ZMR250 Quad Build Log - My first quad build

[offaxis]

I have finally began the plunge into a 250 quad build and will need a lot of help from this great community. I purchased a Hubsan X4 and have a blast bashing the thing around the house at my wife's dismay. Our apartment is pretty small (600sq ft). Thankfully is hasn't ended up in her hair yet like many have warned and she has given me her blessing on building this quad.

Now that the weather is cold out, it is build season!

Goals for the build:

Get me familiar with components, building, tuning, and flying line of sight. And dive into the FPV world with this platform once I become proficient and the funds become available. I might also bump up to 4S setup in the future.

I would like quad to be serviceable as much as possible without the use of a soldering iron. I have access to one and know how to use it, it just more of a convenience thing.

Share the knowledge of building a quad with others who would also like to start from scratch.

Current Components:

SunnySky X2204 2300Kv motors $22.80 EA
Velotech Magic 12A ESC with 1A BEC $Came Free with motors
ZMR250 Composite Carbon Fiber Frame $24.95
Massive32 Flight Controller Pre-soldered $31.95
The Squid Quad Breakout cable 3.5mm bullet to XT60 $10.99
Naze 32 - RC Breakout Cable for RX $2.99
RMRC 5A UBEC $9.99
2mm Bullet Connections for between Motor/ESC $3.66
3.5mm Bullet Connections for between ESC/Battery $3.98
5x3 GemFan Props $3.00/set
1300mAh 3S w/ XT60 connector $~10-15
Turnigy 9x w/ HK T6A RX
Battery Straps
Nylon standoffs for FCB
M5 lock nuts

Need Components:
I believe I have everything on order

Future Upgrades/Components:
F-12A-HV Fire Red series High Voltage OPTO (2-4 Cells) SimonK-(RapidESC)
ImmersionRC 5.8GHz 600mw Audio / Video Transmitter
ImmersionRC 5.8 GHz SpiroNET Antenna Set RHCP (SMA Connector)
FatShark Goggles
Mobius

My Initial Thoughts:
I bought 5 motors and ESCs to start. The Velotech ESCs came free with the motors, so I'll give them a try and see what happens.

Looking Back:
One ESC stopped working properly so I had to swap it out. I'm glad I bought a spare. I think I got to much "snow" under the heatshrink and killed it.

While out flying I noticed that while in acro mode the red light would flicker on the board and it would auto level. I pulled the board and checked all the connections and found that the AUX1 pin (3 position switch defining flight modes) was not properly seated into the plastic housing and caused an intermittent signal. This caused the board to default to horizon mode. After putting it back together, it was back to operating normally.

-Blake (Offaxis)

 

[offaxis]

The Build

So I realized that I ordered 5 CW motors, and didn't know that SS22024 motors were available in CCW. To remedy this problem, I will be using lock nuts on the motor shafts. This will prevent the nuts from spinning loose during flight.

The arms had to be drilled out to allow for the M3 screws that bolt on the motors.

I began laying things out and realized that 250 quads are a lot smaller then anticipated. I 3D printed some frame spacers from RCGroups so I could run the power wires between the two lower frame plates. This should hopefully save on some space.

Because I decided to use connectors for everything its not going to be the cleanest build. Maybe the next one will be better.



There was a poor solder on the FCB that caused the pins to push. MassiveRC is sending me a replacement.

 

[offaxis]

Ahhhh. So many wires!! That’s just the way it is when you’re building a quad. I soldered the 2mm bullet connectors to the motor wire and 3.5mm bullets to the ESC power wires. Because I used connector and didn’t shorten the motor wires, I had to place the ESC’s on the center frame. It works out pretty well, but I had to be a little creative with the wire routing.


I powered up the quad for ESC syncing and insuring prop motor spin direction before heat shrinking the motor connectors together. By using one piece for the connectors, it should prevent them from pulling apart. The ESC’s where zip-tied in place. I also realized that the motor wires run the risk of being sliced by the props because frame spacers have the motors sitting lower, so I put more zip-ties on. I’m going to have to revisit this because the arms are tapered; the zip-ties just wiggle loose and slide out to the end.


Continuing on, I began hooking up the ESC signal wires and the receiver wires. I took me a few tires to come up with a routing that I liked. I finally settled with wrapping the esc signal wires down between the frame plates and back up under the flight control board. This route was just the right length to make up for the excess wire. For the receiver wire, I tucked them under the board as well and up the top plate where I fixed my receiver. In the side view picture you can get a pretty good feel for the routing of the wires. I finished by bundling the ESC power wires together and tying them off to the top plate and by putting the antenna up threw the vibration mount hole (this will be moved in the future when it becomes an FPV quad).





After setting everything up with the cleanflight configurator, it was time for the maiden flights. It was definitely a learning experience. Hovering was stable and feels locked in, even with the default settings. While trying to autotune, the quad raced skyward. I quickly flipped back to horizon mode and nervously brought it back in. When I was trying to land, the quad flipped over and smashed into the pavement. I’m not sure what caused this and it was quite scary. The frame was fine but my main power wire was sliced open. I put some electrical tape on it and it should be fine. I will have to try out autotune another day.

 

[offaxis]

Ugh, free shipping from china is so slow, the price I pay for being cheap. I desperately waiting for my 3.5mm bullets to show up so I can finish the connections.

 

[OPO]

Thanks for sharing! looks amazing so far, did you make the harness yourself or did it came with the parts?

 

[Team_Monkey]

Axis, I just built one of these last weekend using similar components all purchased from Buddy RC. I have the same frame, motors and ESCs as you do. But I used a Diatone PDB w/ LEDs for power and a CC3D FC board. The ZMR frame is very tough with thick arms but I wish for two things, make the motor slots 3mm instead of 2mm and put a note in the box to put the upright supports on the middle deck plate before assembling the arms and bottom deck.

There are no connectors on my bird. The ESCs go right to the PDB and I removed the motor wires from the ESCs to just solder the motor leads directly to the pads on the ESCs.

The CC3D set up easily and was locked in from the begining. Please let us know about the massive board. Is that a multiWii type?4

 

[offaxis]

Thanks for sharing! looks amazing so far, did you make the harness yourself or did it came with the parts?

I purchased the harness from readymaderc. See the component list for: The Squid Quad Breakout cable 3.5mm bullet to XT60 $10.99. Due to its size i believe it is intended for a slightly larger quad.

I've purchased the components from various vendors. If you would like me to put that information into the component table I can.

 

[offaxis]

Axis, I just built one of these last weekend using similar components all purchased from Buddy RC. I have the same frame, motors and ESCs as you do. But I used a Diatone PDB w/ LEDs for power and a CC3D FC board. The ZMR frame is very tough with thick arms but I wish for two things, make the motor slots 3mm instead of 2mm and put a note in the box to put the upright supports on the middle deck plate before assembling the arms and bottom deck.

There are no connectors on my bird. The ESCs go right to the PDB and I removed the motor wires from the ESCs to just solder the motor leads directly to the pads on the ESCs.

The CC3D set up easily and was locked in from the begining. Please let us know about the massive board. Is that a multiWii type?4

I also wish they used 3mm slots. I also had to drill the arms out to mount the motors.

In the future, I probably will use a PDB but would prefer one that is the same size as the FCB so they would stack nicely. I'm not very good with the solder iron and am concerned about burning out components due to overheating while soldering. I also expect to crash a lot and feel that with connectors, it will give me the flexibility to service the quad in the field.

The Massive32 Acro is a Nase32 type board flashed with Cleanflight. That is my understanding, so I think that puts it into the multiWii category.

 

[PhenomPilot]

Offaxis, come over to my place and I can solder up your harness or make one to fit. I might also have enough connectors. If there weren't snow on the ground, I would let you fly my zmr250.

 

[jhitesma]

One thing I'd suggest is some O-rings on the FC mounting screws for vibration dampening. I've run without and it can work...but you'll get far more reliable flight performance with them and you'll be able to raise the gyro_lpf higher in value which will allow you to push your PID's even more for even better flight.

Overall it's looking great!

The ZMR frame is very tough with thick arms but I wish for two things, make the motor slots 3mm instead of 2mm and put a note in the box to put the upright supports on the middle deck plate before assembling the arms and bottom deck.

So those lower upright support screws aren't accessible once the bottom is on on the ZMR frame? That's a bummer. That's one of the things I really like about the emax/nighthawk 250 frame I have - there are access holes in the bottom plate so you can get to those while leaving the bottom section fully assembled. I've had those screws come loose a few times (still haven't found aluminum safe thread locker locally and too cheap to pay more for shipping than the item itself!) and love being able to give them a check before flight. Plus it makes taking the top off for repairs/upgrades/tweaks nice and easy.

 

[offaxis]

One thing I'd suggest is some O-rings on the FC mounting screws for vibration dampening. I've run without and it can work...but you'll get far more reliable flight performance with them and you'll be able to raise the gyro_lpf higher in value which will allow you to push your PID's even more for even better flight.

Overall it's looking great!



So those lower upright support screws aren't accessible once the bottom is on on the ZMR frame? That's a bummer. That's one of the things I really like about the emax/nighthawk 250 frame I have - there are access holes in the bottom plate so you can get to those while leaving the bottom section fully assembled. I've had those screws come loose a few times (still haven't found aluminum safe thread locker locally and too cheap to pay more for shipping than the item itself!) and love being able to give them a check before flight. Plus it makes taking the top off for repairs/upgrades/tweaks nice and easy.

Thanks for the O-ring tip!

They should be accessible. There are definitely holes in the bottom plate, I'm just not sure if they are big enough to fit the Allen key through.

Anyways, I got the quad in the air yesterday. So here is a short video of the maiden flight. Final build pictures to come.

I was flying in acro mode. When I tried to autotune the quad, it launched up to 60+ feet and I quickly switched back to horizon mode to bring it back in. When I got it back down to about 5 feet, it suddenly flipped over and smashed into the pavement. My brother and I looked at each other trying to understand what just happened. Nothing broke, but my main power wire got sliced a little by the top plate. I wrapped it with electrical tape and went back at it. Then after that, it would only fly in acro mode. I was in a low hover in acro mode and switched to horizon(or angle) and the motors just cut out. EDIT: I realized I assigned the arm mode to the third position on my TX, hence the reason it would only arm in the acro mode and the typical down and right to arm wasn't working.

All in all, I consider the day a success despite what is happening.

 

[Team_Monkey]

Axis, there are setscrews on the sunny sky motor bells, just under the prop hub. remove them and re-install with blue threadlock. I lost one shaft and almost another by missing them.

I thought the bells were press fit onto the shafts but they're not. Great motors, I just missed a detail.


Here's my quad and I right after I had maidened it.
Normally the Rx sits on top and I put the battery on bottom. However I think I'm going to re-arrange it and put the LiPo on top and move the Rx inside.

 

[SnowRocker88]

Have you done any waterproofing to the quad?

 

[offaxis]

I will check those set screws. Definitely don't want to loose them.

I haven't done any waterproofing yet. I have a bottle of CorrosionX that I will probably coat the individual components. Probably should have done that before putting it together but I didn't want to wait any longer.


Does any one have a link or insight to PID tuning quads?

 

[SnowRocker88]

Does any one have a link or insight to PID tuning quads?

Have you searched YouTube?

 

[jcar01]

I just finished building my ZMR 250 and used these motors http://www.altitudehobbies.com/suppo-motors/suppo-m1806-2660-brushless-multicopter-motor-ccw Great price and you don't have to wait 30 days to receive them. USA business.

JC

 

[offaxis]

I finished updates to the build log. Let the adventures begin!

 

[cranialrectosis]

I just finished building my ZMR 250 and used these motors http://www.altitudehobbies.com/suppo-motors/suppo-m1806-2660-brushless-multicopter-motor-ccw Great price and you don't have to wait 30 days to receive them. USA business.

JC

Altitude is my favorite go to shop for parts. I am (of course) a bit biased in that I live < 100 miles away and often get my parts in one or two days. His prices are fair and the service is the best there is.

These new motors are new to Altitude. I may have to try out a set on my Polakium SS Quad. Thanks for the link.

 

[Team_Monkey]

Axis,
Sorry to hear of the flight problems. it looked fine in the video though. Glad you got it going.
Good luck getting it tuned and set up for your style. I started with two flight modes, stable and "spirited". I think I want to make it three now; stable, spirited and "FLIPS!"

 

[offaxis]

I was able to get out flying on Sunday. I updated the quad to the most recent version of Cleanflight and reconfigured everything to get a fresh start. I also coated the board and receiver with corrosionX to help combat the wet snow that I was bound to crash into. While out flying I noticed that while in acro mode the red light would flicker on the board and it would auto level. I pulled the board and checked all the connections and found that the AUX1 pin (3 position switch defining flight modes) was not properly seated into the plastic housing and caused an intermittent signal. This caused the board to default to horizon mode. After putting it back together, it was back to operating normally.
I only broke a few props and successfully did a few large loops, but most of the flying was done in angle or horizon mode. I&#8217;ll dedicate more time to acro mode soon. I also plan on trying to autotune on my next outing.