Mini-Tricopter Build on RCExplorer.se Frame

[califrag]

[Build Log] Mini-Tricopter on RCExplorer.se Frame

I purchased one of David's frames from the FT store awhile ago and made it into a "classic" tricopter to learn with. After crashing it several times, I put it away in the parts bin and cut a wood frame with a jigsaw so I wouldn't break the original.

The time has come to do something with it, and since I'm really enjoying the mini-rotors right now I figured I would build it into a mini-tricopter using some of these carbon fiber square tubes from HK and some of the rotorbits.

150mm (x2)
250mml
Motor Mounts (x2)
Servo Motor Mount

Here's my progress so far:

The front arms were cut from 250mm booms and are approx 152mm with the holes drilled about 23mm from the end, so the pre-cut 150mm booms should be good with the hole drilled at 20mm.



The 10mm booms are a little bit smaller than the rear arm mounting screws section, so I used some rubber aquarium tubing to both protect the booms and provide the snug fit. I also used them where the front arms rest against the 'stop' screws, to prevent wear.



I ran the 250mm boom all the way up the middle of the frame and it feels really sturdy. I plan to add the wood dowel reinforcement as well for additional strength.




Right now the arms are about 290mm spacing "MTM" (but will likely be around 330mm once I get the rotor bits).





It weighs about 91g as you see it without the rotor bits mounts, which I'm still waiting for them to show up.

I wanted to use FliteTest rotor bones parts that I bought when I got the frame, but they only work with 12mm booms and I want to use these 10mm ones. I tried to adapt the rotor bones parts but they are just too big with these booms, it looked like it was wearing Shaq's shoes.

I'll probably put a KK board on it first, but I'd like to get an Acro Naze32 for it.

I want to use some of the Dragonfly MN1806 2300kv motors if I can get them to fit, but not sure what ESCs I will use yet.

I've only seen a few mini-tricopters on the forums here but they really inspired me to do this build. I'll update again once I got more parts.

 

[cranialrectosis]

That is a nice, elegant frame and I love what you have done with the HK CF tubing. I think the rotor bits parts will only add to the polish and appeal of your copter.

I do think it will be pretty heavy for the 1806s to lift, particularly once you add the wood dowel. That said, a 330mm David W tri-copter should draw a ton of views.

I have been looking for a small tri-copter (Armattan is pretty expensive and IMO boxy and ugly as crime). Most of the David Ws I have seen are in the 370-500mm range, so this build is of particular interest.

Nice set up califrag. Please post details. I am sure lots of folks will want to see this one fly.

 

[Twitchity]

Very nice setup indeed. This (the mini Tri) is something I've been wanting to get into designing and might tackle next.

Looking forward to seeing more pictures of the build.

 

[cranialrectosis]

Very nice setup indeed. This (the mini Tri) is something I've been wanting to get into designing and might tackle next.

Looking forward to seeing more pictures of the build.

I was gonna ask after the PDB comes out.

 

[Twitchity]

I was gonna ask after the PDB comes out.

Well now you don't have to I'm going to be out of state until Friday so unfortunately I won't be able to get any work done on my projects until then.

 

[califrag]

That is a nice, elegant frame and I love what you have done with the HK CF tubing. I think the rotor bits parts will only add to the polish and appeal of your copter.

I do think it will be pretty heavy for the 1806s to lift, particularly once you add the wood dowel. That said, a 330mm David W tri-copter should draw a ton of views.

I have been looking for a small tri-copter (Armattan is pretty expensive and IMO boxy and ugly as crime). Most of the David Ws I have seen are in the 370-500mm range, so this build is of particular interest.

Nice set up califrag. Please post details. I am sure lots of folks will want to see this one fly.

Thank you cranial! I had been looking at the armattan for a long time but agree that it looked too bulky, let alone the cost deterrent.

I am not sure what the final AUW is gonna be so I am a bit concerned too.

The Dragonfly 1806's thrust chart says it should put out ~530g on a 6" prop at 3S. I'm thinking if I can get 1.5kg of lift from the three of them, as long as I stay around 500g-600g AUW it should provide a decent ratio.

Very nice setup indeed. This (the mini Tri) is something I've been wanting to get into designing and might tackle next.

Looking forward to seeing more pictures of the build.

Thanks Twitchity!

I'm really excited about your mini spider hex PDB and am very anxious for you to get them into production.

I am definitely planning to get one as soon as you open the gates and if there is a way to be put on a pre-order list, PLEASE let me know.

 

[kah00na]

I just ordered a simplecopter mini tricopter yesterday. I started on a 550-ish tricopter then went to mini quads. I'm looking forward to the precise yaw tricopters give. I have to find some SunnySky's and ESCs... yes, I know they are in stock everywhere, I have to sell off some stuff before I can order them.

 

[califrag]

That simplecopter frame is really really nice. It was one I considered before forging ahead with the DW frame.

I am gonna be using the same small helicopter landing skids (in black if I can find em), i think they really look great.

The yaw control is what hooked me too.

 

[califrag]

The rotor bits pieces showed up yesterday and as I expected they increased the MTM to approx. 305mm between front motors and 335mm between front and rear.




I am thinking I may cut the arms down a little bit more to reduce the MTM to 255mm between the front and 270mm between front and rear. That should still leave enough room to swing a 6" or 7" prop




The servo I'm using is a Corona CS-929MG.

I'm kind of on the fence about using the rotor bits servo mount for the rear due to the weight. The two regular motor mounts are fine at 11g each, but the servo mount is almost 40g. The rotor bits with the servo add another 70g to the frame, almost doubling it.

I would really like to use a couple ball-bearings and a metal or carbon rod for an inline pivoting section similar to the simplecopter design, and then just use another regular 11g motor mount.

 

[califrag]

I didn't realize how old I've let this build sit, but I've finally gone back and made some progress on it and figured I'd post a couple small updates.

Unfortunately the little Dragonfly MC1806 motors I planned to use would just not work with the rotorbits so I ended up just using them and the esc's for this project on a Diatone fpv250 build I had sitting, since they fit perfectly for it.

The carbon arms seemed a bit weak being hollow so I found a 5/16" wood dowel at walmart and cut some pieces down to size and glued them inside with regular elmers white glue:



I need to get a weight total with the wood added, but the strength it added (lots) vs. the weight added (little) is worth it.

Next I had to cut down one of the motor mounts to match the servo mount one, as I am probably gonna make this into a mini Y6 build once I start ordering the motors.



In order to fit the gear piece, I had to take a round file and remove a little material from each inner side and it pressed right in with no slop (unlike the original mount which had a lot of play in it).

The little plastic end cap that fits the original mount wouldn't work right if cut down, so I grabbed a ball bearing from the parts I had around and it fit perfectly:



The ball bearing is a 1/8 X 5/16 flanged they are pretty cheap about $5/ea. They are from an rc car and are Team Associated part #3655

The arms ended up getting cut down to bring it down to a 250-270 size and only one of the holes on the rotorbits mounts was drilled since the other one was really close to the end of the arm.



I'm going to be using one of these Red Rotor mini pdb on the bottom to keep all the wiring nice and tidy.

I've already got three KISS 18A ESC I can use for this project, now I just need to wait for payday so I can order more POWAH. ;]

 

[Cyberdactyl]

Thanks for the rundown califrag. I built David W's tri about 2 years ago and have really loved it. But time has passed, and my flying skill has improved, and my old tricopter with the DT750's has slowly become a lumbering dog.

Don't get me wrong. it works great as a slow and strong lifter for projects such as my 3600 lumen search beam and my laser module lifter, but the opportunity to use those novelty attachments are infrequent. I'm now ready for a much more agile tri such as what appears you are building. I have everything I need really, even the 750's can be used. All I need to do is cut off about 4" of boom length, put on 9 or 10" props and switch to 4S. I've been thinking about doing it for awhile, and your build gives me a lot of encouragement.

 

[ztoon]

Hi,
I'm building the "same" (150mm booms) tricopter and waiting for motors order to arrive (sunnysky 2207).
I also have 3x18A KISS esc waiting to be tried since summer.
Flight controller is a crius se running multiwii 2.3 with a D4R Rx taped on it. The bluetooth dongle is installed between the main frame and the 3A/5V bec taped under it.

 

[SnowRocker88]

Very cool tri's you guys have going together! Looking forward to more progress!

 

[califrag]

Thanks for the rundown califrag. I built David W's tri about 2 years ago and have really loved it. But time has passed, and my flying skill has improved, and my old tricopter with the DT750's has slowly become a lumbering dog.

Don't get me wrong. it works great as a slow and strong lifter for projects such as my 3600 lumen search beam and my laser module lifter, but the opportunity to use those novelty attachments are infrequent. I'm now ready for a much more agile tri such as what appears you are building. I have everything I need really, even the 750's can be used. All I need to do is cut off about 4" of boom length, put on 9 or 10" props and switch to 4S. I've been thinking about doing it for awhile, and your build gives me a lot of encouragement.

Nice those are some great projects! My large tri has evolved through three frames and now is built on a wood frame using the optimized template for 12mm booms. When I first started flying multirotors, I purchased all the rotorbones pieces from the flitetest store, but didn't wanna crash them so had them sitting around until about a week ago. I finally redid the large tricopter frame, put the NTM 1100kv and Afro 20Amp I had on my SK450 and put the rotorbones pieces on it. Now I just need to get a proper servo that fits. I definitely agree that the build really starts to feel quite heavy and lumbering after flying the minis. Sounds like it will be a beast on 9"/10" 4S with the 750's!!

Hi,
I'm building the "same" (150mm booms) tricopter and waiting for motors order to arrive (sunnysky 2207).
I also have 3x18A KISS esc waiting to be tried since summer.
Flight controller is a crius se running multiwii 2.3 with a D4R Rx taped on it. The bluetooth dongle is installed between the main frame and the 3A/5V bec taped under it.

Wow that looks awesome! Super clean running the wires through the booms. Did you have any problems drilling the arms through the 'seam' ? I drilled mine with the line running along the side rather than the top cause I was afraid of the boom splitting along it. Those sunnysky 2207 are really good from what I've seen. Did you 3D print a little end cap for the front of the frame? It looks like it fits perfectly

 

[ztoon]

Wow that looks awesome! Super clean running the wires through the booms. Did you have any problems drilling the arms through the 'seam' ? I drilled mine with the line running along the side rather than the top cause I was afraid of the boom splitting along it. Those sunnysky 2207 are really good from what I've seen. Did you 3D print a little end cap for the front of the frame? It looks like it fits perfectly

I was afraid of splitting too at first.Maybe I'm wrong but when looking close, it's more like a "mold trace" than a seam to me. I don't see anything like a seam on the end part, just on 2 "faces", so I didn't take much care after all.
Plan is to use David's carbon booms which I already have, but for upgrading my bigger tricopter. So I ordered a new set for the mini. I can feel by hand that's it's top quality CF = looks quality, feel and sounds like it (click it with you finger nail, it sounds so stiff like a metal alloy).
The little end cap is indeed 3D printed, not by me but from David's kit and yes, it fits perfectly (very light too).
I ended using my tricopter V3 kit partly for my big tri and for my new mini.
I expect some good results with the sunnysky x2207 using 5030 prop and 4S.

 

[ztoon]

I received my sunnysky motors today, but no time to build right now, just a test fit.
HK booms changed for David's CF cut down to 150mm (back boom is 165mm).
Servo back to vertical position as motor is tall enough for prop clearance.
Fingers crossed with this tiny KISS esc's...

 

[ztoon]

Motors rotation checked (easy to change with jumper JP2, nice).
ESC calibration : I decided to make the economy of the negative signal wire from esc to flight controller. It works, but then how to do the calibration routine? Hopefully I recall multiwii has an internal routine to do them all at once without unplunging anything. Lucky this time... It was necessary as one motor start slowly spinning right after arming the tricopter. Everything goes normal after calibration.
PID are set "low" to start (mostly the yaw to stop the motor 'dancing' too much)

Weight is 362gr. My fpv gear (700tvl cam + 200mW vTx + CL antenna) will add about 50gr. but will test without first.
Ways to save some weight : servo is overkill, screws (20) are steel made, FC could be lighter (naze32 for ex), adjust wires length...

Ready for first test flight tomorrow.

 

[1387]

Looks great! I'm considering building another Windestal-style tri with shorter arms aswell! But my KK2 broke today so I have to wait for HobbyKing to send me a new one (this time Hard Case version). I built my big (original size) tri out of aluminium only. It seems quite heavy but it is cheap and can take a punch. Maybe not as much as the carbon, but for my usage, it's definatly enough.
It doesn't look as nice though, because it isn't black but shiny aluminum.
Congrats on this nice design, looking forward to you reporting back how it works! Would be nice to hear your setup summarized again, if it works well!

-1387

 

[PHugger]

Your hybrid wood carbon booms are just like what I'm doing on my Fortis. Only difference is that I used polyurethane glue. The foamy stuff (Gorilla Glue). The Elmers doesn't seem like it would bond to the CF very well.


Best regards,
PCH

 

[ztoon]

I built my big (original size) tri out of aluminium only. It seems quite heavy but it is cheap and can take a punch. Maybe not as much as the carbon, but for my usage, it's definatly enough.
It doesn't look as nice though, because it isn't black but shiny aluminum.
-1387

Consider trying wooden booms. It's also a great material.
Paint it grey or black and you get what I call "100% natural carbon fiber booms".