Has anyone considered or tried 11 inch props on the Iris?  What about 3 blade or 4 blade props?

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I figured out the problem. The fix will be difficult.

First I added 3 ceiling fan balancing weights to the left rear motor shroud to counter the fact that the front right motor is always working harder (according the output of RCOU Chan1). 

No change. Bird drops dead at 10.7 volts and gets to 10.7 in 5 minutes with a zippy 5000.

I have noticed for quite some time that the rear left motor seems to have stronger magnetic fields than the other motors. When you slowly move the props with your finger the rear left motor magnets (or magnetic fields) have much more resistance than the other motors.

So I bit the bullet, flipped the Iris upside down, cut the wires and swapped the front right and rear left motors, and soldered them back. What a pain in the arsse!

The problem remains except the rear left motor's output is the one that maxes out causing the others to cut back.

I have one motor that is much stronger (or more efficient) than the other 3 motors. The Pixhaw and ESC is always sending much more signal strength(or voltage) to the motor diagonally opposite the motor that is stronger than the others.

What to do next?

I need better quality motors than the 3dr blue motors. I have another spare motor that I can put on but I have a feeling that the fun will never end as long as I stick with Iris design. I have no issues with any of the electronics. The motors suck.

I would rather install some different motors than ask for a refund and send everything back. I am very confident in the problem solving process I have implemented.

Are there other higher quality motors that that have the same diameter as the 3DR 850KV blue motors? The diameter is 27.6mm.

I don't know how may Iris customers  are having severe issues with Iris flight times when the gimbal and go pro are installed but I will bet a paycheck that this could be their problem. It only takes one oddball motor to make this happen.

BTW - I have totally given up on 3DR support with this issue that I have been busting my ass on for months. I'm the kinda guy that likes to go down swinging but sometimes you gotta throw in the towel.

But first I'm gonna take that one really bad ass motor off and put a new spare in it's place and see what happens. If that doesn't work I'm gonna take all of the electronics and wiring out put the whole thing in a hydraulic press and watch the pieces fly!

Mark Prince


Just curious. What kinda problems are you having? Mine are so numerous it would take pages. 

I fully agree with Grandpa. They should have listened closer to the customers that bought the first consumer versions back at the first of the year.

They are willing to supply parts under warranty but that only supports our multitudes of troubleshooting efforts.


Ok. I swapped out the suspect badass motor with a new one. No difference. Rcou chan1 always dominates. I can't even use 2000mah of a 3850 mah battery. I can attach logs but it's useless. Same old story. I am done. Barely 5 minutes (not reliable) after months of diligent testing and soldering with everything I can thing of trying and trying everything 3DR tells me to try. I don't want my money back, I just want to crush it.

the only hydraulic press I have quick access to is only 4" wide. When I find the right one I will post the video. I have already stripped it down and am shopping for a new chassis. 

What a ripoff. I will most likely be banned after this message so if you want to keep communicating after this while we build a flyable bird my addy is mprince7596@gmail.com

6 elfin months of frustration. Thanx 3DR for the lessons in what not to do.

All I wanted was 10 minutes with a gimbal and go pro for slight over $1,000 I paid(plus the $400 camera)f. I doubt anyone has put the effort into it that I have. There are other people posting that have that. I wish I knew what the secret is but it doesn't matter now anyway.



 Just sent you an email just in case you get banned, lol. It sounds like you made up your mind on what you what to do so it sounds like you're done messing around with the IRIS. Dont smash it, I just bought mine so I may need a chassis. I will buy it from you!

If not then bring on the video, lol.


Hey mark, they're too wimpy to ban you unless you get really obscene or like that, so stick around. Here's the deal: You sound like a builder, not someone who has to have an RTF quad. So build one. When you buy an Iris or any other assembled or bundled quad you are of course paying for someone else to build it. They in turn need to keep the price within reason, so the tendency is to go cheap-ass on at least some components. And maybe on some labor as well. You can get a whole lot more bang for the buck doing it yourself. Use your Pixhawk and the 3DR GPS unit and lose all the rest. Buy T-Motors, or Scorpions, etc. Buy decent ESCs, either Castle or maybe a 4-in-one. Buy high quality props, like Graupners. Buy a frame. And so on. You'll spend little if any more money, you'll have fun, you'll learn a lot, and you will certainly have 10+ minutes of flight time (suggest Venom batteries, not too pricey and excellent). 


I stripped it but I'll hang on to it for a little while. Have to hide it to keep from pulling out my big hammer:)


Thanx for the input. Your right, I've been building, flying, driving, racing R/c stuff most of my life. The coolest thing I did was race nitro power outrigger hydros at over 100 mph for about 7 years. There are not RTF stuff in that world. You design and build from scratch. I think i breathed too much nitro methane, glue and resin in those days though.

This is just my first venture into the autonomous stuff. I would much rather fly than build and understood from the start that I would have to work on it a lot but never expected the bird to fall so short of advertised specs.

that being said I am going to do exactly what you suggested. Build my own with high quality components. I would order a chassis and motors and ESC's today if I knew what I was going to order. I am open to suggestions from folks who have running birds.

Thanx for your time,


Hi Mark

Sorry you're having a bad time with the Iris.  I don't have one but it looks pretty cool.

I started in the R/C / drone thing only a couple of months ago being completely new to all this wanted something simple to build to start with.  I think I lucked out into a really good combination that sounds like it might be perfect for you.  I went with essentially the DJI frame/propulsion, and the 3DR electronics so get the best of both worlds.  I get 25 mins hover/slow flying from a cheap 5000mah 4s Zippy with landing frame but no gimbal, and around 17-18mins with a gimbal.  

Frame: DJI Flamewheel 450

Propulsion (Motors, ESCs, Props): DJI E300

Electronics: 3DR Pixhawk, 3DR Telemetry radios, 3DR GPS/Compass, FrSky tx+rx (taranis+X8r) - similar to what comes with the Iris I believe.

By the sounds of it you could reuse all the electronics and just get yourself a Flamewheel ARTF kit - this includes the frame and the propulsion set in one package and are widely available for very cheap.  It's dead simple to setup and run - the props and ESCs all pre-balanced and calibrated so there's none of that malarky to go through.  I've lost count of the times I've crashed mine - including multiple drops from hundreds of feet, and apart from broken props and arms (which cost a few bucks each, get lots of spares!) everything else is still miraculously working.  You can just concentrate on the flying rather than the building..

Like others have said you really need at least 4s power for a gimbal, and you might even be better off with a hex - you can also get cheap hex flamewheel ARTF kits (F550 + E300 6-axis).  The E300 is the same propulsion that is used in the Phantom 2/vision, and you can get parts everywhere really cheap, including ebay/goodluckbuy etc and lots of 3rd party extras as well like landing assemblies, good c/f props etc.

If you want a similar layout as the Iris, look at the TBS Discovery which uses the flamewheel arms but provides bigger longer body with the front arms further outstretched like the Iris, so the props/legs don't get in the camera shot.

Good luck!  Don't take a hammer to the Iris, I'm sure it's something simple that you or 3DR or someone else will figure out in due course.

Mark, check out a new info site (not a vendor) at dronesarefun.com, this guy seems experienced and there is a lot of basic info and options there.

I would stick with a quad, and if photography is going to be the thing then the "dead cat" configuration.

Research the power system carefully, good motors are not cheap and it can be hard to make changes. You are looking to match the prop size/pitch to the motor wattage and KV. Remember bigger props are better. For hauling a gopro, 10 inch min. 11 or 12 is better, with motors to match.

Pay a lot of attention to vibration elimination via balancing and the mount for the FC.

Don't get hung up about frame strength. Stiffness matters at the motors, but strength in a crash can actually be a liability. Look at Goodluckbuy and Hoverthings (among many others) for frames. Frames and parts are pretty cheap and when you build your own changing out parts is no big deal.

Here's a key thing. You already know how to fly, so you'll be good to go in that regard (all sorts of idiots try to fly these things purely autonomously without being able to fly manually at all - a guaranteed bad experience sooner or later). But still be very conservative and methodical about trying both radical manual maneuvers and working into the auto stuff. Fly only in Stabilize (manual) first, then maybe try Altitude hold, then Loiter, etc. Be ready to take manual control back instantly.

Also: there is a lot of chatter here about flying down to voltage failsafe routinely. This is not only sketchy from a safety standpoint but is hard on LiPos. You already know that, but apparently lots of people don't, and vendors like 3DR are not about to tell you to shorten your flight time. Fly to 80% of your nominal battery capacity based on time of flight, once you've figured that out.

Have fun.

Ahhh, there  is nothing better then the smell of nitro in the mourning!!!

Replying to my own post: There is a lot of confusion about 4S vs. 3S batteries. Simply going from 3S to 4S will not automatically increase flight times, and may do the opposite. Given that the two batteries have the same overall capacity, the immediate functional difference will be in motor/prop speed. The prop speed needs to be matched to the aerodynamics of the prop. For our purposes this is usually determined experimentally. Be ready for that. But a second factor is also at work and can obscure the issues,namely motor efficiency. Our brushless motors are designed to operate most efficiently at a particular voltage. Some motor makers publish those figures. Anyway, the point here is that it's not so simple as just increasing voltage to gain longer flight time or more lifting power.


Coming to this a bit late.

So for iris + Gimbal a lot of the problem is those heavy legs. Ive been pointed to this site and have ordered these. It may help:


Batteries I use the 5000Mah 3S zippy as mentioned here already.


Much better than the supplied 3500 3s (which tend to over heat Im finding)

I notice on hobby king there is a 5850Mah Zippy that would fit the bay also. (maybe better since shorter) and higher C rating


Props Im testing quite a few:

I like these ones at the moment. They are cheap ass and nasty..but look and sound kool haha


Here they are below. This setup was over heavy and didnt fly well :P

Ive got no figures to make any of this post worth reading tho :)

Maybe next outing I can time it.



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