Building The Tarot TL250A Mini FPV Frame

An unfortunate incident with my 250 quad and a goalpost gave me a good reason to get building with this frame. Here are a few of the highlights of my afternoon and how I found the frame to work with.

Like many other people, I wasn't interested in buying any of the proprietary components from Tarot (camera, VTX, OSD-GPS, etc.) as I've already got parts which I want to reuse. I pretty much transferred everything from my old quad straight onto this frame:

Naze32 flight controller (full)
12A Ultra Light AfroESCs
Emax 1806 2280kv motors
- OrangeRX R615X receiver (case removed)
- TS351 video transmitter + clover leaf antenna
Mobius ActionCam
Turnigy nano-tech 45C 1500mAh LiPo


In addition to the parts I already had, I also swapped out my FatShark 600TVL CMOS camera for a HS1177 board camera and upgraded to some tasty Emax (probably re-branded Gemfan) 6030 carbon fibre props - the option to use 6" props on this frame was one of the reasons I bought it. 

I'm certain plenty of people will want to mount a Mobius to this frame and I wanted to as well. Tarot definitely didn't design the frame with this in mind which is absolutely their prerogative, it's designed to be a light FPV racer with bags of power. Don't worry though, it's definitely possible 


The obvious first step was to swap the XT60 connector for the correct gender. It's not much trouble but I found myself rolling my eyes from the outset, wondering whether Tarot had opened up the production line for high school Work Experience week. Anyway, I took the old connector off and mounted the new on the underside of the PDB since I wanted to under-sling the battery rather than top-mount it:

Tarot TL250A Mini FPV Frame

* * * MISSED A FEW ASSEMBLY STEPS HERE - COULDN'T HOLD CAMERA AT THE SAME TIME AS STABBING PALM WITH HEX DRIVER * * *

As many other people have found, the frame's fits together like a low tolerance Tetris flavoured sandwich. Holes are off, mounting points are virtually non-existent for non-proprietary components and solder pads are tiny/irregular. It all fits but only just and it's certainly not as enjoyable an experience as I've had with the larger Tarot frames. That being said, despite its diminutive proportions, once it's assembled the whole whole things feels solid and I have no worries about it falling apart (which is good because I don't fancy putting it together again in a hurry).

I ended up using the PDB for ESC and motor connections only, everything else I ignored - if you don't want to use the rest of it you don't have to. Once I'd managed to wrap my head around the correlation between the Tarot motor numbering convention and the Naze32's (hint: there isn't one), I soldered the two supplied servo wires onto the ESC connection points. Signal wires connected to all four ESCs, power and ground connected to just one as Tarot (quite rightly) recommend. If you're planning on soldering header pins onto these connection points, forget it. The frame's forward arm would foul half of the pins sticking up here - another Work Experience Week moment from Tarot:

Tarot TL250A Mini FPV Frame

As you can see, I was very clever and labelled the servo wires appropriately. What wasn't so clever was realising that they were to short to reach my Naze32 in the middle of the frame. Time to warm up the soldering iron again and grab some longer wire:

Tarot TL250A Mini FPV Frame

I initially soldered the wires from my FatShark CMOS camera to the relevant pads on the front of the PDB (as intended by Tarot). The traces run towards the aft of the frame and I intended to break them out (signal wire to my VTX and the power wires to my Naze32 ESC/Servo headers (5V)). The wires however kept snapping at the solder points due to stresses and so I opted to use a 12V board camera (HS1177) which we had in stock instead. The FatShark CMOS camera had performed admirably but as well as needing a 5V power source, it had always been a nightmare to mount. The HS177 however can run straight off the battery and comes in a cracking little case which lets you tilt it up for fast forward flight.

The board cam's case bracket can actually be mounted directly onto the forward silver spar which would be a good option other than being a little exposed and leaving no options for mounting a Mobius. I decided to move the forward battery stay to the underside of the frame and used the centre hex screw to hold down the board cam's case bracket:

Tarot TL250A Mini FPV Frame

The camera is now well behind the front of the frame and needs no additional mounting fixtures, the included square camera mount plate can also be discarded. With 6" props the clearance is 4-5mm:

 

Tarot TL250A Mini FPV Frame

Tarot TL250A Mini FPV Frame

The Emax 1806 motors went on without a hitch. Both the 12mm and 16mm pitch mounting points were accessible so I opted for the wider spaced 16mm pitch holes (these were admittedly right on the extremities of the motor mount slots in the frame arms but they do fit):

Tarot TL250A Mini FPV Frame

If I'm unhappiest about anything it would be the tidiness of the ESC mounting. I don't have any desire to shorten the ESC or motor wires as this would likely make them useless in another build but I'm well aware of how messy they look. At least they're functional though:

Tarot TL250A Mini FPV Frame

Here's how it was looking before a coffee break:

Tarot TL250A Mini FPV Frame

Next job was to mount the TS351 VTX - it's a little on the heavy side for this sort of build and if I was being picky I'd swap it for the lighter TS5823. Unfortunately though it's January and I can't justify shelling out the best part of £30 to shave off 17g. It's just mounted with self adhesive foam for now - once I've worked out where to run a cable tie or two, I'll get it secured more convincingly:

Tarot TL250A Mini FPV Frame

R615X receiver mounted on top behind the Naze32 - case removed and wrapped in kapton tape. Also added the circular polarized antenna to the VTX. You can see the aft prop clearance nicely in this picture - don't worry, they aren't as close as they look:

Tarot TL250A Mini FPV Frame

With all the essentials happily in their new homes, I was left with a lovely little spot at the front of the frame for the Mobius: You can see that a 1500mAh LiPo fits nicely between my VTX and Mobius - the CG is bang on centre too.

Tarot TL250A Mini FPV Frame

Tarot TL250A Mini FPV Frame

The Mobius' mounting sleeve is stuck down in front of the battery and mounted upside down (I'll flip the video in the firmware). I'll be honest, it's definitely exposed and although the sleeve is a good tight fit, it's not impossible for the camera to come out. It's also got minimal vibration isolation. When I've got a little more time I'll revisit this issue and try to fabricate a vibration isolated plate for a more permanent mounting solution. It will do for now though.

Final Thoughts:
The frame is pretty frustrating to put together with some questionable design choices and if you want to mount anything other than Tarot's own line of parts you'll need to think a little outside the box. Not only are there few/no alternative mounting holes, there is barely any available material to drill your own. 

Don't take all this the wrong way though, I actually really like the frame. I don't see how it could weigh any less, it's a solid construction with high quality materials and aesthetically speaking it's a stunning breath of fresh air. I can't wait for the weather to improve so I can get this quad in the air but until then, here are a few pictures of the final build:

Tarot TL250A Mini FPV Frame



Tarot TL250A Mini FPV Frame

 

Tarot TL250A Mini FPV Frame

Tarot TL250A Mini FPV Frame

Tarot TL250A Mini FPV Frame

Tarot TL250A Mini FPV Frame

Total weight including Mobius = 494g

Tarot TL250A Mini FPV Frame

Leave your comment
Comments
1/4/2015 1:48 PM
Hi,

I have a few questions prior to building this frame up..

Can you confirm if there would be enough room on the top section (where your security cam is located) to fit a GoPro between the props? (All your photos show the props facing forward)

I was also planning on using the space in between the top plate and the PCB bottom plate as a place to mount the esc's (would extend the cables from the motors). It seams to be wasted space. Perhaps the naze32 would fit into that gap too?

I love the compact design but really want everything as out of the way as possible!

There i'snt much in the way of info on these frames yet. What are your thoughts on the stiffness and durability of the arms?

Looking forward to your feedback!
Thanks

Tom
1/4/2015 1:54 PM
UPDATE: Apologies, it seams like the page hadn't rendered properly first time round. I can now see the section posted regarding prop clearance and the additional photos.

Thanks again for a great write-up!

Tom
1/5/2015 9:09 AM
Hi Tom,

No a GoPro will not fit on this frame, definitely not between 6" props anyway. It's possible that you could mount it to the front of the frame but it would be really exposed and the mechanics of mounting it might be a little tricky.

The space between the PDB and the top plate is ~3.75mm, it would be really tight to get your ESCs under there and I would say impossible to get a Naze32 in there.

In regard to the stiffness and durability, I can't really say with much conviction. It feels pretty solid but I haven't been able to fly it yet. I was a little spoilt with my last quad, it didn't need any PID tuning at all - this one certainly will do though!

Dave
6/13/2015 5:53 PM
Thanks a lot for this steps, it raised a point that puzzled me for a while: why do you put the FC in the center?

From the design of the frame, I believe the FC is meant to be mount in the front, I have done that for my Tarot 205 as well, however the result is just pool, the QuadCopter keep pitch forward badly, tried CC3d and NAZE32, both have the same problem.

for all of my research I believe that the FC does not have to be the CG, is that true? and I see you placed the FC in the middle of the frame regardless of the design, any particular reason for it?

thanks a lot in advance!
Dell