale. i'll also be forming a cover dome for it at some point if it does well. arms are going to be 1/2" square, i'm using aluminum, Emo's using carbon fiber.

 

[RTRyder]

With the Nex series of cameras the focal length is well beyond any piece of the frame, I'm not anywhere close to seeing any part of the hex with the AV130 positioned at the center of the gear rails. With most cameras that use interchangeable lenses it's never going to be a problem unless you make the arms 2 feet long, then maybe there might be a chance of them popping into view once in a while.

A GoPro with standard lens is a different story depending on which setting you're using. The one I have with Sunex lens doesn't have that problem though and it's only when there is extreme tilt to either compensate for wind or in waypoint flight that the front arm occasionally is in view.

From the redundancy perepective the Y and X coax configs are a good idea but for a better camera FOV it really doesn't make a lot of difference what configuration you use unless you're using super wide angle lenses like the standard GoPro or trying to fly in hurricanes.

Ken

 

[Bartman]

the nex field of view is 83 degrees so the frame/mount i'm designing will just barely be in view when the lens tilts up. the goal of what i'm doing is to have an aerial system that you can actually fly without fear of lens wobble. to lean the kopter forward and fly it you have to have some ability to face the camera up a bit. The gopro is a different story with its extreme wide view but it will be lower on the camera plate so it may work just fine as well.
we'll see in time how it goes.

 

[Emowillcox]

The other thing I like about Bart's idea is that it could possible help from a perspective point of view.

 

[RTRyder]

the nex field of view is 83 degrees so the frame/mount i'm designing will just barely be in view when the lens tilts up. the goal of what i'm doing is to have an aerial system that you can actually fly without fear of lens wobble. to lean the kopter forward and fly it you have to have some ability to face the camera up a bit. The gopro is a different story with its extreme wide view but it will be lower on the camera plate so it may work just fine as well.
we'll see in time how it goes.

My point is the bigger lens on the Nex puts the focal point farther out than any part of the frame on the average size hex, even when I have the 16mm wide angle lens on it still focuses out beyond the frame perimeter. With a GoPro the focal point of the lens is pretty much right in front of it so naturally it will see just about everything. If you have both GoPro and a DSLR with at least a 18mm lens, do the same flight with both and you will see the DSLR image is quite different than the GoPro in terms of where the point of camera view is, the bigger cameras are a lot more tolerant of frame bits sticking out the front. I've only rarely seen a hex frame need to tilt far enough for the front arm to come in view unless the camera FOV is very wide and located close to the lower center plate, usually its a case of the multi is getting bounced around too much from extreme wind so the APV conditions aren't that great to begin with.

As to the arm layout, I seem to recall Rusty built an MK with a similar wide spacing but narrow front to back and it worked OK with MK electronics. I don't see any reason why yours wouldn't work, might have to tweak settings a but more than usual but it should fly without any major hassles. Only thing I can see that may feel different in flight is it being a bit more sensitive to elevator inputs for the tilt axis and less sensitive to aileron on the roll due to the difference in motor spacing. Appropriate expo settings would fix that easy enough.

Ken



Ken

 

[Bartman]

Hi Ken,
Thanks for the input. Part of what is driving this little project is the need for a smaller package that I can fit into the trunk of my Honda Civic for AP work related to residential real estate. I also want an AV mount that can fly without regard for smoothness while recording great video. The wide spaced front and rear motors is just something that I thought I'd try in the process as it seems the Y-6 owes its popularity to the spacing of the front arms with AP/AV users.
Like you mentioned I've been figuring I can balance the flight controls with exponential in the radio but it'll be interesting to see if the MK FC cares much about the roll/pitch imbalance when it's in GPS modes.
Bart

 

[Bartman]

The build continues

Mounted standoffs for MK gear then cut four arms to length and drilled for the frame and motor mount holes. Put the arms in place then added the motors. The motor
mounts are from Hobbyking.com and the aluminum spacers outboard of the motors are from Mcmaster.com.

I may be able to start wiring the motors to the power board tonight then maybe have a first flight before adding the gear and making a camera mount for it.

But will it fly?? Stay tuned..........

View attachment 1309View attachment 1310View attachment 1311

 

[Droider]

Looking nice and clean there Bart..

Dave

 

[DucktileMedia]

you should use your extra Xaircraft FC for this. If it works as well as mine you will be in great shape. And if it blows up or goes down in a flaming crash, it's much less of a loss.

 

[Emowillcox]

Good looking build. I like how you mounted the motors.

 

[Bartman]

just starting with the motor wires, listening to 1071thepeak.com and keeping the forums up on the laptop

 

[Bartman]

battery leads are on the power board and it passed the 9-volt battery test....moving right along to the FC power and I2c wires now...not using the molex connector

 

[Bartman]

grrrrrr....don't have heat shrink tubing for the battery leads.....going to bed early tonight

 

[Bartman]

well, it just needs some landing gear and a battery strap and it's ready to fly. it also needs a very obvious front/back reference as i still have to look at the arrows on the electronics to know which way is front and that won't work so well once it's flying. probably a ping/pong ball across the rear motors.

if the winds are less than 15 tomorrow then we fly!!! long live the XY-8!!

edit: if it flies I'm definitely going to have to replace the bearings in the motors, they're a bit noisy.

View attachment 1327

 

[Droider]

Bart you need a couple of Ross's LED's... look miles better than a pingpong ball..

If the weather is good just hand launch it and leave the landing gear for another day!

Good luck

DAve

 

[Bartman]

it flies!!

just did a 13:30 flight with a 5000 mah battery so if it will do 8 minutes with a mount and a Sony NEX then I'll be in good shape.