Tricopter FPV

[0636]

I always want to do FPV "heli" style but never dared to put FPV gears on my helis (even on most stable one - Trex 600).

Well, tricopter is an answer for those who crave for slow and smooth FPV flying. Airframe is cheep and pretty stable. I've spent about 80 bucks on it plus FPV gear... and here is the result...

[ame]http://www.vimeo.com/11792998[/ame]

[Crash9]

Nice job. I've been looking into building my own designed Tricopter or Quad. $80 seems cheap. Is that for the complete ARF Tricopter...just add radio and battery or is this a home built Tri. Any links or build info on your set up like what gyros, how many if any? Also if you can answer.... How does a Tri handle high winds and heavy payloads? the reason I ask is I fly in the wind a lot out in the desert and it's always blowing 15-35 knots and my 600 rex has no problems with wind....450 different story . Any info would be greatly appreciated. Thanks

[0636]

Crash9, I saw you are flying Trex600 and even T450 by FPV... I never dared to put FPV gears on my helis, even on T600... with lack of peripheral vision and intimidation of 600mm CF blades swinging at 2200rpm...
But I always crave for "heli" style FPV and here we go, I guess, tricopter is a ticket.

Well, I'm flying CP helis for 3 years (some 3D moves etc.) and on a scale from 1..10 I can give tri-copter solid 4. It's somewhere easier then CP heli but somewhat different.

Hovering is stable - no problem. Slow flying - fine. Tri-copter likes a smooth cyclic. Turning has a bit lagging response, it's understandable, cause of that motor pivoting thingy. Changing altitude - a bit lagging too and sensitive, tri-copter can tolerate rapid ascend but does not like fast descend at all. On rapid descend, tri-copter become unstable and have tendency to flip over. I think it's due differences in ESC, gyro channels, once you have it tuned at hover level it wont stay in perfect tune at different power levels. So, again, smooth and small changes is a key.

The video above is done with some wind gusts up to 10mph. Tricopter handles it well, just small bumps.

I found that better to trim tri-copter using correct CG, this way it can hover 5-7 sec. hands off. Overall I think I can get used to these differences in piloting tri-copter.

My config:

17 inch arms
motors AX-2213N 800kv (3x6 bucks = 18)
ESC - HK-SS30A (3x7 bucks = 21)
props - GWS-RD-9047 (needs to be balanced before use)
gyros - HK401B (3 in rate mode, DS on and tail in HH mode and normal) (4 x 13 bucks = 52)
radio - Futaba T6EXHP 72Mhz ( just had a free rx for it, so using it instead of my DX7)
servo - 85MG (got one old)
some lipos 3s 2200 (got plenty from Trex450)

So total expenses to build tri is 91 bucks and one weekend to tune it.

Arm gyro's input connected on A, E and P channels on rx, all 3 gyro gains are combined and connected to Throttle channel. Outputs go into corresponding ESC.

I don't use external BEC, just all 3 ESC's voltage regulators connected in parallel through common power bus.

Tail gyro goes as usual, to rudder and gyro channels and controls servo which pivots tail motor assy.

Arms Gyro gain in Normal Mode - 10% flat on throttle channel (this is Futaba radio) I've tried 8% and got just tiny bit of shaking... but 10% is stable enough. When I put FPV stuff on it I even lowered gain to 16% - still stable but less pron to vibrations.

Tail Gyro in HH mode - 85% (little bit of a drift, may be because of vibration but this is ok)

All gyros - limits MAX, delay - MIN

120 degree Swash - A 32, E 32, P 100
Pitch curve - 20, 30, 40, 50, 80 . Actually controls ESC. Starts with 20 (in my case motors is about to start at this point) and get some flat curve at middle. This way I can hover at middle stick and can control rpm more precisely.

If you put bigger props, say 11x4.7 or 10x4.7 you can get away with more load. I've tested mine and got about 400-500g load capacity. Of cause at the expense of current consumption. I found that my current props are doing best for my config.

EPA - 100%
Expo on cyclic - 30%

FPV camera KX191 with video tx 500mW 900MHz. Got power from main lipo through some filters.

total AUW - 1000g
current in hover - 13Amp (by ET data logger)

so, can hover about 2200 * 0.8 * 60 / 13000 = 8.12 min - not bad, but in reality I would never go more then 7 min. in fear of ESC cutting power and there is no way tri-copter would auto-rotate.

Well, that's about it. There is a lots of reading in RC Groups about this, I've spend several days just to go through 450+ pages... someone contribute a very valuable info but someone just likes to blabber wasting space and everybody's time.

http://www.rcgroups.com/forums/showthread.php?t=1142429

PS: I intended to change my current rc rx into something with fail-safe on ail, elev, and pitch channels... the reason if rc link is lost - all three motors become unpredictable. With fail-safe it will just shut ESC down.

[Crash9]

Man!! you have answered a lot of questions I've had over the past year about the Tri's. I tried reading through that thread back in the start and Mongrals thread at RCG but your right it gets of topic and a lot of jibber jabber. I asked these same questions over there and got a poor responses. Thanks for taking the time to answer... as it is much appreciated and other readers can learn also.

So I'll get into building one myself and save the $200 they cost. After reading your post I think it would be good for close by and low video shots that I like to do from time to time. I won't use it to replace any of my CP helis but will add this to the fleet for a different FPV/AP platform . I'll report back as I get going on the Tricopter. Thanks again, Scott

[maxout]

That looks great 0636. I tried the RC Group forum myself, so I applaud you for hanging in there and pulling this info. Thanks for posting your findings 0636.
Crash9, I know you'll be flying one of these in no time.

[0636]

Last weekend I was flying over marina. Little bit scary, cause in case of any mishap tricopter would be lost but was fun anyway.

[ame]http://www.vimeo.com/13812359[/ame]

[modeleryang]

The tri-copter setup resemble exactly the Swash place setup, it should only needs three gyro (Roll, pitch, yaw), a flymentor should be able to handle it. this is my thought though

Can you explain a bit on How do you compensate the torque of tail rotor, it seems you don't have a forth totor.

Good job buddy, thank you for sharing.

[0636]

Torque is compensated by pivoting tail motor. By the way, there is 4th gyro in HH mode which handle servo which does pivoting tail motor.

[0636]

Btw, here we go with another video. This time I was using ingenious floating device strapped to tail boom.
It should provide additional buoyancy but I really was not up for testing it.

[ame]http://www.vimeo.com/14116468[/ame]

[chrisjdoran]

Hi all,

Like you guys i got hooked on the cheap tri copter builds, mine is based on David Windesthal's from rcexplorer.se...

The build was great using all HobbyKing stuff, it took me nearly two days to complete, it's my first rc build lol but i think it's almost RTF.

The only thing left to sort out is the motors are spining the props the wrong way, pushing the tri into the floor, which is definitely better than shooting up on startup!
I use an external UBEC as a "Jump Starter", then fire up the esc's.
Ailerons and elevator etc are all working fine, i'm using the Futaba 6ex 2.4 TX and rf606 receiver, i managed to get it programmed alright.

Is it a simple case of re-wiring the moter wires tothe esc's or can i do it through the TX?

Any advice would be of great help
Thanks,
Chris.

[0636]

The only way to change direction of motor rotation is to swap two of tree ESC-motor wires.

PS: nice tricopter, are you going to FPV with it?

[chrisjdoran]

Indeed i do mate, this is the perfect platform for a certain type of FPV that planes just cant offer
Exploring the wilds around my house!

But having said that i really really want to do a nice long final approach from say a radin, while looking at the F16 type HUD, haha i will get that going sometime!

[PNut]

Nice rig. I gotta try that!

[maxout]

Originally Posted by 0636

I always want to do FPV "heli" style but never dared to put FPV gears on my helis (even on most stable one - Trex 600).

Well, tricopter is an answer for those who crave for slow and smooth FPV flying. Airframe is cheep and pretty stable. I've spent about 80 bucks on it plus FPV gear... and here is the result...

http://www.vimeo.com/11792998

Thanks 0636 for getting me going on my tricopter project. It took a while with every thing going this summer, but I finally got it built and hovered it today. I had to hover inside because the weather was lousy today. I went all aluminum and my setting are pretty close to what you had suggested. I had to settle for a mystery ESC 30A, so far so good. HK had all of the other ESC's on back order, when I order. Thanks again to you and all the guys here on HF and those over on RC Group. Here's a few photos of my tricopter.

[jockstrap]

Way too cool guys - I'd love to build one of these..

Can anyone give a good detailed build / setup and pic of the tail control and how you made it pivot.. is it just some simple rod into the wood end or do you have some fancy pivot pin setup you use??

[maxout]

Hey jockstrap, I went with all aluminum for my build. This was just a preference I chose. I used 3/4" square aluminum tubing for my arms. I cut 1,1/4" from a piece of 3/4" solid aluminum and drilled a 5/16" hole in the center of it, parallel with the length. The solid piece was inserted into the square tubing and a 5/16" x 3,1/4" aluminum rod was inserted into the solid aluminum, holes were drilled, through all three, and tapped and 2 screws hold everything in place. I left 2" exposed to mount my motor base onto, which was made of light weight aluminum bent into a modified upside down U shape. The top portion of this bracket must be large enough to mount your motor. I drilled 5/16" holes into each end. The motor mount slides onto the 5/16" rod and pivots. I had to determine where I wanted my servo to set and how I was going to attach my motor mount to my servo. There is also a spacer between the motor mount and the end of the arm. I also attached a piece of 6061 aluminum to beef up the inner side of the motor mount, which I attached a ball link, to connect to my servo arm. Keep in mind, there are setups that guys have made that do not require aluminum (wood) and work maybe even better than mine, so don't think you've got to go with aluminum. I chose aluminum because I like working with metals and will take hours making up say a servo bracket, all by hand. If you go aluminum, you're going to have a weight issue. I had to drill holes into my arms to reduce the weight. Hopefully this gives you some idea of what is involved in building a tricopter's tail assembly. These guys, here on HF, like 0636, crash9, signguy over on RCGroup and others, follow their guidelines and tips, you will get there.

[jockstrap]

Hey - thanks heaps for that...

I was looking at "Mikes Tricopter" design - the first one with the camera mount at the front and sort of looks like a manta-ray... not sure if you know which one..

But his website seems not to respond - he was selling them for about $75 I think...

Do you or anyone know how to contact him or where to buy from ?

[maxout]

Originally Posted by jockstrap

Hey - thanks heaps for that...

I was looking at "Mikes Tricopter" design - the first one with the camera mount at the front and sort of looks like a manta-ray... not sure if you know which one..

But his website seems not to respond - he was selling them for about $75 I think...

Do you or anyone know how to contact him or where to buy from ?

I've looked at many designs over the last couple of months, I'm not recalling Mikes design. I don't know if you have looked at FPVPilot.com., he's got a good design. He has good workmanship and the price is right. If I had not built my own tricopter, I would have purchased the one he's producing.

[jockstrap]

Ah - yes I've seen that one.. the alu one.. not bad but not my thing..

This is the one I was interested in - http://www.rcgroups.com/forums/showp...3&postcount=11

[Coburg]

Just before any asks, the "Mikes" is not mine ok .

Jock, have you seen th Jakub Tri frame kit. Comes in below the same price as the "Mikes" but is a little close to the 6061 in styling?

http://www.kkmulticopter.com/index.p...=annonce&id=37

I have one on order to see what they fly like, and while your on the site check out the controller boards as well

Mike.

My built thread is over at http://www.heliguy.com/Forum/my-tric...ad-t52550.html