Easy and cheap tricopter landing gear

by stefan | March 15, 2013 | (4) Posted in Tips

Hi People,

I want to share an idea I had after building my tricopter, following the design of David Windestål.(http://rcexplorer.se ; Thanks David for sharing, great thing ;-) ).

I used aluminium booms from my local hardware store. One piece of 2 meters for about 5€. I cut three 50cm pieces and mounted the motors after dooing the tail motor mount with a BMS-385DMAX digital servo.
I again followed David's design with the front wheel steering mounts for the yaw mechanisms.
As it is sometimes difficould to get the right part in germany, for a reasonable price, I hat some additional work to manipulate the mounts I could get. The finished setup works fine but it took aboud 2 hours to get the Graupner front weel mounts right. [I linke my Dremel]
So far I spent about 33€.
With the central mounting plates, I was lucky to have a good friend, who did 1mm aluminium plates for me on a laser cutting machine for free (Thanks Udo).


As a basis I uses again David's design and added four holes for mounting the KK board directly ont top of the  plates, with nylon srews.

The additional parts I used were:
3x Turnigy Multistar 20 Amp Multi-rotor Brushless ESC 2-4S (OPTO)
1x Hobbyking KK2.0 Multi-rotor LCD Flight Control Board
1x Turnigy 3A UBEC with Low Voltage Buzzer
1x Graupner GR-12 Receiver
3x Turnigy D2836/11 750KV Brushless Outrunner Motor
3x 9x4.7 Props (2x CW, 1x CCW)
60cm Turnigy Pure-Silicone Wire 14AWG red
60cm Turnigy Pure-Silicone Wire 14AWG black
srews, shrinktube, externsion servo wire, zipties, asf.
Over all cost with some small additional items: 150Euro (today about 195 USD)

I flashed the KK2.0 board with the KaptainKuk FW 1.5 and made some adjustments.

After plugging in a 2200mAh 3S LiPo the maiden flight was OK.

But I was not satisfied with the landing gear I did.

So I developed the simple setup I want to share:
As the original setup was not very stable, a little heavy and got very dirty when getting into rough areas  outside, I wanted something else. -> And my solution is very cheap and easy to build.

Here is it:

I choose three 1,5mm, and 30 cm long pieces of piano wire and bend an L edge to one end in the first step.


Then I did a Z and bend the piano wire arround a 10cm diameter metal pipe (piano wire is quit strong).

Then I cut off about 11cm, but this depends on the amount of space you want to have between the ground and your copter frame.

Then I drilled two 1,5mm holes in the buttom side of the each boom. 5cm from the end and 10 cm apart.

After inserting the bend piano wire I fixed it with a ziptie and was ready to got.

The advantages I see with this are, the quick and easy build (15 minutes). It is very cheap, only three pieces of piano wire and three zipties are needed. I does not get dirty in rough areas and if, it is easy to clean. The air from the props is not blocked or has no bad influence when reflected. Depending on the "stiffness" of the piano wire it does give you some shock absorbation when landing a little harder. -That's it !

I hope you enjoy this idea, as it is not totally new. But I did not see this on a multi rotor setup yet and I hope to have added some development to the project you all are working on.

Kind Regards

Stefan



COMMENTS

x3mperformance on March 16, 2013
Nice solution.
However you Loose strenght in your arms, by drilling the holes in them. Everything here is a hard desission, between weight, strenght and design/esthethics.
Three Things that almost never goes along!!!
I find it better to use cable ties / Zipties as landing gear. Much more flexible, very cheap, easy to replace and no structural weakening of the arms. Weight...
Ohhh Cra.... Thats a different story.
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svefro on March 16, 2013
I see that you use D2836 750kv motors with 3s and 9x4,7prop. how is the lift with that setup?

I use D2836 1100kv with 9x4,7sf props and im not impressed with the lift. (i have a talon tri).
all up weight with fpv and camera is 1,36kg
i have tried 10*4,5 props also and that's way better but then i get allot of wobbling when decending.
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x3mperformance on March 17, 2013
I use a variaty of props on mine.
But i do not use the Turnigy D series motors.
I'm swinging 9x4,7 - 10x4,7 and 11x4,7 and they are driven of my NTM Propdrive 28-36 750 KV BL motors, rated at 350 watts.
With 9x4,7 it only draws 217 watts/18 Amps, mesured.

I see the D2836/11 750 KV is rated at 210 watt.
and the D2836/8 1100 KV at 336 watt.
So it seems like the are a bit short of the NTM 2836 serie.

But you are utterly right in the better stability and control goes hand in hand with bigger props. Think therefore the NTM serie is a better choise, for use in a Tricopter.

As for comparison, my tricopter weighs in at app. 1250 grams complete with batt, GoPro Hero3, FPV gear and all.
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stefan on March 17, 2013
Hi svefro, hi x3mperformance,

Thanks for thecomments.
I used the 9x4,7 props from my hex-copter where I could not use bigger ones as the frame limits the max. distance. On the hex-copter I used the D2836/8 1100kV with theses props and they work fine. So I reused them on the tri-copter. The tri-copter weight is exact 930grams with the batterie and the amount and speed of lift is far enought form me, as I am not a very experenced pilot.
I rated the over all sytstem power consumtion at 235 Watt on full trottle. It was quit hard to keep it on the ground and the booms were bending a bit. I will test bigger props as soon as they arrive (3-5 weeks) HK to Germany alway takes it time :-(

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svefro on March 17, 2013
in the article it says that you are using the D2836 750kv version with a 3s. im allso using 3s lipo on the 1100 kv version and the same props so the reason for the question was that you had slower turning props than i have witch again would give less lift.




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stefan on March 17, 2013
Sure, but also less vibrations.
I just ordered NTM Prop Drive 28-36 1000KV / 400W Brushless Motors to see how they do on an other tri-copter I am gooing to build of the Hobbyking X900 Tricopter Glass Fiber Multi-Rotor Frame. I also ordered several props like:
- Three Blade 7x4.5 Propeller
- APC Style Propeller 9x6
- 10x4.5 SF Propeller
I will try them to see whitch typ fits best for my flying level.

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svefro on March 17, 2013
Yes i have been struggling a bit with vibrations on the gopro, but proper prop and motor balancing takes care of most of it.
I personally like faster motors with smaller props and less angle. They react faster than larger props and descending doesn't wobble so much as larger or sharper angled props.

That X900 frame looks way better than the talon. also cheaper :) just hope they get spare parts for it. Motors seems sweat also :)
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x3mperformance on March 17, 2013
Balancing is essential...
Motors, spinner/prop mounts and props. All needs to be balanced to get a really good result at a GoPro.
With the NTM's i always use the acessory prop mounts in alu, they have a really good quality. and with the motors, it's a blast to balance. Have only come across one single engine, that needed some serious wok, to get in balance.
And i use lazer light to balance my motors with. See on Flitetest how to balance with lazers. :-) It's cool, and it Works soo well.

When you build tri or quads for video shots, it is important to get low KV motors, that's due to a broader band with, Resolution....
And it also eleminates some of the worst high resolution vibrations. And the can manage the bigger props. Power on demand, and lots of it.
See Ycopters video on how to setup a tricopter, and you will see how good it can get, with a Little bit of Work.
After a proper balancing job, you can take it even further, with some really good dampening of the camera mounts. See also Ycopters Projects.

Stefan.
I like your Pictures, good quality, informative together with the text.
Nice.

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stefan on March 17, 2013
I did a quit measurement of the amount of lift the my tri-copter produces. I took a scale like one for fishes or luggage an fixed it in the ground. On full throttle it stoped a 2.34kg.
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Easy and cheap tricopter landing gear