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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Shaun, can you provide a link for the "new packs at 22ah as well, but 2.35kg" battery ? :)

Did you say X6, what exactly is an X6?   I have a few hexcopters, my main ones are 800mm with 13" Props & 380KV and a Tarot960 with 17" props 320KV, I am getting limited flight time from both of these with 2x6000MAh 6s +camera and gimbal and I was thinking of fitting both with bigger props and increasing the Motor on the 800 to 320KV. 960mm currently gets 7mins flight time with the 2x 6000MAh 6s and the smaller 800mm gets more like 3mins and I am trying to work out how to work out the prop/motor/battery formula to fix this.   I was thinking to increase the motor size on the 800mm to 320Kv and using 2x6000 MAh 6s with 14" props to hopefully get closer to 10min and increase the prop and battery on the 960mm to 18" 22000 MAh 6s 320KV  hoping for closer to 13min.   I can get 22mins on the 880mm set up the way it is using 380KV and the 13" prop without camera and gimbal but the prop clearance is getting tight on it with about 2&1/2 " gap so I think 14" will be the limit before I get into issues with the prop wash interference thing cutting into efficiency.   If I go with anything bigger than the 2x6000MAh 6s the way it is it will be too over loaded so I think the 14" set up with 320KV will hopefully get me closer to 13mins, but I am just doing it hit and miss with my calculations as I am not using any kind of formula that will help me figure out the thrust to weight and flight times, to be honest I don't even have scales to weigh my drones I just add up the manufacturer specs and do some handling tests.  I normally test the drones and see how fast it can recover from rapid loss of altitude and pitch roll tests to see if it is able to recover a high speed stop etc, to see if it can recover from an emergency situation and if it looks like it is going to tip or flip from a recovery then it is over weight.  maybe I am a hack but I know an unstable drone when I see one and I am doing as much as I can to make a safe rig for flying my $10,000 worth of equipment on as I can but if anyone has any tips to calculate that S#!+, I will do my best to figure it out so I can get better flight time but keep a stable machine.  

Gary McCray said:

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

Sorry I hijacked the thread I was just on a roll thinking how to increase flight times as well.

Or you could buy this one : )

Attachments:

It's a tricky thing getting good flight times and stability.  They definitely don't play well together.  My 1300mm X8 is a handful to get over 30min.  Big props lead to all kinds of problems.

This is what I achieved regarding to the topic:

I build a quad for a customer two years ago that flies 45 - 50 minutes 1700 gr AUW  , 250 grams of payload and standard Lipo batteries.

It has been used by dozen of hours of flight for aerial mapping without any problem.

Guess that with recent Li Ion batteries it should fly around 70 minutes.

For 1 Kg payload my hexa has a max flight time of 30 minutes, customer use a brushless gimbal and a Sony Alpha 7R , AUW around 3300 gr .

The Hexa has some special features as :

- can fly with rain

- has a rapid change gimbal, just your hands and in 30 seconds you can change the gimbal

- partially foldable to be carry in a backpack

These features make the hexa  heavier so if do not needed it would be lighter and flight time will increase.

@Luc and @Sergey

please share your setups to understand how you achieved those flight times.

Thanks! happy flying.

Martin, the setup is nothing special , 16" props, 440 Kv motors , custom frame, high density Lipo battery.

It is the way the multirotor is build that makes the difference and allow  to reach 11 - 12 gr / Watt efficiency.

The "secret" is to make the multirotor  the more light that you can .

Each element is chosen upon his weight i.e. aluminum  bolts or using XT30 connectors instead  of XT60.

Little things that finally have a huge impact on the final weight of the multirotor .

Of course since you will use it  for work , you'll need a real frame and not something build just to  reach a flight time record.

It is since 8 years that I build multirotors I did a lot of tests , I bought dozen on of propellers and motors just to test them on a bench , remember that manufacturers usually lie about the performances of their products , I had a big dispute with T-Motor because they claim in their data charts a certain performance with a esc-motor.-propeller combination but in the real world it was 22% less, finally to justify the missing 22,2 % , they wrote  me that the air was different in Europe and China.

Another manufacturer, in his XY graph , use "variable" X values to "adjust" the curve of the graph and give to it a nice shape.

To achieve some results you have to make some choices and use custom parts.

If you choose for an Hexa a standard carbon frame i.e. a Fy680  from Tarot that weight 810 gr , you are done .

For my hexa the brushless gimbal for the Sony A7R is  a stock gimbal  for a lighter camera that was modified to fit the A7R. The reason ?

Because the existing gimbals for A7R were too much heavy while mine weights only 350 gr with the electronic board and the quick change bracket.

One of the limits for multirotors is the size of the propeller, above 16" you start to have problems because the inertia of the propeller make more and more difficult to control quickly the speed of the motor .
Also the weight of large  propellers become a problem , you'll need then heavier motors and the benefits of larger props goes away.  So I'm not a fan of 26" propellers...

If you want to go further you have two solutions in my opinion, a helicopter or a VTOL plane.

I choose the VTOL plane and I'm working on a project for a VTOL plane that can carry 1 kg camera and fly for 100 minutes but with enough money you can reach 3 or 4 hours .

With a plane you can increase the payload without killing the fight time and the plane can fly well even with consistent wind .

@Martin GW

I made a pretty good setup description for this youtube video, just type it here:

My own KroozX combo flightcontroller with OSD and proper Blheli_S ESCs https://www.flickr.com/photos/1503764...

Custom made full carbon fiber frame https://www.flickr.com/photos/1503764...

4S3P NCR18650GA LiIon battery https://www.youtube.com/watch?v=Yz24HLIIqWw

DJI E305 motors 800KV

9450 propellers

Tarot GoPro 3DIII 3-axis brushless gimbal

SJ4000 camera

5,8GHz 200mW FPV transmitter

AUW 1320g

You could probably know my old flight time records:

Multirotor flight time record 129min 37sec

Octocopter longest flight 122m 20s

so regarding what Luc said, I'd never recommend to go over 12" propellers if a long flight time and good video quality in different flight conditions needed. Even with 12" propelleres it's pretty hard to achieve both of the qualities.

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