The Golden Leopard GEP-LX5

By Whiffles on Jul 06, 2017

11 3,224  35 

I've been very impressed with the quality of the GEPRC frames, so despite the fact that it's a clone I just had to give this one a try. This isn't a lightweight frame, but it's not a brick either. It should hold up to a fair bit of abuse. Both the flight controller and 4-in-1 ESC are the same ones I used on my Race Frog build. They work well together and are a proven combination.

The quad weighs 329g bare and nearly 400g with the Runcam 3.

Knolling shot

Frame & Stack Assembly

The frame is rather straightforward to assemble, but keep the instructions handy. Pay close attention to the length of each gold screw as they all have a particular place. I opted not to use the gold standoffs in the stack and used vibration dampening spacers and nylon standoffs instead. The gold bits just won't work well with these boards. Another thing to pay attention to is the sunken screw holes on the gold plates for the camera. Be sure to mount those with the sunken parts out. This kit includes two sets of side plates with different screw hole positions. I believe one will mount your camera in a single centered position while the other lets you sink the camera further back in to protect it from impact.

I don't know why they always include such tall standoffs with these kits, so it's a good idea to invest in some 6mm M3 nylon standoffs. You'll never need anything taller than that. If you follow the included instructions you won't have enough clearance below the 4-in-1, so I had to get creative. I started the stack with the vibration dampening bobbins, but due to their shallow screw holes I had to shorten the base screw by adding nuts to the underside of the frame.

Frame & StandoffsBobbins

Wiring the Motors and ESCs

The first thing you'll want to do is mount the motors. It's always a good idea to use some blue Loctite on the screws to prevent them from vibrating loose. Now for the most tedious part of the build: extending and wiring up the motors. While using a 4-in-1 ESC is a huge time saver, the motor manufacturers haven't quite caught on and continue to make motors with short leads. I hope this trend changes, but it's good practice joining the wire bits together. You'll need some spare 20awg wire to extend these, so dig through your stash or buy some beforehand. I use 550 black Paracord to protect the wires, but this is entirely optional. You'll also need some shrink tubing to cover your joints.

ESCs and Motors

Powering the Flight Controller

So you've got a little flexibility here with the Foxeer Arrow V3. This camera has an OSD that will report the battery voltage back to your headset. Normally you'd run power from the battery to the vbat pad of the flight controller to monitor voltage over Betaflight OSD. The problem with that is the 5v linear regulator on the flight controller will produce a lot of heat. There are two ways to avoid this: physically disable the linear regulator by removing it from the circuit or avoid feeding vbat to the flight controller in the first place.

Disabled linear regulator

Since this build uses the 5v regulator of the 4-in-1 ESC to power everything you don't need the 5v regulator on the flight controller. What I did was pass power to vbat and physically disable the on-board linear regulator. That way I can monitor voltage with Betaflight OSD without any excess heat. It's done by snipping the connectors of the regulator itself as shown here. If you're hesitant to snip your flight controller you don't need to feed power to vbat and instead power your camera from the battery. You'll still want to use BetaFlight OSD for tuning, so you'll have overlapping OSDs. This is perfectly fine if you lay them out properly. Of course you don't need to disable the regulator. I've left it alone in the past and while the board does get hot it still functions properly. I'd just be careful flying on a hot day.

Wiring the Receiver

Next you'll want to wire up your receiver. I decided to tuck mine away under the 4-in-1 ESC. I ran just enough wire to reach around to the flight controller. Refer to the photos for the correct wire placement. One trick I like to use here is to pass the wires through the flight controller holes to hold them in place. Then I'll slide each one down until the tip of the wire rests within the hole as I solder. The antennas are mounted to zip-ties extended from the backs of the front arms. This keeps them well protected and doesn't diminish range at all.

Wiring the RXWiring the RX

Wiring the Camera & Video Transmitter

At this point the wiring is fairly straightforward. Everything is powered via the 5v wire of the 4-in-1 ESC wire harness. Unfortunately I didn't take any photos of this, but it's a short 4cm series of wires with a plug on both ends. It was included with the 4-in-1 ESC. This simply plugs into the front of both boards. The camera and VTX are powered by the VOSD pads of the flight controller. These pads aren't on the 5v circuit by default and you have a choice of feeding VBAT or 5V to these pads. We want to pass the 5V along. This is done by bridging the 5V and "MC" pads of the board. Look for the little loaf of solder in the photo to see how this is done.

Finally you need to solder the VTX and camera wires to the 6 pads along the side of the board. Be sure to refer to the wire diagrams of both the VTX and the camera to understand how the video passes through the FC to the VTX. You can optionally remove the mic or vbat wires from the camera wire harness by prying the little white tab with a tiny flathead screwdriver. You can leave the OSD configuration pigtail and tuck it away for future tweaking.

MC and 5V

FPV wires

The VTX03 is mounted on a cushion of double sided foam tape to avoid any possible shorts.

BetaFlight Configuration

I won't get into the details of configuring this in Betaflight, but here is a general overview of what you'll need to accomplish:

  • Flash firmware to the latest version of BF.
  • Use resource commands to order the motors.
  • Use BLHeli Configurator to set motor rotations.
  • Bind TX/RX and set inputs and ranges.
  • Set switches to arm and change modes.
  • Configure OSD.
  • Set your rates.
  • Use camera OSD to adjust your camera settings

Final Thoughts

This build was one of the easiest I've done. The only adjustment I might make is to find motors with longer wires. Unfortunately you won't find any gold motors that fit the bill. It's not a huge burden to extend the wires, but it does add a little time. Also, be sure to pay close attention to the frame instructions as there are some details you might overlook such as which screws to use and where. As with any frame kit you have some flexibility in what parts you use, so don't feel that you need to use everything E.g. the gold standoffs. Another thing to consider is GEPRC makes a stretch version of this frame with blue side-panels, so you can go with a different color scheme and flight characteristics.

Final
Final
Final

Photos

Part List

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Discussion

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Poptart56   3 days ago  

This thing is awesome looking. Wanting to build one. Question for ya, what size did you end up building? They've got 3 available I noticed.

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Poptart56   1 day ago 

How do you like the 2300kv? Would more be better?

Whiffles   1 day ago 

They make for a very smooth and easygoing flight. This isn't as punchy as my Frog 218mm, but I like it. Sometimes I don't want to fly at light speed. If you want power try the Cobra 2207 2450kv motors.

daveofdefeat   20 days ago  

Amazing write-up! I just completed a very similar build a few weeks ago too but I already broke an arm and motor on it...
https://rotorbuilds.com/build/4559

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5150fpv   6 days ago 

hate to ask a dumb question, but is this for sale??

daveofdefeat   6 days ago 

are you asking me or Whiffles?

Croops   9 days ago  

Always love your builds - very inspiring!

Can you please add the source for the Runcam 3 mount?

Cheers!

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Croops   8 days ago 

Great - I noticed the bottom mount is curved - does this mean it will only work on these types of curved frames?

Whiffles   8 days ago 
1

It's specifically designed for this frame, so it won't work on anything else. If you want a more universal mount try this one.

Matt_Kord   10 days ago  

Are those battery's seriously 110c? Because I am planing a build with emax 2306 2400kv motors and they draw alot of current with tri blades. So are those batterys accualy good and are they 110c?

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Matt_Kord   10 days ago 

From what I know about banggood isn't all their stuff knock offs? So the batts probably aren't manufactured as well as ones made by the actual companies. So that could be the problem and/or a problem.

Whiffles   10 days ago 

They've been pushing hard into the "race" battery scene with high current packs, so I think the quality has improved. Just don't buy the Zop packs. It seems CNHL has really made a mark on the battery scene, so there are quality packs coming out of China. They just need to be discovered.

notmojack   12 days ago  
1

Art. This is art in its purest form. Nicely done!

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ricardovasc   13 days ago  

What do you think about the range of this stock VTX antenna?

Whiffles   13 days ago 

It's been great for me. I have no problem going up to 200m and it penetrates quite decently for what it is.

ricardovasc   13 days ago 

I see people just telling this VTX is one of the best in the market right now, but I never see anyone using circular polarized antennas on it.

AngryRedBarber   14 days ago  

Very nice what was the final weight of the quad?

Whiffles   14 days ago 

It's 329g bare and about 600g fully loaded with the Runcam 3.

Whiffles   17 days ago  

I had my maiden flight today and wow, those motors are smooth. I just love the sound of them. I wasn't flying very aggressively because I had a new friend following me.

Bandafpv   14 days ago 

Wow.. probably the best build log ever for this frame anywhere. Very nicely done.. was a pleasure to check this thread out! Well done bud !

Whiffles   14 days ago 
1

Thank you and welcome to the site! It looks like you added quite a fleet there.

EuthaNasi   19 days ago  

Did your kit incluse the other camera side plates? I've build a LX5 before and it had 2 sets of sideplates: one for (I think) Runcam and one which suited my Foxeer Monster V2. Lost the drone and just received the LSX5 for my new build but it only had the sideplates for the Runcam. Curious if GEPRC took them out To sell separately or that it's a packaging fault...

Whiffles   19 days ago 

Mine came with both sets of gold plates. Maybe they only produce the blue plates in a single style?

FlyKow   20 days ago  
1

Beautiful build and love the 4in1. What do you think of the motors? Powerful enough for this weight? I have a similar build with the Cobra 2500 2300kv and it seems a little under powered.

Whiffles   20 days ago 

We'll see when I get my proper camera mount printed. There's no way I'm flying this camera with velcro alone!

SadisticLeprechaun   20 days ago  
1

OMG drone porn! Awesome stuff!

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