Drone Build Questions - First build

[Crimond84]

Hi Guys,

I have been toying with building a drone for AP for some time, and have started to get a kit list together.

Firstly - The Why

I am after an AP drone for when I am out off-roading in the countryside. I've visited some lovely places in the UK, and my only pictures are often of a narrow lane! I am very keen on being able to get a drone built that could support either my GoPro or ideally, my Sony A600 camera to get a much better perspective of where I am.

I've been looking at frames to start with, and really would like something foldable. As the frame will be relatively large to support the camera size and a battery for a half decent flight time, I am looking at something like the Tarot FY690S.

From there I started to look at motors, and an FC, which is where everything went downhill!
I have read that from a thrust perspective I should be working out the total weight, times it by 2 and then divide it by 6 for the thrust per motor. Easy math, but my first issue is that I couldn't relate that figure to anything on the motor specs I was looking at!
My second attempt at figuring out what motor power I needed, lead me to a post where people with similar rigs were recommending between 750kv and 1000kv. Great - Apart from the fact I then found that figure is not a constant and it depends on the battery voltage.

In short, is there a beginners guide to working out a compatible kit list for such a project?

Thanks in advance for your help.

[Crimond84]

Just to add a little more meat to the bones, I thought I’d stick my neck out with some items on the build list, as I appreciate its easier to challenge a line in the sand, as opposed to the open and vague request of my first post!

Also, I have taken the view to kick things off with a cheap kit-list. Ultimately it’s more expensive in the long run, but I don’t expect to be putting a camera in the rig for some time, and would rather find my feet with a lower entry point and upgrade as / when I can.

So:

tarot 690s
6 Racestar 1000kv motors
Props - 13x5.5
FC - read good things about the Pixhawk
ESC - Racestar Rs30A
APM 2.6 Power Module
Matek  System PDB
5500mah 4s battery - would add a second in parallel at the point I add a gimbal

[hoverfly]

Not a bad list although if you don't have any experience with flight controlers the Pixhawk can be a bit of a pig setting up and the DF13 connecting cables are crap.
I would consider an Eagle Tree Vector  if you shop around you can get them below list price. The advantage they are plug and play and very easy to set up.  They are also smaller and lighter.

[Tryingto]

Just to add a little more meat to the bones, I thought I’d stick my neck out with some items on the build list, as I appreciate its easier to challenge a line in the sand, as opposed to the open and vague request of my first post!

Also, I have taken the view to kick things off with a cheap kit-list. Ultimately it’s more expensive in the long run, but I don’t expect to be putting a camera in the rig for some time, and would rather find my feet with a lower entry point and upgrade as / when I can.

So:

tarot 690s
6 Racestar 1000kv motors
Props - 13x5.5
FC - read good things about the Pixhawk
ESC - Racestar Rs30A
APM 2.6 Power Module
Matek  System PDB
5500mah 4s battery - would add a second in parallel at the point I add a gimbal

Reasonable list, although I would stay away from Racestar as they are of questionable quality. You dont want to rely on them.

[ched]

I'm not sure 1000kv motors are ideal with 13" props. I have a much smaller F450 (4 motors) with a 3 axis gimbal and it runs 920kv motors with 10" props.
There is an online calculator that might help. https://www.ecalc.ch/xcoptercalc.php No idea how accurate it is and in free demo mode you can only select certain components but it might give you some clues.

A google search on the frame you are thinking off might find some builds that again will give you a clue about what motors people have used etc.

Also have a look at iNav it's software that can run on lots of Flight Controllers that I believe does 6 motors and waypoints. Not sure it can do 6 motors plus 2or 3 signals out to a gimbal?

It's great that you are looking to build your own and don't let me put you off (I enjoy building as much as flying) but have you considered a DJI Phantom? They are easy to fly, even the older ones have reasonable cameras and can be bought as 'refurbs' or even second hand for reasonable money. Then you will get 25-30 mins flight time, good images etc.
Getting a 3 axis camera gimbal setup working well without 'jello' may not be that easy. Some times they can be tricky but then again it give you a sense of achievement when you build and it flys for the first time than again when the gimbal is working nice and stable. 

[Crimond84]

Not a bad list although if you don't have any experience with flight controlers the Pixhawk can be a bit of a pig setting up and the DF13 connecting cables are crap.
I would consider an Eagle Tree Vector  if you shop around you can get them below list price. The advantage they are plug and play and very easy to set up.  They are also smaller and lighter.

Thanks Hoverfly - It certainly makes sense to start with something more plug n play for me.

I've checked it out and it also had all the autonomy features I'd like in the long run too.

Thanks for the recommendation 

[Crimond84]

Reasonable list, although I would stay away from Racestar as they are of questionable quality. You dont want to rely on them.

Noted.

Given I am looking at a hexacopter, the number of motors and ESC's really racked the price up for something I am only just getting in to.

I was working on the assumption that should a motor fail, I could get it back safely and then reassess. The question then is, would I be replacing the motors that quickly its not worth buying in the first place...

[Crimond84]

I'm not sure 1000kv motors are ideal with 13" props. I have a much smaller F450 (4 motors) with a 3 axis gimbal and it runs 920kv motors with 10" props.
There is an online calculator that might help. https://www.ecalc.ch/xcoptercalc.php No idea how accurate it is and in free demo mode you can only select certain components but it might give you some clues.

Thanks - I'll check this out.
In addition to getting the right power motor, I was concerned about a 'miss-match' of voltages between the motors, ESC, FC and battery.

A google search on the frame you are thinking off might find some builds that again will give you a clue about what motors people have used etc.

Good shout - I've been looking at generic builds, but not specific to the frame I am looking at

Also have a look at iNav it's software that can run on lots of Flight Controllers that I believe does 6 motors and waypoints. Not sure it can do 6 motors plus 2or 3 signals out to a gimbal?

It's great that you are looking to build your own and don't let me put you off (I enjoy building as much as flying) but have you considered a DJI Phantom? They are easy to fly, even the older ones have reasonable cameras and can be bought as 'refurbs' or even second hand for reasonable money. Then you will get 25-30 mins flight time, good images etc.
Getting a 3 axis camera gimbal setup working well without 'jello' may not be that easy. Sometimes they can be tricky but then again it give you a sense of achievement when you build and it flys for the first time than again when the gimbal is working nice and stable. 

I am a tinkerer - I am likely to be happy spending more time building and tuning than actually flying. Buying something out of the box has never appealed to me. Having said that, I don't want to run before I can walk, so deffo want something to ease me in.

[ched]

OK so RacerStar motors are not the best motors but they are not bad motors. There are a few that slip through quality assurance and may have bad bearings etc. For the money they are good.
I have had a set of 4 on my little MartianIII 220 and they have been fine. OK so not the most powerful or torque(y) but they are budget motors. Bang for buck I would say they are good.

I enjoy the planning and building very much too. Always something to adjust or tweek  ::)

As for voltages... Most components (esc, motors) are rated in cells count 3S,4S,5S etc So just get components that meet or exceed your intended battery.
Flight Controllers (FC) some will need a 5v supply others will take between 2S and 6S all depends but dont get the input voltage wrong as it will destroy the FC.

Just keep asking questions.
Hope that helps.

[Crimond84]

So i'm properly building my shopping list now, and working with ecalc.ch in the process to try and ensure everything is going to work as expected.

The first issue I have is that many of the options against motors etc within ecalc are greyed out, and I cant figure out why?

Secondly, skirting around the above issue, I am always showing up as running overloaded in one way or another.
I started googling Tarot 690 builds as mentioned by someone above, and in the majority of cases, i've seen sub 1000kv motors used within the builds, some as low as 580.

Two examples being;
https://www.rcgroups.com/forums/showthread.php?2008147-Tarot-690S-Build-Log
and http://www.instructables.com/id/Building-a-Monster-Tarot-690s-Hexacopter/

Based on the conversation above, it was suggested that I should be going more than 1000kv (I think the original poster suggested they were running 950, and I'd need more to facilitate the load or size of props etc).

I'm going to do some more reading on the technical specs of motors tonight to get a better idea, but am I missing something obvious here?
Running a 4s battery, what (roughly) kv motors should I be looking at to carry a total load of 2.5 - 3kgs?

[ched]

The reason some options are greyed out is that unless you pay its just demo version.
I suggested it as it might give you a rough idea. ie select weight, cell count, hex, and desired flight time then you play with Motors and props and see if anything works.

Basically bigger props spin slower. Mt F450 is about 2.5kg and has 10inch props on 920kv Motors running 3s. If I remember correctly if I ran 4s I would use 8inch props on same Motors.
So at a guess running 6 Motors 3kg 12inch props 600kv Motors would be about right but that is a guess.
For a camera ship I guess total thrust should be a at least double the weight of the quad but I would build a bit of safety like 3x weight as thrust.

If you look at this the 4s build uses 13 inch props with 620kv Motors http://www.helipal.com/tarot-fy680-pro-hexacopter-frame-set.html

[Crimond84]

Thanks everyone for your help.

First three items purchased tonight;

Racerstar 920kv motors
Racerstar RS30A ESCs
ZOP 4s 6000mah Battery

Will be looking to by the FC (Eagle Tree Vector), and props from HobbyKing, and am yet to finalise where I am buying the frame from, and also need to start looking into receivers.

I want to get the FC and Frame ordered ASAP so I can at least get to work on the wiring while figuring out the rest.

Just a minor gripe about HobbyKing - Fantastic range of products on there, but the searching & filtering is awful. This results in me using other sites to search for products, and ultimately buying elsewhere too!

[ched]

For UK supplier have a look at HobbyRC, they are very helpful and reliable plus you get a little slice of Blackpool Rock in the delivery 

If you can wait try BangGood. They have a  Tarot 680 frame and probably every item you could ever need.
They are a Chinese supplier so deliveries take a while (2 weeks maybe more) they are usually cheap but you can get caught by vat,import duty and collection charge but they normally slip through. Beware that ordering from Hobby King (non uk or eu warehouse) you may get stung for import. I have been stung once and that was a Hobby King order never (fingers crossed) from BangGood.

[Crimond84]

Thanks.

My first order was actually from Banggood - I don't mind the wait as an often busy with other things.

I'll give HobbyRC a look too


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[Crimond84]

Bit of an update.

Ordered the frame this weekend. Was really difficult to find anywhere that had it in stock, particularly in the UK. Ended up ordering through eBay but from China. Fingers crossed I don't get a tax bill to follow...

Been watching a few more build videos of the Tarot - seems like it can be quite a crampt setup, so debating having the ESCs mounted near the motors on the arm - Thoughts?

I've also seen a review of the DJI set (FC etc) and I have to say, it looks really nice.
Currently weighing up between that and the eagle tree.


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[ched]

ESC on arms is quite neat and your motor wires may b=not be long enough any way. So easier than extending wires.

Which DJI FC are you considering? I have a Naza Lite (Flashed to Full V2 Naza) and it is good but has limitations. I don't think you can set waypoints and not much in the way of ground station. Suppose it depends on what you want and how much tinkering you fancy. I consider DJI stuff a bit like Apple products in that they are great as long as you want to do things that THEY want you to do in the way they want you to.

Have you looked at iNav? It runs on 'normal' F4 fight controllers and I think does 6 motor outputs. I believe it aslo does way points etc.. It will be more fiddling about but might be a good learning curve.

[KANEGI]

I like this forum very much.

[KANEGI]

A question that is useful to the substance.

[Crimond84]

The FC I am looking at is the Naza M V2 with GPS;

https://m.aliexpress.com/item/32433037204.html?trace=wwwdetail2mobilesitedetail&productId=32433037204&productSubject=Newest-Brand-New-DJI-Naza-M-V2-Flight-Controller-with-GPS-All-in-one-Design-Naza&src=google&albslr=221764721&isdl=y&aff_short_key=UneMJZVf&source=%7Bifdyn:dyn%7D%7Bifpla:pla%7D%7Bifdbm:DBM&albch=DID%7D&src=google&albch=shopping&acnt=494-037-6276&isdl=y&albcp=658432961&albag=33762888219&slnk=&trgt=66391061561&plac=&crea=en32433037204&netw=g&device=c&mtctp=&aff_platform=google&gclid=CjwKCAjw9e3YBRBcEiwAzjCJukHv_aJOCkmRwEWqo5imoT_evo1MmnxxgaXk772UMuc-3SmvO1QYrBoCefkQAvD_BwE&gclsrc=aw.d




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[ched]

Personally I would save quite a few quid and go with a  Naza Lite at less than £80. Then Flash it to use same software as Naza. If you look in Flight Controllers section here you can see the instructions. http://www.multi-rotor.co.uk/index.php?topic=11295.0

The naza V2 vs Lite hardware is identical as far as I am aware it's just the firmware that is better in the V2. It is better at holding position etc. But when you flash the V2 FW on the Lite it makes it the same  ::)

I would also get the 3rd party OSD OSD at about £20. It gives you lots of data on your fpv screen. Like direction back to where you took off, height, gps co ords, battery voltage etc.

[Crimond84]

Awesome advice, thanks mate.
Always annoys me when vendors make such a cream from firmware enable services when the hardware is there and capable!


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[Crimond84]

Didn't take long to get to my first hurdle!!



The mounting plate for the motor doesn't appear to have hole that align with the motor...
I can't even get 2 to align, as they are offset just enough that you can't screw them in 🤦🏻‍â™,️

Is there a recommended solution for this, or is it DIY?


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[Crimond84]

I've half a mind to delete the above post to hide my stupidity.

Looking back at the pictures I spotted the holes were not evenly space. I turned around the mounting plate and hey presto, they align after all...

[hoverfly]

I've half a mind to delete the above post to hide my stupidity.

Looking back at the pictures I spotted the holes were not evenly space. I turned around the mounting plate and hey presto, they align after all...

Nobody else has ever done that... :embarrassed Keep at it.

[Crimond84]

It seems the frame I've got doesn't have a PDB (I thought the 690 pro came with one), so will need to get one ordered.

Now I've got the frame, I'm struggling to see how best mount the ESC's.
Think I'm going to try on the arms as my first attempt and go from there.


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[ched]

ESC on arms is normal. It's usually easier as wires are normally long enough to put esc sort of mid point on arms or closer to centre if motor wires allow. Then esc power and signal wires might be long enough to go to pdb and FC.

Motor holes having 2 different spacings is something normal but I have no idea why. Watch how long the motor bolts are as they can too long and hit the windings!!!!! I would also suggest using thread lock on the motor bolts once you have checked everything is working on the bench. Don't know if you have all motors with clockwise threads or some with reverse but you should get the right ones where they are supposed to be so that when the motor spins the prop nut tightens. You can change direction of motor rotation by swapping any 2 wires from motor to esc or if running a FC with BetaFlight pass through you maybe able to use BLHeli.

Have fun and take your time.

[Crimond84]

Thanks again - very useful stuff.

I've gone to add connections to all the motors and ESC's, but the only bullet connectors I have are about 4 or 5mm, which seem way too big.

I've had a quick scout around on HobbyKing, and can't find anything smaller.

Do you guys just fill the void with solder, or is there a smaller connection available for the ESC and motors?


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[ched]

I just had a quick look and you can get 2mm ones from ebay here: https://www.ebay.co.uk/itm/UK-40-2mm-3-5mm-Gold-Male-Female-Bullet-Banana-Plug-Connector-for-RC-Battery-ESC/152604537269?hash=item2387f071b5%3Am%3Am6ocrVzqa6z5vXoYH_rc6tA&var=452047085109
Basically you solder them onto the motor wires and either solder directly to esc or esc wires. Then you use heat shrink to ensure when they are plugged together they can't short.
Just had a quick look and here is a vid to show you how to solder them. They are using a weird soldering iron but it should give you an idea. https://youtu.be/oLgZkAGgV0o

You can just solder wires from motors to esc and not have bullets if you want. ESC are fairly reliable these days plus not using bullets means less weight, less weight means more flight time. Not that a couple of grams will make much if any noticeable difference but 'every little helps'  ::)

[Crimond84]

Cheers - soldering the connections would make life easier.


Am I right in thinking I will need to solder half the motors one way, and swap any two wires over for the other half for CCW & CW?

First pic is removing the existing wires, then having the motor soldered directly to the ESC. Not the cleanest joint but should be fine;







I may Tim beck the heat shrink to the size of the ESC


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[Crimond84]

And here's the potential positioning on the arm - looks good, although I may choose to shorten the motor wires a tad to reduce the overhang.

Apologies for the quality of the photos






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