Welcome to the SeeMeCNC Community

I've been working on a quadcopter lately. I've been learning DesignSpark Mechanical as I go, and I've been printing prototype pieces like crazy to tweak every last detail out of each part, and here's what I've got so far!

[img]http://i.imgur.com/7NO2gvi.png[/img]

The idea was to use carbon fiber arrow shafts as the main structural elements, and to use full length tubes that go through the frame instead of cutting them in half and having 4 separate arms to try and attach/immobilize. I created a "frame sandwich" that holds the tubes in a stacked X shape. The top piece of the sandwich incorporates a vibration isolating mount for the flight controller, and the bottom piece fits the speed controller. More on those later.

[img]http://i.imgur.com/gI1d3Q5.png[/img]

The motors mount to a tube clamp that serves both purposes, instead of having a tube clamp separate from a motor mount that have to screw to each other. This is another advantage of the smaller diameter CF tubes, they fit inside of the motor's mounting pattern!

[img]http://i.imgur.com/dKy18xZ.png[/img][img]http://i.imgur.com/vPvXL1i.png[/img]

As you've probably noticed from the last picture, in all of the places where plastic needs to clamp to carbon, I've used o-rings around the tubing that fit into a groove on the mating plastic piece to isolate the plastic and carbon from hard contact with each other while keeping a tight grip. Hopefully this reduces vibration transfer.

The flight controller is floating on 3 platinum silicone dampers that I designed and printed a mold for: http://repables.com/r/431/ I arranged the isolators to all be 90 degrees away from each other so that differences in their strength wouldn't dampen vibration in any direction any differently. (54.74 degrees are the elevation angles of the 3 sided right angle pyramid model that I based this on, if you're curious. It's the same thing as one corner of a cube) I also made a "slot" for the flight controller circuit board to slide into out of silicone aquarium tubing both to dampen more vibration and because I'd heard horror stories about shorting the boards with metal hardware and I was too impatient to order plastic M3 screws

[img]http://i.imgur.com/4Og2iiT.png[/img]

The speed controller is a 4-in-1 unit called the QBrain that adds a little bit of weight, but tidies up the wiring and power distribution of the whole aircraft. Instead of having metal hardware to clamp it down, it fits between the main arm-body's bottom piece and the adapter for my tube landing gear. I added little captive slots in both pieces for zip-ties to clamp the ESC sandwich together. (So there's a flight controller / silicone tubing sandwich on top of a carbon fiber frame tube sandwich on top of a frame / ESC / landing gear sandwich.... I'm hungry)

[img]http://i.imgur.com/uAIXou0.png[/img]

Other design considerations that I included are that the frame sandwich uses a standard 45x45mm mounting hole pattern, sou you could conceivably add your own frame accessories from places like HobbyKing. I also made my landing gear mount tube spacing 60mm on center to match some of the off the shelf items out there (they do use a different diameter of tubing, but that would be an easy enough modification at a later date). I'm also trying to make cutouts in some of the pieces for wire management. You can see a little bit of that in the second picture down. Hopefully I end up with a pretty presentable finished product!


I have some of the last few parts designed roughly, but I need some more time to print them and tweak them before they'll be done enough for me to use. It's been a really fun project so far, and I hope it turns into a really cool copter when it's done. What do you think? Any design tips?

Here's my full Imgur album of build photos. I haven't been keeping it 100% up to date, but it does have some more pictures, if you're interested.

http://imgur.com/a/saqbM

I almost forgot to mention, I also modded a 9X radio with a SmartieParts programmer and telemetry module and have the newest OpenTX firmware running on the radio. http://makerhive.proboards.com/thread/9 ... s-upgrades The OpenTX thing is a pretty cool project if any of you are RC guys. It's my first go at this, so I've been learning uphill, but having fun the whole time. I got my battery terminals soldered on and got my motors to spin with my radio on Thursday! (I'm quickly approaching the danger zone where there are spinning props and flying objects inside my house)

I look forward to seeing how this comes along. I have been milling a bit of carbon fiber of late and i think a quadcopter is not too far down the road. I've been doing some carbon fiber cutouts for a few local quadcopter guys and it really has given me the bug watching them fly so often. Looking forward to seeing how this one flies!

Looks good.

Just a quick question. In quadcopter design is there a preference between top heavy and bottom heavy?

Sling batteries under the bottom and it's ALWAYS going to be bottom heavy.

Battery(s?), speed controller, someday a camera and gimbal, and landing gear will definitely make it bottom heavy. The motors on top of the carbon tubes make each tube top-heavy, but the assembly definitely isn't.

I believe that centralized mass would be ideal for agility, but for stability bottom heavy is probably better (dihedral like).

Never really looked into this, but definitely looks like fun (long time RC car enthusiast here). In general what does something like this cost to make?

This is really cool.
Got me to thinking that you can also have the CF tubes extend past the propellers, and that will protect the props from a crooked landing.
Also I am not sure how required it is but you could then have another set of tubes ABOVE the props, and hooked into the bottom tubes so that the props are protected from an inverted 'landing'. Looking at videos of these things is seems like flying isn't so crash likely anymore, so maybe none of that is needed.

Someone else just posted pictures of a drone they are printing, and a link to a cool video.
Which I cannot find anymore, because they didn't use the words 'drone' in the posting. Can anyone remember which forum thread that is????

EDIT: http://www.thingiverse.com/thing:511668 I found it, here at work my browser has a page open to it. At home I never looked at it which made searching the history fruitless.

0110-m-p wrote:In general what does something like this cost to make?

Well, the plastic is about $30/kg (just kidding )

The flight controller and speed controller are both under $30, cheap motors are about $15 a pop. Batteries vary a great deal, but I've got some that ran about $25... If I were to add up the radio and receiver and battery charger and absolutely everything, I'm probably in it about $250.

250 isn't bad for something like this, looks god so far!

There were a few things about your design I'm unsure of;

1) Will having O-rings in grooves allow slippage of the CF shafts over time? How do you get the angles lined up perfectly?

2) Are there any parts that have high stresses, especially in the areas where the arms come in?

2) Are you going to print a precision 2 or 3 axis camera gimbal? That would be awesome. Something military grade with FLIR and all that.

Generic Default wrote:1) Will having O-rings in grooves allow slippage of the CF shafts over time? How do you get the angles lined up perfectly?

The profile of the o-ring grooves are undersized so that pressure is applied to the rubber, and the cross section is elliptical to let the o-rings squish wider as this happens without pinching or binding unevenly. It's pretty snug.
To align everything, I used the handy dandy aluminum extrusions on my Rostock as a guide to draw a fine line down both shafts (like the old door frame trick from model rocketry). The plan is to first visually align the line with the seam between the pieces of the frame sandwich, and then to confirm that everything is square by just laying it out on a flat floor or table. Whether or not they shift over time - time will tell

Generic Default wrote:2) Are there any parts that have high stresses, especially in the areas where the arms come in?

That's why I decided to use full length tubes that go through the center frame. It seems strong enough right now, but it would have been ten (ok, 4) times harder to do if I cut the arms and had them attach individually. I think the center frame section is as strong or stronger than the flex of the tubes themself.

Generic Default wrote:2) Are you going to print a precision 2 or 3 axis camera gimbal? That would be awesome. Something military grade with FLIR and all that.

That's why I am using the 60mm tube mounts for a "crab" style landing gear. Those same tubes can be the mount interface for lots of goodies down the road. http://goo.gl/RYWqSH is the gist of what I had in mind. I might have to shed the weight of the FLIR camera to winch disaster victims out of raging waters, though I haven't delved into a gimbal itself yet. There are already some nice designs out there ( http://www.thingiverse.com/thing:110731 ) but I'd just about have to build somebody else's to know what I want to change about it, you know?

Plan A is to make it fly, then to strap on a cheap camera, and then to deluxify the camera and its mount. I'd really like to do FPV flying with it, and several of the guys at The MakerHive want to host the quadcopter olympics and figure out obstacles and an FPV course to fly them on, so that's my stretch goal.

Jimustanguitar wrote: That's why I am using the 60mm tube mounts for a "crab" style landing gear. Those same tubes can be the mount interface for lots of goodies down the road. http://goo.gl/RYWqSH is the gist of what I had in mind. I might have to shed the weight of the FLIR camera to winch disaster victims out of raging waters, though I haven't delved into a gimbal itself yet. There are already some nice designs out there ( http://www.thingiverse.com/thing:110731 ) but I'd just about have to build somebody else's to know what I want to change about it, you know?

Plan A is to make it fly, then to strap on a cheap camera, and then to deluxify the camera and its mount. I'd really like to do FPV flying with it, and several of the guys at The MakerHive want to host the quadcopter olympics and figure out obstacles and an FPV course to fly them on, so that's my stretch goal.

60mm? Your tubes look like they are 8 or 10 mm in diameter.

In your first photo it looks like you intend for it to carry an exercise ball - that would be awesome!

I was looking at the FPV stuff, and it looked like about $400 from the fatshark people (for goggles and camera + whatever).
Are there cheaper setups? There was a reference that implies the hero (3?) camera can be used for FPV.

The tubes are almost exactly 7mm in diameter, you are correct. The on center spacing between the two tubes is 60mm. That's where that dim came from.

GetFPV.com is a good resource for getting into FPV. I think that decent systems can be had for $200ish and up. There's another guy at The MakerHive who's our resident FPV guru, so I haven't paid much attention to it myself yet. I'll just ask him where to spend my money when it's time

I just ran across this guy in a video production magazine, not for the budget minded!
http://www.blackarmoreddrone.co.uk/

Carries a 20 pound HD camera!

[img]http://www.blackarmoreddrone.co.uk/s/cc ... 839305.jpg[/img]

A dodecacopter? Wow! 9kg stabilized payload, that's more weight than an entire DJI Inspire. They've created quite the heavy lifter. I wish they published more specs on total weight, flight time, battery capacity, etc.

I'm definitely aiming for something more simple, light, and hackable. If I shorten the tubes it will be agile and acrobatic, and if I leave them bigger it will be stable and hopefully have some reasonable payload capacity (like 1 or 2 pound max max max).

Making progress! I'd say I'm at about 95% on the whole project.

I need to order different props, and I need to redesign the landing gear to be a little more stable. Otherwise, I'm quite happy with the overall design. It's been very fulfilling to design every single piece, educational too! Although, I need to print it all in the same color, that's bugging me

Without a battery I'm at 549.1g and with a 3000mAh battery I'm at 816.8g. I may add a second battery and be just over 1kg. It will depend on what kind of thrust I can get out of the new prop/motor pairing.


[img]http://i.imgur.com/5sNrCjR.jpg[/img]

[img]http://i.imgur.com/Tku3Y1t.jpg[/img]

[img]http://i.imgur.com/7R88yBV.jpg[/img]

[img]http://i.imgur.com/TQ0DQei.jpg[/img]

[img]http://i.imgur.com/GYCszyY.jpg[/img]

Cool project and very cool color. Are you going to provide stl files?

I will definitely post the files, I just want to reach a point where I feel like it's finished first.

Hopefully that'll be relatively soon. I do have to wait on new props in the mail, but the landing gear redesign and a few other tweaks shouldn't take long. It's moved relatively fast so far, I didn't even start learning to draw 3D models again until the last week of October, so this has been a 3 month project from conception to creation. Gotta love rapid prototyping!

Larger props I hope.

barry99705 wrote:Larger props I hope.

Yep, that's what I need. I bought a set of 5030's (3 blade) when I placed another order on Black Friday (because they are the ones used on the FPV250 class quad) but they're a poor match for this application because I'm only using 3s batteries and have different KV motors. I need something more like an 8045 prop.

They look extremely small because I didn't cut down the arrow shafts at all, so it's a 620 size quad that weighs 550g without a battery.

I saw the green props and thought you printed them for a second. Seems like the sorta thing that would be ideal for rapid prototyping, trying different attack angles, length, and widths. Not something you'd want to delaminate under strain mid-flight though...

Is that the octive abs? And has anyone built a quad capable of lifting a person? Lol

Yes

https://www.youtube.com/watch?v=L75ESD9PBOw

lordbinky wrote:I saw the green props and thought you printed them for a second. Seems like the sorta thing that would be ideal for rapid prototyping, trying different attack angles, length, and widths. Not something you'd want to delaminate under strain mid-flight though...

I've had normal props shell out in flight. It's not pretty.

I ordered larger props, this time according to my motor specs and the craft's actual weight... It didn't turn out so well.

barry99705 wrote:I've had normal props shell out in flight. It's not pretty.

You too, huh? I didn't even get off the ground before they exploded from the force of spinning.

[img]http://i.imgur.com/qARq2Ee.png[/img]

DavidF wrote:Is that the octive abs? And has anyone built a quad capable of lifting a person? Lol

No, it's neon green PLA from Inventables.