Black Widow - a heavy FPV spider quad project, #1

by olex | April 24, 2013 | (9) Posted in Projects

I've been flying my X525-based FPV converted quad for a couple months now, and I'm pretty happy with what I learned with it. However, I've been noticing more and more negative points about the frame and the general construction for my purposes. The main three problems with the X525 for me are:

  • Space. There simply isn't enough to make room for all the FPV equipment (GoPro, video TX, OSD & co.) without making complex and heavy modifications to the frame.
  • Weight. The X525 with its aluminum arms and ridiculous sprung landing gear is simply way too heavy to carry much payload.
  • Stability. Although heavy, the aluminum arms bend slightly after multiple flights. The motor holders are useless.

So taking all this into account, I've decided to go for a scratch-designed frame. My inspiration came in form of the Spidex v2 frame by Quaternium, and my design strongly resembles it. However, I've made some important changes. Here's the results of my first ever encounter with LibreCAD:

 Overall top view of the frame

Top and bottom center plates

Motor mount

Battery and GoPro holders

Propellers drawn into the top picture are 11". Larger size could be possible with longer arms.

The most important difference to the Spidex is the fact that I'll be using 16mm carbon tubes for the arms instead of alunimum. They will be held in place with pipe clamps from the Flyduino FCP HL frame (23mm hole center distance). Plates will be all cut from 1.5mm strong GRP on a CNC machine by a colleague later today.

Motor distance is 58cm diagonal. The arm lengths are chosen so that all 4 arms can be cut from one 1m tube - 22cm on the front, 28 on the back.

An important feature are the two 50cm long tubes running along the frame. Those will be mounted on top of the top center plate using clamps and vibration dampeners, and the battery and GoPro holders will be attached to them on the front and rear of the frame. This way, the camera is isolated from eventual vibration of the drive, and the battery acts as a counterweight and can be moved forwards and backwards along the tubes to tune the CG.

Later, the camera mount on the front will be replaced by a 2-axis brushless gimbal. Haven't decided on the controller yet - either AlexMos or the open-source brushlessgimbal.de controller.

A simple heli landing gear will be fixed underneath.

Now, for the electronics that will be flying this beauty. I'll re-use everything currently mounted on my X525 frame, which is:

  • Motors: NTM 28-30 750kv
  • Props: Graupner E-Props, 11x5
  • ESCs: HK Blue Series 30A
  • FC: Crius SE v0.1 w/ MultiWii 2.2
  • GPS: Drotek I2C GPS
  • LiPo: Nanotech 4S 4500mAh
  • Camera: GoPro 2
  • Video TX: ImmersionRC 5.8G 25mw
  • OSD: MinimOSD w/ KV-Team-OSD firmware for MultiWii

All in all, I hope to be able to keep this frame under the current all-up weight of the X525, that is 1.8kg. Flight time of the X525 is ~15 minutes right now, so with a little less weight I hope to get 16-17 minutes per battery out of this build.

Last but not least, the current state of things: almost all the parts are already here and ready to be mounted. I'm only missing the CNC plates, those will be done this evening by a colleague, and with any luck I can pick them up tomorrow to start the build. Prototype plates were already cut from hard foam to make sure the design works with the CNC machine, and it worked flawlessly:

After the build is done and somewhat tested, if there is interest, I will gladly publish the DXF files for the frame, so anyone can cut the plates and build one of these.

Progress updates coming up, stay tuned!

COMMENTS

tech69x on April 24, 2013
Nice frame if want to see the real black widow go here
http://www.rcgroups.com/forums/showthread.php?t=1847381
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olex on April 25, 2013
Dang, I didn't know the name was already taken :) Oh well.
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austntexan on April 30, 2013
Fantastic frame and great name. If you want to see the real Black Widow though, go here. . . http://en.wikipedia.org/wiki/Latrodectus
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saitek93 on April 24, 2013
Nice frame! I always love the scratch built ones because that's what I've been working on too.
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yeojalviz1981 on April 25, 2013
would you like to share your cad file?
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olex on April 25, 2013
Once the frame is built and proven to work, yes, I will share it. The build starts today.
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liveyourdreamsRC on June 13, 2013
Nice, are the pictures to scale? Also where can the cad file be found now?
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TheNoob on May 30, 2013
This is actually really amazing. It seems like a good quad. It has a cool look to it too. I can't wait for the cad file.
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skelator on December 12, 2013
olex can you publish the cad? or dxf file? would love to have this cut to replace my ATG-650 quad plate :)
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JakeyPlay on June 19, 2015
Hey man.
Can you share cad files? Of course if you still have them.
Thanks
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hh@kendo.nl on July 10, 2015
I have done some thinking about your frame and the Quaternium Spidex v3 and if you are interested, I have some suggestions for improvement. Just let me know. You see, my email address is my forum name.
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hh@kendo.nl on July 10, 2015
guys, If Olex does not respond, I can convert the jpeg pictures to CAD files. It is some work, but it can be done.
If I ever make this frame, I will make it foldable, add a 3D gimbal (Feiyu-Tech G3 ultra) and adjust the with of the arms to that (53,4 mm) ..and maybe put Tarot motor mounts on it so I do not have to make them myself.
..and some other things. I will use the Pixhawk controller, 1285 GHz video and 433Mhz transmitter and a smaller camera like the polaroid Cube or Gopro Session.
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hh@kendo.nl on July 10, 2015
I really admire your design! I would like the CAD file too. In return, I will send you the 3D file back, alsi in Sketchup PRO format if you want.
Your design has some resemblance with the Quaternium Spidex v3, but there are some things in the Quaternium design I would like to change.
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Black Widow - a heavy FPV spider quad project, #1