Armattan Gecko 3" build log

[CornishMule]

Ever since I finished the SabotageRC Bangarang 3" build (https://multi-rotor.co.uk/index.php?topic=23352.0) I've been bothered by the motors and props being in view on the HD split footage.

I was hopeful when the mini Alien frame came out, but sadly the HD footage I've seen on Youtube suggests props are still heavily in view.

So, I waited until Armattan had a 20% offer and took the plunge on the Gecko.

My plan is to swap the internals from the Bangarang into the Gecko, only swapping out the R-XSR for a nano Crossfire Rx.

HGLRC XJB F440 40A 3-5s BLHeli32 4 in 1 ESC & VTX
Runcam Split mini camera
Brotherhobby Tornado T1 1407 3600KV motors
Lumenier AXII Stubby 5.8GHz Antenna
TBS Crossfire nano Rx
HQProp DP-3x4x3V1S propellers 
Buzzer
LED

This thread will follow the build progress and I'll also share learnings along the way.

Initial thoughts on the Gecko frame (having literally just opened the package):

• The metal FPV cage tolerance into the base plate is another fine example of Armattan detail.
• The strange little mounting plates for the FPV cam might be a weak point of failure. Will need to crash and see.
• Fewer bolts than the Chameleon, which has to be a good sign.
• I actually got an instruction leaflet with this one, so won’t scratch my head as much as I did with the Chameleon
• Nice detail on the VTX antenna groove in the back plate
• Ugh, sunk nuts

[UrbanFPV]

I was thinking of getting one of these as a 4" with a very similar stack setup.  Micro Alien 4" is also a possibility.
Will be interested to know how it handles with the FC slightly offset.

Which split are you using?  And if it's the split 2 mini, what diameter is the lens on yours (assuming you bought it very recently).  It seems they've changed the lens size between the first revision.  (I have a 12mm diameter lens, but Runcam seems to list current ones as 14mm).

[ched]

Looking forward to the build log, been a bit quiet lately.

As for the 'strange little mounting plates for the FPV cam' I wonder if they are intentionally mounting on a single point each side to try and eliminate vibrations? If they had 2 mounting points each side then that may have been too stiff and transmitted all the vibrations to the camera?

[CornishMule]

I was thinking of getting one of these as a 4" with a very similar stack setup.  Micro Alien 4" is also a possibility.
Will be interested to know how it handles with the FC slightly offset.

Which split are you using?  And if it's the split 2 mini, what diameter is the lens on yours (assuming you bought it very recently).  It seems they've changed the lens size between the first revision.  (I have a 12mm diameter lens, but Runcam seems to list current ones as 14mm).

Hey Urban,

I got the Split mini 2 back in May, so it's not a recent purchase. I think it's the 12mm version though.

Looking forward to the build log, been a bit quiet lately.

As for the 'strange little mounting plates for the FPV cam' I wonder if they are intentionally mounting on a single point each side to try and eliminate vibrations? If they had 2 mounting points each side then that may have been too stiff and transmitted all the vibrations to the camera?

After chatting with ZeroG and Jakalas they both said that Armattan didn't want the frame to be responsible for transferring force onto non-warrantied items (e.g. the FPV camera), hence made the camera braces the weak point on purpose. This makes sense now, I'd rather break the brace in a crash and claim under warranty than break the camera.


A few update photos from last night's progress of lengthening the motor wires as the runs between motor and ESC are longer than the bangarang. I looked at TBS race wire minis, but the arms aren't long enough, so went with a solder joint. The tape at the back holding the wires is only temporary to keep them flat while I fit the ESC.



Other learnings, the holes in the baseplate for the rear stack are M3, whereas the HGLRC stack has M2 holes, so a small piece of antenna tubing reduces the hole from M3 to M2 perfectly (thanks for Jakalas for this tip!)

The XT30 tail looks to be best ran out the back of the frame to avoid prop hits, but this rotates the HGLRC 4-in-1 ESC so the USB port is inaccessible, so I'll resolder the XT30 pads to orientate the wires 90 degrees (pic to follow)

[daich]

this is great! following this log.
I'm building a 4" version of this at the moment. Same stack too! I'll be running geprc 1408 3750kv.
will be going separate HD camera so running micro eagle in the awesome shiny Ti cage

The sunk nuts aren't too bad (like the rooster was)... as they aren't going into carbon but into the rubbery plastic vtx antenna holder...as it's molded it goes in easy.

[CornishMule]

Build update:

- Got the motors wired to the 4-in-1 ESC, lots of fiddling to route the wires neatly.
- FC stack installed
- VTX, Runcam Split and Crossfire Nano Rx wired to FC (Nano RX wires need tidying)
- XT30 tail also need shortening, but this will come almost as the last step.




Lessons learnt:
- Runcam split bottom board needed to be raised by an additional set of M2 copper spacers to allow for enough room for the front motor wires to route back to the ESC
- Measure thrice and cut once ...


Next steps:

- Figure out where to mount the immortal T antenna and nano rx
- Fit buzzer and LED somewhere

[ched]

Looking good. Any guesses on all up weight?

[CornishMule]

Looking good. Any guesses on all up weight?

Will have a look tonight, hoping for the magical sub 250g but then again I’ll be registering my 5” quads so no real problem adding another to the mix. I’m sure the police would have questions over why I carry digital scales with me anyway 😜😜

[Elmattbo]

Top tip for the sunk nuts - fit them using a steel screw and a washer. Don’t do what chris from armattan says and whack them with a hammer. Just pop the washer on the screw and gently tighten the sunken nut into the carbon. It should go in easily and smoothly - and straight!


Sent from my iPhone using Tapatalk

[CornishMule]

Work, traffic, chores and exercise hindered too much progress last night, but a few steps were made:

- Found somewhere for the Crossfire antenna to sit (the cable ties might be temporary, I've seen a 3D printed plate to hold the antenna in this position, but it would require removing the entire stack, which I can't really be bothered to do at this stage ... let's see how the cable ties hold up)

- Dremelled out a channel in the top plate for the VTX antenna coax to sit in

   

Next step is to get a plate printed to mount the Crossfire RX on. This will keep everything on the stacks and avoid sticking stuff to the top plate and getting in the way of the battery strap.

It's getting there .... 

[mo_miah]

Will have a look tonight, hoping for the magical sub 250g but then again I’ll be registering my 5” quads so no real problem adding another to the mix. I’m sure the police would have questions over why I carry digital scales with me anyway 😜😜

i was considering a gekko build but most of what i've seen on rotorbuilds has an AUW of over 250g
i don't mind registering but no doubt their will be a cost involved which is what puts me off
for now im avoiding spending anything of the 3"+ drones and am now building my whoop fleet