Howdy all, I've finally got around to post a build log of the new addition to my fleet. For a long time I wanted to build a 3" - mainly because of Kaity's countless mentions on how fun those little guys are. Also I wanted something I can fly around smaller parks & gardens.

So let's start with the parts list:
Frame: Armattan Gecko 3"
FC+ESC: Mamba F405 Mini FC + ESC stack
Motors: HGLRC Flame 1407 3600KV
Camera: Caddx Turtle V2
VTX: AKK Nano 2 (the one I won in a contest here, thanks again Oscar!) with Lollipop V2 Super Mini antenna
Receiver: Frsky R-XSR


Yeah, I think it will fly 

Let's start with the frame. It comes in a simple plastic bag where different parts are divided in their own compartments. Frame is super simple to build, just a couple of screws to hold it together.


First I tried to dry-fit the main boards (FC+ESC and Turtle board). This frame is supposed to be designed to easily fit both of them, but boy is it tight.
Rotating the Caddx board 180 degrees was not possible as I wanted to use the connector and that would not fit at all.


You can also see those funny standoffs the Caddx board is sitting at. Unfortunately I don't have any M2 plastic hardware and the board didn't came with any, so I had to be creative. I got some antenna tubes which turned out to be just wide enough and soft enough that you can screw an M2 screw through them. So I cut standoffs out of those. Doesn't look the nicest but hey, if it works it ain't stupid


Let's start with soldering things up. Motor wires and XT60 soldered up, nothing burning, yay!



Wired up camera and confirmed it lights up (but not in flames). I also routed a camera extension cable through the bottom of the frame.


Receiver goes under the main stack as the standoffs are quite tall and it fits nicely.


Originally I had the RX flashed with F.Port firmware and tried to use TX6 on the FC, but I had no success. Later on I found that it seems that only the TX3 would work with F.Port, but since that was also reserved for the SmartAudio, I had to change my strategy. Decided to flash the RX with the normal SBUS firmware and use a dedicated wire for the SmartPort telemetry (using the uninverted signal hack).


Next one I threw a VTX in there, wired up and confirmed that it is working, including the SmartAudio.


I also really wanted to fit a Vifly Finder 2 buzzer as the quad is kinda small and finding even a 5" in a all grass after my battery ejected was hell. The space is soooo tight, but I managed to squeeze it behind the camera. It prevents the camera from tilting to a high angle, but I guess I'm okay with the allowed range (so far).
You can also see the way the VTX is mounted. Just thrown on top of the camera board. This is actually a very bad design as both VTX and camera board get hot and after a while sitting on the bench the camera actually shut down because of overheating (it even said so in the camera OSD). I will redo this once my M2 hardware arrives, probably 3D printing some sort of platform to put the VTX on top of the camera board.


Another tricky part - how to mount the antenna. This frame is designed to have the antenna coming from over the main stack, but since the stack is so tall, it doesn't fit. I routed the UFL to SMA extension through the bottom and originally intended to have it sticking out from the back like I have it set up on my 5" quads (see https://intofpv.com/t-iflight-ix5-v3-the...d_49597-10), but I couldn't secure it properly using zipties there. So then I decided to mount it to the back aluminium frame standoff. It seems to be working quite well. Let's see how well does it hold in crashes... 
RX antennas are mounted on the arms using zipties, this proved to be a solid and secure way on my other quads.
Here's a pretty much a finished product.


And here's the fully completed build with the 850mAh battery sitting on top. It's kinda huge compared to the frame size


And lastly, two pictures with the whole fleet. Looks like a small happy family 



I've already did the maiden flight last week, just a single pack. Stock Betaflight 3.5.7. Doesn't fly bad, but not great - a lot of jello on hard throttle, a lot of propwash. I did some adjustments in Betaflight but am still waiting to try it out. Wanted to do it yesterday, but I've travelled to visit my parents in Czech republic for the Easter, and even though I brought all my gear, I forgot the charging cable at home... Gotta buy it later today in a local hobby shop.

Thank you for your attention 

Nice build!

I've got a lot of the same guts (Mamba Mini stack and Turtle V2) going into an Acrobrat in the next few weeks. I've done a test fit and had the same problem on spacing, so I think I'm going to spin the Mamba 180 degrees so the connectors don't foul on each other.

I was thinking about that, but I guess that at least on this frame, the XT60 pigtail and the capacitor wouldn't fit. But it's fine, I put a piece of tape between the Mamba wires and the Caddx board so that the Caddx board doesn't cut it and it seems to work just fine. I should also move the Caddx board a bit higher because now it's really difficult to remove the SD card since there are motor wires right under it. But again, I have to wait for the M2 hardware...
Anyway, looking forward to see your Acrobrat build log!

Nice looking build.

That's a great build. I'm using the same motors on my Acrobrat but with a different flight stack. I would be very interested to know what the AUW is with and without the 850mAh Lipo because I want to use those capacity LiPos on my Acrobrat but was worried about how those motors would manage with all that weight. Apart from the jello and propwash, if the handling is generally fine otherwise then 850's seem to be a goer on a 3" frame.

Thanks guys. Unfortunately I don't have a scale at hand, but I might get around one later this week. Hopefully I'll remember to measure the weight then.
I also have a few 650mAh Ministars, so I'll measure the weight with that one too. I haven't tried flying the 650mAh yet because of the forgotten charging cable, but I'm hoping to try it tomorrow.

OK, thanks. When you are able to take some weight readings it would be good to know.

What props are you running there? Are they the DAL Cyclone T3056C? I've got some DYS 3045 bull nose props for my Acrobrat but they don't look aggressive enough for my liking so I might need to have a rethink. I got the DYS props because they were the only 3" props I could find in transparent orange which was going to be one of my colour themes. I think I might need to use a different theme because the 3" Cyclones, Gemfans, and Azure Power props look much better, but none of those come in orange.

I guess I could weigh it tomorrow evening or Thursday during the day earliest.

I'm running the DAL T3056C currently and I also have some Gemfan Flash 3052 but I haven't tried those yet. The Cyclones are definitely aggressive enough for me, they just scream, I like it. I also did some tuning to the quad, played around with PIDs and filters (mostly according to the BF wiki recommendations plus some other guys' posts) and the difference is night and day. Jello on punchouts is gone, most of the propwash too. Just a little propwash on hard accelerating forward from a backwards flight, but nothing too dramatic.

What I am really disappointed though is the Caddx Turtle FPV feed quality. It's so bad compared to for example the Caddx Micro F1. Takes forever to change expo from sky to ground, not that much detail, just blah. I was flying today during sunset, so hopefully it will be better during the day. Well, at least the HD footage is quite nice.

I also tried the 650mAh battery and I have to say I can definitely feel the difference in weight. It flies great on the 850mAh, but on 650mAh it's a rocket. I was planning to fly around my parent's house garden, but now I'm afraid it will be rather handful to handle

(16-Apr-2019, 08:08 PM)izzy26 Wrote: I guess I could weigh it tomorrow evening or Thursday during the day earliest.

I'm running the DAL T3056C currently and I also have some Gemfan Flash 3052 but I haven't tried those yet. The Cyclones are definitely aggressive enough for me, they just scream, I like it. I also did some tuning to the quad, played around with PIDs and filters (mostly according to the BF wiki recommendations plus some other guys' posts) and the difference is night and day. Jello on punchouts is gone, most of the propwash too. Just a little propwash on hard accelerating forward from a backwards flight, but nothing too dramatic.

What I am really disappointed though is the Caddx Turtle FPV feed quality. It's so bad compared to for example the Caddx Micro F1. Takes forever to change expo from sky to ground, not that much detail, just blah. I was flying today during sunset, so hopefully it will be better during the day. Well, at least the HD footage is quite nice.

I also tried the 650mAh battery and I have to say I can definitely feel the difference in weight. It flies great on the 850mAh, but on 650mAh it's a rocket. I was planning to fly around my parent's house garden, but now I'm afraid it will be rather handful to handle

Yes, I think I will swap my prop choice to either the Cyclones of the Gemfans. If they work as well as you say with those motors then it sounds like a better choice.

That's not good to hear about the camera. I have the same camera but obviously haven't used it yet. Maybe there is a firmware update available that might fix the issues (?) I did wonder why some people fit dual cameras to the Acrobrat, so that is maybe one of the reasons why (example HERE).

It sounds like it's probably a good plan to have a mix of both 650mAh and 850mAh LiPo's depending on your mood so maybe I'll do that.

Yeah I was also thinking about dual camera setup already, but the space is rather limited on Gecko, so I don't know. Anyway, let's see how does it perform in a long run, maybe I'll get used to it.

I have been flying the Lumenier 3x4x3 props spinning on 1407-3600kv motors as well. They are the best I have found so far for my Japalura. It appears they are phasing them out (go figure), but the pink ones are available still. Just have to find the ones that work for your build best and that can vary from craft to craft.

These little ones tend to be sensitive to smaller weight gains and 10 grams can mean the difference between awesome and WTF flight characteristics.