www.RCHELISPOT.com

Building a Tricopter

Author:  321 [ Tue Aug 03, 2010 9:09 pm ]
Post subject:  Building a Tricopter

Drawings nearly completed (they're never completed), fabrication has begun on my new tri-rotor heli.  Actually, the frame and motor mounts are already finished and assembled.  Here's a video of the motor mount material being cut:

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Author:  blighty [ Tue Aug 03, 2010 9:58 pm ]
Post subject:  Re: Building a Tricopter

you need a cnc Thumb Left but you cant beat doing it by hand  Embarassed

good job!

Author:  GhostWolf [ Wed Aug 04, 2010 5:13 am ]
Post subject: 

No way I can believe that "all thumbs" tag now.   You must be a surgeon in your day job!

Author:  Reflex [ Wed Aug 04, 2010 7:49 am ]
Post subject:  Re: Building a Tricopter

Great job

I need one of those tables !

Author:  SENECA [ Wed Aug 04, 2010 7:54 am ]
Post subject: 

Nice work!

Author:  321 [ Sun Aug 08, 2010 10:38 pm ]
Post subject:  Re: Building a Tricopter

Finished up the swivel bearing carrier assembly, but hand-fabricating it was a little bit insane.  Stacked a servo on top and tested its operation.  I am really glad that whole procedure is over with and the tri-rotor is finally starting to look like something.

Image

Author:  fufu70 [ Mon Aug 09, 2010 4:39 am ]
Post subject:  Re: Building a Tricopter

pretty cool Thumb Left  Very Happy

how much more until it gets airborn Question

Author:  321 [ Mon Aug 09, 2010 6:05 am ]
Post subject:  Re: Building a Tricopter

fufu70 @ Mon Aug 09, 2010 4:39 am wrote:
pretty cool Thumb Left  Very Happy

how much more until it gets airborn Question


So far, no work has been done on the flight stabilization circuit board so I still have to order the parts, assemble and program the main chip.  With lots of other non-RC things to do, I'd be happy with 3 or 4 weeks to maiden.

Author:  SENECA [ Mon Aug 09, 2010 6:32 am ]
Post subject: 

That is one strange looking bird.

Author:  321 [ Fri Aug 13, 2010 2:04 pm ]
Post subject:  Re: Building a Tricopter

OK, all my electronics components for the controller are here.  Talk about getting in over my head; the resistors are about the size of a pin head (if that) and the markings are so small I can barely read them!  Not only is the soldering going to be a delicate operation, but I will need to be super careful not to lose anything or get any components mixed up.

The chip programmer also came.  I'm not even going to look at that until a circuit board is assembled.

I have two circuit boards in case something goes wrong with the first one, but I'm hoping to get 2 controllers out of them.  Wish me luck!

Author:  SENECA [ Fri Aug 13, 2010 2:50 pm ]
Post subject: 

Good luck!  Smile

Author:  321 [ Sun Aug 15, 2010 8:34 am ]
Post subject:  Re: Building a Tricopter

Thanks Bill.

Call me slow, but I spent my Saturday working on the controller board and finally finished the soldering at 1 in the morning.

It started with the disassembly and desoldering of 3 hobby king 401 gyros to rob parts out of.  At $13us a piece, this is the cheapest way to obtain the rate sensors needed for the controller.  They also yield SMD pots.

To do the reflow soldering, I fluxed the SMD pads and applied a dome of solder to all of them (on the spare PCB also).  Then, on an aluminum sheet on the stove, I positioned all of the resistors and capacitors onto their respective positions.  To get everything positioned as if it were done by a machine took 2 hours.  Next, the stove element heat was turned on.  It very soon became evident with a glass-top stove that temperature was going to be difficult to control.  The solder started melting rather quickly and I turned off the element before my infra-red thermometer peaked at 410F.  Since that's not a lot higher than the melting point of the solder, it should be ok.

After the smoke cleared (the exhaust fan saved my marriage) from the hot flux and the board cooled down, things looked pretty good.  But many of the components floated like a boat on the solder before they settled down and so they weren't positioned perfectly any more.  Not a problem, except one resistor looked like it was too far out of place.  An ohmmeter confirmed that it was an open circuit and the resistor was then repositioned with the help of a soldering iron.

SMD reflow soldering done and double-checked, there was still plenty left to do.  The thru-hole components--the headers and voltage regulator--had to be soldered to the board.  Getting the headers straight required a lot of monkeying around.  Then the rate sensors were hot-glued into position.  Finally, the rate sensors were wired to the PCB, yet another picky task.  But in the end, one board assembled!

For the spare PCB, I'm going to try to find an old toaster oven to do the reflow soldering in.  Better temperature control and the job can be more appropriately done in the garage instead of the kitchen.

Next, I will attempt to load a tricopter program on the board's microcontroller.

Author:  SENECA [ Sun Aug 15, 2010 11:43 am ]
Post subject: 

Its gonna be interesting to see this thing through to the end. Wink

Author:  321 [ Tue Aug 17, 2010 9:47 am ]
Post subject: 

SENECA @ Sun Aug 15, 2010 11:43 am wrote:
Its gonna be interesting to see this thing through to the end. Wink

Ha, I hope it is not my biggest public failure.  Boo hoo!

The program upload to the microcontroller (MCU) has been done.  Of course, there had to be several variations in the design of this MCU, so the options presented to me for this one were different and I had to make a guess or two.  Most notably, this MCU has brown-out detection and I chose to disable it, reasoning that I don't want this thing shutting down in flight before it physically fails.  But it's still a guess since I don't know what the controller actually does when it detects a brown out voltage level.  Should it encounter one, I'd imagine the helicopter would pretty much be in big trouble regardless.  Power is everything on this bird.

I won't know for sure if this controller is properly functioning until flight testing.  So far, though, it looks promising.

Next is the wiring of the speed controllers, weight and balance, and placement of the controller and receiver.

Author:  SENECA [ Tue Aug 17, 2010 10:09 am ]
Post subject: 

Cant wait.....seriously. thumbright

Author:  fufu70 [ Tue Aug 17, 2010 2:23 pm ]
Post subject:  Re: Building a Tricopter

what motors will you be using  Question

Author:  blighty [ Tue Aug 17, 2010 3:28 pm ]
Post subject:  Re: Building a Tricopter

just a tip for soldering.

put the solder down on 1 pad of each component, get component in some tweezers and place in front of the soldered pad, re melt the solder and with surface tension the component will be sucked on to the pad. once you have done this with all components solder the other side.

this works for any SM device from D size tants to 0201's

sorry if you know this Very Happy

Author:  im4711 [ Tue Aug 17, 2010 8:26 pm ]
Post subject:  Re: Building a Tricopter

Sure looking forward to this one fly. Thumb Left

Author:  321 [ Wed Aug 18, 2010 5:35 am ]
Post subject:  Re: Building a Tricopter

fufu70 @ Tue Aug 17, 2010 2:23 pm wrote:
what motors will you be using  Question

Pulso X2212L/34 695kv...I'm not aware of anyone else using these so it remains to be seen if this was a good choice or not.  The idea was to get a good combination of ample thrust along with low revs in the hope of keeping vibrations to a minimum for video purposes.  The low revs might sacrifice agility but first and foremost this is supposed to be a small camera ship.

blighty @ Tue Aug 17, 2010 3:28 pm wrote:
just a tip for soldering ...  

No, I didn't know that trick and it sounds like a good one!

im4711 @ Tue Aug 17, 2010 8:26 pm wrote:
Sure looking forward to this one fly.  

Shouldn't be too much longer!

Author:  321 [ Sun Aug 22, 2010 9:38 pm ]
Post subject:  Re: Building a Tricopter

Spent much of the day cutting wire, soldering, crimping and heat shrinking.  Now the receiver and flight controller are mounted, speed controllers fully wired and the receiver is connected to the controller. That pretty much completes construction; no plans to do a landing gear just yet.

Now it's down to prop balancing and electronics set up and preflight testing.

Image

Author:  SENECA [ Mon Aug 23, 2010 6:06 am ]
Post subject: 

VIDEO!!!

Author:  321 [ Mon Aug 23, 2010 8:28 pm ]
Post subject:  Re: Building a Tricopter

On first power up, one speed controller and the flight controller board went poof, complete with smoke.  I don't have the rate sensors for the spare board, so this is a considerable setback.

Author:  321 [ Mon Aug 23, 2010 9:55 pm ]
Post subject:  Re: Building a Tricopter

Might have lucked out.  Molten shrink wrap centers on the voltage regulator on the controller, a through-hole component that will be easy to swap out with the one that was meant for the spare board.  Also, the spare speed controller just powered-up uneventfully in a quick test, so that should also be an easy swap.

Author:  321 [ Tue Aug 24, 2010 10:28 pm ]
Post subject:  Re: Building a Tricopter

Today's efforts yielded a working flight controller and everything was set up and ready to fly when another speed controller for a different motor started crackling and died.  So the bird is grounded until I can get 3 new speed controllers of a higher quality and rig a whole new wiring harness.  At least this time there will be measurements to go by.  But the flight controller and motors were working just awesome.  It sounded pretty cool with all three motors spooled up and automatic thrust adjustments by the gyros.

Author:  SENECA [ Wed Aug 25, 2010 6:39 am ]
Post subject: 

I can smell the smoke all the way down here in Fort Myers.

Author:  321 [ Wed Aug 25, 2010 8:26 am ]
Post subject:  Re: Building a Tricopter

LOL, I could smell the smoke in the living room this morning, where I left the tricopter overnight.

I ordered 3 Hobbywing controllers this morning.  People seem to like them for multicopters, they are available in the US and they're only $16 a piece.  I looked at Castle, but at $80 a piece they're just impossible to justify.

Meanwhile, there's a bit of time to do some propeller balancing.

Author:  _Buzz_ [ Wed Aug 25, 2010 11:40 am ]
Post subject:  Re: Building a Tricopter

When I was learning about electronics many many moons ago, the guy teaching me saw a circuit I'd just breadboarded go up in smoke.  He immediately said "That's that then, it'll never work now, you've let the smoke out. Electronic Circuits run on smoke, let it out and they'll never work again." !!

Author:  321 [ Thu Aug 26, 2010 11:50 pm ]
Post subject:  Re: Building a Tricopter

OK, I've had a chance to do some digging and found out the wire lengths between my battery and the speed controllers were too long.  As it turns out, this is a major no-no.  There are heated discussions regarding whether this is true or not, but I have two blown speed controllers that say that it is.  Some ESC's deal with it better than others but even if they can they're still getting hit hard with voltage spikes if the leads are too long.  It's weird science.

Author:  Anonymous [ Fri Aug 27, 2010 2:48 am ]
Post subject: 

Add -more- capacitance across the ESC battery inputs.  Replace the Electrolytic capacitor installed with one that has the same voltage rating but twice or three times the microfarad rating.

And...uhhh...note and observe proper polarity when installing the cap.  Electrolytics can make a helluva pop when installed backwards.  

For EXTRA nerdiness, install a .47mFd polyester, 50v cap too.  That'll dampen any higher frequency noise across the rails too.

Author:  Reflex [ Fri Aug 27, 2010 8:30 am ]
Post subject:  Re: Building a Tricopter

321 @ Fri Aug 27, 2010 4:50 am wrote:
OK, I've had a chance to do some digging and found out the wire lengths between my battery and the speed controllers were too long.  As it turns out, this is a major no-no.  There are heated discussions regarding whether this is true or not, but I have two blown speed controllers that say that it is.  Some ESC's deal with it better than others but even if they can they're still getting hit hard with voltage spikes if the leads are too long.  It's weird science.


I'd normally prefer to extend the motor leads
but Always twist/lace the wires together (reduces EMI)

If you add/replace capacitors at the esc, always use Gold Caps (low ESR)
normal caps. can't take the high currents.

Author:  321 [ Fri Sep 03, 2010 2:00 am ]
Post subject:  Re: Building a Tricopter

Finished installing the new esc's.  They are obviously better quality and might not have needed extra caps, but they got them anyway.  Plus the wiring was shortened up a bit.  Again, this is a hotly debated subject but I think it's safe to say long wires don't mix with cheap esc's.  This time testing went a little better.

Author:  321 [ Fri Sep 03, 2010 12:08 pm ]
Post subject:  Re: Building a Tricopter

The tricopter had its maiden flight!  The good news is that with no payload it used 601mAh of a 3300mAh 3S battery with 5.00 minutes of flying. She flew beautiful, but as a video camera platform it is a complete failure.  While it is a super steady platform, the resulting onboard video swims like a bitch even though I spent about 4 hours dynamically balancing all the motors and props to what I thought was an exceptional smoothness.  It is very disappointing because its only purpose was to shoot great video but I can see that is a lost cause.

Author:  SENECA [ Fri Sep 03, 2010 4:30 pm ]
Post subject: 

We need some video of it flying.

Author:  GhostWolf [ Fri Sep 03, 2010 5:22 pm ]
Post subject: 

Could it be frequency interference from the electronics?

Author:  321 [ Sat Sep 04, 2010 8:51 am ]
Post subject: 

GhostWolf @ Fri Sep 03, 2010 5:22 pm wrote:
Could it be frequency interference from the electronics?

Good thought, but the video doesn't have any snow or artifacts that look like noise.  The video swim is something I've battled before with different mounting locations of the camera on the T-Rex and the trick that helped there was to reduce vibrations and to mount the cam directly to the frame instead of on extremities like the canopy or an extended camera platform.  On this tricopter, there's some flex in the airframe's wooden arms which might be amplifying vibrations.

I'm a little taken by surprise by the learning curve on this project, as more and more issues present themselves.  For instance, I just tried a set of heavier, shorter APC propellers and the bird wouldn't fly at all.  When I dynamically balanced these props, they had a shake at low RPM which smoothed out upon reaching running speed.  I don't know but it might be something that just has to be expected with heavy propellers because all three have the same characteristic.  In any case, when attempting to fly them, the gyro controller overreacts to the low RPM shake during spool up.  This, in turn, makes the yaw servo jump into action.  I mean it goes nuts!  Even with much lower gyro gain.  Then I realized that the motor hinge has an inherent design flaw: it is below the motor assembly's center of gravity.  So when the servo suddenly rotates the motor, the resultant weight shift actually tries to yaw the airframe in the wrong direction.  Hahaa, one more little thing to add to a growing list of fixes!

Author:  321 [ Sun Sep 05, 2010 1:56 pm ]
Post subject:  Re: Building a Tricopter

I was hoping to get some video for you, Bill.  But the winds were kicking up and the tricopter just wouldn't handle it no matter what I tried on gain adjustments.

The motors were momentarily shutting down at random, making it a real basket-case to fly.  I don't know if it's a software or hardware issue.  There are a number of possibilities.  Motor RPM's at hover are low and it might need shorter props (but not heavier Wink) to get the speed controllers throttled up more.  Or maybe the ESC's don't agree with the controller or the motors.  Or maybe the motor timing needs to be changed.  Etc., etc..

This blew the better part of another day so I'm shelving it until some different props arrive.  The time sunk into this is beyond reasonable already, so it's time for a break.  At least she had a couple of good flights.

Author:  Reflex [ Sun Sep 05, 2010 2:33 pm ]
Post subject:  Re: Building a Tricopter

I flew a Tricopter for the first time yesterday

I was surprised how easy it was,reminded me about the old FP days
only much less maintenance.
Orientation is the biggest problem

I started a build also  Wink

321 easy solution to the Yaw motor CG problem
is to flip the motor underneath and reverse its drive shaft
this puts the motor mass below the pivot

Although I have to say the Tri. I flew yesterday had the Yaw motor above the pivot
and didn't seem to have any problems.

Hope you get the motor shut off problems sorted

Author:  321 [ Sun Sep 05, 2010 5:42 pm ]
Post subject:  Re: Building a Tricopter

Reflex @ Sun Sep 05, 2010 2:33 pm wrote:
I flew a Tricopter for the first time yesterday

I was surprised how easy it was,reminded me about the old FP days
only much less maintenance.
Orientation is the biggest problem

I started a build also  Wink

321 easy solution to the Yaw motor CG problem
is to flip the motor underneath and reverse its drive shaft
this puts the motor mass below the pivot

Although I have to say the Tri. I flew yesterday had the Yaw motor above the pivot
and didn't seem to have any problems.

Hope you get the motor shut off problems sorted

Thanks, my opinion about flying them is similar to yours (when it was working ok).  Good luck with the build.  It'll keep you busy, that's for sure!

Author:  321 [ Thu Sep 09, 2010 6:01 pm ]
Post subject:  Re: Building a Tricopter

Tonight I loaded some new firmware on the microcontroller that is supposed to help servo jitters, which I was seeing big time on the windy day.  That also meant the gyro directions had to be reset before flying.  Once up in the air, it was easy to see the new programming was helpful but I had only fixed a symptom.

It was still not acting right and I thought I could see some wave patterns in the prop disks.  So, I held onto it tightly and ran it up over my head (talk about a menace, this thing is the real deal) at hover throttle and, sure enough, it started to shudder.  Then, at 3/4 power, one motor assembly started to shake rather seriously.  Aha!  That's got to be playing hell with the controller.

Now why is the question; I hope the arms are not too flimsy.

Author:  GhostWolf [ Thu Sep 09, 2010 8:16 pm ]
Post subject: 

I'm willing to bet you've already checked the prop's balance and all the bolts and bearings on that arm, so I'm gonna be really curious about the solution.

Author:  Reflex [ Fri Sep 10, 2010 11:02 am ]
Post subject:  Re: Building a Tricopter

321 @ Thu Sep 09, 2010 11:01 pm wrote:
Tonight I loaded some new firmware on the microcontroller that is supposed to help servo jitters, which I was seeing big time on the windy day.  That also meant the gyro directions had to be reset before flying.  Once up in the air, it was easy to see the new programming was helpful but I had only fixed a symptom.

It was still not acting right and I thought I could see some wave patterns in the prop disks.  So, I held onto it tightly and ran it up over my head (talk about a menace, this thing is the real deal) at hover throttle and, sure enough, it started to shudder.  Then, at 3/4 power, one motor assembly started to shake rather seriously.  Aha!  That's got to be playing hell with the controller.

Now why is the question; I hope the arms are not too flimsy.


I had a similar problem
turned out the motors where poorly balanced

This was very helpful

http://www.rcgroups.com/forums/showpost.php?p=15936915&postcount=8839

I left the cable ties on and simply CA'd them into place.

it's much better now  Cool

Author:  _Buzz_ [ Fri Sep 10, 2010 11:59 am ]
Post subject:  Re: Building a Tricopter

Link not working.......

Author:  Reflex [ Fri Sep 10, 2010 12:06 pm ]
Post subject:  Re: Building a Tricopter

Sorry Brian. link amended
Paul

Author:  _Buzz_ [ Fri Sep 10, 2010 2:09 pm ]
Post subject:  Re: Building a Tricopter

Reflex @ Fri Sep 10, 2010 5:06 pm wrote:
Sorry Brian. link amended
Paul


No problem, just pointing out the error.

Author:  321 [ Fri Sep 10, 2010 3:04 pm ]
Post subject:  Re: Building a Tricopter

The Pulso motors seem to be super well balanced.  They spin up nice and smooth without a propeller.

It's time to build a table mount, for a safer and less awkward method of running these motors up to speed.

Author:  Reflex [ Fri Sep 10, 2010 3:22 pm ]
Post subject:  Re: Building a Tricopter

If your certain balance is ok
then perhaps resonance is the problem ?

I changed props. on mine 9x5 to 8x4 to cure this
not the same Tri. but you get the idea

Still. strange you only have problems with one motor  Think

Author:  321 [ Fri Sep 10, 2010 5:56 pm ]
Post subject:  Re: Building a Tricopter

Reflex @ Fri Sep 10, 2010 3:22 pm wrote:
If your certain balance is ok
then perhaps resonance is the problem ?

I changed props. on mine 9x5 to 8x4 to cure this
not the same Tri. but you get the idea

Still. strange you only have problems with one motor  Think

Well, resonance is a possibility and thanks for bringing it up.  For sure these motors were smooth when run individually.  The shudder is most pronounced with one motor but not limited to just that motor.  I'm waiting for a third set of props to try and it would be great if they could solve the problem.

Author:  321 [ Sat Sep 11, 2010 8:01 pm ]
Post subject:  Re: Building a Tricopter

PROPS!  Just when it seemed like the airframe might need some reworking, a new set of propellers saved the day.  A set of EMP 11x4.7 slow fly props (balanced like my life depended on it) performed beautifully today.  Efficiency was also good; the tricopter flew 11:56 empty weight on 1596mAh with a 3300 pack.

Reflex, it would seem that prop choice is important on these tricopters.   Mr. Green

Author:  Reflex [ Sun Sep 12, 2010 1:35 am ]
Post subject:  Re: Building a Tricopter

321 @ Sun Sep 12, 2010 1:01 am wrote:
PROPS!  Just when it seemed like the airframe might need some reworking, a new set of propellers saved the day.  A set of EMP 11x4.7 slow fly props (balanced like my life depended on it) performed beautifully today.  Efficiency was also good; the tricopter flew 11:56 empty weight on 1596mAh with a 3300 pack.

Reflex, it would seem that prop choice is important on these tricopters.   Mr. Green


I couldn't agree more
especially since I'm running 1500Kv motors  Angel

Progress on mine has slowed, due to other projects
and one of my motors is running rough maybe bearing problems.

Radio set-up is also "interesting" and has taken awhile ...................

Author:  Reflex [ Sun Sep 12, 2010 4:36 pm ]
Post subject:  Re: Building a Tricopter

Replaced a motor bearing
and flew the Tri for the first time today  Thumb Left

amazingly smooth, could do with more Cyclic but overall a success  Very Happy
Sorry for the poor quality vid.

http://uk.video.yahoo.com/watch/8228794/21864678

Author:  321 [ Sun Sep 12, 2010 6:16 pm ]
Post subject:  Re: Building a Tricopter

Reflex @ Sun Sep 12, 2010 4:36 pm wrote:
Replaced a motor bearing
and flew the Tri for the first time today  Thumb Left

amazingly smooth, could do with more Cyclic but overall a success  Very Happy
Sorry for the poor quality vid.

http://uk.video.yahoo.com/watch/8228794/21864678

Congrats, she flies nice!  I didn't know heading hold could be used on the gyros but it works, doesn't it?

Author:  321 [ Sun Sep 12, 2010 6:27 pm ]
Post subject:  Re: Building a Tricopter

Finally got to enjoy a day of flying.

Image
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Author:  Reflex [ Sun Sep 12, 2010 6:29 pm ]
Post subject:  Re: Building a Tricopter

[/quote]Congrats, she flies nice!  I didn't know heading hold could be used on the gyros but it works, doesn't it?[/quote]

Yes. it works fine in HH

Like a Heli. set-up and attention to detail is everything

I found it critical to set the Collective (Pitch/throttle  range on these Tri's) to allow enough "headroom" for the Cyclic to work

ie. full Throttle Must allow the motors to change speed (Cyclic)

Author:  SENECA [ Sun Sep 12, 2010 7:17 pm ]
Post subject: 

THat video is figgin awesome!!!
Its like a helicopter and a plane in one.

Author:  321 [ Sun Sep 12, 2010 8:22 pm ]
Post subject:  Re: Building a Tricopter

Quote:
I found it critical to set the Collective (Pitch/throttle  range on these Tri's) to allow enough "headroom" for the Cyclic to work

ie. full Throttle Must allow the motors to change speed (Cyclic)

Yes, I just looked it up and this is also required on my controller board.  It's a great board, but it's a little short on concise instructions. Smile  I was kind of expecting that, but now we know.

Quote:
THat video is figgin awesome!!!

A big thanks to Shauna for getting behind the camera for us.

Author:  321 [ Wed Sep 15, 2010 8:29 am ]
Post subject:  Re: Building a Tricopter

Found my landing gear.  The Trex 500 gear is about perfect; it looks good, has black skids, is tall for its size and only weighs about 60 grams.

In flying the tricopter, it was apparent that orientation is still a little bit of a problem even though it's not a 120^3 configuration (it's actually 109/142/109).  So it would certainly help to color the tail white.  That will happen to go good with the new landing gear.

The new gear will go between the battery and electronics decks to allow the battery to be placed anywhere along its deck for balancing purposes.  This will require a redesign and remake of both decks.  This is also a good opportunity to conform the shape of the decks to the finalized components layout and to beef up and lengthen the fulcrum areas for the front arms.  But no rush on this!

Author:  im4711 [ Wed Sep 15, 2010 10:17 am ]
Post subject:  Re: Building a Tricopter

Looks great. I would loose control of what is suppose to be the tail ...
Great video and definitely an great tricopter Thumb Left  Thumb Left  Thumb Left

Author:  321 [ Tue Sep 21, 2010 10:31 am ]
Post subject:  Re: Building a Tricopter

OK guys, an important piece of information here.  I tried adding a 200 gram onboard camera, which meant the RPM's had to come up in order to hover.  But then my prop problems returned.  Shuddering, especially in the tail assembly.  So I messed around with prop balance some more and found where I could minimize but not eliminate the problem.  Then I held on to the tail with a free hand and the shudder went away and the motor felt super smooth.  What the?  My conclusion is that the 3/8" wood arms are not rigid enough for the job.  That being the case, with the one on the tail being the longest, it makes sense that it is the most troublesome.

I haven't had any luck finding 3/8" square aluminum tubing (channel is also too flexible), never mind that I would need .035 thin wall 6061.  It might be necessary to give the arms a wrap of fibreglass cloth or to shorten the arms (which will mean redoing the wiring harness and a change of balance, ugghh).

Author:  im4711 [ Tue Sep 21, 2010 11:08 am ]
Post subject:  Re: Building a Tricopter

at least sounds like you found the cause. Thumb Left
Maybe instead of aluminum tubing you would go for T profile? shouldn't that somehow be available at Home Depot Lows ...?

Author:  _Buzz_ [ Tue Sep 21, 2010 11:27 am ]
Post subject:  Re: Building a Tricopter

Carbon tube is available from kite stockists online.

Author:  GhostWolf [ Tue Sep 21, 2010 11:56 am ]
Post subject: 

The last time I needed carbon tube, I bought arrow shafts at a local sports outlet.

Author:  Reflex [ Wed Sep 22, 2010 12:28 am ]
Post subject:  Re: Building a Tricopter

321 @ Tue Sep 21, 2010 3:31 pm wrote:
OK guys, an important piece of information here.  I tried adding a 200 gram onboard camera, which meant the RPM's had to come up in order to hover.  But then my prop problems returned.  Shuddering, especially in the tail assembly.  So I messed around with prop balance some more and found where I could minimize but not eliminate the problem.  Then I held on to the tail with a free hand and the shudder went away and the motor felt super smooth.  What the?  My conclusion is that the 3/8" wood arms are not rigid enough for the job.  That being the case, with the one on the tail being the longest, it makes sense that it is the most troublesome.

I haven't had any luck finding 3/8" square aluminum tubing (channel is also too flexible), never mind that I would need .035 thin wall 6061.  It might be necessary to give the arms a wrap of fibreglass cloth or to shorten the arms (which will mean redoing the wiring harness and a change of balance, ugghh).


I have spent Hours balancing motors
By holding the boom, you could just be dampening these vibes

Author:  321 [ Sun Sep 26, 2010 8:14 am ]
Post subject:  Re: Building a Tricopter

Reflex @ Wed Sep 22, 2010 12:28 am wrote:

I have spent Hours balancing motors
By holding the boom, you could just be dampening these vibes

Agreed, but I have also put the time in on the balancing.  It's as good as I can get it without using accelerometers.

3/8" square tube turns out to be mighty hard to find.  Apparently, US industry has little need for it and kites use smaller or else round.  But I did come across it (or possibly it's 10mm) on a slowstick at the LHS.  It's black fibreglass and is used as the "fuselage", which is available as a replacement part.  It felt pretty tough, but now I must wait and see how it works on the tri.

A rework of the main frame will shorten the unsupported span of the arms by an inch, which should also help a little.

Author:  Reflex [ Thu Oct 21, 2010 3:53 am ]
Post subject:  Re: Building a Tricopter

Thought I'd make something different

Video of maiden flight


http://uk.video.yahoo.com/watch/8418744/22511243

Author:  _Buzz_ [ Thu Oct 21, 2010 4:48 am ]
Post subject:  Re: Building a Tricopter

Reflex @ Thu Oct 21, 2010 8:53 am wrote:
Thought I'd make something different

Video of maiden flight


http://uk.video.yahoo.com/watch/8418744/22511243


I can hear Radd shouting in your ear...."TAIL IN, TAIL IN".

Looks quite stable sometimes, then it gets a mind of it's own. If it were me I think I'd prefer a lot more orientation guides.

But hey, terrific unusual flying machine.

Author:  im4711 [ Thu Oct 21, 2010 6:16 am ]
Post subject:  Re: Building a Tricopter

looks cool  Thumb Left
So how do you figure what direction to fly???  d'oh!  d'oh!  d'oh!

Author:  Reflex [ Thu Oct 21, 2010 7:12 am ]
Post subject:  Re: Building a Tricopter

im4711 @ Thu Oct 21, 2010 11:16 am wrote:
looks cool  Thumb Left
So how do you figure what direction to fly???  d'oh!  d'oh!  d'oh!


Watch the LED's
Blue at the back  Wink

Buzz. Just got to sort this "Side Slip" problem
it's unrecoverable ATM

This is it's maiden flight
Lots more LED's to add yet

But only if I can sort the handling problems

Paul

Author:  im4711 [ Thu Oct 21, 2010 7:48 am ]
Post subject:  Re: Building a Tricopter

Need little toy for indoor flying.

Thumb Left  Thumb Left  Thumb Left

Author:  Reflex [ Thu Oct 21, 2010 7:56 am ]
Post subject:  Re: Building a Tricopter

Little ? this is 35" Dia.  Laughing

Author:  im4711 [ Thu Oct 21, 2010 8:52 am ]
Post subject:  Re: Building a Tricopter

Reflex @ Thu Oct 21, 2010 7:56 am wrote:
Little ? this is 35" Dia.  Laughing


ups d'oh!

Author:  Reflex [ Thu Oct 21, 2010 1:15 pm ]
Post subject:  Re: Building a Tricopter

im4711 @ Thu Oct 21, 2010 1:52 pm wrote:
Reflex @ Thu Oct 21, 2010 7:56 am wrote:
Little ? this is 35" Dia.  Laughing


ups d'oh!


No problem LOL

Todays Mod's


Image

Author:  RCcanuck [ Thu Oct 21, 2010 9:07 pm ]
Post subject: 

Wow...that is so cool!!  I want one!!!!

Author:  RCcanuck [ Fri Oct 22, 2010 5:13 pm ]
Post subject: 

More vid with the the new mod!!!!???

Author:  Reflex [ Fri Oct 22, 2010 5:32 pm ]
Post subject: 

RCcanuck @ Fri Oct 22, 2010 10:13 pm wrote:
More vid with the the new mod!!!!???


Probably get some Monday night

Author:  RCcanuck [ Fri Oct 22, 2010 11:03 pm ]
Post subject: 

Looking forward to it.

Author:  Reflex [ Sat Oct 23, 2010 7:51 am ]
Post subject:  Re: Building a Tricopter

Apologies to 321
I seem to have hijacked your thread
It was never my intention

Please post your Tricopter updates

Regards
Paul

Author:  SENECA [ Sat Oct 23, 2010 11:03 am ]
Post subject: 

THat "flying saucer" tricopter is cool!

Author:  RCcanuck [ Sun Oct 24, 2010 10:28 pm ]
Post subject: 

I also like 321's version too.  Man..It would be a hit at the indoor flyin this winter with either one of them.  Kind of out of my league to build one though.  Now if either one of you can come up with a kit...Im interested in buying one!

Author:  Reflex [ Tue Oct 26, 2010 2:39 am ]
Post subject:  Re: Building a Tricopter

Last nights flying
Still unstable I'm convinced I have a setup issue ...
but at least the Side slip problem is gone.

http://uk.video.yahoo.com/watch/8471613/22630906

Author:  RCcanuck [ Tue Oct 26, 2010 5:02 pm ]
Post subject: 

Damn...I thought it would be stable in this vid.  so what in the setup do you think is the problem?

Author:  Reflex [ Wed Oct 27, 2010 11:44 am ]
Post subject: 

RCcanuck @ Tue Oct 26, 2010 10:02 pm wrote:
Damn...I thought it would be stable in this vid.  so what in the setup do you think is the problem?


Too early to say

Author:  Reflex [ Tue Nov 09, 2010 8:46 pm ]
Post subject:  Re: Building a Tricopter

I reverted to my HH Cyclic Gyro setup
results below taken Air to Air from a T copter


http://www.youtube.com/watch?v=_mVAk5RXz7w&feature=player_embedded

Author:  321 [ Tue Nov 09, 2010 9:01 pm ]
Post subject:  Re: Building a Tricopter

From what I've experienced,  the rate gyro system gives the bird some unsettling flight characteristics and a HH system certainly seems like it would be of help.  I've been wondering if a flybarless controller wouldn't be exactly what it needs.

Author:  Reflex [ Tue Nov 09, 2010 9:12 pm ]
Post subject:  Re: Building a Tricopter

Yes. these Tricopters don't handle as expected

I wonder also about the ESC's
most have a Log throttle curve,which is fine for Planes etc

But useless on a Tri. as it will upset the ECCPM mixing

The Ultimate Has to be a Collective Pitch version imo


 
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