My Bonkers Buckinghamshire Build

[BettsyBoy]

Hi all

I'm new to this forum and this is my first post, although I have read a lot and watched hundreds of YouTube videos!

I got into quadcopters a few months ago when I bought a Hubsan X4 which I have been using as a trainer in my Buckinghamshire garden.

I'm now looking to move on and want to build a platform that I can grow over time as and when I have the money, time and knowledge to execute. Only problem is I have no RC or electronics experience.

I've come up with a partial list of components that I'm happy with. I'm hoping that some more experienced pilots can offer some feedback.

Flight Controller, GPS, Telemetry
Ardupilot 2.6
6H GPS
OSD
3DR Radio
http://www.banggood.com/APM-Flight-Controller-Set-APM-2_6-6H-GPS-OSD-3DR-Radio-Etc-p-932840.html

Frame
Tarot Ironman 650
http://www.ebay.co.uk/itm/281391743919?_trksid=p2055119.m1438.l2649&ssPageName=STRK:MEBIDX:IT
HK Predator 650

ESC
Afro ESC 30Amp Multi-rotor Motor Speed Controller (SimonK Firmware)

Transmitter/Receiver
FrSky 2.4GHz ACCST TARANIS X9D Digital Telemetry Radio System (Mode 2)

FrSky X8R 8/16Ch S.BUS ACCST Telemetry Receiver W/Smart Port

Battery
8000-10000MaH 4S LiPo

Power Distribution
Quanum Power Distribution Board and Dual UBEC In One

Power Module
HKPilot Power Module with XT60 Connectors and 6 Pin 150mm Cable
http://www.hobbyking.co.uk/hobbykin...th_XT60_Connectors_and_6_Pin_150mm_Cable.html

Motors
Not sure. Maybe lower KV SunnySky?

SunnySky V3508 700KV

Props
No idea what size/type would be best but guessing 10-12 inch

Eventually I'd like to add FPV and a Gopro with gimble but that is some time off. Flight time is more important to me than speed and agility - this is clearly never going to be an acro quad!

Would really appreciate some guidance. I'm sure I must have missed loads of things off the list so please flag.

 

[Hugh Hemington]

(this rambles -- tough it out)
I cannot tell if that Tarot frame includes a power distribution board -- I suspect it does not. If you're already ordering from Banggood, here's a link: http://www.banggood.com/JK-Dual-BEC-ESC-Power-Distribution-Board-With-LED-100A-p-932720.html
The power distribution board connects the battery to the ESCs, and this one includes two BECs (voltage converters) to provide 5v and 10-20v, so you'll be ready to power a camera and video transmitter without additional power gear later. If you wind up ordering anything from HobbyKing, consider the Quanum power distribution board (also with two BECs) -- it's smaller.
If you are reluctant to solder, become less reluctant ! That frame seems to accommodate the ESCs directly adjacent to the motors which is great, but you don't want to just wrap up all that extra wire, and the ESC power leads are unlikely to reach all the way back to the center of the frame from there. If you insist on plugging things in, you should get a power distribution board with connectors on it; the one I linked to has no connectors. Your Afro ESCs have 3.5mm "bullet" connectors. HobbyKing sells a board with 3.5mm connectors. I bought one and removed them all, but they'd work if you left them on. Basically, if you won't solder, life is going to be far more difficult than if you're willing to. These small deck frames get very messy very fast if you try to spool all the extra wire up! Seriously consider mounting whatever power distribution board or arrangement you select UNDER that bottom deck in the gap between that and the deck (you add) for the battery. It would help shield your controller, receiver etc. from power wire interference if you laid down copper foil on the bottom deck, then insulated it with packing tape. That would get all your power down and away from the critical electronics.

Looking at the flight controller bundle again, I see the power module does not come with pre-soldered battery and power leads. That's unfortunate! Tinning and soldering wire that large requires a LOT of power -- more than any "pencil" soldering iron I've ever seen can produce. I have a professional digital readout Weller, and it JUST handles it, driving the tip over 800 degrees (F). You should seriously consider choosing your battery with a connector already on it that will match a power module's terminations. In other words, buy another power module! I like the XT-60 connector -- that's the yellow one with one side shaped like an arrow. I know RCTimer sells a power module for APM (I believe they're all the compatible) with XT-60, and it's a very common battery connector as well. HobbyKing sells power modules like it, but they cost more for some reason. You'll still have to figure out how to connect the other end of the power module to your power distribution board, but you'll have 2 of the 3 baddie connections off your plate.

In case it wasn't clear, the power module is installed in-line between your power source (lipo) and the power distribution board in order to measure current, to feed you that data as part of the telemetry complement. It also measures voltage, but that could be done from anywhere. So the "power module" actually feeds power to the APM controller with only two of the six wires of the interconnecting cable. The rest is data.

Looking at the frame listing on Amazon and other sites, I see it doesn't come with a battery plate or holder -- that would be a small carbon fiber or fiberglass plate suspended below the bottom deck with stand-offs. Usually they have slots pre-cut for velcro straps. People appear to be ordering them separately, so factor that in.

(continued)

 

[Hugh Hemington]

Of course, once you've hung a big battery under your quad, hanging a camera gimbals under there too is going to be a challenge. The best camera mount method is to get the whole works out in front of the deck, so you can avoid seeing props or landing gear in your footage. The most common solution is to use 10mm (O.D.) tubing (carbon fiber is preferred), spaced 60mm apart (that's an on-center measurement) from which Tarot "arms" hang, snapping onto the two tubes. Usually an isolation plate assembly mounts to the bottom of those arms, with the gimbal assembly under that. The reason I bring this up now is that you may wish to plan for and mount the cushioned tube clamps for those tubes as part of the initial build. That will save you tearing your quad apart later to add a camera. Or settling for a less effective but more expedient method. If you can mount the power distribution board in the "gap" as described, you should be able to mount the tube clamps between the two decks of the frame as supplied, on either side of your flight controller. (The APM 2.6 has no horizontal connections on the long sides.) You may have to hunt those clamps down if you want a different supplier; here's mine: http://www.newegg.com/Product/Produ...0&cm_re=fpv_camera-_-9SIA2RP1924490-_-Product

The Tarot arms are easier to find, but seeing this link/picture will help bring the package into focus for you: http://www.newegg.com/Product/Produ...7&cm_re=fpv_camera-_-9SIA2RP0ZB5277-_-Product

(I ordered from Newegg because HobbyKing was out of stock on them) I've got a good carbon fiber stock supplier on eBay when you need one.

Of course, you could mount the camera on top somewhere, or you could put an FPV camera on top, and an HD video camera on a gimbals, but most people like to use their HD camera for FPV also, because you can see what you are recording. And since your frame decks sandwich the motor arms, they aren't going to be "clean" of vibration. Even an FPV camera will exhibit "jello" from it without some isolation.

 

[Hugh Hemington]

Continuing with Banggood, consider the SunnySky X3108S 720kv motors http://www.banggood.com/buy/X3108S.html

Those will run on your 30a ESCs, on a 4S lipo and drive 12" props. Start with plastic props. You can graduate to carbon fiber when you stop hitting things and want to do video. Plastic props will send you to the emergency room with lacerations, but carbon fiber props can actually REMOVE things! Even though you can't use the OSD module before you do FPV, and the telemetry radio isn't necessary to get started, it's probably best to figure out how to mount it all, right up front, during the initial build if you intend to use it ever. Otherwise, you'll go back in later and find the available real estate wanting. Again, the tricky part of these small deck frames is achieving separation! You may have to play with spacing and position with the controller, receiver, GPS and telemetry powered and working to find an arrangement they all like. With the telemetry radio and X8R you have two transmitters, and later when you add FPV, you'll have a THIRD transmitter in the air.


The X8R "receiver" is actually a transceiver -- capable of sending telemetry back to the X9D (awesome radio by the way, you couldn't have chosen better for the money). And the next thing that will occur to you is: "Hey, I've already got telemetry with the 3DR!" Yes, but that feeds back to your laptop (or tablet) via the USB transceiver, not your radio. Of course FrSky sells a line of sensors that connect directly to SmartPort, but you really want to know what the controller flying your quad thinks, not what some other sensors think. You may elect to omit the 3DR telemetry link entirely in favor of seeing telemetry data on your Taranis display. It's possible to use both. The best work on this is being done by Rolf Blomgren, using an "Arduino-lite" product called a Teensy, to convert the telemetry data coming off your APM controller and piping it into the SmartPort on the X8R. You can read all about that in this thread on DIYdrones.com: http://diydrones.com/forum/topics/amp-to-frsky-x8r-sport-converter?commentId=705844:Comment:1599145


As the name implies, it IS teensy, but still another piece of gear to power and wedge into that tiny deck space. Have you picked up on my dislike for your frame choice yet? You don't have to buy a "spider" to get a folding quad. Consider alternatives that will preserve your sanity. Here's a good one: http://www.hobbyking.com/hobbyking/...Kit_US_Warehouse_.html?strSearch=Predator 650

I have the Alien 560 -- smaller and a little different, but loads of space. The point is, you can get space for your gear AND portability.


Without going into too much detail, as you haven't even built this thing yet, you can have your quad send back telemetry to BOTH the X9D (via Teensy) and the USB transceiver, but since there is always a "rub", here is the one in this case; the APM has to see a "heartbeat" signal from one and only one data partner, so you only connect the transmit pin from the 3DR transceiver, not the X8R/Teensy. But then you HAVE to at least power both, or prepare to disconnect the (dead) tx lead from the 3DR and connect it from the X8R when you wish to use only the X9D for telemetry reception. Have I used enough TLAs? (three-letter acronyms)


So to recap the tools/parts/skills you'll need:

A GOOD soldering tool -- preferably a "solder station" style. (watch YouTube videos on how to solder, and how to care for your tips)

Solder. You generally use 60/40 rosin core. If your country has succumbed to the whackadoodles, lead solder will be hard to find.

A good pair of wire cutters. (double as wire strippers if you aren't a spaz)

At least one pair of pliers to hold wires when soldering. (or asbestos fingers)

It's very helpful to have "magic fingers" -- the weighted base with two alligator clips to hold things when soldering. Sometimes they come with a magnifying glass too.

That Tarot frame kit will probably use 1.5, 2 & 3mm hex screws or some combination of those sizes, so you'll need GOOD hex tools. Note: "bad" hex tools are not tempered, and quickly become bad ROUND tools after two or three uses.

A cordless drill is handy, because you'll want to attach things, and holes are never where you need them.

A heat gun. You can use a lighter or the barrel of the soldering iron to reduce shrink tubing I suppose, but just buy a heat gun and be done with it.

A selection of shrink tubing, or nearby supplier. You can take your parts to the supply house and match the leads to the tubing so you don't buy unnecessary supplies. (It looks like you need to cover the telemetry modules and OSD there too, and it's best done with large shrink tube.)

You'll want a fairly decent hardware supplier too, for stand-offs, screws and other things.

If you've read this far, you're likely to have the patience to enjoy this hobby. So welcome!

 

[BettsyBoy]

Hi Hugh

I'm really grateful for all the info. You're fingers must have been bleeding by the end!

Regarding soldering, not that I'm against it but would just rather not for the sake of ease. Also would be good if I could quickly alter or dismantle parts of my configuration without having to reach for the soldering iron. Wouldn't mind shortening/extending ESC cables, seen YouTube on that.

Understand what you're saying about the power module, will add that to my list. I was hoping to use a breakout cable rather than a PDB, can you see any problem with this? That setup as recommended on the newbie guide. With breakout cable how would I power peripheral components from main power source e.g. gimble, LED?

Re telemetry I was wondering about that and guessed that I'd end up with a dual setup with those parts. I'm still not entirely sure how these components function or what I'm going to do with them. My aim is to be able to plan autonomous missions from the field using DROID Planner 2 android app. Not sure if further equipment is required on board but was guessing I'd at least need a USB OTG cable for nexus 7.

Frame you suggested looks great. Would love to use that. It was the type I wanted in the first place, not sure why I didn't spot it. Only slight concern is the additional weight. I've had a go at ecalc and the best motor/prop setup I could get was as follows

 

[Hugh Hemington]

Nice work on eCalc! I'll have to say one failing of both the Alien 560, and Predator 650 frames is prop size. Even an 11" prop overhangs the deck significantly, and a 15" prop on the Alien would chop off that GPS platform. If you find you need to run props larger than 12", you're better off going with a "spider" frame. I'm a little surprised eCalc arrived at such a short flight time with such a large prop. I suspect their formulas are generally conservative in that value.

Did you try higher kv motors too? 485kv may be overkill. According to SunnySky's data, that motor will pull 460g at 50% throttle on a 4S with 30a ESCs and 15" props, which means four of them will lift almost 2kg when your all-up weight will be closer to 1.5 with a smaller battery, even with those heavy motors. That puts hover at somewhere around 38% throttle.

I don't know where you find a 10,000mah 4S lipo that weighs 250g. My 5000mah 4S is more than double that weight. HobbyKing's "Battery Heaven" applet returns nothing but giggles when looking for a lipo like eCalc cites. This 8000mah battery is 845g: http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=16226

I don't know about the 750g pre-drive weight either. The frame is 476. If you add the entire APM kit and misc. wires, I don't see 750g there. (but then the battery was too light) Try to put some tighter numbers into eCalc before making motor/prop decisions based on the results.

On the power distribution front, there is this: http://www.hobbyking.com/hobbyking/...wer_Distribution_Hub_for_OctoCopter_1pc_.html
You could solder wires or standard sockets into all remaining holes for both poles and use them later. I'd be concerned that trying to leave some empty would make it harder to populate them later. You could attach BECs to the unused leads at a later date, to power camera/gimbal/transmitter, or just attach the leads directly to power harnesses if "bus power" will work with your devices. Of course, using this breakout or something similar will lead you to continue with 4mm bullet connections rather than XT-60, but consistency is more the key to convenience than style. I believe there is a similar unit designed with six sockets and 3.5mm bullets. You could still mount your power distribution between the bottom deck and battery plate, using this or any similar method.

 

[BettsyBoy]

I'll try and run the numbers again tomorrow if you think the model weight (without drive) is too low.

There does appear to be a persistent error in the battery weight field but the error does not appear to affect the calculation (check the drive weight total at the bottom).

It might almost be worth holding off buying the motors and props until I know what the weight of the model will be?

I took a look at the Quanum PDB, looks quite tidy. Looks like a different configuration to others I've seen with the positive/negative on opposite sides of the board. Would this create a wire mess? It appears that board (or an extremely similar one) is on Bang Good at a cheaper price. Although BG is rated at 100A add opposed to HK 50A.

http://www.banggood.com/5V-12V-Adju...C-Distribution-Connection-Board-p-914876.html

Also, you said earlier that I might have trouble soldering large gauge wire for the breakout cable with a small soldering iron (so you recommend PDB). Would I not have the same problem trying to solder the 12v cable to the PDB?

I hope you've realised that I am open to your ideas!

 

[Hugh Hemington]

I figured the pre-drive weight of the frame was high actually, but it's a good idea to see how it turns out, and a better idea to try to make it a net-weight figure. It sounds like you are committed to a 4S configuration, and Afro 30a ESCs provide enough power for a wide variety of motors. I'd start with a set of cheap plastic 11" props to start and go from there.

Good job finding the PDB on Banggood. I get in a rut ordering from HobbyKing because they have so many more parts.
I ordered that Quanum PDB from HobbyKing, and anticipated cutting the ESC leads (or extensions) at different lengths, routing the leads headed for the other side under the board and up the center hole to lay flat on the closest pad. That means I only have to get four wires up through the hole -- two from each direction. Since the BECs are on the sides, no wires need to cross them. I may try to put the PDB in a similar gap as my recommendation to you; I'll have to wait and see. I'll include at least one more of those boards on my next Banggood order! That's too low a price not to put a couple in stock.

My comments on soldering were in light of the heat sink effect of the large wires usually attached to large lipo packs, and my experience changing the wires on a power module where other wire is in close proximity and drawing off heat. Coupling battery leads is also a challenge due to wire gauge, but terminating to most connectors is not a particular problem. I didn't really have any difficulty soldering the ESC wires to a different PDB either, and since you should not need to swap those wires as you might the three motor leads to change rotation, I see no reason not to solder them. ESC leads are always smaller than battery leads. I even considered sending two wires to each end of my latest quad and branching off from those to the ESCs. I'll have to see what works best once I have the PDB and ESCs in hand. I have some 8mm carbon fiber tubing and tubing clamps, so I might use that as "conduit" to keep things clean.

 

[BettsyBoy]

Hi

I calculated out the Model Weight (without drive) again. Came up with:

Frame: 646 (g) - verified from multiple sources!
Receiver: 16.8 (g)
GPS: 10 (g)
FC: 33 (g)

That puts my model at about the 700 (g) mark without any drive equipment. I've run ecalc again and was playing around with the 700KV SunnySky motor and 11-12 inch props. Results seem pretty good to me. Could use either size prop to get me started but according to ecalc would need the 12 inch for FPV/Gopro combo.

Think I figured out what's happening with the battery weight field in ecalc as well. It's automatically dividing the total bettery weight by 4 to take into account the 4 motors. I used a 8000MaH battery for this calculation. Would be quite interested to try the new Multistar 10/20C batteries but I have to order from USA warehouse

Would it be worth upgrading to a 40A ESC to future proof? Also would the Afro integrated BEC cause problems for the BEC on Quanum PDB? I read that you're supposed to turn off ESC BEC if another BEC is used elsewhere. Don't think you can do that on Afro.

 

[Hugh Hemington]

I'm surprised your eBay frame source was so far off on weight! If you stay with 4S-capable motors, your amps won't rise to where a 40a ESC is necessary. I see others flying the Iron Man 650 with Sunnysky X4108S 600kv, MultiStar 610kv, 690kv, etc. with props between 11" & 15", all on 4S. I think anything between 500 & 800 will fly it fine. I also see a lot of people dropping the ESC-integrated motor mounts and putting the ESCs back in the center. I think they want to run the wires through the tubes, and having the ESCs behind the motors makes for a mess of wires.

The "BEC collision" issue is related to your controller. Since you will use a power module, you won't be relying on the ESCs for controller power. I suppose to be thorough, you could clip the +5 lead on the four ESC wires connecting to your controller, but I haven't noticed it causing any problems on my APM 2.5.2 board. The +5 lead is the center (usually red) wire in the three-wire mold. Others on the DIYdrone forum can confirm this, since you're buying an ArduPilot 2.6, which is the focus there.
The Quanum board BECs are not impacted by those in the ESCs. They'll run just fine, and so will any load you put on them. After looking at that board on both the HobbyKing and Banggood sites, I'm convinced they are identical and are being over/under rated by one or both sites in terms of amps. Although I routinely harsh on HobbyKing's shipping delays, I think I get things from their International warehouse faster than Banggood. It is odd that the price is so different though.

HobbyKing did a video on those new low-C lipo batteries. They claim you don't need as much current capacity as people think, and lower-C translates to lower weight due to lower density of the cells. I'm waiting for third-party confirmation that they fly without incident.

 

[BettsyBoy]

Probably didn't make it clear earlier but I have decided to drop the Ironman in favour of the Predator. That's where the additional weight is coming from. I've updated my original post to show all the parts I'm now working with.

Was watching some YouTube videos by RC JOSEB last night which I found very useful. He goes through an APM build step by step and at a slow pace (good for me).

I found a power module on HK that I think would work. I could also source this from eBay or Banggood. I guess I'd just need to chop off the XT60 female connector, strip the wire and solder to PDB?

While we're on the subject of the power module I can't find one with an XC90 connector which would make it compatible with the Multistar batteries I've been looking at. Would i have to change the connector on the power module or are there adapters?

 

[Hugh Hemington]

There are two issues with the Predator frame. The first is minor -- with the center tube design, there are fewer "decks" to actually mount things on than on a box/plate design like the Alien. The second is, the folded-in tube clips are not supported at the ends (if you look closely, you can see the ends protruding), and they tend to break at the hang-out point. In the worst case, you'll wind up using a long Velcro strap to keep the arms "put away" for transit. I think they designed the Predator before the Alien, because mine has those clips back inside the deck plates. Still a great frame, and with much better motor mounts than mine. Not sure how those legs will survive, but you can always go "crab" on that.

Yes, any "APM" power module will work. The ones on RCTimer are even cheaper, and I had anticipated you'd want to eliminate the connector and solder the leads directly to a power distribution board. As for the XT-90 connectors, I find it curious that the batteries they stress as not needing as high a current discharge rate have a higher-current connector on them. The XT-90 is a 5mm version of the XT-60. Ultimately you want your quad to have a power connector that matches all your lipos or those you intend to buy in the future. Yes, there are adapters, but none for XT-60 to XT-90. XT-60 is rated over 60amps continuous duty (hence the name -- XT90 are rated at 90+), and so long as the lipo has a discharge rate under that, the total mah capacity of the battery is irrelevant as it never approaches "forever".

Even if you need to completely mod the power module, I'd still favor one with the leads already soldered on the PCB in the center! The pads on that module look innocuous now, but when heaped with a mountain of molten solder, it takes a lot of power to keep that and the solder in and on a large wire melted all at once. You will find that soldering just one wire on a connector pin is much easier, since the cup delivers heat to the solder within more effectively than a flat pad. Even the PDB pads are easier. And adapt your quad TO the battery! I would solder the wires coming out of the battery to new connectors as a last resort. If you do, hack the old connector up as much as it takes to de-solder the lead, so you retain the tinned end; don't chop the lead off and try to tin it without a solder pot. And this is a safety precaution too, because you REALLY don't want to see what happens when the two wires coming out of a high-discharge battery come together. Something to remember when you're hacking away at that connector!

Here's a tip: If you're soldering wires onto (actually into) a male connector, have it connected to a female connector fit snugly in a vice. It does add heat sink, but it also keeps the pins aligned, so that they plug into the battery connector later. And don't forget to put a piece of shrink tubing on the wire first, and slide it at least two inches away from where the soldering is going on, or it will reduce in place and be useless. If you have a very large hemostat, it makes a good wire holder, and heat sink, preventing premature shrink tube shrinkage.