Reliable products for AP?

[thijmen5]

Hello everyone,

Im going to build a hexacopter for professional AP and want it to be as reliable as possible.
I mailed a shop which is selling herkules board, but he advised to take hobbywing funfly esc's since 80% of the herkules boards is being returned. Thought there isn't anything better than the herkules?

Now I'd like to know if the funfly's are really that good for the DJI? Or is there something else better? Don't mind if it is more expensive than the hobbywing, it just needs to be good if there is an expensive camera hanging under the hexa. If one of the speedcontrollers fails, I can still land the the hexa safely right?

Also noticed here on the forums that people find wookong being less stable in higher winds. Is it really that bad? Or is it just the setup? I'd find the DJI to be the most attractive since I'm not much of a soldering hero. Or will the Mikrokopter be the best choice for stable AP (in windy conditions)?

For the motors I had the avroto m2814-11s in mind with APC props. Cameramount is going to be a AV130 hanging under a self made carbon frame.

Can you guys give me advise?

Regards,
Thijmen

 

[mailman35]

ive heard alot of mixxed things about the apc's they are a pain to balance id say go with the grapners
you just have to find a place that has them in stock, but if u are running 2814 with a 4s lipo then the 9x5's should be good to fit on with no extra prop adapter needed. assuming its a 6mm shaft.

 

[jes1111]

Or Xoar/JXF props.

Reliability is all about the weakest link - so everything has to be good, particularly the connections - in order of reliability: crimp > solder > locking connector > non-locking connector.

 

[thijmen5]

Thanks for your answers, but I'm not understanding the word 'crimp', translate also doesnt give me the right translation:upset:. The graupners are on my list!:nevreness:

Since a hexa won't fly if one motor falls out I am thinking now of an octo in X config. I can't allow the hexa coming down, especially for commercial flying.

How seriously will the flight time be reduced in X8 config? (thinking of 2 x 5000mah 5S) What other cons are there for a X8 octo?

EDIT: noticed the avroto's only work on 3-4s. Also will need other motors instead..

 

[jes1111]

Crimp: the kind of wire connection where you crush the wire inside a metal tube or U-shape using special pliers - surprisingly, more reliable than solder because not affected by vibration.

I wouldn't worry about 4S vs. 5S - I've found the differences to be minimal when there's eight motors. See http://www.ecalc.ch/xcoptercalc_e.htm?ecalc

The Avroto motors are (I believe) made by RCTiger - see MT2814. Very high quality - their fat/flat motors are very good for coax designs - MT4006, MT4008. You can email them and buy direct (and specify long wires, etc.), payment via PayPal.

 

[thijmen5]

Is there a minimum or maximum distance between the motors when you're using them in coaxial setup? Otherwise would the 2814 be a better option (price is total 160usd less).

Than I stick at 4s, the only thing i might change would be the discharge rate? So instead of 20-25C go to 30?

Is it an option to connect 4 motor (bottom ones) to 1 lipo and the other(upper ones) 4 to another lipo? So if one connection or cell fails the other 4 motors can still run, it wouldnt fall as hard as zero motor. Or is it just my theory?

 

[tstrike]

I don't think flight controllers work that way. I thought you were looking for reliable, what size camera are you going to sacrifice to the gods of air for your endeavors? Figure that one out and go from there. More reliable=less moving parts to fail...imho.

 

[thijmen5]

I havent figured out which camera I will take yet (500-1000€ for start, maybe a sony nex-5N). The more moving parts the more parts can fail makes total sense. At a hexa you have 2 motors en 2 esc less, but if only 1 fails, it comes down. On a X8 octo you have more parts, so higher change at failure, but if one fails it still flies. The chance of 2 motor fail at the same time is reliable enough for me.

 

[holco]

There is no problem using the Avroto's ore others on 5S with multirotor use if you don't fly Warthox style

The only range you use is hovering and temporarily clime-outs at max 3ms.

Lets say you need 800g lifting (4800g total for a hexa) for each Avroto motor when hovering thats +/- 113,4W with an Graupner E 11x5 prop

Avroto on 4S 800g

16,2V X 7A = 113,4W

Avroto on 5S 800g

20,6V X 5,5A = 113,3W

As you can see the Wattage never change because thats the power you need for a determined rotating speed of the prop, same prop with the same rpm on the same motor will give a fixt Wattage that never change, the numbers that change are V and A, more V is less A and less V is more A.

The Avroto's can deliver 350W max (and more) so 114W is a piece of cake

Greetings,

Mario

 

[Stacky]

With respect to the X8 arrangement and loss of efficiency in terms of flight times my experience with my X8, then Hexa and Y6 is about 15% to 20% loss in flight times. I have messed about with different prop setups, having bigger higher pitch props on the bottom motors gives me a small increase in efficiency. There was a thread somewhere which talked about how coaxial arrangements should be more efficient than flat arrangements but the discussion was above my level of knowledge.
What Im talking about is just my own personal flying experience and isnt based on any scientific measuring so there could be things Im doing wrong.

As far as props go I have been lucky in that all the various APC props I have bought havent been too far out of balance and all props I have bought from varying manufacturers have needed some level of balancing. I have just recently tried Graupner 10*5s and they were similar to APC out of the box but still needed tweaking. As far as reliability goes in 15 months of flying I have never had an APC prop break in flight on me and I fly 3-5 times a week. Thats using a wide range of APC props and sizes. The props that I had trouble with were EPP props.

One last thought on being able to fly a configuration if you have some sort of motor/esc/prop issue is that flying ability will help a lot with your chances of landing successfully. Also flying conditions can have an impact. So a beginner on a calm day with nice visibility hovering could land an Octo but on a gusty day with sun in your eyes and while in some sort of directional momentum a beginner might even have trouble with an Octo.

I had a Hexa nearly a year ago that kept crashing because of a poor soldering connection on a bullet connector I had made. Back then I couldnt land it but from the video footage I have of those crashes I know with my improved flying ability I could have saved it if the same thing happened now.

I had a X8 blow a cheap EPP prop on me whilst hovering. The broken prop whizzed past my head and as I reacted to that I fell over. The X8 was 15 meters away and only 5 meters up in the air. I was able to land it but it was a very ugly landing. Conditions and circumstance have as much of an impact on landing when a problem occurs as does the configuration.

One of the forum users on here, jamienz was flying FPV with a quad with a NAZA fc. The video footage he showed me is very cool. You can see the prop spin off but Jamie was able to bring the quad down in a spiral rather than it flipping. The landing was essentially a crash but it was controlled to a certain extent. I didnt think that could happen with a quad till I had seen it.

The more real world flying practice you get in all sorts of conditions will help you massively. Flight sims are great for getting muscle memory movements in place but real world flying is the biggest asset.

 

[thijmen5]

In that case it wouldnt make a difference if you fly 4 or 5s. The only difference would be for the lipo right?

How much flying time are you getting with the x8? Im aiming at 10 min, with 2x5000-5800..
I never flown a multirotor in real except for the sim, which is quite easy. I fly a protos 500 in 3d style so I think a octo wont give me any problems.

 

[Stacky]

Currently Im am just slowly testing this version of my X8. I am still making sure my power distribution can handle the current draw.

However I have had a couple of flights and with 2 * 5000mah 4s batteries I got a 10 minute flight. That was without a camera or gimbal. My X8 without camera and gimbal weighs 4.3kg. Also the flight I did was a simple hover so the X8 wasnt climbing or flying around etc. I stopped flying before my alarm went off and I had my alarm set to 3.6v per cell. So I am expecting maybe a 7 or 8 minute flight fully laiden when the alarm goes off.

I havent looked into flying 5s batteries, I havent check if the esc's I use will take 5 s batteries. If you can fly a decent sized Heli 3d then I doubt an Octo will give you much trouble at all.

In that case it wouldnt make a difference if you fly 4 or 5s. The only difference would be for the lipo right?

How much flying time are you getting with the x8? Im aiming at 10 min, with 2x5000-5800..
I never flown a multirotor in real except for the sim, which is quite easy. I fly a protos 500 in 3d style so I think a octo wont give me any problems.

 

[holco]

More S lipo's will be easier on the lipo's and ESC's because of the lower Amp's.

In that case it wouldnt make a difference if you fly 4 or 5s. The only difference would be for the lipo right?

 

[thijmen5]

Since i have more lifting power with 8 motors i can take bigger lipo's for more flying time.

How do you connect all esc's to 1 lipo and for the wookong?

 

[thijmen5]

I've seen that some people find DJI not working very well at large multicopters. How are the experiences from other users?

As I know somebody how has CNC lasers, therefor I'd like to know if anybody has tried it before? Does it look nice when finished cutting?

What esc's are recommended?

 

[MombasaFlash]

... The props that I had trouble with were EPP props ...

I did a photo job last week and went up first with an MK Octo and a small compact camera, because it is so quiet and unobtrusive. Both blades of one prop flew off. The previous outing a single blade broke off. These were the EP props that the Octo was supplied with. Since the Octo seems to be completely unconcerned by losing a prop I had decided to wait until I run out of spares before changing to more robust items.

If I fly it often enough that won't be long now!

BTW, the Octo was sent to the corner of the room in disgrace and the AD-8 was brought out to do the photo job with a NEX-5n.

 

[thijmen5]

How do you guys do the power distribution on the octo's. Every powerdistribution board I see won't take enough amp's..

Maybe just connect all esc directly to each other is the best option? If so, how would that be connected the best way if 8 cables turn into 1?

 

[Stacky]

I used a Minsoo Kim distribution board, scrapped off the protective paint and then added solder to the copper tracks. Completely unscientific in approach and I have no way of measuring what current it is now capable of carrying but so far after only a few test flights I havent found any overheating at all or issues so far. However I have a decent length of test flights planned to see if this will be ok. Another user on here called Shawn who uses the nick of Mactadpole had a very tidy method using copper wire etc. This is his profile, he will know where the link to his distribution ring is http://www.multirotorforums.com/member.php?250-Mactadpole

How do you guys do the power distribution on the octo's. Every powerdistribution board I see won't take enough amp's..

Maybe just connect all esc directly to each other is the best option? If so, how would that be connected the best way if 8 cables turn into 1?

 

[thijmen5]

Came across a post from afropower board man himself and he said adding extra layer of solder doesnt make any difference. For octocopters he suggested make a spiderwire connection. In that case I'd like to know how people make these with good/reliable connections?

Thanks for the link!

 

[thijmen5]

As i'm not will be using a power distri board it will be a spider wire connection. So each lipo will power 4 motors and one of them is powering the DJI and receiver aswell. If the lipo that powers 4 motors, DJI and receiver fails how will I be able to use the other lipo? Do I need an extra BEC or something?