Hi All

I would like to have a Quadcopter that would carry a GoPro (preferably with a brushless gimbal) and try and get close to the hour mark in flight time.

Does anyone have an airframe/spec that get even above 30 mins and would they mind entering into some Long Distance R&D with me to try and spec something up.

Tried a lot of innovations with frames, props and motors but not got past 25 mins mark myself

Thanks for any replies/specs

Cheers

Ewen

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Hi Troy,

The larger diameter the prop the higher the actual efficiency, normally also slower moving at hover which is where it counts.

That is a pretty immutable fact and is the single most important factor in efficiency.

However, big slow moving props do introduce other problems.

The bigger and slower they are the more a "quadcopter" tends to actually teeter around according to current asymmetrical prop Blade alignment / misalignment with each other.

With faster props this teetering is nullified or barely noticeable, but as the props get larger and slower it actually becomes a noticeable effect.

Also, big slow motor / prop units tend to respond to application and removal of throttle more slowly so it introduces sluggishness.

Also current blade position when throttle is applied or removed can actually introduce additional asymmetric trust offsets.

The net result is that copters with big slow props tend to be less responsive to flight command inputs (pilot or automatic) and tend to have more problems in gusty winds.

You also don't want to get prop blade tips too close together because coincident prop tip turbulence can induce vibration and "choppiness".

My Hoverthings Flip Pro FPV with extended arms exhibits all of these phenomena with 14" props (about 1/8" tip clearance).

My friend Oliver"s identical quadcopter with 13" props does not and fies smoothly through a very wide range.

I will be going back to 13" props myself because of this phenomenon even though it will result in a 5 to 10% loss in efficiency and endurance.

Best Regards,

Gary

Hi Gary,

Thanks for your response. 

Do you think that having another blade on the propeller might solve the teetering caused by "asymmetric thrust"? Having another blade (or two) might average out that effect similar to how it's averaged out with fast turning props. 

Perhaps an X8 configuration would solve that problem as well. What do you think?

Troy

Hi Troy,

My freind Oliver tried 3 blade props and I have a set myself (Master Airscrew).

They did not actually work very well,but it may well be that their skinny blade design is at fault, more of an airplane prop than a multirotor even though claimed to be multirotor.

I think the qualified answer is that with the right prop and under some circumstances they could probably work better.

As for X8, it is a good way to stuff a lot of thrust in a relatively small package, but you lose 15 to 20% efficiency through the coaxial dual prop design, period.

There is no way to eliminate that loss, even with top and bottom prop sizes and pitches optimized.

It is possible that it could still be more efficient than a roughly equivalent Octo however because the Prop diameter could be considerably larger.

So it is a trade off more smaller props versus Coaxial loss.

A efficiency optimized quad with optimal propeller diameter and motors will always beat either an "equivalent" X8 or an Octo though (or Hex for that matter because of the smaller propeller diameters or coax loss.

Hex's and octo's are smoother than big quads and an X8 can be used to lift a heavier payload.

You really need to design your copter for what it does, Hexs and Octos are popular for big camera craft because they fly smoothly because of the more small props.

Generally Coax's are pretty smooth too.

So its a choice - maximum efficiency = quad with biggest possible props.

Smoothest flight = Hex or Octo or Coax X6 or X8.

Best,

Gary

I'm wondering what is the range that you are flying. If not too far maybe a power tether would work, i.e. trade your battery weight for a power converter and cable and you get infinite loitering. And if you can move around with your ground power source, you probably would still be able to cover a decent size area. 

Hi Shaun,

Just read about your D130 and stability problems. We have just assembled our first quadcopter (U8-10 motors,170kv,28" prop,6s battery) and done a first flight...it was a little twitchy at transmitter sticks in roll and pitch and it oscillates hugely to compensate.I just wanted to know what flight controller did you use (ours is apm 2.6) and if you finally get a stable and easy manoeuvrable flight (beggining with almost no windy conditions).

Many thanks! 

Excellent summary, thanks!

Hi Ariel, can you please tell me more about the Hives? I am really interested because I am developing automation technologies for multirotors to increase mission persistence. Thanks

Sure.

Here is a bit more on the project http://diydrones.com/forum/topics/hiveport-airports-for-drones-so-w...

We are actively working on the software (connective tissue) to bring together the people who want to use the Hives with the Hivekeepers.  

- Creating your Hive

- Scheduling / Discussing flights to/from the Hive

We have the core of it working on Android and will release shortly.

Have to chat more -- send me an email at ariel at hivemapper dot com

Hi Rob, that's pretty good going.  What motors/props are you using?  I've got a tarot 650 with dji e300 that are clearly underpowered and I'm struggling to work out good replacements.

I'm thinking to a hybrid solution. If low kv suffers of instability and high kv suffers of endurance, one might think to a mixed configuration. Some large props for hovering and others only for enhancing the attitude control

http://diydrones.com/profiles/blogs/46min-loiter-on-3d-printed-hexa...

so we have achieved 46 min of stable  flight using 490kv motors 15x5 propellers and a 16ah 4s lipo we have since reduced the frame weight from 640g to 480g we have not run another endurance test we are retuning we replaced the apm 2.6 with a pixhawk so we can actually get a full log the 2.6 wont hold that big of a log file

https://www.youtube.com/channel/UCzRBlqkKB4R7BMgb5T-hphg

there are some videos of it flying on our YouTube channel

we are nailing down the supply chain right now but we will be offering a ready to fly version in the very near future

 

Hi Shaun,

What exactly is your motor/ESC setup on your hex? Flight controller? How is the Devourer performing?

I am building a Tarot X6 for a friend (long duration flight, light payload) But am finding few 5010 motors. 

Thanks

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