Sooo... I started out with an Eachine Trashcan, then got a GepRC Phantom and recently made my first own build with an Armattan Tadpole frame.

Now I'm ready to make my dream kwad with an Armattan Gecko frame! I liked it ever since I saw it in the Liftoff simulator, and I've flown it for countless virtual hours. With the Tadpole I learned that Armattan frames are totally worth the high price.

The frame got back in stock at droneshop.nl so I immediately ordered it. It'll be here in Belgium next week but to keep the total cost down I'll get my other parts from Banggood, so I'll need quite some patience before I'll be able to build and fly it

Anyway... I've spent some time trying to decide which motors and flight stack to get, and wanted to get your opinions about my choices.

For the motors I considered the T-Motor F20II, Xing X1408 and Mamba 1408 but I think I will get the GepRC GR1408. They get good reviews and I trust the GepRC brand because I love the Phantom. Surprisingly, these motors are also quite a bit cheaper than the other options. So what are your opinions? Are these motors a good choice or am I better off with a different brand?

I'm also wondering which motor KV is the best choice for the Gecko? I'll probably go with Gemfan Flash 3052 props and 4S Tattu batteries so should I get a 3500 KV or 3750 KV motor to get a decent balance between performance and efficiency?

For the flight stack I'm looking at the Mamba F405 Mini MK2. It's very affordable and I don't see why other stacks would be better?

All opinions, suggestions, do's and don'ts are welcome!

nice i like the geckoframe

all your choosen motors seems nice choices, i own the f20 II 3250kv, they are very nice. i bought 3250 as i liked to use them with 4inch, but befor the gemfan 4023 they wasnt enjoyable, i flew them with 3inch.

i would build the gecko as buddy did, with the 1306 emax. prop options are a bit rare for t-mount.
the emax 1408 could give a 6s 3inch.
i would choose the emax about value for money.
another choice could be the 1505 betafpv-rcinpower 3600kv, or even some 1404.
it should be a bit less weight over all with the t-mount option, this should result in the same performance bit higher effiviency than a high stator 1408. probably im wrong, would be my actual choice, but i fly 1408 aswell. i fly the 1505 3600kv, they are less quality than the f20, but i like the 1505 size.

on a 3inch and high stator, i would choose up to 4000kv on the azure 3060 and 650mah 4s.

blheli_32 esc would be better, but about value for money the mamba mk2 is nice.

I think Mamba F405 mini mk2 is a solid good value choice for 4S. 1408 is popular and i don't think you will get a bad one from the brands you listed.

I fly a 4 inch Gecko Caddx Vista with T Motor 1507 + Mamba F405 mini mk3 and 1300mah 4s. Gemfan 4023 props.
Solid and tough frame. Easy to build. One of my favourite quads.

Btw, I had a Trashcan and still fly Phantom and Tadpole 3".
Similar choice.... You will have fun.

Here is Gecko 4 flight from a few weeks ago.

I have used Emax 1306 and Emax 1408 for 3-4inch build. I like the 1306 for lighter 3" build but not a fan of the Emax RS
1408 motors ( heavy Acrobrat and ultralight light 4" ) super notchy, power hungry and noisy ( higher pitch buzz during flight). And with its T mount, there is limited choice of 3 inch props to make good use of its power.

TMotor F20II *all* day. Had those on 2x 3" Gecko builds. The thing screams with those motors lol.

I run the geprc 1408's. I've used the same set on multiple builds and they still perform like new even after some pretty heavy crashes. I run the 3750 kv version myself, very powerfull and fast. My flight times are fine. 5 min on a 850mah 4s or 4 on a 650mah 4s flying freestyle, no cruising.

Thank you for all the feedback guys, really appreciate it! Really cool videos also

I almost decided to go for the GepRC motors but then I read the last comments on the "GEPRC-GR1408-3500KV Thrust Tests & Overview" video on YouTube which aren't that positive. Checking the prices of the T-Motor F20II on AliExpress I found they're selling for nearly the same price as the GepRC on Banggood, so that made it easier to pick those. I ordered 5 motors just in case there's a problem with any of them; wouldn't want to wait another month just for a little problem.

Also ordered the Mamba F405 Mini MK2 stack from Banggood, it's surprisingly cheap compared to the alternatives. I'll use JEsc on the Blheli_S ESC so I don't really see why a 32-bit ESC would be better? I'm also unsure why an F7 would be needed when an F4 can get the job done. The only other FC I find intriguing are the TwinG controllers from iFlight; the double gyro should read out less oscillations. Anyway, I'm sure the Mamba will be good enough.

Can't wait for everything to arrive now

I would avoid any iFlight electronics. We've seen nothing but headaches and other troubles with them on here. You get what you pay for. Some of the new Mamba stacks also unfortunately seem to be exhibiting some of the same type of design issues. Roll the dice.

(15-Jun-2020, 11:42 AM)SnowLeopardFPV Wrote: I would avoid any iFlight electronics. We've seen nothing but headaches and other troubles with them on here....

What seems to be the issue with them? Anything in particular?
I ask because I too am putting together a Gecko build and like some more info... especially picking between 3 and 4 inch.

I intend on using:
Succex-D 20x20 F7 DJI stack
Xing 1408 3600 kv
Gemfan 3052
Caddx Vista
Crossfire Nano
Tattu 4s 650mah (already have several)

I want the smaller 3" size, but have concerns with ease of tune, weight or other flight oddities on the 3".
I'm kinda thinking I should go 4" for flexibility, but what 4" prop should I run on the 1408 motors and 4s 650s?

gemfan 4023x3

as the parts arent smaller in the middle of the frame on a 3inch, compared to a 4inch. the most 3inch quads are bigger than small 4inches. i use an exlair 3inch frame baseplate as 4inch baseplate, without props its very tiny.
https://intofpv.com/t-4%E2%80%9C-oldfashion

(16-Jun-2020, 09:35 PM)Dashunde Wrote: What seems to be the issue with them? Anything in particular?
I ask because I too am putting together a Gecko build and like some more info... especially picking between 3 and 4 inch.

I intend on using:
Succex-D 20x20 F7 DJI stack
Xing 1408 3600 kv
Gemfan 3052
Caddx Vista
Crossfire Nano
Tattu 4s 650mah (already have several)

I want the smaller 3" size, but have concerns with ease of tune, weight or other flight oddities on the 3".
I'm kinda thinking I should go 4" for flexibility, but what 4" prop should I run on the 1408 motors and 4s 650s?

Iflight seems to have some QC issues. I've had nothing but trouble. Tried multiple stacks, they all burn oit really fast or even d.o.a. Their motors are really good though.

I had the impression that iFlight is a pretty good brand, and Diatone is even better? For what it's worth I have the iFlight SucceX Micro F4 V1.5 in my Tadpole and no real complaints about it. The only thing I really miss in that one is a current meter; the stack on the GepRC Phantom has one and I can always accurately fly up to the battery's 450 mAh. On the Tadpole I have to watch the voltage but it's not always clear if there's some temporary sag or the battery is really empty.

Dashunde, I was also considering the 4" Gecko but after watching Emax Babyhawk-R Pro WHY FOUR INCHES IS BETTER THAN THREE OR FIVE  I'm sure 3" is the one for me; anything bigger would be too close to a 5" and those are really too scary to fly around at the places near me.

I received my frame yesterday and I LOVE it. In one way it's not even that much bigger than the 2.5" Tadpole, but on the other hand the carbon is thicker, it has nice M3 screws instead of fiddly M2 screws, there's the gorgeous titanium cage and there's SOOOO much more space in her belly.

sorry i like to rant: its such a bad video of jb, what a shame for fpv on general
one reason we dont have 4inch market support is because of jbs review about 4inch.
rater than give any focus what 4inch would need to provide unique benefits, he tell 4inch isnt something to enjoy. kabab tell the same about 4inch, probably you know the way how the micro market turns after his suggestion. the weight of their words for the hobby has a very ugly side.
i dont like jb as a reviewer, i like his tutorials and how he explain things.
why should any size doesnt have own unique benefits?!
everyone should proof such a crazy theory
4inch isnt more close to a five inch than to a 3inch, not as good as 5inch quad: just weired words, a theory about a propsize while trying a 4inch pnp.
hurts my 4inch soul xD
a person which doesnt fly 4inch, didnt explore the size regualary cant make decent comments about all 4inch builds. its just another payed review, from a person wouldnt try the thing if he wont receive money ;-) there was just some words fillng the minutes and not much informations, some missinformation.

the babyhawk r is a tanky 4inch racer, its an awesome piece, value for money is unbeatable. the babyhawk r doesnt represent all kind of 4inches.
the stack in the babyhawk isnt made just for the babyhawk, 6s ability isnt a buffer zone, another weired theory. against jbs words, some people can fly these 4s motors on 6s;


a review from mrshutterbug, knowledgable about various sizes of quads and props, a lover of ultralights:

there are different sort of 4inch build possibilities. if you are no racer, the only special reason about the babyhawk r 4inch would be value for money.

4inch is different than 3inch and 5inch.
its my overall favorite prop size, it has the widest range off abilities i like: accrelation, topend, nimbleness, durability.
i dont need the momentum of heavy a 5inch and i appriciate the efficiency of 4inch on high speed compared to 3inch. a 3inch can be faster in topend and accrelation than 4 or 5inch, but it has a lag in efficiency, it can provide topperformence for 30seconds. 4inch is more silent on high speed, i am able to fly more spots on high speed with my 4inches without scaring others by the noise - the opposide what jb told...

xD he told its the fastest under 250g xD
and a diatone gtr3xx has a lag on topend... he is pretty wrong with his informations
for the need of 60degree cam angle, there was no racing speed near a need of 50degree xD i can see that, i race above 50degree cam angle on my 4inch.

please dont beleive in a wild theory, every propsize have its own benefits, speciqly 4inch has a lot benefits. its just a mistake, with todays lighter parts, 4inch has a bunch of benefits. give it a try
do not make a value about 4inch until you tried different kind of 4inches.

I already got most of the parts so I started soldering, testing and configuring a bit. The motors will also arrive very soon but the 4 batteries I ordered at Banggood are still waiting to be shipped, I guess the special handling they require causes a lot of delay now during the pandemic. Unless I see a status update soon I'll probably get 2 batteries from Amazon, it won't hurt to have 6 batteries in the end

Here's everything ready for the final assembly after I get the motors:



I'm putting the ESC and FC in the back where the frame has M3 holes. This allows me to use rubber standoff grommets which provide vibration dampening between the frame and the stack M2 screws. The ESC has M2 holes while the FC has M3 holes with its own vibration dampening grommets. Hopefully this double dampening will keep vibrations seen by the gyro to a minimum.

On the top left you can see I attached the Lollipop 3 antenna with lots of shrink tube and two zip ties; it's not going anywhere. I've bent the coax to take away any stress force to the fragile UFL connector, and to align the Rush Tiny Tank VTX between the notches where the battery straps will go.

On the right there's the 25v 470µF Panasonic capacitor that came with the flight stack. I'm not entirely sure yet if I'll solder it to the top or bottom pads on the ESC, and if it'll stick out straight to the back or angled upwards. When I get my batteries I'll figure out how long the battery leads need to be and how to take care of stress relief.

Below that there's the Fullspeed Lucky Box beeper. I'm really not sure where to put it to keep its button reachable, perhaps on one of the front arms or maybe just ziptied on the back of the rear posts.

On the bottom left there's an HMDVR-S to record some analog footage. I was looking at the Runcam Split and Caddx Turtle but I read they have fairly high latency, so for now I'm going to stick with this simple SD recorder. I originally got it for my Tadpole but it doesn't fit anywhere within the frame and I only made one video after temporarily attaching it to the bottom of the frame.

There's a FlySky X14S waiting to find a good spot somewhere in the front (probably between the motor wires and then the recorder on top of those). I've updated the firmware with a modded version which provides RSSI information. This receiver doesn't support telemetry like the Oversky XR602T-A I used in the Tadpole, but it should give me more signal range, which is much more important. After setting it up in Betaflight it turned out that the channel values were slightly shifted; they ranged from 1030, over 1519 in the middle and 2008 at full stick deflection. I'm not sure why this is, but it can easily be fixed with "rxrange {0-3} 1030 2008" lines in the config.

The hot red Gemfan Flash 3052 is eager to get a spin and the bright yellow Caddx Ratel will be my eye in the sky. It's the 1.66mm lens version which works best for the 16:9 aspect ratio of my €5 SKY01 goggles.

So... hope to finish the build by next week and if the weather gods here realize it's actually summertime I might give this Gecko her maiden flight

@L0stB1t ; I am looking forward to your finished build and flight videos.

@the.ronin ; Is the "Rockafeller Skank Remix [Armattan Gecko 139]" a 3 inch? Also, what are the specs on F20II motors?

I have a TomoQuads Katana 2 ( 4 inch) frame that I am collecting parts for; will post build thread when I get there.

Although I am still testing (actually just barely started) with my Phantom projects (especially the Phantom-X) and a Flywoo XBot 3, I believe the 4 inch platform to be be where I settle in for long range. I am not sure that you gain anything by going up to 5 inch in the sub 250g category, but we will see. 

One the other hand I really like flying the 2.5 inch and 3 inch quads; they are just plain fun. For the money, it is hard to beat the GEPRC Phantom. In fact, it costs more to buy the same parts and build it yourself. 

Regarding electronics:  I have been well pleased with the GEPRC 16x16 stacks and AIO products (26x26 whoop style). I have not had any issues and the tune is pretty decent right out of the box. I do have one quad, Phantom-i, with the iFlight SucceX 16x16 stack (with motor connectors on the ESC). Except that the orientation of the connectors could be better, the quad flies good on the stock tune and so far I have had no issues with it; time will tell. Thing is, these are all in the 12A to 15A range so might be a bit small for the requirements of a 4 inch build.

I am also considering the Flywoo stack. I have an XBot 3 which has been pretty impressive. I thought it was a little clunky at first, but I believe I damaged a motor on one of the first flights. Once I discovered it and changed the motor (yes, I always try to have spare motors), it flies really well. We will see how it holds up over time.

Also, I agree that the less-than-positive comments from JB and KababFPV about the 4 inch format do carry some weight. I believe things will change as the 4 inch size becomes more popular; especially given the forthcoming FAA regulations.