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        Discussion Calling all experts (long flight times)

#1 Dietr777 Oct 07, 2012 11:46 AM

Calling all experts (long flight times)
 
Gents,

I am getting ready to build my first Hexa and would like to sling a GoPro underneath. I am looking for any suggestions on motor, esc, battery set up that might (using that word lightly) get me 30 minutes of flight time.

Is this just a pipe dream or do you guys think it can be done??

Please let me hear your thoughts and suggestions.

EDIT: More info: I am starting to build a 700mm hexa with a wookong-M (soon to be waypoint version) flight system. I would like to see what types of ranges I can get out of the wookong with the 900MHZ datalink with the addition of some amplifiers and antennas. The reason for this thread is to receive suggestions on how to get max range and flight time out of a multirotor in order for me to properly test the systems capabilities.

Thanks for any inputs,
Dietr (The Newbie)

#2 s.hantiu Oct 07, 2012 12:11 PM

15-20 minutes it's really easy to achieve.
for 30 i think you should go for some very expensive battery :)

#3 Dietr777 Oct 07, 2012 06:41 PM

Any help??

#4 kosins Oct 07, 2012 07:24 PM

You probably need to study a little.
A wealth of information is available on these boards.

If you are more specific as to what you are building other than "a hexa and a Go Pro" you may get more replies.

Lastly...30 minutes flight is unlikely at entry-level builds.
With common configurations, you'll get about 8 to 16 minute flight times.

#5 Lpbug Oct 07, 2012 07:32 PM

I think it's really not practical to achieve 30+ min of flight time on multirotors. Trust me, I used to dream of hour long FPV missions on my fixed wings (and even then you'd have to pack quite a bit of Coulombs in those battery packs to get that time). Multi rotors excel at one thing- close up, cinematic shots that fixed wings cannot get. Multi-rotors are incredibly inefficient compared to fixed wings for all the upward thrust is provided by the propeller, and not a large airfoil wing. If you're thinking about a hexa with a gopro, it would be more than 10-12 amps just to keep the thing hovering. If you add on the weight of the battery (which goes up as the capacity goes up), you're looking at more than 15 amp hover. You can easily do the math of how long you can get by dividing your mAh by the A you're pulling. So theoretically you are flying with a 3600mAh pack: 3600mAh/15A=3600mAh/15000mA=6/25 h. This equates to about 14 minutes. Which is already pretty good. This is assuming that you're hovering and there is absolutely no wind. If other variables are considered, it would probably be substantially less. Why do you need 30 minutes of flight time anyway? You can do a lot in 10 minutes!

#6 Jdmagoo Oct 07, 2012 08:15 PM

MK can achieve this, but you need a good battery and not to much manuovering

#7 rmteo Oct 07, 2012 09:25 PM

30+ minutes of flight time is doable - but you'll have to forget about multi-rotors and electric power. Single rotor (conventional heli configuration, which is much more efficient) and gas engine is the way to go. You can get an off-the-shelf kit of a VTOL craft for around $1,000 that will easily give you >30 minutes endurance (and better payload capability than most electric multi-rotors - which can be traded for even longer flight times).

#8 flyingdogfilms Oct 07, 2012 09:28 PM

You should do some research but what you ask is not impossible. A place I would start would be looking at Ferdinand's flights (EndOfDays) He's got a flight of 65 minutes on a quad as well as a 6.5km quad flight.
Quadrocopter 65min 29sec flight time (8 min 5 sec)

#9 jy0933 Oct 07, 2012 09:42 PM

get a 6s 10000mah battery +low kv motor+12"~14" prop easily got 30mins+

but what is the point... you will get so sick to fly such a long time w/o autonomous system

#10 Dietr777 Oct 07, 2012 11:26 PM

Flying Dog,

Your awesome for helping me with this while others just seemed to have blown me off. I will definitely do some more research now that I know it has been done.. Its funny how everyone is so quick to say it cant be done when they truly dont know..

Thanks again for your positive inputs,
Dietr

#11 Dietr777 Oct 07, 2012 11:28 PM

Jy,

I will be testing the full range capabilities of my new WooKong. Just wanting to try some new things.

Thanks for the good inputs, I will definitely crunch the numbers on your suggested set-up.
Dietr

#12 Sad Sack Oct 08, 2012 12:53 AM

This information is readily available if you look for it. This time is easily achievable with a larger multirotor drone and minimal payload. Look at the setups used for SkyJibs and S800 frames.

You will need a frame of 600+ M2M because you want to swing 14" or 15" props.

Run 6S 5000mAh batteries and large stator motors around the ~320kV to ~400kV mark. Run the batteries in parallel, so you get 10,000 or 15,000mAh battery.

Experiment with different props to get maximum efficiency.
You will get there if you do the work.

#13 jseyfert3 Oct 08, 2012 01:01 AM

Quote:

Originally Posted by Dietr777 (Post 22941587)
Flying Dog,

Your awesome for helping me with this while others just seemed to have blown me off. I will definitely do some more research now that I know it has been done.. Its funny how everyone is so quick to say it cant be done when they truly dont know..

Thanks again for your positive inputs,
Dietr

They blew you off? :confused:

Quote:

Originally Posted by s.hantiu (Post 22936611)
15-20 minutes it's really easy to achieve.
for 30 i think you should go for some very expensive battery :)

Need a pretty expensive battery, which is true. The weight of your battery must equal the weight of the rest of your quad for max flight times, and with a bigger quad that's an expensive battery/batteries.

Quote:

Originally Posted by kosins (Post 22939843)
You probably need to study a little.
A wealth of information is available on these boards.

If you are more specific as to what you are building other than "a hexa and a Go Pro" you may get more replies.

Lastly...30 minutes flight is unlikely at entry-level builds.
With common configurations, you'll get about 8 to 16 minute flight times.

Said the info is here, just gotta research (I've found it myself). Notes that being more specific with your goals will help with more specific answers. Says 30 minutes in unlikely at entry level builds, but didn't say it wasn't possible with more expensive ones.

Quote:

Originally Posted by Lpbug (Post 22939903)
I think it's really not practical to achieve 30+ min of flight time on multirotors. .... If you're thinking about a hexa with a gopro, it would be more than 10-12 amps just to keep the thing hovering. If you add on the weight of the battery (which goes up as the capacity goes up), you're looking at more than 15 amp hover. You can easily do the math of how long you can get by dividing your mAh by the A you're pulling. So theoretically you are flying with a 3600mAh pack: 3600mAh/15A=3600mAh/15000mA=6/25 h. This equates to about 14 minutes.

He gives you one rough estimate for one battery based on your vague "hexa with a GoPro" statement of what you want.

Quote:

Originally Posted by Jdmagoo (Post 22940226)
MK can achieve this, but you need a good battery and not to much manuovering

Says it's possible, but need a good battery.

Quote:

Originally Posted by jy0933 (Post 22940932)
get a 6s 10000mah battery +low kv motor+12"~14" prop easily got 30mins+

Again, saying you need a good battery.

Notice all the relationships? Nobody said it was impossible, they just said it's not easy and you're going to need good (read: expensive) batteries. Two people not only said it was possible, but also said you'd have to do research. You also didn't provide a lot of info. Do you want FPV on that hexa too? Is this your first multicopter build? Are you familiar with RC in general? Have you ever flown a multicopter? Heli? Airplane? Do you see where I'm going with this post?

#14 flyingdogfilms Oct 08, 2012 07:19 PM

Hey little Dietr just needs to fly.

One thing I'm curious about which I've seen very little information on is the power consumption of the different flight boards. I originally started with the KK board and when I moved on to the multiwii I saw a noticeable drop in flight time. I'm curious how MK Naza HF and all the others would stack up all other things being equal.

#15 jseyfert3 Oct 08, 2012 11:41 PM

Quote:

Originally Posted by flyingdogfilms (Post 22948894)
One thing I'm curious about which I've seen very little information on is the power consumption of the different flight boards. I originally started with the KK board and when I moved on to the multiwii I saw a noticeable drop in flight time. I'm curious how MK Naza HF and all the others would stack up all other things being equal.

Is that the board's power draw itself or how the board runs the motors?


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