GEPRC Sparrow GEP-MX3

Very impressed with the reviews of the GEPRC Sparrow 3inch quad. I almost bought the BNF version. But the flightcontroller was an older F3, and it did not have a OSD onboard.

So instead I bought the GEPRC Sparrow frame, with the same motors as the BNF, added a more recent F4 FC with OSD, 28A 4in1 ESCs, and to make it complete I bought a Runcam Split 2 for it.

Also bought a few batteries, 4S 850mah with XT30 plug, these should be perfect considering the weight/performance/flighttime.

Will post some pics when the stuff arrives from China, and I can start the build.

Heh. I also got this frame when I got the diatone one.It`s pretty much a smaller
version of the leopard and is awesome ! GEPRC make great stuff and the frames
are fantastic quality.
Haven`t been able to decide what I could put in this yet,could you leave a link to
those 4 in 1 ESC`s please ...

muckyman wrote:

Heh. I also got this frame when I got the diatone one.It`s pretty much a smaller
version of the leopard and is awesome ! GEPRC make great stuff and the frames
are fantastic quality.

Awesome   I see you also bought the single plate bottom version, looks stronger then the other one.
I also like how it comes with LEDs for on the back, though not sure I put them on the quad.
The Runcam Split 2 I plan on using consumes extra batterypower to operate, already reducing flighttime somewhat, so the LEDs may be too much.

Quote :

Haven`t been able to decide what I could put in this yet,could you leave a link to
those 4 in 1 ESC`s please ...

I bought this FC + 4in1 ESC stack for €51 :

6.5g 20x20mm HGLRC XJB F428 Micro F4 AIO OSD BEC Flight Controller & 28A Blhel_S BB2 2-4S 4 in 1 ESC (link)

The 4in1 ESC module has pins for the ESC signals that lock into the FC, so no need to use a plug or solder the signalwires.  
There is also a version of the HGLRC stack with matching VTX for €69, but I'm going to use a VTX from Eachine. (VTX03 Super Mini)

Yeeee Only 6 days from China to my house.

Also bought antivibration pads for the motors and o-rings for the flightcontroller. Going to start building in the weekend. In theory it could be done in a day. But I do still need to figure out how to fit all parts first, already have an idea, though not sure if it works as planned.

This pic shows how I plan to install the Runcam Split. Fitting perfectly.

Looks good.I will see how you get on and then maybe get another split
to put on my sparrow if your`s fits nicely at the end.
What do you think of GEP rc now you have one of their frames ?

The GEPrc carbonfiber looks better quality then the cheaper Lisam frames I used so far.
Also very much like the thicker bottomplate for this small size quad, 3mm instead of the usual 2mm.

Quote :

Looks good.I will see how you get on and then maybe get another split
to put on my sparrow if your`s fits nicely at the end.

The only thing that will be a little tricky is mounting the camera in such a way the frame is out of view.
To do it right I have to remove those 2 little bumps on the aluminium parts of the frame,
Otherwise the lens is too far back and the frame will be visible on the sides.
I don't really mind the props being in view, but it won't look nice if the frame is visible.
I'll probably try drilling most of it out, then file away the last remains.

Softmounted the motors and ESC 4in1 module. Also made a little space for the batterystrap.
Can't have the strap too close to the fragile electronics, cause when strapping the battery you could accidentaly rip one of the small component loose.  

A few pics of the progress before I'm finished already. Taking it easy, but it's still going too fast.
Only need to solder a few parts, place the Runcam, do some finishing touches, and then I'm done.
I've updated Betaflight, and the ESC firmware, corrected the motordirection with BLheli.
Made a small package from the receiver and the miniVTX, which will go on top of the stack.

Next pics it will probably be finished.

All the soldering is done. The Runcam Split is working, and the OSD too.
Now I only need to mount the camera and fix the antennawires, and it is ready to fly. 

Wow ! Really fast work there canner 

Looks good,you just need some nice dry sunny weather to finish off.

Yes, I desperately need some nice dry sunny weather.

When the quad is finished I can fly inside carefully, but for real testing I need to go outside

Drilled and filed away the little bump on the aluminium frame parts, and now the camera fits like a glove.
As you can see on the pics the lens is just outside the frame, couldn't be better.
Not finished yet, still need to tidy things up, but at least everything is going to fit.

Final pics of my latest build.


Fixed the floppy VTX antenna to a tiewrap with a piece of heatshrink.


I prefered taping the antennawires to the arms, instead of using the fragile antenna holders that came with the framekit.
The antenna holders look good on pics, like at the start of the topic, but they are certainly not durable.
On one arm I taped an antennawire pointing to the front/side, on the other arm it is pointing backwards.






Had to be a bit creative with placing the Runcam board, to have enough space for the receiver/VTX and camera.

Now waiting for the weather to improve so I can do a testflight.

Looking really nice now canner m8,it is really tidy
I can hardly see any wires at all.
Hopefully you get some good weather soon and go
give it a good testing.

 

muckyman wrote:

Looking really nice now canner m8,it is really tidy
I can hardly see any wires at all.

The great advantage of having a 4in1 ESC board, no need for ESC power/signal wires.
Not only saves soldering and having potential weak points, it also saves a little weight. Plus it looks better.

Went for a testflight today, but it didn't go as well as hoped. First tried flying with a small 3s 500mah, but this was already half empty before take off. The Runcam Split appears to take up so much energy, you can see the battery drain 2 or 3 mah every second. For further testing I took a 1300mah 4s, but even this one had troubles. Every throttle punch the beeper beeps there is too low voltage. But this even when there still is +50% battery left. Possibly the Split has a short, or maybe somewhere else on the quad, but there is no strange smell, sparks, or excessive heat. Despite the issues, the recording looks pretty good, the quality is slightly less then my Gopro. No interference indicating a short or something. If I can't find the short, I will put the Split on one of my 5" quads. This will be better anyway, cause the 3" with a battery large enough to support the Split, doesn't fly very well. Rather fly it without Split, then to fly a brick. Apart from the battery draining too quick, the quad flew quite well. Will post update how it works out.

Took the Split out of the stack and put it, still wired up, next to the quad. Plugged in battery, and it still drains mah like water.
So it's probably not a short, just very powerhungry. Instead of 2-3 mah per second, it is actually more like 8-10. Maybe I am missing something about how this mah value works. But it seems like the Split messes up the readings. Normally a 500mah battery is empty when the quads OSD states 500mah used. Only with the Split attached, when 500mah is used, there still is like 80% power left in the battery. Bit weird, I wonder how it is going to work on another quad. It's kinda shit it didn't went as well as hoped, the Split is just too heavy for the 3", Specially the fpv camera is quite weighty. I do like the how 3" quad will me a lot lighter now. Not even finished, but already can't wait to see how it flies without Split. Nice to have hd recording of the flight, but in the end it's not about making videos, it's more about flying.

Used the voltmeter to rule out any short. Once I desoldered the Split, the weird mah draw was still going on. So at least the Split is fine. After messing around in Betaflight on the power/battery tab, I realised that it probably is a broken current sensor. The voltage reads out ok, but the mah/current reading is false. For now I disabled the current meter. The quad can still fly, but without current meter active on this FC, the lowbatterybeeper won't function properly. Thinking about applying for a refund, or resend, cause this flightcontroller is faulty.

CANNER wrote:

For now I disabled the current meter. The quad can still fly, but without current meter active on this FC, the lowbatterybeeper won't function properly. Thinking about applying for a refund, or resend, cause this flightcontroller is faulty.

Refund not necessary, think I figured out the problem. Maybe that current meter is a new option in Betaflight, next to the voltage meter. But since this is a micro FC it's probably not supported, though Betaflight still registers something. Should have turned it off from the beginning, but I didn't know. Seen that option for the first time, so I thought it was enabled because it was detected from the FC, which apparently it isn't. Put the quad back together, now waiting for better weather, and the 4s 850mah batteries I ordered when I bought the parts for this quad. Batteries still haven't arrived, which is normal for batteries, can take up to 3 weeks. Btw the voltagebeeper does work now, just needed to also detach the USB when rebooting the quad with battery.

Am a bit lost now,teehee.So dows it still use to many mh or was it
just the faulty / unsupported current sensor ?
Hope you get it sorted out soon.

Im also a bit lost, I don't want to cry at Banggood for a refund, but starting to look like it really is a faulty current sensor. Though the voltage does appear to read ok at first, when flying it drops fast, way below what is acceptable for the batteries health. Voltage per cell should never drop below 3V, so for a 3S battery 9V is the absolute minimum, maybe a short dip is ok, but I've seen it go to and stay on 8V, this within secons after takeoff. But when I land there is still 82% batterypower left. Now waiting on the other batteries to arrive, if the result is the same, which it probably is, I'm going to contact Banggood.

New test with the current sensor turned off, voltage sensor turned on. But still the same.



Really sucks this problem, cause the quad does fly quite nice. Hopefully Banggood will be so kind to send a replacement FC+ESC combo.

Decided to transplant the Split to another quad. First need to get this little one flying okay.
When it's finally good, I will buy another Split for it.

While back I rebuild my KISS stuff into a lightweight 5inch that can't really carry a gopro.
I've got the KISS quad flying awesome now, a Split on it would be perfect.

Yeah that does start beeping quickly.
Sounds a bit off aswell,maybe just the props it`s hard to tell.
Different batteries may help,will wait and see what you find out.
Good luck n8.

muckyman wrote:

Sounds a bit off aswell,maybe just the props it`s hard to tell.

The propsound is so high pitched it is blending with the sound of the beeper. It's also hard to hear the beeper when flying around. Though the quad itself isn't even that loud. 

Before contacting Banggood, I should desolder everything and test for defects. If the FC is stripped from all parts, cleaned and still showing this weird mah drainage, then I'm sure the FC is faulty. If the FC appears to work good at all, then perhaps one of the motors has a short inside. Never had that before, but can't rule it out. At least the screws are not too long, but maybe a defect from the factory.