Hexa Belt F550 Build Thread

[jperkosk]

Turns out I've been quite good this year because Santa dropped off this under my Christmas tree (disclaimer: "Santa" and "Christmas tree" are registered trademarks and are referred to as general concepts rather than any specific subjects):




So I started building it backwards, beginning with landing gear and GoPro gimbal. Took me day and a half to put it together, the kit is fiberglass of medium quality, requires some filing, sanding, drilling and modifying. Some screws were missing, the roll servo link was way too long: had to cut it in half and CA the non-threaded part into the plastic ball link. The results below, tested by plugging roll and pitch servos directly into the Rx:


[ame]http://www.youtube.com/watch?v=lwwOggpf7nI[/ame]

[Tomstoy2]

It's evil, I say. Evil!

No good will come of this!!!

Quick, box it back up and send it all back, now! Get out while you can!!!!

[jperkosk]

Naaah, you know I could stop any time I wanted
Plus, this is a build thread, not "send it all back" thread. I mean, should we face the beast head-on or run away and hide?

The quality of the the X468 was somewhat disappointing. Made in the US, I suppose, because all screws (they use mostly nylon screws in the kit) turned out to be imperial sized rather than metric. Manual is quite bad, as well, I think Align manuals are better, Chinglish notwithstanding. I mean English in the manual is good (lacks British accent so it must be American), photos are decent, but some steps are skipped, others barely explained and the whole manual feels as if it was written for the beta version of the gimbal and never updated.

Even more disappointing are some poorly fitting parts and missing screws. No major problem, just a PITA. Requires heavy use of the file, Dremel and sandpaper. Servo fit terrible, roll servo hole was way too tight and servo screw hole pattern was a reflection of utmost confusion in the manufacturer's Autocad department, I mean do the 9g servos with 4 mounting holes even exist?

The writer of the manual was confused about what servos to use. In a few pictures and in one part of the text they're using metal-geared digital Savox servos, in the other part they advise to use analog servos because digital ones can "twitch" affecting camera's stability. I just used the metal geared version of our all time favorite TP SG90, called MG90. Connected directly to the Rx, the gimbal movement seems smooth enough, we'll see later with Naza gimbal stabilization.

[sutty]

Looking forward to this Jerry. Why did you buy two of them though?

Cheers

Sutty

[jperkosk]

I didn't, not really. One box is ARF kit to get my v1 going (there are also bigger motors and 12" props on the slow boat from China, as well, but that'll take another month or so), the other box is just a $48 airframe for spare parts, meaning 6 arms, top and bottom plates and some screws, was easier to order than individual spares.

[Tomstoy2]

What motors did you pick up for it?

I'm not sure 12" props will even fit?

[jperkosk]

Right now stock DJI 920kV motors that are rated for 10" props @ 3S and 8" & 4S. I'll be using them with 10" props @ 4S. Ran a quick calculation, I should be OK because of 1900m here altitude the props move about 80% of air compared to the see level, so the load on the motors should be similar.

Slow boat from China carries these motors together with 11"x4.7 Slow Fly props, so again, I should be fine power-wise with a bit more bite at hand:



I was plainly wrong about 12" props, it's 11" as my final goal for this frame. I'm mounting arm extensions to accomodate larger props, pictures tomorrow

[Tomstoy2]

A couple things real quick.

The stock DJI motors, cut off the bullets and change them out to a good quality standard style bullet.
When final rototion is all set, heat shrink over the bullets.

You know not to use DJI stock props, right?

2810's is a good choice but to swing 11's is going to be a close fit. 12's would be really nice with those motors, but you will need an extension kit.
They make these nice little extention plates, or they are now selling longer arms now, too.

Twist every lead, make them semi-tight.

Tie down all wires so they don't vibrate against anything.

Naza gets mounted as firmly as possible. Many even use zip ties. Make damn sure the arrows on the Naza point to the front of the multi. Sounds dumb, but it happens all the time.

Gimbal servos are best powered by a bec.

Your vtx needs to be mounted as far away from everything as possible. Might even see what you can do about mounting it on the landing struts?

Ooohhhhhh, this is sooo exciting!

[jperkosk]

Ok, you warned me long time ago, Tom: it looks simple, but everything is multiplied by 6!!! Meaning 6 extension plates, six motors, six ESCs and so on. Exhausting. Mounted extension plates and motors on the arms today, that's all.



Extension plates are made of heavy aluminum, so I decided to locktite the motor to the plates, but not arms to the main plate: arms are plastic and have threaded brass bushings where the steel screws go, so there will be no way to heat them up later to soften the locktite. Plates to arms problem no problem: they are fixed using steel screws with nylon lock-nuts.




DJI ESCs have female bullets built into them. Also because of the extension plates the motor cables barely reach, so there is no way I'm cutting them shorter, Tom. I'm leaving them alone for now, it's only temporary powertrain anyway.

Did I mention the thing is beginning to look BIG? 6HV in the background:

[Tomstoy2]

Jerry, there are just way too many reports on these stock bullets. All you need to change out is the motor side.
This really pretty much is a must do move. An ounce of prevention here can save you big time issues later.
Besides, you're going to be a soldering fool tomorrow anyway, (use flux).

[jperkosk]

Used plenty of flux...
I did some research and people just solder the ESC wires into distribution plate. Seems wrong, plus the wires in my case are too short because of the extension plates, so decided to make extension wires. Does anyone realize that to do power extension for 6 ESCs means 25 bullet connectors to solder and heatshrink?



Then soldered the extensions into the bottom plate, which serves as a power distribution board, very neat concept. Looked into the design and liked it a lot: I think some reports of the power distribution board failing are the result of a poor soldering job: as Tom said, you have to use lots of flux to assure proper solder flow and adherence:



Washed the excess flux off the bottom plate and assembled the arms and installed the ESCs, everything looks good so far

[sutty]

OMG, it is starting to scare me already.

[nuttzzy]

so what would happen if you ran 4S with the 10in props at sea level? just to much load on engines and drain batts quick?

[jperkosk]

Not necessarily. Remember, this is a fixed pitch aircraft, so the lift is defined by the RPM. It's a balancing act between the payload and propeller/motor selection. If you don't load the hex my guess is it would fly fine with 10" props with stock motors on 4s, but you'd be possibly on 40% throttle level, resulting mushy response and inefficiently operating (and possibly overheating) ESCs. Add some payload and you may blow the motors by putting too much of torque on them, so technically speaking you'd need larger motors for them.

So far my landing gear/camera mount + GPH2 + arm extensions add 600g. The battery I'll use is very heavy as well, 700g (Pulse 4s/6600mAh), I'm really not sure if my hexa will lift/fly well with this payload with standard motors & 10" props, but it should The real test will be some test hovers and checking motor / ESC temperature.

[Tomstoy2]

I wouldn't worry too much about the stock motors pulling the weight. These things are pretty configurable.

I'm pulling a ton of weight on a slightly smaller frame. Once you dial in props you won't notice the weight, until you try a recovery.

Dialing in on the correct props for your set up is the pain in the ass part. Every prop change flys differently.
What I do is to start at a mid size, find the manufacturer that gives the performance out to the acft frame, then once selected dial in the correct size to fine tune the feel I'm looking for, then the pitch to get her to hover mid stick.
Takes a few props to do, but your done, your done.
After that it's on to experimenting with gains.

As for air pressure and how it affects flight, it's really not that noticable in flight. You'll feel like it might take a little more power and consumption does go up slightly.
I live at a mile up in altitude, and frequently fly at altitudes up to and over 10,000 feet.
Even that high up, she flys really well.

The drawbacks with weight change is often discussed, but one serious consideration of flying heavy camera ships is overlooked way too often.
The 'splat' factor.
The more she weights, the bigger splat.
Get a good enough splat and you can rupture a cell, starting a fire.
Always keep that in the back of your mind when you set out for a day. Seeing a 6 pound dead weight falling out of the sky is a sickening sight.

Guess what I'm saying is, it's all great fun, but don't bite off more than you can chew.
We always need to push the boundarys to advance in skill. However, it's very easy to develope and over confidence in flying these things. The one thing they do not give you is the ability of developing recovery skill.
There is no recovery, only, hopefully, a slight chance to choose the crash site and amount of damage ensued.

What I love the most about these things, is the challange.
You set a goal, develope your ship and your skills, and slowly work toward perfection.
My goal is simple, I love fpv. The ability to explore and record your adventure to re-live and learn from is just way too cool for me.
Now, if I can just figure out how to work a flyrod with one, now that would be just too much,,,

[jperkosk]

Finished wiring today, finally




Powered up: smoke from #1 ESC Had one spare ESC and motor, so changed ESC over: no smoke, but it was getting hot just sitting there under the power. Changed the motor over: no problem. Powered up and did the first time rough configuration, then powered up and checked and fixed the motor rotation. #5 motor twitchy. Will re-solder bullet connectors on it tomorrow, hope that's the only problem, otherwise no more spare, although #1 seems OK now, so maybe it looks like I mounted it on the conductive Al extension plate in a way that shorted the bullet connectors out? No idea, but it's possible

Measured the bird rotor-to-rotor, by adding the extension plate I stretched it from 550mm to 680mm, so that's why it looks much bigger than it should...

[nuttzzy]

I crashed my 550 broke and arm. Prop was fine.. So I modded it till I can get another arm. And it flies AWESOME!!




Beep, Beep, Honk, Honk, Over and Out Rotorhead

[Tomstoy2]

Ready to here what you did wrong?

All those esc wires need to be removed, twisted and reinstalled.

Why, Helps tremendously with fpv, plus assists the Naza by eliminating rfi.

Trust me on this, you do need to do this, including the l1 and l2 leads along with the bec leads, ( not that your 30a opto's are a bec, but you understand.

To get truely good fpv reception you need to twist every lead thoroughly. Evey tiny bit adds up in the end result. It has to be done at this stage of the build.

Other than that, buddy, it looks ok.

Lets see, you're using a hexa x conversion, arrows on the Naza are pointed between the 2 red arms, indicating front, so the right front motor will be your #1 counter-rotating motor.

The battery lead needs to be secured, you don't want anything bouncing around creating vibrations.
Ar8000, plus telemetry.

How do you have the Naza mounted? It needs to be as rigidly mounted as possible. Lots of people even wire tie it down as tight as possible.
Accessing the usb port might be a pain when done. Might want to think about making a small usb extension cable and mount it now, makes hooking up to the assistant a lot easier. You'll be hooking up to assistant a lot during tuning.

All the wire bundles can be easily secured in place by sandwitching foam at stratigic points when mounting the top plate.

Not bad, my friend!
You know I'm only offering constructive critism, trying to set you up for success. Do what you want, but if you do choose to twist the wires you will be so much happier later.

As far as the motor/esc issue, well, it happens. That is why I do go on about the test flights and burning in the components.
Those male bullets that DJI uses are a huge pain in the ass, and why I recommend not using them.
I've watched so many people come on line, pulling their hair out and ready to give up only to discover their only problem was those stupid bullet connectors.
9 times out of 10, all eratic behavior, high temps, burning out motors or the esc's themselves have been troubleshot back to the male bullets.

Trying to remember, don't those extension plates push her out to 630mm motor to motor?
When do you expect the other motors to arrive?
Might be worth it to do as I suggested with the wires while you wait for the motors, complete it then.
The stock motors kind of suck. Personally, I'd wait. Proper motors will make a huge difference.

What props are you going to use? If those in the pic are the stock DJI props, remove then and use them for something more fitting, stiring paint or something. They are worthless.
APC is a good quality prop.
You'll want to balance the props. So if you don't have a balancer, perhaps borrow one from a club member.
Don't use tape. Sand the back side of the heavy blade to balance out, and do the same to balance the hub.

Ha, thought you were getting close, didn't you!

[jperkosk]

Originally Posted by Tomstoy2

Ready to here what you did wrong?

All those esc wires need to be removed, twisted and reinstalled.

Why, Helps tremendously with fpv, plus assists the Naza by eliminating rfi.

Trust me on this, you do need to do this, including the l1 and l2 leads along with the bec leads, ( not that your 30a opto's are a bec, but you understand.

Are you sure, Tom, about fpv? From what I read it's about not generating magnetic field that would confuse Naza compass, that's all. And to do that it's best to twist all DC wires, although running them close together is nearly as good: the worst is to have them separated. AC side doesn't really matter, and neither do signal wires. Saw pics of people twisting ESC signal wires, that's plain silly. All my ESCs DC supply wires dive under the boom and are twisted once, couldn't do more because of space constrains. Power supply cables (such as main battery) use parallel cable and are spiral bound. I should be OK here.

Originally Posted by Tomstoy2

The battery lead needs to be secured, you don't want anything bouncing around creating vibrations.

It's ziptied at the end and it'll be all ziptied inside after I finish electrical tests; I'm still moving the wires around.

Originally Posted by Tomstoy2

How do you have the Naza mounted? It needs to be as rigidly mounted as possible. Lots of people even wire tie it down as tight as possible.

One solid slab of 3M 1mm 4010 clear tape, it feels rigid enough

Originally Posted by Tomstoy2

Accessing the usb port might be a pain when done. Might want to think about making a small usb extension cable and mount it now, makes hooking up to the assistant a lot easier. You'll be hooking up to assistant a lot during tuning.

Piece of cake. Naza has USB port on the BEC/LED unit, mounted it on the rear face of the landing gear, very accessible, will take a picture later

Originally Posted by Tomstoy2

Not bad, my friend!
You know I'm only offering constructive critism, trying to set you up for success. Do what you want, but if you do choose to twist the wires you will be so much happier later.

Always appreciated, Tom, I mean it Expecting to have fewer moments later although you know they can't be totally eliminated

Originally Posted by Tomstoy2

I've watched so many people come on line, pulling their hair out and ready to give up only to discover their only problem was those stupid bullet connectors.
9 times out of 10, all eratic behavior, high temps, burning out motors or the esc's themselves have been troubleshot back to the male bullets.

I can see that, but was just to lazy to do the complete re-solder of all bullets. Will do this today on 2 motors, the #5 that probably has a cold joint and #4 that twitched once on the initial start and was smooth afterwards.

Originally Posted by Tomstoy2

Trying to remember, don't those extension plates push her out to 630mm motor to motor?

680mm

Originally Posted by Tomstoy2

When do you expect the other motors to arrive?
Might be worth it to do as I suggested with the wires while you wait for the motors, complete it then.
The stock motors kind of suck. Personally, I'd wait. Proper motors will make a huge difference.

They're just about arriving to NYC right now, but I won't put my hands on them until February. Right now I have a build window till mid-January, so no way, can't wait, will have to maiden with stock motors.

Originally Posted by Tomstoy2

What props are you going to use? If those in the pic are the stock DJI props, remove then and use them for something more fitting, stiring paint or something. They are worthless.
APC is a good quality prop.

SlowFly props are on the same shipment as the motors, so maiden will happen on 10" DJIs, the risks notwithstanding

Originally Posted by Tomstoy2

You'll want to balance the props. So if you don't have a balancer, perhaps borrow one from a club member.
Don't use tape. Sand the back side of the heavy blade to balance out, and do the same to balance the hub.

Sir, yes sir !!!
Got the balancer, was using it for 450 blades . Do I sand the back edge making a blade a bit narrower?

[Tomstoy2]

Yep, I know it sounds silly, twisting every damn wire, but it truely does help.
There is a guy over at Multi Rotor Forums, Kloner, ( goes by a different handle over here ), that I've become friends with.
He and I started flying multi's at the same time. He's very, very heavy into fpv. Some of his vids has him miles from home point, very impressive vids. He's studied everything he could get his hands onto, done a hell of a lot of testing, and as a result has become somewhat of an fpv guru over there.
Most of what I have learned from this I discovered thru his testing. He knows what works, what doesn't.
He's a fanatic about twisting.
Me, I'm not going to argue with a guy that flys miles away, a couple feet off the ground as fast as he possibly can! I mean to tell you, it's impressive as hell what he does!

Sounds like you are well on your way. Good that you can access the usb port easily. Once you get her all dialed in you won't have need for it much. The Naza doesn't under go the massive ammounts of firmware updates like the WKM does. Understandable.
The main thing with the Naza is it's mounting. There are tons of reports that even a small trapped air bubble under the double sided tape can cause issues.
Personally, I think that is pretty damn cool, a controller you don't have to vibration isolate!

Too bad you can't just wait for the motors, but Feb. is a long way off. Just fly her over grass, that way if something goes wrong damage will be minimized. Get some fun out of her, get the feel of how she flys, that sort of thing.

As far as balancing goes, yes sand the back side of the blade, the bottom flat as you will, to remove material on the heavy blade, until it balances out horizontal.
Then do the same to the hub by standing the blade vertical and sanding the hub itself to remove material from the heavy side.
Easy to do, but a little time consumming.

Lots of people just use tape and get away with it. This is not the 'prefered' method. You don't want to throw a tape in flight.
This isn't so much about eliminating vibrations to the Naza, but getting the twitchyness out of the contols that the Naza would constantly be trying to correct for.


I'm expecting some really good vids from you, buddy! I think you have chosen your system well. It should perform exceptionally well for you.
She's big enough to handle all the weight you will need to carry. Hell, it could lift a ton more than what you are going to be lifting.
So much so that you ought to be looking at how to mount 2 batterys in parallel on that frame, plan for it.

Mounting the fpv gear, care must be taken is seperating the vtx as far away from everything else as you can.
Mine is mounted underneith on a cf plate to block noise from going up into the rest of the system. Works a charm.
Get yourself some cloverleaf antenna's. These make a HUGE difference in the range while still being non-directional. They come individually, but the set comes with a 3 lobe for the vtx and a 4 lobe for the rx, and are pretty damn cheap.

Just this last year fpv has taken off like wildfire. Before, everybody was trying to make vtx's that put out a hell of a lot of power to get the range. This causes swamping of the other signals.
This last year people started experimenting with different antenna designs, realizing that power wasn't the answer. As a result, there has been major improvments in antenna design. It's been staggering just to watch what has transpired!

I imagine you have acess to a label maker from work? If so, make yourself some labels and put them by your switches on your tx so you know what they are for, keep the confusion to a minimum.

Get 'er done, my friend!!! I'm anxious to see some vids!!!