Tricopter ?

I've been attracted to the notion of building either a quad or tricopter. Enough that I've visited several sites and am reading several forums.
Still, I know squat about them, but maybe just enough to get me into trouble (LOL).


So here are some noob questions:
The tricopter's i've seen have a servo on one axis, the quads don't.
Why? For that matter, how do quads manuver at all?


The openpilot control board appears to have some expandability up to 6 motors. Can the same board be used on small or large craft? Does size matter?


I have the concept that the motor size (kv/rpm) and props are dependant on the payload. Where do you start?


If a motor specs call for a 20a ESC, will a 30a ESC work?
I'm fairly confident that if the motor requires a 20a ESC and you run it with a 15a ESC there will be issues.


I'm liking the tricopter design for its ability to fold like this one.
http://www.ebay.com/itm/Multi-Rotor-Helis-Y3-Y6-Tricopter-Carbon-Fiber-Airframe-/170717491673?pt=Radio_Control_Parts_Accessories&hash=item27bf8e31d9#ht_14489wt_932


Any clues on how to determine motor/prop/thrust would be helpful.

Hi Smitty - I'm about to go out the door, but let me at least answer some of your questions. 

The mystery with quads is how they can rotate like you said.  It's done by motor torque.  It has two sets of counter rotating blades.  When you want to turn, you slow down two and speed up two.  This results in the same amount of thrust you started with so it maintains the same altitude.  What changes is the amount of torque in one direction or the other.  That causes it to rotate!  The tricopter only has three motors so that doesn't work.  The solution is to control the back motor with a servo to control direction.  That actually gives much faster and better control.

The OpenPilot board is the most configurable of all available boards.  You can do just about anything you want with it whether large or small.  The HobbyKing board has manual gyro gain controls so it adapts to different sized birds pretty easy.  The HoverFly board I have not tried, but I have a feeling you'd be in trouble if you deviated much from their design parameters.  Their boards are excellent, but they don't give you much control of anything.  If you stick with something near their basic design, it's a wonderful (and expensive) performer.

As for where to start with with motors and props, there is no hard and fast rule.  If you are thinking of building one, I'd follow someones lead.  There is discussion of this on the Parallax forum I referenced earlier in this section.

ESC's - You can always user a larger ESC than required.  You don't want to get carried away with this though, because bigger means heavier and you have several of them.  Weight is never a good thing on something that doesn't have wings.   I'd plan to match the motor and ESC as close as possible.  You're right about the 15A ESC on the 20A motor.  That will only fly you to the crash site.

Tricopters are really cool and I think they are probably easier to fly since you have fewer orientation problems and more direct control.  At least on a tri you know where the front is when it's zooming through the air!  I've only built quads, but I'm not far from building a tricopter.

Think I answered most of your questions.  Hope you decide to jump in and build one.  Pretty cool stuff!

...Tiger

Thanks Tiger, I was hoping you would respond. I'm really leaning towards the openpilot board, but as of yesterday both usa distributors were our of stock. The Canadian distributor had them but wouldn't divulge the shipping costs until after the order was placed. That was a show stopper for me.

Smitty - You need to place an order with one of the two US distributors and join the waiting list.  I know that sucks, but it's the only way you'll get one any time soon.  They NEVER have stock?  The demand is greater than the supply and has been from the get go.  You just have to wait your turn.   I have ordered from and talked to both of the distributors and they were good guys.  While you're waiting, you can download the OpenPilot software and play with that a little.  This is one slick unit.

...Tiger

Thanks.
I've already installed the OpenPilot GCS.


It appears that I am committed.
Just placed and paid for an order for the OpenPilot Control Board.
Here's where the "committed" comes into play.
I just paid $90+ for a product the supplier does not have. (LOL)


Looks like I really want to build this thing!

Better to be committed than to have been committed.  Prepare for fun!

...Tiger

So I guess I'm jumping on this TriCopter bandwagon.  Just ordered one of these today: 

http://www.opensurprise.com/y3-y6-tricopter-carbon-fiber-airframe-p-124.html

Normally I would scratch build, but this looks really nice.  Let's go Smitty!  You're to blame for this.

...Tiger

Now you've gone and done it!
You not only called, but raised the ante on me.


That open surprise kit was what really attracted me.
I just didn't know If it could trust buying from China.


So, you'll be my test.
If you have a good experience, then I'll pop for one too.


Have you given any thought yet about what motors you'll be using?

I've bought tons of stuff out of China and never had a problem.  I ordered this in the wee hours last night and I had a HK Post tracking number from them within an hour.  I was impressed!  Actually, I ordered two of these.  Rick Taylor (Redwood flying buddy) is going to build one with me.  I don't know what parts Rick is going to use.  I'm probably going to use Hacker A20-22L (960kv?) motors just because I have two of the three already.  If I didn't have those, I'd get KDA 20-22L (Hacker clones) or Turnigy 2217 860 kV motors for half the money.  I ordered HobbyWing ESC's (same as Turnigy Plush) today.  I think I've got everything else. 

You're falling behind Smitty.  You need to get your order in!

...Tiger

Yeah, I'm so far behind, all I see is you dust! LOL :-\


Just completed the order process with open surprise for the Y3-Y6 TriCopter air frame.
I won't be able to afford motors for it until February. So... maybe by Spring it'll be ready.

February?  No way!  I'll destroy mine before then so I can loan you my motors. 

Destroy?!?  I'm counting on you to help me learn to fly this thing with no wings!
Besides, isn't carbon fiber indestructible? LOL

Indestructable???  I guess we'll know real soon. 

Just a quick status update on my TriCopter project.


Nov. 3 = ordered the Open Pilot control board from Innov8tive Designs. No news yet.
Nov. 8 = ordered TriCopter airframe from Open Surprise. in transit on slow boat from China.
Nov. 18 = ordered the motors and ESC's from My RC Mart. Hopefully they won't wait for the first boat to return.


Besides some wire, connectors, servo and a receiver, I've accounted for all of the major components.



RCX-HOBBY RCX07-015
RCX A2830-12 850kv Outrunner
http://www.myrcmart.com/rcx-a283012-850kv-outrunner-brushless-motor-airplane-free-mounts-p-3723.html
Model:  RCX A2830-12
Motor size: 28mm x 30mm
Shaft size: 3.175mm
Weight: 52g
KV(rpm/v): 850
Max Power: 187W
Max Current: 12.9A
Max Pull (Approx.): 875g
Suitable Propeller: 11x7 / 9x6 / 8x6
Suitable Battery: 2-4S Li-Po
Suitable ESC(A): 30A
Ri(M Ω): 0.136


RCX-HOBBY RCX07-33
RCX 30A ESC (G series)
http://www.myrcmart.com/rcx-30a-esc-brushless-motor-speed-controller-programmable-series-p-3786.html
Continuous Current: 30A
Burst Current: 40A
Input Voltage: Lipo 2-4 Cells
Input Voltage: NiMH NiCd 6-16.8V
BEC: 5V  2A
Size:  26x23x11mm
Weight: 23g

I've estimated the finished total vehicle weight to be between 750-800g
This should give me a payload capacity of around 500-550g
Of course, never having done anything like this before, I'm most likely TOTALLY WRONG! LOL

Looks good Smitty!  I'm about in the same boat.  The tri-copters are taking forever to get here.  I ordered before you did.  They show as shipped on the tracking, but there has never been an update since it said they were headed for the US.  My motors from HK tracking as far as California so they could be here any day.  I have received the ESC's and I already had the OpenPilot board.  So the hangup at this point is the tri-copters that seem to be lost in the ozone.

...Tiger

Update!  Just got my HobbyKing order (motors, props, and misc parts).  Now I have EVERYTHING but the frame.  It's still lost in the ozone.

Getting close!

...Tiger

WaHoo! ;D
My TriCopter air frame arrived today.
All the way from OpenSurprise.com
And, it didn't come by boat. Cause it says "air mail".

Welcome to the darkside Smitty ...  It (will) feels good to fly in the sky, yeah

Although I'm a little jealous as my plans for a Multirotor came up short in dollars ... Before summer I get me one

[glow=maroon,2,300]w00d[/glow]