Build A Tricopter
First build thread for me here. Seems lots of you want to build a tricopter for AP. I have been using my copter for some time now, and it has proven very reliable. The frame is very basic. I will include close up pictures to help you build a frame. This is by far, not the cleanest looking machine. There are many more refined ways to do this. This build is for a basic AP tricopter. It will fold, and take lots of abuse. It will also carry a 6-8 oz camera with ease.
here is a video of the final project...
Picture of tri using hk401's with instructions
picture 2 has bad info. Set delay all the way ccw, and limit to half way. The line should point straight up
Here is the go pro soft cam mount. NO JELLO AT ALL!
Here are more details on the new cam mount
Corona receiver arming
Another way to do the yaw motor mount, Thanks Tom!
Arming with eurgle/turnigy/imax 9ch 2.4 radios
An easy way to make your copter more visible post from page 160, there is a video near the page middle too.
A simple fuselage to make a predator copter
Balancing motors with CA
A youtube video of the correct way to balance motors, YES, you should balance motors too!!!!
parts you will need...
A transmitter capable of CCPM mixing, dual rates, and expo. I use an OPTIC 6 from Hitec, and an EURGLE ( imax 9, turnigy 9 ) radio available from R2hobbies $104
DT 750 motor X3 http://hobbycity.com/hobbycity/store...utrunner_750kv
$12 total $36These are now $8.99 each, if you can get them!
Get a 4mm drill bit, 4mm washers, and some 4mm nuts to hold on your props, they won't hold on by themselves..
New Better motor
Same power as dt750. but much smoother and only $9.99
Other PROVEN motors with DT750 power
Speed controls for DT750 X3 http://hobbyking.com/hobbyking/store...ies_25-30A_ESC
I don't use these, but they are said to be better than the card programmable speed controls, because they work well with the HK401 gyros.
You could also use tower pro 2410-09 motors with 10x4.7 props
You can use any motor in the 600-1000kv range. The lower the Kv, the more resolution each step of the speed control will give you. Motors over 1000 Kv are more difficult to make stable. That said, some have used ducted fans and made it work.
Speed controls X3 Use 10 amp versions for 2410-09 motors
$10 total $30
speed control programmer X1
$7 This just makes things easy, its worth $7
Battery X? this battery works great.
$14Now only $9.99
3.5mm connectors X2
$4 Total $8
$34 total $102
A better gyro HK401b
Get 4, they work great on the tail too. You will need a separate gain channel for the tail gyro
Yaw gyro X1
Or use a HK401b listed above
Volt warning A must have!!!!
This is $230, you still need wire, battery plugs, a servo.
The yaw gyro listed will work fine, but the E-SKY EK2-0704 is a great gyro, available from R2hobbies around $15
Almost forgot You will need three ( get lots of extras.) 11X4.7 gws slow flier props. Or reduction drive props as Hobby City list them. These are the best I've used, they are light, cheap, and reasonably durable.
FOR AP!!!! Get apc 11X4.7 slowflier props. The gws are not durable enough for carrying weight.
My frame is built from 1/4" birch plywood, available from Home Depot / Lowes. I buy it in 2'x4' sheets. You could also use midwest 1/4" ply, or any similar material. The picture below shows the frame center blank, with the stiffener that mounts under the arms, using the nylon bolts that are threaded into the arms.
The arms are cut from 1/2" poplar sheets, also from HD and Lowes. I ripped the arms 1/2" wide and 20" long. You could rip them a little wider. The arms on my copter are a little too light. 1/2"X5/8" would be a little stiffer. The PDF file is the center frame, formatted to fit on an 8.5X11 sheet. You will need two arms cut to 20" long, and one cut to 18 1/2" long.
The short arm will be the rear "yaw" arm. The rear arm will also need a groove cut in the bottom, to accept the carbon rod for the yaw pivot. All the rods are drilled and tapped for 1/4"X20 nylon bolts. The holes are drilled about 5/8" from the ends of the arms.
Here is the most difficult thing to build. The yaw pivot. I have made an attempt to build a robust, simple mechanism. There are lighter, more exquisite ways of doing this. This tri has proven itself in at least 5 hours of flight without any mechanical problem. It looks tough, but works great.
You can use a carbon rod, or tube. A carbon arrow shaft works great. This rod only needs to be 6-8 inches long by 1/4" in diameter. The rear arm ( the 18.5" long one) needs a groove cut in the bottom. The groove needs to be sized to snugly fit the carbon rod you will use for the yaw pivot, leaving it standing slightly above the top of the arm. The rod is fastened to the arm with wraps of strapping tape ( the glass fiber type). Don't skimp, it should be wrapped very tightly, down the complete length of the rod. The rod should stick out past the end of the arm by 2.5".
The motor mount I am using is made from 1/2" pvc. This is also sold as trim board material called azec ( I think) You can use a piece of the same wood as the arms ( poplar ) or build something from laminated plywood. I drilled a 1/4" hole ( size this to suit your yaw pivot rod) in the block for the pivot rod. Then attached a piece of .040 aluminum sheet to the face with screws for the servo rod connection. The red tube behind the motor is a short piece of surgical tubing that stops the motor mount from sliding off the tube. The servo is attached with double stick tape, then wrapped with strapping tape for security. Again, not elegant, but functional.
I use strips of .040 aluminum for the sacrificial folding clips. These clips will allow the arms to release during a crash, and hold them securely during flight. The strips are bent to go around the frame center and arms, and leave enough length to wrap two slices of surgical tubing around the bottom. They are bent in, then outward, to leave a "hook" to hold the surgical tubing.The strips should be cut 1/2" wide by about three inches long.
Instead of the clips, you could use two wraps of the strapping tape. It will be a little harder to remove the tape to fold the tricopter, but it does work, and will break free in a crash.
A picture is worth 1000 words.............
United States, AL, Foley
Joined Nov 2005
Thanks for all your efforts and information sharing. I've got all the parts on the way from HC per your list. I want to use one of these machines for AP as an alternative to my AP heli and plane.
Gotta make some trips to Home Depot now.
The meat and potatoes
Here are a couple diagrams showing the wiring, and receiver wiring. This seems to be a problem for some. The main wire harness should be made to fit your tricopter. You may want to place your speed controls at the motor, or on the arms, or under the center frame. All of these will require different lengths for the main harness. Sharpen up the soldering skills. A bad joint here WILL crash your copter, and its camera payload ( ask me how I know...). The deans plug " switch" is not totally necessary. It will allow the gyros to arm first, not allowing the speed controls to go into programming mode. It is also a safety item, but, can be thought of a a point of failure too. I don't use one now, but its up to you. Use a BEC, or a simple 7805 voltage regulator. It is cheap insurance against speed control BEC failure.
The second diagram below does not show the gyro gain wires. These can be grouped together, and attached to the throttle channel, or the gyro gain channel. You can use a servo extension cable to connect all the gyro gains. Just remove the outer cover of the female end of the cable ( the end you would plug the servo into). This exposes the three pins. Attach the gain plugs side by side so that the signal wire is attached to the pins. cut the servo extension, and remove the positive and negative wires from the male end ( the part that connects to the receiver ). You should have one wire coming from the male end, and three from the female end ( with gyro gain wires plugged in) Just connect the single signal wire to the three ( pos, neg, signal) wires from the other end of the extension.
You can also cut, and strip the gyro gain wires and solder them to the signal wire of a servo plug. Either way, the three gain wires should all connect to the signal pin of the channel you want to control the gyro gain.
Ithaca, NY USA
Joined Oct 2000
Thank you for all of the research and design and testing you (and others) have done to create and perfect this machine. Thank you also for your generosity and time to generate and share the plans and instructions.
I think there's going to be a rush on parts from Hobby King.
You will need to setup your radio for 120 degree ccpm mixing. Attach your gyros/speed controls according to the diagram in the last post. It is very important that the gyros be placed in line with the arms, with the cable and speed control connection facing down the arm. As you can see in the picture in post #4, the gyros must be parallel to the arms, but not necessarily at the end of them. The gyros can be placed anywhere, as long as they are in the correct orientation. The gyros should be set to Reverse set to A, and std-digital set to std. I have not had luck with the digital setting on the gyros. But Sebastian or bas10an uses the digital setting and is very pleased with the performance.
The basic setup for the radio ( on the hitec ) is...
swash ch1 80% ch2 80% ch6 100%
pitch curve 0 inh 50% inh 100%
throttle curve set to 8% on all points. This is actually your gyro gain for the telebees. If you have enough channels to have a separate gyro gain channel, go for it.I needed ch 5 for the camera trigger, so I used ch 3 for the gain. because the throttles are running on the pitch channel you will not have throttle lock. Be careful.
dual rates & expo acro ( for loops and general fun flying )
D/R ch1 90% ch2 90% ch4 125%
expo ch1 -15% ch2 -15% ch4 +100%
Lower rates for AP
D/R ch1 85% ch2 85% ch4 +100%
expo ch1 -30% ch2 -30% ch4 +100%
The lower rates make it fly like a honey bee fixed pitch, the high rates is where I fly 95% of the time. I would like to get more yaw movement, but it is enough for fun flying.
I will post setup for the EURGLE when I get that radio into a tricopter with the telebee gyros. Right now it is in the GWS gyro tricopter, they don't have a remote gain.
If you have a tricopter flying with a different radio, feel free to post your setup. Mike, are you out there?
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