*Links to other HOWTOs*
DIY MultiWii Shield and pinout information
DIY ESC firmware flashing

Hello everyone!!! I also posted this as a blog, but I figured it would reach more people here. I hope this can help others make a cheap multi and start having FUN!!

Wanted to share my current tricopter (also Y6) design. I am on my third big crash and nothing broke on the frame yet! (30ft+ dead drops...)

It is all made from 6mm Plywood, 12mm wood rods and 6mm diameter nylon threaded rod cut to size.

Updates and links:

You can see how I use masters to make the parts and how you can make one using the same principles up to 12 arms: http://www.rcgroups.com/forums/showt...7#post19134004

This is a link to a post in this thread of a build log of a newer version of the tricopter frame: http://www.rcgroups.com/forums/showt...2#post19178391

Latest 120 degree FPV/AP GoPro quad, pictures and video: http://www.rcgroups.com/forums/showt...4#post21221504

The tricopter:

This is how it looks from the top:





On this picture you can see the two top frame layers. They are screwed together with the nylon rods and nuts and the pressure holds the booms tight, but loose enough to give in case of a crash. The top plate only has holes for the boom holding rods, the bottom plate is cut a different shape to have holes for the lower plate support

You can see how the booms are held on this one:



Same principle for the motor mounts, which are coaxial ready:



This is my yaw mechanism, very basic. The 450 blade holder is simply screwed in the wood boom You can find a close up picture and some discussion about it in that post on page 2 in this same thread: http://www.rcgroups.com/forums/showp...0&postcount=22



Finally the electronics plate of the frame. It is help by long nylon rods and all of the weight is located there. Battery + MultiWii + GoPro. This imo helps a ton with vibrations and makes it very easy to separate the "drive" part of the frame from the "control" part of it.



If you guys can see ways on how I can improve on the design I'd love to hear it.

Hope it helps others get into the multi rotors hobby with a very basic, cheap and durable frame. It is very easy to modify for as many arms as you want, just make different center top plates and you can always keep the same lower plate for "control" electronics!

Onboard GoPro video showing vibrations, or lack thereof, at a PID setting of 11 P in the Multiwii GUI in acro mode, no auto stab setup yet. Also to note that my props are terribly unbalanced RCTimers EPP 10X4.5 clones and cheap RCTimer 2830/14 motors. The only noticeable wobble is during straight and fast vertical descent. I guess I could lower my P a bit and work this out. I have no idea if the results are good compared to other multiwii tris.

Testing (2 min 24 sec)

Also you want to make sure your props are properly balanced, blade and hub. Here is a good video on the subject:

HorizonHobby.com How To - Prop Balancing (13 min 41 sec)

Then you will want to balance your motors, spin em up and try to find the lowest possible noise. Video showing the method:

balancing motor rotor and open your ears... (2 min 30 sec)

After all this you will want to balance both together. Put the prop and the adapter on the motor in one position and check vibrations, rotate the mount/prop by a few degrees and try again until you find the best prop/mount position. This is dynamic balancing and is probably the most important of the three as it can also counter for bad prop and motor initial balancing.

Then look into vibration isolation solutions for those you just can not get rid of.

That video looks really good vibe wise, nicely done!!!

Curiosity, why the zip ties on the motor bell?

Paul

Originally Posted by Helidaho

That video looks really good vibe wise, nicely done!!!

Curiosity, why the zip ties on the motor bell?

Paul

If I'm correct, sometimes, the motors are so out of whack on weight that you can take some of the smaller zip ties and snap them to the bell. Then run the motor up to speed and listen for the sound. Keep turning the zip tie till you hear barely any sound at all.

That way, it balances out your motors and such. On the ones I've balanced, I have never had to go more than a few layers of clear fingernail polish to get them balanced out.

Thanks guys, and yes this is to balance, but both the motor and prop.

I always have crazy vibrations right before mid throttle, after that it kind of dies out.

So what I did to dynamically balance it all together is disconnect all esc save one, and run it. See what prop position gives me the less vibrations. Then add a ziptie for finer balance and rotate it around the sweet spot.

I don't think my motors are that much out of balance, but the props and prop mounts sure are. I think the best way is to balance everything separately first, then all together. If you don't do the dynamic one it is kind of pointless.

Great job mate
I like the round dowel booms.
I have been toying with round rather then the square I use now.
How have you stopped them from rotating, just friction on the bolts or are they pined?
Rob

Originally Posted by onlyifamppowered

Great job mate
I like the round dowel booms.
I have been toying with round rather then the square I use now.
How have you stopped them from rotating, just friction on the bolts or are they pined?
Rob

Hey Rob, thanks for the kind words. On the tri pictured in that thread I had the nylon rods exactly 12mm apart, the diameter of the dowels. Just pressure and friction prevents the booms from turning, even with a little force. In case of a crash they would still pivot and absorb the bulk of the hit.

Now on my motor mounts I tried to space the rods tighter so the dowel boom barely fits. Been working real good as well so I plan my next frames with that newer tighter spacing, probably 11,7mm.

The round booms also have two major advantages for me. They can be rotated a bit to give angle offsets to your motors for more yaw authority if needed, and in the same weight factor will be stiffer than squares and less prone to wraping.

I made a new "master" part to make any kind of setup from quad, tri to dodeca (12?), will snap a pic of it tomorrow.

GREAT STUFF i love homebrew

Great stuff
I have a new idea to try now !
Thanks
I have been building with 18mm Sq dressed pine and like the way it absorbs vibs and ease of use but have always felt the large flat face to the airflow was a problem. I was going to try the dowels but you just answered all the questions for me.

People can have their pretty hi-tec carbon wizz bang stuff, give me hardware timber !!!

I use the same motors and have not balanced the motors with out any real problems, I do balance the props. I have given up on the rctimer props, too out of balance and fail in flight.
I have just been trying GWS 3 blade 9050 props and love them, sounds great, runs smoother, and can take 4S full noise punch-outs and not throw a blade. Give them a go, you will love it. I have more on order from Backorder King and hope to get them soon ????
Your video is nice and smooth too, I don't own a gopro (yet) but did strap a friends one on my tri to see how it went. No vidbration dampering , no case, just roughly attached with rubberbands and the footage is no so clear. I will post a video of it and a video of my first quad to give you an idea of how "ghetto " my set up's are. The tri's I have built are all ugly and kinda rough but fly well so

LONG LIVE HOME BREW !!!

WiiTee Copter II (1 min 24 sec)

quad first settings.MOV (1 min 45 sec)

Homebreeeeew The fact that I live on a somewhat remote island makes building with local supply a no brainer.

For our applications I don't see why there is not more people flying at least wooden arms to help wih vibrations and cost of repairs. i don't see a real agvantage to cf besides weight and even that can be problem in bigger winds. But I guess people just love the bling hehe, so do I btw. But always function before form ^^

The first video is also very smooth, I need to give those props a try. Was also thinking about ordering some APCs

Thanks for the comments everyone!

Nek,
More video proof that a frame put together for a few dollars can take better video than frames costing 100's of dollars.

To give the blade holder screw a little more strength in the dowel, I coat the screw with release wax, put a few drops of epoxy in the dowel hole, install the screw and let the epoxy cure.

Nice job. Thanks for posting!

Originally Posted by ridgebackred

Nek,
More video proof that a frame put together for a few dollars can take better video than frames costing 100's of dollars.

To give the blade holder screw a little more strength in the dowel, I coat the screw with release wax, put a few drops of epoxy in the dowel hole, install the screw and let the epoxy cure.

Nice job. Thanks for posting!

AWESOME idea!! That was one of my gripes with the yaw assembly. I did not want to glue it in as it would be a pain to change it in case of a crash. This solves all the play issues I could get after little bumps that required a new boom just because the screw got a tad loose.

As a side note, the way it is made you can unscrew all the booms in a few minutes for transport and reassemble at the field just as fast. Gives a chance to double check everything when you do so as well

That's why I wanted to keep plugs from each ESC to the power distribution system. Also very good when you only want one plugged in. I always used deans in all of my RC stuff but I am now thinking about switching to XT60 on all my batts. How do you guys using them like it? Heavier than deans??

For my new power distribution system I want to change deans to 3.5mm plugs, should be able to make something more compact and easy to connect/disconnect for testing purposes and swapping out arms.

So here are the pictures of my masters I was talking about. The way I use them is lay them over a blank plywood sheet (the very small holes are from the nails holding the master and the new part together) then I just use my drill press. Make 2 new parts, cut them to shape and you have a new frame



The one on top is the one I used to make the tri from the 1st post.
On the side you can see my newer motors mounts. Tighter spacing between the rods and wider between each pair for more pressure area.

The lower master is for my next tri or Y6. I used the newer motor mounts master to make the holes layout the same since those mounts been working really good for me. I also made this one much more compact than the first version. I'll see how it holds up abuse, but it should be a tad lighter.



Now I just made this last night!!! The inner row of holes allows for a tighter X/+ 4 or Flat 8. The outer row of holes can be used for 3, 4, 6, 8, 10 or 12 arms!!! Just lay it over two blank sheets, nail them together, drill the right holes and voila, new multi frame

Some holes do not look lined up at all, that is because I used my master one way for the outer holes layout, and the other way for the inner ones, but relative to each other in the same layout they are very square and aligned

Outer holes set are every 30 degrees, inner holes set are 45 degrees apart. No CNC, all by hand and eye lol so yeah it has to be off by a few mm here and there just as my first tri probably is and it flies great so I could not care less haha

Hope you guys like it

another tip

when you cut wood and rill holes grab thin ca glue and coat the edges so for the above pix coat each outer line of the square and for each hole draw a ring round each hole on both sides like how you used to put paper rings round thin paper before putting them in binders?

thin ca/superglue will soak into all the cuts and grain of the wood and transforms it into a much stronger material think its rubbish? leave another piece untreated and go play frisbee with both bits of wood for 30 mins

and always use some wood somewhere in your builds it looks great varnished or not, it helps soak up vibes, it wont kill you if you inhale it?? ( i hope? lol) can be found everywhere (one day i was stopped at the lights and saw 3m ply paneling being ripped out of a shop, next day i had 4 free center plates cut for a quad) and its lighter than carbon if you sprinkle fairy dust on it for us lesser mortals who cant get fairy dust from the local shop the gods have sent us motors props and escs of many varieties and sizes and lipos!

Good point, (wood) It won't kill you when you inhale it ! Might be bad ???
I think the glues used in ply will be bad, however dust from cut/drilled carbon fibre WILL kill you. I think it's the next asbestos. Might not get you this year or next but it worries me enough not to use it.
I have seen wood painted matt black and it looks like poor man's carbon.

With wood ( and pool noodles ) we can have flying machines that I think fly as well as the big $$$$ models
Rob

Very good idea on the thin CA around all the holes, especially for my masters!!

In a couple of days I will probably start working on a newer frame and will try to document the process. I am sure it can help some, and some of you guys will spot flaws and ways to improve here and there, good stuff

Thanks again n3m1s1s ^^

Coincidentally I just ordered three motors like the ones you are using, how much does your tricopter weight and how do the motors handle it?