Octo Build for Aerial Video

[mbsteed]

I just won the DJI flight controller and while my wife was still excited about the win, I have convinced her to let me do a new build. The theory goes something like this; we saved so much money so we need to spend more - you know all the stores try to get you with that same logic - spend money and you will save money. It seems kind of counter intuitive but it works.

Purpose: I plan to take quality aerial video footage and be able to do FPV and at the same time frame the footage in the air with the video downlink.

I would like to be able to lift a large DSL if necessary but will probably start with the Canon Vixia G10 Camcorder.

I have a couple of concerns: I am assuming I will need at least 2 - 4s batteries to power those larger motors but not sure. What ESCs would folks suggest - I have been happy with my Maytech 30A but those are probably not quite enough for these motors. I can't seem to find any 40A Maytechs. Any suggestions there?

I have done some reading on FPV systems and I think what I have there will work but this is totally new territory for me, so I could be off base. Will a 2S battery be sufficient to power the video transmitter?

Has anyone had experience with the Pro Mount 200 Camera Gimbal?

Here is what I am thinking:

Droidworx Octo HL V3	http://shop.quadrocopter.us/AD-8-HL-Airframe-Kit_p_125.html
QUADROPOWER MOTOR QC-3328	http://shop.quadrocopter.us/QuadroPower-Motor-QC-3328_p_392.html
PRO MOUNT-200	http://shop.quadrocopter.us/Pro-Mount-200_p_188.html
Maytech ESC 40A orCastle Creation Thunderbird 54A ESC	http://www.maytech.cn/eng/proesc.asp?type=2				http://www.nghobbies.com/cart/index.php?main_page=product_info&cPath=2_150_14_46&products_id=757
DX10 Transmitter	http://www.greathobbies.com/productinfo/?prod_id=SPM2800US
APC Props 14”	http://shop.quadrocopter.us/APC-SlowFly-Prop-14x47SF_p_410.html
APC Props 14” pusher	http://shop.quadrocopter.us/APC-SlowFly-Prop-14x47SFP_p_409.html
LM 1.2GHz Portable Receiver	http://www.nghobbies.com/cart/index.php?main_page=product_info&cPath=1_5_93&products_id=328
1W LM 1.2GHz Transmitter	http://www.nghobbies.com/cart/index.php?main_page=product_info&cPath=1_83_58&products_id=172
Standard 1.2GHhz Antenna	http://www.nghobbies.com/cart/index.php?main_page=product_info&cPath=1_10_39_78&products_id=357
1.2 GHz 8 dBi Flat Patch Antenna	http://www.nghobbies.com/cart/index.php?main_page=product_info&cPath=1_10_39_78&products_id=223
Goggles - EVG920 Video Eyewear	http://www.nghobbies.com/cart/index.php?main_page=product_info&cPath=1_170_171&products_id=114
Flight camera - 3D FPV Camera	http://www.nghobbies.com/cart/index.php?main_page=product_info&cPath=1_8_112&products_id=393
Turnigy nano-tech 6000mah 4S 25~50C	http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=20682
ESC distribution board _ PhotoshipOne	http://photoshipone.com/shop/index.php?main_page=product_info&cPath=40&products_id=251

Any thoughts?

 

[BorisS]

Hi Mbsteeb,

congrats on you winning the WKM. My general thought it that you could also consider a Hexa instead of a Octo in case of wanting mainly to fly with a Camcorder and two lipos. But maybe a calculation in eclac would give you somewhat assurance what would be the better choice. Eventually a hexa will safe you time and money.

Concerning the components.

The QC-3328 are nothing else than expensive Rc tiger motors, and you can also consider those http://www.quadcopters.co.uk/?PageID=ShowItem&Item=3536PRO&Desc=Torxpower 3536 Pro (Short Shaft) which are imho excatly the same ! I guess you just have to calculate
tax and shipment, but it should still be cheaper.

Props you will not be happy with the APC 14" with the WKM setup. I would tend rather to light 12 3.8 carbon props but really the light ones like the 11 grams from the MK shop or the graupner 11 x 5. Ken has tested those several times and gets his best performance with them. I prefer the 12 3.8 11 grams from the MK shop but to tell the truth cant deal with their price anymore.

AV 200 Pro mount. I think you mean the PH. I was never super happy with it others are. Depending on the time frame you are planning for your build i would wait for results concerning the CS gimbal and eventually the WKM DJI gimbal. If that gimbal is a good as promoted (lets see) you are going to bite your ... for having bought the AV 200. Although I am starting to suspect that PH ( for the reason its already delayed and PH has been a DJI dealer since some time) is designing the DJI gimbal which i am not happy about if true, which could also mean that this technologie will also be available for different FCs.

4s Lipos. WKM likes higher rpm thus 5s is a voltage you should consider to test. I wouldnt from beginning set all my horses on 4s.

Concerning the Maytech or Castle creations i cant tell you if thats a good choice but i also think it could be a bad one. Certainly they are of better quality than the usaul suspects Turnigy dys tiger whatever they are called, which are all the same anyways. But the best footage i have seen up to now was made with these Chinese ESCs. Confused at the moment maytech could also be the same. Check the rcgroups forums.

Photoship One dist borad is not a good choice. 60A or 80a capable with multiple batteries. For sure you should be using two of these boards for your Octo setup to be on the safe side.

If you are a friend of DW and like they way their frames are designed than its just a question of taste. Having had both frames DW Octo V2 and now the CS 8. I would only go for the CS frames from now on. The concept is just simple and to the point. The vibration isolation of the CS frames really works and again safes you time and cash in my eyes. Of coarse the later EC or EM (whatever its called) updates from DW are very tempting.

Boris

 

[Jules_B]

I just won the DJI flight controller and while my wife was still excited about the win, I have convinced her to let me do a new build. The theory goes something like this; we saved so much money so we need to spend more - you know all the stores try to get you with that same logic - spend money and you will save money. It seems kind of counter intuitive but it works.

Purpose: I plan to take quality aerial video footage and be able to do FPV and at the same time frame the footage in the air with the video downlink.

I would like to be able to lift a large DSL if necessary but will probably start with the Canon Vixia G10 Camcorder.

I have a couple of concerns: I am assuming I will need at least 2 - 4s batteries to power those larger motors but not sure. What ESCs would folks suggest - I have been happy with my Maytech 30A but those are probably not quite enough for these motors. I can't seem to find any 40A Maytechs. Any suggestions there?

I'm flying a Droidworx octo (SkyJib 8) with Axi 4120's. At the moment it's carrying a 5D for testing. With that sort of payload I find it likes 5s and 6s best. As I plan to carry heavier cameras I factored some headroom into both the motors and ESC's and went for Fentium 80A. I know people are going to say that 80A is total overkill but I always like to keep components as stress-free as possible whenever I can. I've only been involved with multirotros for a few months so can't give any proper advice on the nitty-gritty stuff like Boris can but thought this info may give you some idea for comparison, at least as a starter. Here's a link to some test flights using the Wookong: http://vimeo.com/ju1esb/videos

Jules

 

[Macsgrafs]

I also fly a Droidworx SJ8 using 60A ESC's & emax GT2820 motors on 12x6 props APCE (not slofly). As for the video TX, you will need a 3s lipo, 7.4v will not even switch it on!
Basically you want to do what I want to do, I want to have my DX201 FPV cam mounted so that I can get in closer to objects if needed & I also have a live video out from my panasonic camera mounted underneath on a gimbal...but that is controlled by my fiancee, so less strain for me.

Ross

 

[Sebas600]

If you want to use the AV200 get the AD8-HLE otherwise the landing gear is shorter than the gimbal

 

[mbsteed]

Thanks for all the comments and suggestions. I like the redundancy of the octo over the hex, the droidworx CS frames doesn't seem to be in the league in terms of carrying a payload. Yes I was planning on the Extended version to accommodate the Camera Gimbal. I trust the Maytech ESCs and I don't care where those are made but those won't be around for a while so I will look into the Fentiums 60A. What is wrong with the 14" props? Those quadro motors can support those. I am looking into slightly longer booms (465mm) than the standard setup to accommodate larger props. I could easily go with 5S batteries if folks think those would work better on this setup, 4S work great on my current setup but it is overall much smaller than the this setup so I can see why 5S might be useful here. In terms of motors, I don't want trashy motors. I am willing to spend $100/motor. What I am finding is you pay for what you get (. Would I expect better performance and balance out of AXI motors?

Boris, when you say WKM likes higher rpms does that translate into higher Kv on the motor? Why do you think the Quadros are trashy motors? Do think they are just relabelling a cheap motor and selling for a higher price? Oh, by the way I don't think video footage has much to do with the ESC per se. The reason I am concerned with ESC is reliability and compatibility more than anything else. However, I notice the DJI site suggest that the wK-M supports ESC 400hz refresh rate - the Maytech ESC was one of the few that had this spec. Would that possibly translate into smoother flight?

As I have reviewed camera gimbals, I think these companies are still trying to figure out this technology. Most of the camera gimbals on the market get mixed reviews at best. They don't do a good job of vibration dampening and in terms of roll and tilt composition, I don't want any camera gimbal that is directly driven by a servo given the nature of servos (too much jitter even with the higher resolutions). I think the only way is for it to be belt driven with a gearing system to smooth that out.

That is why you folks like this trying to modify their gimbal:
http://www.multirotorforums.com/sho...ormance-of-a-PS1-mkTR-Pro-camera-gimbal-mount...

 

[Macsgrafs]

The reason I am concerned with ESC is reliability and compatibility more than anything else. I notice on the DJI site suggest that the wK-M supports ESC 400hz refresh rate - the Maytech ESC was one of the few that had this spec.

All ESC's should be a minimum of 400Hz, thats a standard ESC.

Ross

 

[BorisS]

Thanks for all the comments and suggestions. I like the redundancy of the octo over the hex, the droidworx CS frames doesn't seem to be in the league in terms of carrying a payload. Yes I was planning on the Extended version to accommodate the Camera Gimbal. I trust the Maytech ESCs and I don't care where those are made but those won't be around for a while so I will look into the Fentiums 60A. What is wrong with the 14" props? Those quadro motors can support those. I am looking into slightly longer booms (465mm) than the standard setup to accommodate larger props. I could easily go with 5S batteries if folks think those would work better on this setup, 4S work great on my current setup but it is overall much smaller than the this setup so I can see why 5S might be useful here. In terms of motors, I don't want trashy motors. I am willing to spend $100/motor. What I am finding is you pay for what you get (. Would I expect better performance and balance out of AXI motors?

Nothing is wrong with 14" in combination with a different FC. I am flying the QC on my CS and I would love to have bigger props on them but its a no go with the WKM since the platform will not be as stable and smooth as it could be. But give it a try graupners are not that expensive that you couldnt try them later. For props just refer to Ken s threads he is much more precise on explaining than i am and you will understand what i am getting at.

Concerning AXI QC or Tiger RC motors, i cant base my opinion on any data or tests i have done with a test stand. My feeling though tells me having been using two different version of AXI on a Octo and a Hexa that the AXIs are a noch better. On the other side i had 2 axis on my octo that became loose and the motor bell i think one calls it had play. Some said its not of concern, I still think it wasn't a good sign. The quality difference concerning vibrations doesn't play such a big role anymore if you have a good vibration isolation for your gimbal.

Boris, when you say WKM likes higher rpms does that translate into higher Kv on the motor? Why do you think the Quadros are trashy motors? Do think they are just relabelling a cheap motor and selling for a higher price? Oh, by the way I don't think video footage has much to do with the ESC per se. The reason I am concerned with ESC is reliability and compatibility more than anything else. However, I notice the DJI site suggest that the wK-M supports ESC 400hz refresh rate - the Maytech ESC was one of the few that had this spec. Would that possibly translate into smoother flight?

It translates into higher KV on the motors and the voltage you use. Thats why i was pointing out since you were posting rather low KV motors that 5s would be a better choice for you. Refresh rates etc. responds time jada jada etc. is all nice and thrown out and only one part of the game more essential is the actual firmware on the ESCs allowing fast speed changes. Often ESCs firmware have filters implement that swallow certain commands, which makes them not multi friendly.

Oh and i never said the QC are trashy motors they are just completely overprice if you have ever written tiger motors a mail and ask quotes for equivalent motors/the same motors just ofter Kv. We are talking about 30$ a piece and again with that i am not saying they are trashy.

Boris

 

[mbsteed]

So the Fentiums would probably be up to that spec then. Okay.

Perhaps I would be better off with a MK3638 motor - it has about the same amount of thrust as the Quadro motor. Oh that one has low kv as well.

http://www.nghobbies.com/cart/index.php?main_page=product_info&cPath=59_119_121&products_id=769

 

[BorisS]

you ll want a little more max current load than the MKs seem to be able to suck, in general the specs of the QCs are better. Sorry if i got you confused the QC or Axis are a good choice. I was just pointing out you can get the same motors like the QC for a lot cheaper, really the same motors no difference Like mentioned before the torx from Geoff. To go sure ask him.

Boris

 

[BorisS]

you will be fine with fentiums ! same as plush have them in my hexa they work great

 

[mbsteed]

Interesting video on the AV200
http://www.1001copters.com/lang-en/stabilised-camera-mount/59-enhancement-kit-for-av-200.html


What do people think of the AXI 2814/22 short shaft? Would that do the trick? I am having trouble tracking down any specs on it. Ah found the specs:

SpecificationAXI 2814/22
Voltage range3 - 6s Li-poly
RPM per Volt 765 RPM/V
Max. Efficiency 85%
Max. Efficiency Current 8-19 A
Max. Loading 25 A/30 s
Internal resistance 168mW
Dimensions 35x37 mm
Shaft Diameter 4 mm
Weight 106 g
Recommended model weight 1000 - 1800 g
Properller range. Direct drive. Special quadrocopter use 12"-14" prop

I think I will probably go with AXI - it is tried and true and I have no desire to conduct a testing laboratory.

If I go with these motors will the Maytech 30A ESC be sufficient or will I still need the Fentium 60A? The specs indicate that Max load is 25 A, so my logic (limited understanding) would suggest that a 30A ESC should suffice but I don't want to fry an ESC in the air.

 

[BorisS]

japp its good. But much more interesting it would be if there is actually a cam on it and filming and we can see the footage. Just because the response is faster doesn't mean that the way there is actually smooth. The question is if one should dial the gimbals in for such extremes which they will not level out to perfection with servos anyways, or if a perfect hovering minimal roll and tilt to perfection setup would actually make more sense.

 

[mbsteed]

I was going through the WK-M manual and found this, see attached image. Does that mean if you do the octo configuration, that you sacrifice camera gimbal control?

View attachment 1804

 

[BorisS]

If you dont use S-bus as a receiver than you sacrifice the gimbal stabi from the WKM in case of an Octo. You could also use a S-Bus converter with a normal Receiver to keep the two ports on the MC free that you need for cam stabi.

 

[mbsteed]

Is this what you mean?

http://www.snhobbies.com/product_info.php?products_id=3610

...so if I used that, it would free up those two channels for camera control even though I would have an octo configuration?

 

[BorisS]

japp thats an option, people have done it that way, their success I havent monitored though ! You have no chance of using futaba. What radio do you have at the moment maybe there is a futuba modul for you radio. S-bus just makes thing when it comes to WKM a lot easier, cleaner and also considering fail safe.

Boris

 

[mbsteed]

Boris, Thanks for you input. I was going back over your comments about the CS frame - I thought you meant the DW CS frame, now I assume you were talking about the cinestar, sorry my previous comments were off base - that looks like a fine platform but a bit more expensive than DW.

In terms of a transmitter I have DX6 and I like Spectrum so I thought the DX10 would be a good choice because it has some special features that lend itself to aerial video (the trims are adjustable in the sticks - good for slow controlled flight which would be a plus for aerial videography).

I am thinking of XOAR 13 x 6.5 props, I have been told that those work well:
http://www.thunderboltrc.com/index.php?main_page=index&cPath=73_78

I am just checking to see if they can get the pusher variety as well.

Here is my eCalc results so far - it says max current over the limit of the motor - if I reduce to 1 4s battery then it seems fine but that doesn't make sense to me. Am I doing something wrong?

 

[mbsteed]

I am concerned that even with S-Bus adapter I would still need all 8 ESC ports for motors. It appears to me from this diagram that the camera gimbals are used up by the 8 motor ESCs regardless of wether you have a s-bus adapter or not. I don't think I gain anything with s-bus adapter.

View attachment 2989

 

[BorisS]

nope octo with s-bus or s-bus adapter you can use f1 f2 m1...m6 for your ESCs and than you use T and R ports on the RX side of the MC to connect your gimbal.