I realised that I don't have a good 4" build in my collection any more (apart from my Armattan Hexacopter) so I was thinking of building a new one based on the Brotherhobby Tornado T1 1407 motors.


Looking around, it seems that a lot of 4" frames have 16/19mm motor mounting holes instead of the 12mm that I need for the 1407 motors.

Can anyone recommend a good 4" frame?

I can ABSOLUTELY recommend the Garage Crab from Falcon Multirotors.
http://falconmultirotors.com/garagecrab.html

I have 2 of them now. One running 1306 4000kv motors with biblade props and one running 1707 3200kv with triblade props. The most common motor used with them is the 1407 though.

This frame is superb. Amazing quality carbon. TONS of hardware. Can be built with a regular 30x30 stack or a 20x20 stack. It comes with a carbon fiber top plate, but you can also get a 3d printed pod (that ONLY works with a 20x20 stack) for weight saving and speed.

This frame was built to be a race quad, specifically for racing in parking garages, so it is both fast and VERY durable. I think, to date, one person has reported a broken bottom plate to the designer.

Check out the race video in here to see some insane speed on 1407s.

If, for some reason, you wanted to be able to also try out larger motors, they recently came out with the Kingcrab, which is basically the same frame, but slightly more carbon and reworked motor holes to be able to do up to 22xx motors (but still only 4").

I ADORE my crabs. I have known multiple people who have completely switched to these for racing, even competing with and beating 5" quads. A crab on 1407s only lacks in top end and long straights, but it's ability to punch out of corners more than makes up for it.

And did I mention durability? I have used mine for racing and freestyle. I've used both the carbon fiber top plate and the 3d printed pod and have abused these things, and they're just fine. The only thing I've ever broken on them is battery leads during crashes.

At my last race, I broke my 5" quad at the beginning of the day. I used my 1306 running crab for the rest of the day in both the 4" and 5" class and had a blast.

Get some crabs man!

Nice frame! Shame the only places that sell it are in the USA.

Have you had a look at the 4" Armattan Japalura? I have the 3" version and although it's not exactly a lightweight, it's basically indestructible. I love the design too, it's basically a baby Chameleon

http://www.armattanquads.com/japalura-4/

I've been eyeing the 4" Japalura for the best part of the day...

I'm a big fan of Armattan frames and I'm seriously tempted. I can even order one from the UK and have it shipped via DHL so that I can avoid the disaster that is the Swedish post office. By all accounts, you're suffering the same way in Canada when it comes to the post.

I just put in a big order with Banggood and paid extra for expedited shipping just so I can avoid the months of uncertainty that entrusting anything to the local postal services means these days.

I have the Japalura on the bench getting build right now.

I also looked into the geprc LX4 or LSX4 when I was researching. I ended up with the Sparrow because I didn't have a 3 inch.

I did look at the GEPRC LX4, but they were out of stock. I didn't much like the look of the LXS4, so I passed on that one.

So, I now have a silver 4" Japalura on the way to me from the UK! It should match the silver BH 1407 motors nicely.

What will you be putting in yours? I know there's going to be a Runcam split in mine, but I'm unsure about the flight controller at the moment. The receiver will be a FrSky XSR. Seeing as they are so cheap now, I put a couple in my order from Banggood. For the VTX, I have one of the new Matek boards coming.

Do you think there's room for a three board stack?

I was wondering whether it would be worth only using the 30.5mm mounting for the split board and using the 20x20mm for the FC etc?

(06-Sep-2017, 05:59 PM)Tom BD Bad Wrote: I was wondering whether it would be worth only using the 30.5mm mounting for the split board and using the 20x20mm for the FC etc?

Possibly, but I'm starting to think that the ultimate flight controller for the Japalura might be the KISS CC (https://flyduino.net/KISS-CompactCTRL-CC-All-in-One_1)

Being able to get an F3 flight controller with 4 16A ESCs on one board that will fit nicely into the frame might just tick all the boxes for me. It's not cheap though!

I decided to take a chance on this:



A StarF4S from Racerstar. F4 processor, Betaflight OSD, BLHeli_S 30A 4-in-1 ESC, current sensor, 5V 3A switched mode BEC.

As I won't be pulling anything like 30A per corner or anything like 3A on 5V, I reckon it has a good chance of working!

The only thing missing is a black box recorder, but if I need to do some logging, I can always plug in an OpenLager when needed. It does get me back to a two board stack though, even with the Runcam Split. I'm looking forward to this build already!

(06-Sep-2017, 04:11 PM)unseen Wrote: I did look at the GEPRC LX4, but they were out of stock. I didn't much like the look of the LXS4, so I passed on that one.

So, I now have a silver 4" Japalura on the way to me from the UK! It should match the silver BH 1407 motors nicely.

What will you be putting in yours? I know there's going to be a Runcam split in mine, but I'm unsure about the flight controller at the moment. The receiver will be a FrSky XSR. Seeing as they are so cheap now, I put a couple in my order from Banggood. For the VTX, I have one of the new Matek boards coming.

Do you think there's room for a three board stack?

FC: CL Racing F4 ( I have to say a well layout FC.)
Motor: 1407 Oomph
VTX: TBS Unify Race HV on top of the Whitenoise board with XSR on the bottom side.  Just enough room for the FC with soft mount second tier.  Three boards might be not be possible if you put the XSR in the stack.  But your VTX is thinner than mine, so maybe possible if XSR is somewhere else.  There is a lot more height than the Chameleon.
Camera: Runcam Swift 2
ESC: Spedix GS30 BLHeli 32 (overkill but they are so small, I said why not)

That's a nice selection of parts. I'd be interested to hear what you think of the CLR F4 when you have everything finished. The onboard buzzer is an interesting idea, but I hear that the IMU gets affected by it when it makes a noise, which could be a problem if it's being used as a low battery alarm. Otherwise, I agree that it looks like a well laid out and fully featured flight controller. The price is excellent too!

I'm a little worried about the Racerstar board that I've ordered. The IMU is just 2mm away from the inductor that's used in the onboard BEC, but hopefully the regulator's switching frequency is high enough that the IMU won't be affected by the resulting magnetic field around the inductor.

Hopefully, all my parts will be here next week and I might actually get a chance to maiden the Japalura before the winter starts!

Good luck with your build. Will you be making a build thread here?

I will probably not make a build thread. I am so busy with life, that sometimes I don't have the time to continously build. This thing can sit on my bench for months before I finish. You will likely complete before me. I will consider taking pictures and sharing when I finish.

What batteries are you considering? I am thinking 850-1000 but have not figured out brand yet.

I guess the build thread is down to me then!

For something this size, I'd say that 850mA/h is the largest that will give good performance without making the quad handle like a bus.

I have a couple of Turnigy Nanotech 850mA/h 4S 45-90C batteries already that I'll be trying out on the Japalura. I'm not expecting a current draw over 15A per corner with 4045 two bladed props, so that's well within the battery's capabilities.

The Turnigy Graphene 850mA/h 4S 65C batteries might also be a good choice as they have much thicker wires (only 18AWG on the Nanotech ones which is really too small) and are very durable, which is always a good thing for a bottom mounted battery. They do come with a 12g weight penalty and a €5 price penalty though compared to the Nanotechs.

In case you're trying to decide what FPV setup to go with, the Tramp fits perfectly