Catalyst Machineworks Merica 3 - RC Groups
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Jan 08, 2018, 07:14 PM
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flydynamics's Avatar
Discussion

Catalyst Machineworks Merica 3


After the Merica 5 that was apparently well received by the community and the awesomely amazing Merica 4 (I like the new generation of 4" frame since I started to test them almost 2 years ago), I couldn't pass on the Merica 3 (If you prefer to use 3.5" props, there's enough clearance for them).

This build will be way different than my previous 3" experiences as I won't chase the tenth of gram but go for a basic powerful set-up on 4S to see if different is good sometimes
The huge improvement on 3" prop designs and their diversity as well as their relatively reasonable price and the profusion of small 4S capacity packs convinced me to try this option.

This thread will live until the maiden next week-end and will then be available for every Merica 3 owners / future owners to share knowledge on this little beast.

Set-up used:
Merica 3 (Of course )
BH 1407-3600Kv
Cicada 20A opto (not ideal as no BEC but since I have it and I'm not chasing grams)
5V micro regulator
Xracer V3.1
XM+
Runcam micro
VTx03
HQ 3x4x3
4S 650-850mA



The frame follows the same philosophy as the Merica 4 and 5. Light, solid, easy to work on, fun, cool. Replacing an arm takes literally 2 minute. On the Merica 3, arms are extremely short and probably even more durable that on its big brothers since they are 4mm thick !
Price of a spare arm, is 3.5USD.
Dry frame weight with all included fasteners and canopy comes to 42g. Not the lightest, indeed, the SL3 comes at 25g, however it seems to be light compare to a popular Jalapura that shows 57.4g on the scale

The flight controller and FPV camera are mounted to the TPU canopy. You read that correct.
The FC is NOT mounted to the carbon fiber frame. Mounting the FC to the TPU canopy means that any board you choose is soft mounted by default.
The canopy is made of TPU and the quality of the printing is absolutely perfect.
The FPV camera is mounted at the top of the canopy. This mounting scenario helps to dampen vibration before it reaches your camera.

There is plenty of space to fit 'standard sized' components with 30.5mm x 30.5mm mounting holes. There are also 20mm x 20mm mounting holes if you decide to save a few grams.

Last but not the least, the price. 45.99USD frame + 13.99USD for the canopy which makes the frame + canopy at 59.98USD, not bad at all for the Catalyst Machineworks quality and service you get from the W brothers . You get what you pay for and MORE!

Some pics and I'm getting back to building
Last edited by flydynamics; Jan 08, 2018 at 09:17 PM.
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Jan 08, 2018, 10:03 PM
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Installation of motors and test fit of props + canopy
You'll notice that the purple canopy is not clean as it intensively used on the Merica 5 before I switched to the GoPro Session canopy + it's Session mount.
Jan 11, 2018, 09:45 PM
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More details on the build tomorrow.

The little demon is ready to rock'n roll
Jan 11, 2018, 11:40 PM
Forward ever, backward never!
Brainstorm's Avatar
It really does look daemonic with those big claws and single eye!

It seems like 4" props could almost fit, certainly 3.5" props. Or is that an optical illusion due the perspective of your photo?

I'll be curious to hear how AUW on the 3" build compares to AUW of your Merica 4". My suspicion is that AUW will be quite close, and that 4" will have better "floaty" feeling (lower disc loading). But your real-life testing and feedback will obviously be more relevant than my speculation!
Last edited by Brainstorm; Jan 11, 2018 at 11:45 PM.
Jan 12, 2018, 09:43 AM
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Quote:
Originally Posted by Brainstorm
It really does look daemonic with those big claws and single eye!

It seems like 4" props could almost fit, certainly 3.5" props. Or is that an optical illusion due the perspective of your photo?

I'll be curious to hear how AUW on the 3" build compares to AUW of your Merica 4". My suspicion is that AUW will be quite close, and that 4" will have better "floaty" feeling (lower disc loading). But your real-life testing and feedback will obviously be more relevant than my speculation!
You're right in mostly everything you wrote.
The frame accepts, with margin, 3.5" props.
Weight is 161g before pack, keep in mind I use a 5V micro regulator as my 4in1 ESC doesn't have any BEC and this add a good 5g with cables, heat shrink, double sided tape.
Merica 4 is 169g with bigger props

I think you could save another 5g which could give you a Merica 3 15g lighter than the 4.

the other option is to use lighter motors as the 1407-3600Kv are a bit too much for a 3" machine. The new Emax 1106-7500kv motors would be a very good option, I think. It would remove another 15g on motors giving you a good 30g difference between 3 and 4. I think it would be the sweet spot.
Waiting for a set to try later
Last edited by flydynamics; Jan 12, 2018 at 10:28 AM.
Jan 12, 2018, 10:25 AM
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Some pictures of the build.
Nothing very complicated; build starts from the bottom to the top and with some little planning it's going to be fast. it took me 1h45 to complete it but I also build a Merica 5, and Merica 4 previously.

To build a Merica frame you will have to assemble the arms on the bottom plate without the top plate; make sure your arms are in position.
Once that done, install you 4in1 ESC; allow some room under it to pass a strap to hold your pack in place. Strap will be added at the end of the build.
Cut and solder motor cables to the 4in1 ESC.
In my case I needed to solder an voltage regulator to power the FC and VTx since no BEC on my 4in1 ESC.
Install the receiver and test fit Voltage reg + Rx. Once position of them Ok, use double sided tape to secure them in place.
Once that done, remove the screws from the arms and bottom plate to build the frame properly with its top plate sandwiching the arms; make sure your arms are in position.
Route the ESC cables to the top and solder ESC, Rx and FC power cables (5V BEC or 5V from voltage regulator) to FC, keep a little bit of margin to be able to remove your canopy (Remember the FC is in the canopy) for eventual maintenance.
Lock XT60 cable using the tongue on the back of top plate. this will protect your 4in1 ESC pads from being pulled away if you crash and your power cable got pulled.
Install Camera in canopy
Fire up the electronics with a LiPo (I don't mean get everything in fire ) and check if your radio Rx is properly bound to your transmitter.
Check that the Vtx is transmitting on the frequency you want and check if the camera feed is OK. Once done, unplug the LiPo.
Use double sided tape and tape the Vtx in the canopy or, better way imo, on what will be the up side of the Fc once in the canopy (For most, I bet it will be the bottom of the FC )
Lock the FC in the canopy.
Test fit if you can put the canopy on your frame, if yes, good, lock it with the 4 screws. If not, arrange the cable to have a better fit.
Lock of route the VTx antenna far from the prop.
Use whatever you're familiar with on the bottom of the frame to secure pack and slide the velcro strap.
You're done

DVR should be ready by the end of the WE
Last edited by flydynamics; Jan 12, 2018 at 08:43 PM.
Jan 16, 2018, 09:07 PM
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Quick video of the maiden. since it's -50 million in Canada, indoor only.

45 seconds of Merica 3 (0 min 48 sec)


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