Yup, version four lol wtf.  I guess I just keep going back to this frame.

The reason for the build is that I was having video issues on an Acrobrat Duo that turned out to be due to the frame itself.  So I figured what better reason to get a new frame.  I looked at quite a few and just kept going back to the Gecko.  But I did forget how tight of a build it was ...



I had just bought a T-Motor F7 mini stack that I really liked thinking the video issue on the Acrobrat was a faulty BEC on the FC.  But the ESC on that stack would not fit the Gecko!!  LOL wow.  Even this Kakute F7 Mini ESC was too big at the lipo pads.  I literally had to clip the corners off.  Yea.  Exactly.



I know, I'm big on the thicc caps lol.



This Kakute F7 stack has worked pretty well so far.  I do wish more FC's had a VTX power switch though.



Space is so tight, I had to 3d print stack plates that double as screw nuts to save precious a 2mm lol wow.



These will probably melt lol.



Not that it would even fit without some serious dremeling, but I prefer the Caddx Tarsier far more than the Runcam Hybrid because the Hybrid just has so many random problems.



I opted to separately solder a harness rather than using the connector on the Tarsier PCB because that connector harness butts up against the Kakute F7 stack cable.  I've had to replace that cable because the pins get loose and cause serious issues.



Yup.  Yet another 3d printed stack plate.  Space is *that* tight lol.



I really liked how these TBS Unify Pro Race VTXs with MMCX connections on my racing drones performed so I'm gradually switching over to them.



I hook them up to Rush micro microphones since I really prefer to have volume.  I normally just heatshrink the mic on top of the VTX but in this case, I had no room!  LOL wow.  I had to secure it under the camera.



I've got a TBS Triumph antenna weaving through the only space available once the top plate is secured lol.



Of note, I busted the cable on this practically new Tarsier.  I was getting no FPV feed.  But when I jiggled the cable at the camera, the picture would come and go.  I had to replace the cable and all was good.



I also had to reverse the camera bracket so I can get decent angles with the camera.



It is super tight in there LOL.



I was hoping to kit some LEDs but I'm not sure where since I don't like overlapping the arm tape.



I never planned for this to be a sub-250 so it's coming in a little on the heavy side with the 1408 motors and an 850mah 4S at 295g.  I really prefer a little more weight to freestyle builds though.  Sub-250 just doesn't have the momentum for that freestyle feel.



Everything is working as it should and set up for tuning.  Can't wait to get this thing tuned and rip it.  I like the Acrobrat a lot but I always found the Gecko to be noticeably more responsive and agile - likely because of it's tighter wheelbase.

Nice. I really like Armattan frames.

You packed a lot in there mate, bravo!

Nice build.
You definitely used up every cubic mm of space.
I like those stack plates.
I could have used them to mount an air unit on top of FC in my latest build.

Thanks guys.  Well I went to go tune and saw this ...



LOL dude I was so pissed.  I was so livid I declared war on this thing and wasted most of the day tracking down this issue.  I went step by step.  So Tarsier stack completely separated from the build gave clean video.  Tarsier stack placed where it should be but without screws gave clean video.  As soon as I put in so much as one screw, bad video.  I tried each screw hole and each gave bad video.  This led me to suspect something from the flight stack in the rear was being conducted through the carbon, up the front stack screws to the Tarsier stack causing the bad video.  

Since the rear stack on the Gecko has M3 holes, I tried insulating the M2 screws of that stack with heat shrink.  But no matter how much I isolated that rear stack screws, I was still getting bad video.  Then it occurred to me that there couldn't be anything conducting from that rear flight stack.  The Kakute Mini ESC did not have metal around the PCB holes.  The Kakute Mini FC used rubber grommets.

So then I tried removing the screws from the rear flight stack with the front Tarsier stack screwed in place.  I got bad video.  To be absolutely certain nothing was coming from that rear flight stack, I elevated it with foam off of the carbon fiber ... and I still got bad video.

The Tarsier stack was feeding noise to itself through the stack screws and carbon?!?!  WTF'ing F???? 

I wasn't even sure how to insulate the front stack screws since the Gecko front stack holes are M2 providing no room for heat shrink.  I tried coating the screws as well as the inside of the Tarsier PCBs with copious amounts of conformal coating which didn't work.  Tried liquid electric tape that didn't work either.  So eff it.  Out came the drill.

With the wider M3 holes in the front stack, I was able to insulate the stack screws with heat shrink.




I kept the insulation on the rear stack for good measure and cos, well, war.



You can see how it insulates the screw from the carbon fairly well ...



And waddya know ...



I'm honestly too tired at this point to be pissed at Caddx lol.  I don't know why it's doing this as it is super frigging annoying.  This is a brand new frame from a premium brand.  Yet this thing is causing itself noise wow just wow.

Since I was tearing apart and rebuilding this thing so many times to fix this issue, I decided to make some changes.  I replaced the TBS Race VTX with a Matek 5.8 Mini since I just realized it has pinio allowing powering on and off via radio switch.  It's a decent VTX and also freed up some space.



Now I can actually move the lipo strap around lol.



Also found a place for an LED.



Clearance is still good too ...



So hopefully this problem is truly fixed.  Tomorrow I'm hoping to get some tuning in that I wasn't able to today.  Man what a battle lol.  

Great news. Tuned to crystal clear video this morning lol. I'm still dumbfounded why the Tarsier is doing this. And this is a brand new Tarsier. It was doing this on a used one as well.

I'll admit to grinning quite a bit right now lol.     These little 3 inchers are just so much fun.  It does take some getting acclimated to their super leightweight though.  But for anyone that's interested here the PIDs and filters for my 3 inch Gecko build using 1408 3750KV on 4S ...





And here's what it flies like ...

Hey the.ronin, just got to check out this thread from the link you posted in my other thread. What a gorgeous build and really great video. That thing is tuned really well. Trying your PIDs and will let you know how it goes!

Side question, did you 3D print those skids? I printed some but they're a bit 'meh' wondering if you could share the .gcode and what filament and infill you used.

Thanks!

Cool I'm curious how it works out for you. I wouldn't use those filters though they are kind of aggressive.

Yes I printed the skids but I just used standard settings at 0.2 resolution and 60% infill. I don't really mess with settings too much. I used Proto Pasta carbon infused PLA.

(26-Nov-2020, 04:56 AM)the.ronin Wrote: Cool I'm curious how it works out for you.  I wouldn't use those filters though they are kind of aggressive.

Yes I printed the skids but I just used standard settings at 0.2 resolution and 60% infill.  I don't really mess with settings too much.  I used Proto Pasta carbon infused PLA.

Thanks! Yep, not touching my filters for now, thanks! Where did you get the design for the skids? Can you share a link or stl file?

Hi Ronin,

That is one SWEET build    Very clean and super nice cable management. I like how you routed the motor wires   

Nice videos     You are just too cool 

Thank you sir!!

Took the Gecko out for a quick post turkey rip this morning ... and the lines are back!! WOW!!!!!

I'll cut to the punchline. I ended up putting small plastic washers at the stack screws to further insulate the stack from the frame.



I had wondered why my Katana build which uses the same Tarsier up front and Kakute F7 Mini in back did not suffer from the same video noise issues.



It occurred to me that I had used the same small plastic washers at the Kakute stack screws. But this was not to isolate noise. I normally cut my screws to length but was too lazy this time. So I used the plastic washers to make up for the extra height. Talk about lucky irony!!



And that did it. No noise. I still used the heat shrink for good measure though although I did not use that on the Katana, so perhaps the washer is all that is needed in case others are having this issue too with their Tarsier.

[edit]

Oh yea, also swapped out the Gemfan Windancer 3028's with T-Motor 3140 triblades meant for cine whoops lol. I had these on the Acrobrat and they have noticeably way more bite. The extra "1" though makes it pretty tight tolerance on the Gecko.

This is really interesting. I wonder why we've never seen this issue reported before? Do you think it's specifically a combination of the Kakute stack and the Tarsier? I'll be putting a Tarsier in my Acrobrat frame (although it's using an HGLRC stack) so I'll be interested to see if I face the same problems. If I do then at least I'll know what the solution is, so thanks for sharing all the pain you went through and documenting the fix 

my buddy sorted out the tarsier out of his dave_c 4inch longranger, i have to reask we he did it, probably the same reason.

(28-Nov-2020, 12:53 PM)hugnosed_bat Wrote: my buddy sorted out the tarsier out of his dave_c 4inch longranger, i have to reask we he did it, probably the same reason.

May not be related to ronin's issue, but on the microlongrange, people were getting interference between the tarsier and the GPS mounted too close together.  One of the fixes (IIRC) was to isolate the tarsier's heatsink "from (carbon?) ground" somehow.  (Don't remember all the details right now - but maybe the.ronin's plastic washers and heatshrink are doing something similar.)