quadcopter?

[foxx00700]

Has anyone done any research on these? I recently saw one in a German video, and a couple of home built prototypes. I think it would be ideal for my video requirements, but I can't seem to find any information on where to get one, let alone cost.

[tokenpom]

Hi,

there are at least two german quadcopters, one at each end of the price scale !

MicroKopter, is essentially a kit, with a variety of market-available components, and control software that I think is open-source, the idea being to get this homebuilt UAV into the market,at the lowest possible price.

I think they cost about 1500 GB pounds, but don't quote me on that !

At the other end, is the 'Microdrone', this is a military spec UAV, with gps position hold, etc, etc.

This was quoted to me last year (in Australia) at AU$37,000 - about US $40,000 !

In between is the Draganflyer X6 ($26,000), and its little brother, the X4 (about $19,000)

However, they are not apparently, as rugged, or as stable in flight, as the microdrone.

I hope this helps,

Nick.

[SeismicCWave]

Originally Posted by foxx00700

Has anyone done any research on these? I recently saw one in a German video, and a couple of home built prototypes. I think it would be ideal for my video requirements, but I can't seem to find any information on where to get one, let alone cost.

http://www.rctoys.com/rc-products-ca...LICOPTERS.html

You need a lot of money and know how to get one working properly. Single main rotor/single tail rotor RC helicopter is still the most efficient and cost effective at this point.

[foxx00700]

That does help a little. at least it is narrowing things down a little. from what I've read so far, I'm surprised these are not more popular. The stability and payload capabilities seem almost too good to be true.... 4Kg for 30 minutes of flight time? and no vibration issues?

[SeismicCWave]

Originally Posted by foxx00700

That does help a little. at least it is narrowing things down a little. from what I've read so far, I'm surprised these are not more popular. The stability and payload capabilities seem almost too good to be true.... 4Kg for 30 minutes of flight time? and no vibration issues?

1) It is very expensive.
2) It is not very stable.
3) It is inherently unstable. The stability comes from a fairly complex gyro stabilization system and elaborate software. If there is a computer glitch the quad is toast.
4) Payload is actually very low unless you are talking about the high end models. Then we are back to number 1.
5) Anything that has moving parts will have vibration issues. The vibration frequency is different but the vibration is still there.

[jacs]

Friend has built two quad's now, and they are very well flying and stable in air. Flow one of his last weekend and that was way easier than helicopter. But it cost a bit just for the electronics that comes from Germany if my memory servs me right. Otherwise it's just carbonfibre and brushless engines.

[Trnquill]

There's a loooong thread on rcgroups' AP section on tricopters. Apparently you can build one for about $200 + the frame. The construction is super simple both electronically and mechanically. No state of the art control logic or artificial intelligence in the mix. Here's what a tricopter is in a nutshell (I haven't build one myself so please correct me if I'm wrong!):
-CCPM transmitter
-Reciever, AR6200 or something similar
-Battery and BEC
-Three ESC's, three brushless motors, three propellers
-Three (cheap) gyros
-One servo for tilting the "tail" motor left and right
-Triangular frame to attach all the equipment on.

Theory behind a simple tricopter is sort of substituting the three 120 degree CCPM servos with motors and propellers. Each ESC+motor+propeller combination act like a single CCPM servo. When you "add pitch" all three motors spin faster. If you add forward cyclic, the one motors at the back picks up speed as the two motors in the front slow down. You get the picture. Rudder is controlled by tilting the back propeller left and right to rotate the tricopter around its axis.

The three gyros are installed in between the receiver and ESC's. One gyro for each CCPM channel. This gives stability. A home made Helicommand, so to speak.

For a $200 you can build a tricopter using 3S packs and lifting a point'n'shoot camera. I have not seen any tricopter project using larger packs or doing significantly heavier lifting. And you must remember a tricopter has virtually no autorotation capabilities what so ever! If one motor stops, all hope is lost. An octocopter with eight rotors can function even if one rotor breaks down, a tri- or a quadcopter can't.

[SeismicCWave]

>>The three gyros are installed in between the receiver and ESC's. One gyro for each CCPM channel. This gives stability. A home made Helicommand, so to speak.<<

Have you ever try one of those Ikarus Piccolo with a motor driven tail and a gyro? The problem with a tricopter that you mentioned is the sensitivity of the control. You are talking about using three (I don't think cheap is a good way to go) gyros to control three FIXED pitch propeller. You are only controlling the RPM of the motor. That is like flying three fixed pitch helicopter linked together. Not a very good recipe for success.

Yes you can get enough stability to fly the machine and maybe even lift up some payload. However compare to a single main rotor/single tail rotor collective pitch helicopter stability is still way behind.

The less expensive quad copters are still a toy at this point. Please note the words "less expensive" before flaming me. I have seen extremely capable multi rotors in action but none of them are "cheap". They all have extremely sophisticated software.

[Trnquill]

Originally Posted by SeismicCWave

Have you ever try one of those Ikarus Piccolo with a motor driven tail and a gyro? The problem with a tricopter that you mentioned is the sensitivity of the control. You are talking about using three (I don't think cheap is a good way to go) gyros to control three FIXED pitch propeller. You are only controlling the RPM of the motor. That is like flying three fixed pitch helicopter linked together. Not a very good recipe for success.

I know, that's what I though when I first head of this tricopter concept! But after watching tens and tens of videos of these cheap marvels I get more and more amazed! To get things straigt: I have never seen a tricopter fly live, just watched videos of people flying them inside their houses etc. I would never fly a 450 (or any other similar size heli capable of lifting a 150g camera) indoors; to tricopter I would give a go.

[ame]http://www.vimeo.com/7631508[/ame]

[SeismicCWave]

>>To get things straigt: I have never seen a tricopter fly live, just watched videos of people flying them inside their houses etc.<<

Ok, we are talking about two different things here. You are talking a very benign environment for these tricopters.

My little EFlite mSR also flies very well indoor. It only cost $150.00.

I was talking about a multi rotor flying outdoor doing AP work.

Don't get me wrong I have nothing against multi rotors. I think they are probably the VTOL of the future. Once the software gets more popular then more people will jump in to tweak it. Then some one will add collective pitch to all the rotors and we will have some very good flying multi rotors. They will not be simple nor cheap still.

[Trnquill]

Originally Posted by SeismicCWave

Ok, we are talking about two different things here. You are talking a very benign environment for these tricopters.

My little EFlite mSR also flies very well indoor. It only cost $150.00.

Oh, I knew I did a poor job choosing the demo video. If you search youtube (or preferably walk through the long thread in rcgroups) you'll find several videos of tricopters flying outside. And they really look coaxial stable there, too! But yes, they are only videos and one can never know for sure what the wind was really like etc. I'm yet to see a vid of a 450 (or something similar) and a tricopter flown in same conditions by the same pilot.

You just gave me an idea, though! Maybe I will shoot for the stars and build a tricopter with variable pitch propellers!

Oh well. What I really meant to say when going into tricopters was you really do not need any fancy controlling logic for a tricopter. In addition, one can be built very cheap if the payload is a P'n'S. I'll report back with some AP oriented vids if and when I have my tri built.

[SeismicCWave]

>>Oh well. What I really meant to say when going into tricopters was you really do not need any fancy controlling logic for a tricopter. In addition, one can be built very cheap if the payload is a P'n'S. I'll report back with some AP oriented vids if and when I have my tri built.<<

Unfortunately my gut feeling is that you do need some pretty precise controlling logic for a tricopter to get rid of the tiny little twitch. I have to qualify the statement by saying that I have never experimented with a tri or quadcopter personally.

The only reason I came to the conclusion was from watching what is on the market and how much they costs and who were making them successful.

It will be really interesting to do a multi-rotor with collective pitch. I don't think the tricopter is a good candidate because of the asymmetrical torque from three rotors. Either two rotors or four rotors will be a better choice.

I have been meaning to build a multi rotor for a long time but I am still stuck in the mechanical mode and want to build a coaxial instead. I am sure something like the twin rotor osprey will be interesting but the complexity goes way up.

[Trnquill]

Originally Posted by SeismicCWave

It will be really interesting to do a multi-rotor with collective pitch. I don't think the tricopter is a good candidate because of the asymmetrical torque from three rotors. Either two rotors or four rotors will be a better choice.

I did a quick search on variable pitch rotors/motors and came up with not much. Most of the models are for depron stunt foamies, I guess. Not sure about how much thrust they will produce but the motors on the systems seemed a bit on the weak side. Maybe a true propeller-head-solution would be using 450 or 500 sized tail blocks for variable pitch... One could use 450/500 boom and belt, too, and have a single heli motor sitting center of the frame. Just three tail drive gears on the motor shaft and up we go! I think I'll stick to an ordinary tricopter design first and start to experiment with this kind of grazy stuff a bit later.

[SeismicCWave]

I was thinking more like using four 450 size main rotor heads.

[jakobsen]

here you have an octqopter, Its a man form Norway that fly this. I think its great. [ame]http://www.vimeo.com/8314892[/ame]

Ray!

[Techspy]

Quad/Tri-copters are very viable. They can be cheaply made, they can be very stable and easy to fly. I built and flew my Tri-Copter before ever flying a heli. Here is a video of mine on a fairly windy day. When everything else is grounded at our field because of wind, I fly this with no issue. I have about $200 in mine and used cheap Telebee gyros (approx $30 each), and you can see the results. I did have one bad gyro in the beginning but not a problem since. I have since rebuilt it with more room for electronics etc and plan on using it for FPV with altitude hold and eventually position hold. I use 2 3s 2200mah pacts in paralel and can get about 12 minutes of flight time. Also, just as a lifting experiment I was able to fly with a standard hammer attached with plenty of power for climbing etc.

[ame]http://www.youtube.com/watch?v=4O4HEdlxaUo[/ame]

[must289pwr]

Mix an MSR + Quadcopter + FPV + IPod and you get the AR.drone

http://ardrone.parrot.com/parrot-ar-...videos/#player

Looks like a really cool starter Quadcopter/fpv on your iphone or ipod. Just not sure how much they are yet.

Could also add some video glasses to the Ipod.

[c4v3man]

Originally Posted by must289pwr

Mix an MSR + Quadcopter + FPV + IPod and you get the AR.drone

http://ardrone.parrot.com/parrot-ar-...videos/#player

Looks like a really cool starter Quadcopter/fpv on your iphone or ipod. Just not sure how much they are yet.

Could also add some video glasses to the Ipod.

It's a "premium" starter system... yes the range is short thus equating a starter system, but the technology and the intended market means this thing will be very expensive.

I'm somewhat doubtful that the in-flight video is really in flight... seems too smooth for 15fps.

Still looks like fun!


EDIT: I take that back... the new videos posted up there (not from the ad) look believable for 15fps video.

[foxx00700]

man! you guys are more than a little over my head. wish I had a group of you guys around here.... to pick your brains.

[SeismicCWave]

Originally Posted by foxx00700

man! you guys are more than a little over my head. wish I had a group of you guys around here.... to pick your brains.

That's why you are on a forum like this. To pick brains!