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

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The thing is when they advertise these flight times, the weather is absolutely perfect. no wind, perfect ambient temp around 75 85 degrees. But I don't know of anybody yet that's getting 15 minutes with a stock battery. And there is know way you would get ten with the gimbal and legs. The four longer landing legs are the same weight as 2 gopro hero3 cameras. That a lot of extra weight.

Temperature,  and off coarse weight are the two biggest factors of low flight times.

But I do know they have the ability to put a a product that can get a much better time in the air. DJI is getting great flight times now with with their Phantom 2 and vision.. New batteries, and more efficient props are getting up to 25 minutes with a full fpv on the vision and 20mn with the P2.

DJI batteries are $150 each.

I agree they should do something. I was lured over to the iris because of its autonomous  flight. It was a lot cheaper than buying a DJI wongkong or some other flight controller's that alone around a grand. Of coarse now they have Ground station for the Phantom for around $250 .

What good is unlimited way points when if your lucky to get 6 to seven minutes of flight. Yes you may be able to get 15 minutes with a different battery with out gopro and gimbal. But im guessing 99% of the people that buy these types of quads what them for the videoing platform.

They better get something going with better flight times or they are going to lose a ton of customer base to DJI and even Blade has stepped up to the plate along with walkera with 20 minute flight times with full fpv and camera gimbal.

I am using a 4s 3000mAh battery with an external low voltage alarm. (I just don't trust the low voltage failsafe on IRIS)

Battery is a tight fit, so don't overheat it, land immediately when the buzzer goes off.

10-11mins flight time guaranteed with a GoPro onboard. On a calm day and if I don't go crazy and do a lazy flights I get around 13-14mins (w/o gopro)..

Here are the links for you;



And here is the pict of my installation.


did you ever end up trying the 3 blade props?

No. As of this week I have pretty much given up on the Iris. After about 70 to 80 flights of pure misery due to the Pixhawk pressing on Iris issue I put a mast on it which turned it into a perfect bird with 25 perfect, uneventful flights, then I put the GoPro, gimbal and legs on it and the misery started all over again due to lack of lifting power(see this thread). Then last night I decided to revert to stock and remove the payload. When I powered it back up my LED on the battery door quit working and I started getting pre-arm compass warnings. Tried about 10 compass calibrations(which I usually don't have trouble with) and finally got a good cal and now I get "excess compass offsets" warning keeping it from arming. I have never had compass issues since the mast was installed. I am suspecting I2C issues since the LED and the compass are the only devices connected to the I2C buss.

I am really tired of constantly troubleshooting out of the box issues on an RTF bird only for the experts to tell me that the Iris doesn't have enough power for the payload advertised. I know there are other people getting different results but if you read the thread linked above you will see that I have tried everything except replacing the $140 4n1 ESC and power module which requirers complete disassembly and 16 solder joints. I don't mind soldering at all but I want to be building instead of replacing almost every component on an RTF.

I am going to build a TBS Discovery Pro and put my PIxhawk and other 3DR electronics in it. Have you had issues with the full camera and gimbal payload?

I can say that I have learned a lot more than I would have had I not purchased a problematic product. I chalk it up as a $1k crash course in the APM platform.


you are not alone. tomorrow I will tell you what I went through. shame they do not listen to advice from us users. in short, two times sent back, one replacement and finally returned for a refund. if they would have taken some suggestions many months ago there would have been many happier users. it is being sold as RTF it truly is not if you want the equipment you and I have had to work correctly!

Even though I don't own an Iris (and by the look of the threads, probably a good decision) I have a bunch of other quads and think I might be able to offer sound advice here.

If you are going to use a GoPro with or without a gimbal, you really need to go to a 4 cell battery, not so much to increase your flight times, but just to have sufficient performance to fly properly with the Iris.

With GoPro and gimbal it is a very widely known fact that the Iris is seriously under powered and you really want to hover at about 50% throttle - just to be safe and have proper control.

You also need to use 10" props.

Don't forget a 4000mah 3 cell battery has the same total energy as a 3000mah 4 cell battery, but the flight time with the 3000mah 4 cell battery will not be as long as the 4000mah 3 cell battery because the motors used on the Iris are not as efficient at 4 cell hover speed as they are at 3 cell hover speed.

However, the 33% stronger thrust you get from 4 cell will allow you to use a larger 4 cell battery if you can stuff it in there.

On 4 cell you will need to watch motor heating and ESC heating more closely although I haven't heard of much problem with the Iris.

If the Iris had been made to accommodate 12" props with motors to match it would have been a much more capable copter.

As it is 10 to 12 minute flight times are probably the most you should shoot for with 4 cell battery, GoPro and Gimbal, adding more battery would impact performance more than it would help.

Maybe with excellent setup and a MaxAmp battery of the appropriate size you could squeeze out 15 or 16 minutes.

(MaxAmps can commonly supply 25% more energy per unit weight than the other common batteries so you could go to a 25% higher MAH rating for the same weight.)

Just my thoughts, I am not an Iris guy but I am scratch building a CF tube H - Dead Cat with 515KV KDE motors and 14" props that I fully expect to actually be able to get 30 minutes usable actual flying around time out of with GoPro, Gimbal and FPV.

Just trying to help you tweak the Iris to get the most it has to offer.

General rule - bigger props and high quality lower KV motors = considerably higher efficiency and longer flight times (cost more too).

Hope this helps, took a long time to understand right.

Hi Murat

I have tried the 10" Master air screw 3 blade props, they are too narrow a blade and are no more efficient than 10" two blade props (they are smoother though with less vibration).

Flight time was actually slightly reduced.

A 3 bladed prop for multicopters needs a wider blade though, that's all there is to it.


Great advice. I will look closely into your build. Please keep us posted cuz I am going to build another. I am prepared to spend the extra money on better motors and other stuff. Right now I have some more immediate needs from the Iris and will keep tweaking. Problem with 4 cell is finding one with adequate capacity that will fit into the compartment. In addition, my motors get extremely hot with the 3 cell.

All I have ever expected from the IRIS is 10 to 12 minutes with go pro and gimbal. Right now that is unobtanium. I feel jilted over the Iris purchase but I am not a person to hold grudges. Only action solves problems. 

Back to my flight time issues where the front right motor ESC output is getting maxed out causing the other motors to back off in an effort to maintain attitude.

According to jschall in the log analysis forum, I have COG issues  and closely studying I have come to agree with him. Hear me out.

I added a mast (see attached pic) because of the myriad of issues caused by the GPS contacting the Pixhawk. I really had no choice. The Iris was totally unpredictable and GPS performance was terrible. Installing the mast solved ALL of these problems providing excellent GPS performance. I then added the gimbal, legs and go pro and it all went to sh(*.

If you look at how I installed the mast, the weight of the GPS and the mast is about 1/2" further forward than the stock GPS mounting position. The does indeed shift the COG slightly forward relative to the stock configuration. Since the IRIS is so under powered this slight COG shift has caused the front motors to work harder to maintain attitude. This upset the delicate power balance of an under powered bird. This shouldn't be. I have seen masts mounted way off the COG and not cause these kind of problems. 

This problem could be solved by putting the GPS back into it's original position and moving the PIxhhawk per the 3DR recommendation but I refuse to go back to that setup since the mast solved so many other issues. I am going to experiment with moving the PIxhawk to the back more and installing some COG counterweights. I doubt this will work but I would like to have something to fly while I work on another build. I need 10 to 12 reliable minutes with a gimbal and go pro. My next build is for a downward facing camera and mapping in areas where a plant doesn't work out (golf courses) as well as a copter.

I am also going to order the Nano-tech A-Spec 3s 4500 since it only weighs 278 grams. The Zippy 5000(16 minutes without gimbal, legs and go pro) weighs 404 grams. The A-spec seems to have the highest power to weigh ratio of anything else I can find.

had the stock Iris not had so many issues I would never have tried the mods that has upset the COG but I got tired of waiting on the design change from 3DR. I would say the GPS/Pixhawk contact issue was the major design flaw that has killed the Iris for me. I can assume the ones shipping now don't have this problem. I patiently waited for the consumer version and it just didn't pay off. I would like to try different motors but the arms don't allow any motor with a larger diameter to work.

Gary, thanx again for the advice. Sounds like there is a lot experience behind it.

Mark Prince

Hi Mark, One thing I didn't mention but which is very important for any not fully symmetrical copter is decoupling the roll and pitch rate PID.

Normally they are tied together and have the same values, but the P Value for pitch rate needs to be higher than the P value for roll on a dead cat design like the Iris.

I don't know if default Iris PIDs take this into account, but they should.

The reality is that the wider moment arm between the front and back props versus the side to side props means that less force is required to roll the copter around its center of mass than is required to pitch it around it's center of mass.

There is also a tendency to distribute the primary mass from front to back in a dead cat which actually worsens this situation.

TBS Discovery and Hoverthings FPV Pro type dead cats are probably worse than the Iris because their central mass is very long front to back, but they require very different settings for rate pitch versus rate roll (P value only is usually enough).

Of course with additional mass like camera and gimbal underneath or worse one in front (distributing the mass more linearly front to back) this problem is made worse requiring more difference between roll rate P and pitch rate P.

This actually makes the difference between one of these handling well and not.

Hi jake,

     need to chat with you about same.. considering same action




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