Tricopter - Scratch Build

[Budge]

I built this tricopter using the optimized template from RCExplorer.se. I like the coffin shape because it's easier to cut out and the hole placement is more durable. However, I then ordered the camera mount kit from FT and it is a tough fit. You can drill new holes in the mounts to fit the holes in your frame, but they seem to line up perfectly with the wire from the kit. It's doable, but just FYI.

So if you want to use this kit with an optimized tricopter template: You need drill your new holes in the mount kit carefully, then measure distance between your two sets of wires BEFORE you glue the wire-holding templates to the bottom section of the mount kit. You will need to disregard the lines that are laser-etched there. In my case, the two mounting brackets ended up being closer together than the original markings. And since I glued the wire holding templates down first, my wires will flare outward a bit and give me a little less room between the tricopter body and the camera mount. I'll post a pic soon.

 

[Gopherdave]

Hi:

Thanks for your input Budge, such a nice place here. I got the template from the link on the tri 2.5 build video and like made 20 copies of it as well as the camera tray. I also got the optomised templates from RCgroups and they are different, especially the hole spacing? Don't know whats up with that. I've ordered the Tri and camera frame but I live in Canada and things take forever to get here. I'm impatient so I sprayed the camera and main frame plans with clear coat to make them stiffer and easier to peel off when using a glue stik, cut a set of both out and trial fitted them together, looks OK. I then took a sprayed camera plan and glued it to 1/16 ply, 3 hours later (blood and blisters cause I used a knife) I had a kit for the camera tray. The build went fine but bending the wires took forever but it turned out good. I'm so impatient I thought I didn't have the material or ability to cut the complex curves for the main frame. I found out G-10 is just the fiberglass, not the brown paper, circuit board 1/16 or 1.6mm available locally at electronics shops. I etched the copper off with salt water and electricity, cool, it bubbles and stinks and you feel like mad scientist. Google etching with salt water and electricity. The plans for the tri frame were slightly off, not quite symmetrical, so I corrected them slightly only by a mm or so. As David says in one of the build videos just join the corners together to form a coffin shape, stronger and room for more electronics. I tacked (glue stick) my clear coated template to the G-10, traced it and carefully marked and drilled the holes. I put a fine tooth blade in my jigsaw with the blade backwards, teeth pointing back, turned it upside down and held it between my legs. I now had a flat surface with the blade pointing up and teeth toward me like a scroll saw. This was an easy and very accurate way to cut it with what I had and only took a few minutes . I then double checked all the dimensions and marked it as my master. I now use this to trace and cut more whenever I want, I made it symmetrical so the holes always line up, easy. I sort of regret buying the parts because I now have templates and materials to make more any time. I'm going to make 2 more Kits while I wait for my electronics from HK. I strictly kept to Davids designs and suggestions, tried and tested, as this is my first multi rotor. I hope someone will find something useful in this post. I thought this build thread would be more active, the one on RCgroups is huge from people trying to modify the design but I think David has nailed it. But then there is the V tail TRI, hmmm..

Dave

 

[Nebulus]

Hello,

Thank you for this amazing work.
That decides me to try the adventure and build a tricopter following your build.
I ordered different parts but where I live, I could not find poplar wood. So I bought fir (after eliminating balsa because it seems too smooth and not hard enough).
I have now some 15mm x 15mm fir's boom of 1 meter long.
Do you think that fir will act like poplar ?
Do I have to cut it 12mm, 10mm or let it 15mm ?

I thank you for your attention,
Neb

 

[Nebulus]

bump

 

[xuzme720]

Hello,

Thank you for this amazing work.
That decides me to try the adventure and build a tricopter following your build.
I ordered different parts but where I live, I could not find poplar wood. So I bought fir (after eliminating balsa because it seems too smooth and not hard enough).
I have now some 15mm x 15mm fir's boom of 1 meter long.
Do you think that fir will act like poplar ?
Do I have to cut it 12mm, 10mm or let it 15mm ?

I thank you for your attention,
Neb

Fir should be fine as long as it's not flexing too much. and the dimensions are not that critical, just adjust your hardware length to match.

 

[Nebulus]

Thank you very much for this answer xuzme720, so I will stick with 15x15 mm fir's boom.

 

[kenc3dan]

I asked myself the same thing and posted it in the comments along with some other folks. Seems like the answer is, yes, you can do it, but it might smoke the motors or ESC if you really push it. That's completely based on anecdotes and the posted specs, I'd bet David Windestål knows his business.

I could be missing something here, but the tricopter parts list says to use "4s" (14.8V). The D4023-850 motor specifies that you could use 4s, but it seems to me that using the DT750 motors, you could only use 3s (11.1V)??

 

[kenc3dan]

As we discussed, I used these SIG nylon 1/8 gear mounts and have built two yaw hinges with great results.
http://www.sigmfg.com/cgi-bin/dpsmart.exe/IndexText/FSIGSH113.html?E+Sig
http://www.rcbuyerswarehouse.com/signylonnosegearbearingonly18inch.aspx
The problem they present is that the gap between the two supports is narrower than a support. Therefore you have to remove material from one end of each half to make the supports fit into the gap. I avoided removing material from the area around the mount screws to make sure they stay strong.



The Windestål Yaw Hinge.
$0.76 + a bolt.
Hope they get him to stay here in the states.

I was just notified that Hobby King has them back in stock, although not at the USA Warehouse. So I placed my order right away.
http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=8432

 

[eekay]

Hoping they will be back in stock. Technically, I have one on the way, but I fudged the address and it ended up being RTS last week. Now I have to wait for it to get back to HK, get re-processed, and sent back. I have a feeling this is going to take a while.

As per the specs, and my own personal experience, the Rotor Bones yaw mechanism IS NOT recommended for the DT750, despite the plug in the build video. I've gone through two G-10 mounts and after emailing Bixler about it he pointed out that they're designed for much MUCH smaller motors.

Im about to try using the 3000mAh 4S 20C battery listed in the build. David seems to swear by it, although I think I might feel more secure with Plush 30A's instead of the HK F20A's. Going to be using KK V1.6 as well, have been waiting to do so since I broke the G-10 over a month ago.

 

[kenc3dan]

Modded my Spektrum A5060 servo - cut off one mount, opened the servo and cut rear-exit opening for wires, sanded face flat so it sits flush to the boom. Didn't have to shim it. Axle of servo and axle of hinge lined up perfectly. Had to sand and tweak the hinge ends and enlarge hinge shaft holes to allow loose travel on one half of the hinge, while the other is locked in nicely to the hinge axle.


Tried to find tiny screws for attaching the horn to the servo. Best I could do locally was Sears Hardware #2 wood screw.


Centered the horn exactly over the axle of the hinge, using the horn holes as a template I marked two points where there was some material for the two screws to bite into.


Enlarged both the holes in the servo horn and drilled tiny pilot holes in the hinge end with my finest Dremel tip. Didn't need to go all the way in with the pilot holes, just a few mm. Glued the horn to the hinge end using Griptonite, again from Sears Hardware.


Drove the screws through the horn and into the hinge end, making sure they went in straight. If they angled inward they might poke in and interfere with the shaft.


Trimmed the horn with my Dremel.


Fits nice. Too bad there's no way to use the servo horn screw to attach the horn to the spline. It's just the spline fitted again the plastic horn, if the servo and hinge move apart in any way it might strip the teeth on the horn. When I mount the motors I've gotta make sure those zip ties are tightened down so nothing has any give.

 

[stuntpilot63]

Can the esc's be powered through the kk2 or is the power breakout cable needed?
Thanks

 

[Craftydan]

Hey stunt, Welcome to the forum!

Actually it's the other way around - the ESCs are powered by the battery, then in turn provide power to the kk2 board through their UBEC - a voltage regulator in the ESC, connected to the signal cable. I know - Its wierd the first time you see it that the current flow is reversed on ESCs signal leads.

You will need a power harness or distribution board between the battery and ESCs, but until you're ready to hook up lights or other gear, that's all that will connect to the main battery for power.

 

[Blu-Vector]

Hi, about the props... KK Board, want for the tricopter 2cw and 1ccw , but in the video he uses 3 cw ... Is that a problem? Am i missing something?

 

[cranialrectosis]

David does some amazing stuff. Some of what David does is far beyond....

He gets away with not using a CCW prop by shimming one motor to induce yaw and thereby counter the torque.

It makes it less expensive to buy rotors (possibly the cheapest part anyway) but introduces additional technical concerns.

If this is your first, I recommend you keep it simple and use two CW and one CCW rotor and follow the directions in the KK2.

 

[Blu-Vector]

Yes it's my first.
How it should be shimmed anyway? Are those props ok?

http://www.hobbyking.com/hobbyking/...F_3_Standard_3_Counter_Rotating_Per_Bag_.html

 

[ivorn]

Just finished my Windestål special!

Hi David,
What a hoot. Had great fun building this. Nearly there, ready to go. Burnt out a speedy so can't fly yet.
My 12 year old boy is also making one. Great how 'to do vid of' yours much appreciated.
Here's a pic to date. Wi l will do vid of maiden.
Thks so much.

 

[knife-edge]

Hi guys I just wanted to post a couple pictures of my 3d printed tricopter plate. The plate was drawn in solidworks based off of David's design. It is 3.5mm thick and was printed with PLA. I am using the 3d Systems Cube to print since thats what I had available. The print quality is acceptable, but I am super confident that a normal 3d printer in which you can change major settings on would print much superior to this.

 

[DDSFlyer]

Looks nice, how heavy is it?

 

[knife-edge]

That's where it gets a little disappointing... Just one plate weighs 25 grams. I can't compare that to the normal frame that Flitetest sells but im sure that theirs is way lighter. I really would like a stiffer filament type so that I can print it thinner. I might try printing it with some holes patterned in it. I have no doubt that it is strong enough though!

 

[Blu-Vector]

Could someone explain how can i use my tricopter without ccw props, like david does on his tutorial ? Thanks