Hexacopter 300mm

[evolter]

Introduction
I was looking for some smaller hexacopters that would be kind of "all purpose" type.

I was thinking: small, durable, nice flight times (+10m), maybe racing, some mods,
to carry GoPro (or some other HD) and for sure FPV at some point.

I was looking at Blackout Mini Spider Hex Frame, but I couldn';t find any available with
posting to the UK. So I bought some unknown, cheaper carbon fiber frame.

Since recently, I didn';t pay much attention to the balance. But when I put a camcorder
on, I discovered how bad design it has (or maybe it is just me doing something terrible
wrong :) ). Anyway, now some specs. Rest of the story below ;p

Installed
* Mini HEX Carbon Fiber QAV 6 Axis 300mm Frame
This is my first build so I can';t say much as I don';t have real comparison. It looks like
I';ll have to work a little bit on it to satisfy me, but for the price I can';t be too unhappy.
* Naze 32 Full FC
I';m not using all its capabilities, but it works - almost out of the box :) . I tried baro
and mag but I didn';t felt much difference with the latter. Altitude hold seems to work,
but I wonder if I can make it work even better. Since my first try on tuning didn';t gave
wanted results, I';m using almost stock PID, but I don';t feel very comfortable with it.
* 3x cw & 3x ccw Emax 2206 1900kv motors
I';m not sure if anyone is using thread lock or some other way to make sure that props
will stay on copter, but it looks like cw and ccw works for me. I hope that with time
I will be able to tell more about them, but as of yet - they just works ;]
* 6x Emax BLHeli Series 12A ESCs
I';m not sure how correctly calibrated mine ESCs are, my hex flies but I wonder if motors
could work even better - if I add little throttle they never start at the same time. I don';t
know, maybe they work as they suppose to, and I';m just being picky :?
* Orange R615x
For the price, very good TX. I didn';t experience any problems yet, but since it is very
cheap I already bought spare one.
* Gens ace batteries
- used on copter: 3s 2600mAh 30C, 3s 2200mAh 60C
- not used yet: 3s 4000mAh 25C, 4s 2600mAh 30C
* Propellers
5030 Carbon Fibre - my first choice, pretty nice but since I';m not used to my hex yet,
I decided to use now more safe (I think :) ) 5030 Three Blade ABS, which basically
falls apart on almost any crash.

Working on
Camcorder for videos - not for FPV, but would be nice if handled with remote switch.
Since I own Xiaomi Mi and I';m happy with it, I went with Xiaomi Yi. I can share my
thoughts about it somewhere else if anyone is interested, but in short, as of yet I';m
happy with it as well.

I have stock mounting with dumping, but now I have a hitch, more in the Issues
section of this post :)

Awaiting installation
* NEO-6 V3.0 GPS NEO-6M Module
Return to home or programming route for hex is something nice for show, I find no
other purpose for those two (maybe I will in future :) ). Instead I want to try to make
my hex more stable and I heard that it can be useful for videos. So probably position
hold mode. I';m not sure what else I could do with it yet, but firstly I will need to solder
it and figure out how/where to mount it.

In plans
* I have Quanum DIY FPV Goggle, 5.8GHz 32Ch Diversity RX and TX5805 with Camera.
I would like to get hold of a HeadPlay Headsets, but it looks like it is hardly available now.
Since I';m working on HD Camera for videos, I will want to be able to switch between one
for the FPV and one for the recording. So priority for now is to choose some proper TX.
* LEDs - of course there must be some nice lights at some point :)
* I was thinking about getting Bluetooth module, but now I wonder what I could do with
it except PID tuning... So if I get one, it will be mounted only for tuning time probably.

Current issues
1. Balance
First try of mounting Yi on hex showed me how easily unbalance my hex can be. So now
I need to think of some collocation of gear or even some modding, e.g. battery mount.
[Edit 2015-07-23]
To clarify, the problem is that the battery placed even at the back of the frame is not
enough. The battery must to protrude about half of its length to compensate weight
of the copter alone and even more when with mounted camera (check out new pics).

2. PID
Other part of the coin is that PID isn';t tuned yet. I bound tuning to switches on my TX,
but I couldn';t do it in my limited fly area. So I ended up using changed just a little the
stock settings. I flew couple of times and I still want to tune it, I just need to come up
with some plan. And I think I might focus on weight issues first.

3. Transmitter for the FPV
Ok, when it will fly how I want, I';ll need to choose some TX. For now I know it will be
5.8GHz and as reliable as possible :)

Let';s wrap it up - gallery! (not really ;] )
It seems like a bigger post than I thought it would be ;p and for now, introduction pic
(since I didn';t have enough time to take nicer close-ups):


2015-07-23 current flying state


2015-05-02 trying to figure out COG


2015-05-02 center of the motors is bit further back than mounting holes for the FC


2015-08-02 first test flight (not counting my garden :) ) with the Xiaomi YI on board

Note: any thoughts welcome :) if you like this setup or think anything was/will be a really bad
choice feel free to comment. And I will update this post with time - I hope

[Jazzz]

If this was mine I would get the centre of gravity right first it looks like your battery is to far back on the picture and change those props Thay look realy flimsy.
Then try tuning the PID
If the battery is only a small amount of balance it can make your craft
Drift one way or the other even with self level on .
That';s my experience.
But I';m sure others no a lot more than I do

[quadfather]

A couple of points, and perhaps to manage expectations:

1900Kv is quite slow for 5030 props on 3S.  You won';t get enough lift, certainly not for racing since you mentioned it.  It doesn';t look like the frame can take 6" props, which would be better suited for these motors, but you can try the 4S battery and see how it performs.  Have a look around for your motors and 4S use, and see what people';s experiences are, since they are only rated for up to 3S.  That said, plenty of motors that are officially rated for 3S are flown with 4S, but it';s worth checking.  With your current setup I';d expect the hover point to be above 50% throttle which is quite high.  However, I haven';t built a hex with your specs, so this is a just a guesstimate.

I found Emax ESCs a pain to calibrate.  The best results I had where when I calibrated them directly with the RX.  But even then they were never in perfect sync.  I also found that Emax ESCs came with different programming from the factory, which is not something you can fix by just calibrating them.  For example, if you notice that one (or more) motors spin up slower than others, even though they might start at the same time, it could indicate that they have mismatched programming.  Another example is that some ESCs had low voltage protection enabled, which meant that when the battery ran low it would reduce output to the motor.  Nothing that can';t be fixed, but a common occurrence with Emax ESCs.

You mention switching the FPV and HD camera.  If your plan is to view HD footage in your goggles I';m afraid I have to disappoint.  All the current video transmitters are only capable of transmitting low resolution.  Also, some HD cameras have significant lag in the video feed, which may make it difficult for FPV flying.  If you research a HD camera, which you also want to be able to use for FPV, make sure it can stream and record at the same time.

Regarding the balance, if the battery in your picture is in the same position when you fly then it';s too far back.  Normally a frame is designed so that the flight controller sits at the centre of gravity (CoG).  Try putting your battery as close to it as possible, i.e. above or below the FC.  When you add more stuff to the frame, like a big camera at the front, you can shift the battery to counter-balance it.

The Naze is not capable of automated flight with a GPS.  At the moment it';s just about able to hold its position and if you';re lucky return somewhere near where it took off.  There is no waypoint capability, and I don';t think there will ever be.  If you use altitude hold and the hex stays within a metre of it that';s as good as it gets.  If you haven';t done it yet cover the baro with breathable foam to protect it from prop wash and direct sunlight, as that will affect its accuracy greatly.

Good luck with your experiments and keep us posted.

[guest325]

If you want GPS fully functional I would suggest either an APM mini or a Pixhawk mini, both will do exactly what you want, I have an APM mini and Neo 7 GPS for sale at the moment for a sensible price, if you have any interest let me know.
http://www.multi-rotor.co.uk/index.php?action=classifieds;sa=view;id=325

[evolter]

I have updated main post (pics + more about balance issue).

Jazzz
Unfortunately that is how I must position my battery, to make the hex more or less balanced. And I did use carbon fiber props
while trying to tune the PID.

quadfather
1. If motors are slow, then it means that hex would be less agile, or not only that? Then how about the fact that they have more
torque - I assumed that 3 blade props (or props like 5040, but I couldn';t find any available) would somewhat compensate that
motors aren';t fast enough.
2. Nope, I read that it could fit 6" so I bought 5&6 but the latter didn';t fit.
3. Hover (without camera) was about 40%  -I think, since I was limiting my throttle on TX to not fly away too fast :)
4. I tried to calibrate my motors using Cleanflight (it worked only for the first time), then (I was hoping for luck) I tried to use
TX, but it didn';t work very well, so I calibrate each of the motors separately in the end. Hex flies more or less ok, but what
annoys me is the fact that sounds of the motors on FC start up or moving throttle around minimum doesn';t sound synced :)
5. No, I didn';t mean to see HD quality in FPV (although it would be nice feature to have), but to record HD videos and to
be able to switch from camera used only for FPV, to see what I';m actually recording (can be worse quality than recorded).
I heard that some people were flying FPV using GoPro (and supposedly is not as reliable as FPV ready cameras). Based
on this I thought it would be doable to switch between those two.
6. Yeah, I heard about FC being at the CoG, but it seems to me that this frame is badly designed.
7. Nah, I don';t need to use return to home nor set waypoints, just anything useful for recording - so hold position :)
Although it would be nice to have some fail-safe feature, to make it land on TX signal loss or something.

DarrellW
I don';t know what you mean by "GPS fully functional". What functions do you mean? Do you know the difference between the
ones you mention and the one I own? Like I said, I can think of only hold position to be useful to me, but there may be other
useful features - I just don';t know yet :)

Moreover about CoG, see other hex frames, their design include extended back space for mounting the battery. My hex looks
to me that is moved too much to the front, hence the way my battery is attached.



DIY-Pass-through-Variants-of-insects-3K-carbon-fiber-mini-hexacopter-Frame-kits-RD290-hexa-FPV.jpg
http://fpv-reconn.com/images/RD290/RD290HEX_1.jpg
http://www.goodluckbuy.com/images/ebay_goodlucksell_images/sku_108099_6.jpg
http://fpvlab.com/forums/attachment.php?attachmentid=49628&d=1406356514

Cheers

[Ynot6]

full GPS systems have RTH/L. this is very usefull if you get disoriented, or the RC link goes down. i agree, the frame looks badly proportioned, it';s a lot to ask to get all that on a frame that size. my Y6 is 440 size, and has 2213/935 KV motors with 10x4.5" props, and it';s compact. i';ve now got a mobius, and i';m considering a video switcher to see what is being recorded, if it';s not at the same angle as the flight camera. 
                                                                                                                       for calibrating ESCs together, i made up a lead. take a servo lead, cut off the opposite end to that which fits the receiver. get a piece of vero (strip) board and some inline PCB header pins. cut the header pins into segments of 3 pins and solder into the vero board. strip the cut end of the servo lead, and solder onto the vero board. hey presto, a multi way adaptor to connect all your ESCs to the throttle chanel at the same time. i';ll try to get a picture up later.

[evolter]

I';m thinking of making some kind of a battery mount extension and I want to try mount it underneath of the frame.
I just wonder if battery lowering CoG will make huge difference in fly characteristics - based on what I read, it may.
Actually I';m thinking of flipping the frame upside down, then the HD camera mount would be directed down as well,
but that may be a not bad for recording. I just need to think of some kind of landing gear/protection for the battery.

quadfather
I was thinking about foam for baro, but how about if whole FC would be in some kind of case?

[helinor]

What frame is this? Any link? As you mention it looks a bit strange made.... Are you sure it is put together the right way? If chinese made I know the manuals can be a bit.....
Battery underneath should not be a problem on this kind of frame. The motors will be just above the battery, at least before you flip the frame upside down...

Lest med Tapatalk

[evolter]

My post is dying quick update then :)

helinor
The name of the frame is in the first post. Sorry I was too lazy to check the rules about pasting link on this forum ;p
But if you google it, you should easily find it on the first page - unfortunately this frame isn';t very popular. If you
have any questions about it, just let me know, I';ll try my best to answer.

I did some test flights today, unfortunately it was pretty windy so I didn';t achieve a lot, but always some experience.
I forgot to mention about one issue that annoys me. The rotating speed is very slow. I tried to increase the YAW rate
the other day, but it didn';t help much (if at all). Any advises how to find the cause of it / how to make it rotate faster?

PS I';ve recorded it from the ground and using Xiaomi YI, so I';ll update a main thread as soon as I will do something
with the media - for now it is in the raw format. And for those who likes only pictures ;p see the first post.

[helinor]

Well I found your frame by using goggle but only places that sells it, not any built and flying... Nothing I will be getting though, with that strange CoG. I have a small hex frame cut by a guy on flite test forum that I am collecting parts to build

[evolter]

Yes, unfortunately there isn';t much info about this frame out there. But it is pretty cheap, so I';m going to buy one more for
spare parts. Other frames I have seen were either hard to get hold of, expensive or I just wasn';t happy with some design
solutions. I still can';t tell if I recommend this frame or not. There may be some potential in it? At least if one is not afraid of
modding :)

What actually worries me right now, is slow YAW and (what I forgot to mention) what yesterday flights showed me, weird
behaviour of motors while rotating. My hex couple of times (I think every single time was while I was checking yaw) cut off
all motors for a split second. I';m going to check all wiring if they are fine after some harder landings in past, since I don';t
recall to experience that before.

I hope I will post some videos this week, but can';t promise anything ;p