Good, Better, BEST.

By ThumbzFPV on Apr 02, 2019

25  874  20

Hey guys, I'm just a few days late on this build log (promised the guys over on r/multicopter that it'd be done sooner) but here it is. This is 1 of 2 identical builds for this racing season. The basic rundown of what's different between this and my other ARX-R V2 is this.
**1. This is 5" not 6"

  1. Ditched the enamel wires (I didn't have the patience to do them this time)
  2. BLHeli32 on this
  3. Full size VTX
  4. MUCH stronger
  5. Teensy bit lighter**

I can't say enough good things about this frame and I don't see my opinion changing. This quad is flying on DEAD STOCK BF 3.5.1 and is 100% locked in with ZERO propwash. I don't know what it is about this frame geometry, but it just doesn't have propwash. It is incredibly sharp and responsive due to the very low mass in the arms, and is also very efficient because of the low cross section of the arms. The carbon on this thing is only 2mm thick. I can't name a single frame that has 4mm wide arms that I would trust to race. But I'm so condifent in this frame that I got two of them XD

I forgot to take pictures of what's included in the entire frame kit for the ARX-R, but I assume that what I received will be the standard kit sent to everyone else.

I received 8 spars (makes up for four arms), 2 center plates (identical), a full hardware kit, O-rings for mounting the canopy and holding the battery on, TPU battery pad (works shockingly well, and is form-fitted), zip ties, and a canopy. I know that the canopy is available on Thingiverse if you want to save a few bucks by printing it yourself, but the quality of the print I received was very good, The canopy is smooth with no lifting of layers that I could see.

Also, note that Ryan's 5" frames are currently sold out, but he will shipping out orders on approx. the 6th.

Assembling the frame is fairly easy, and is an absolute breeze compared to the previous iterations of the frame.
Here's a quick view of all the carbon that you'll be using, excluding the motor mountsAlt Tag

Before you start you'll want to mount your stack screws now, as you won't be able to get to them later on.Alt Tag

Your next task is to slot the arms onto the center plates. The method for this is made self-apparent when you have the materials in fornt of you, but for those of you who don't it's sort of and "insert, pivot, hold" process. The arms must all be mounted in an alternating over-under pattern. Each arm (made of two spars) should have one "over" and one "under" spar. I found it useful to use the small rubber bands in the kit to hold tension on the arms while dry-fitting, so that they don't fall out.Alt TagAlt Tag

Next up is the motor mounts. These have two pieces to them. A 2.5mm (I presume) bottom mount plate with countersunk screw holes, and a 1mm top plate. Go ahead and mount these onto the arms and the tension in the arms will keep them in place.Alt TagAlt Tag

Alt Tag
The way the rest of this works is pretty obvious, mount your electronics, solder everything up, and try to stay reasonably tidy. Too much spare wiring will take up space that could be used by components, and to to aid in cooling. In this frame space is an absolute premium so you must be tidy. I hard mounted my RX and I should have gone with a nano sized VTX, but alas. I did manage to get everything to fit, but it is very, very tight. My VTX is entirely to blame.

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Photos

Discussion

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cptandy   May 10, 2019  

Do you find a difference between the flight characteristics of the 5in and 6in?

ThumbzFPV   May 10, 2019 
2

If all else is equal, and you transfer electronics from a 5" to a 6" then the 6" will feel like it has a little more control authority. But this is prely due to increased torque on the frame that each motor can produce due to the fact that it is placed farther away. This goes for any 5" and 6" variant of any frame.

If you're talking about my specific 5" and 6" builds they feel largely the same. The 6" has more inherent control authority, but ends up being about 100g heavier than my 5", with a steeper prop. (I now run APC 5040 props on it) but my 5" is much lighter with a shallower prop. The 6" has much more powerful motors, but the 5" is about 30% lighter. This makes both of them very snappy.

The most significant difference between the 6" and 5" is the range you can get. The extra efficiency of 6" props is even more dramatic with this frame. You must tune it as though it is a 7" because of the resonance of the frame.

catSupremacy   Apr 02, 2019  

how do you mount the battery?

ThumbzFPV   Apr 02, 2019 
1

You use some realy beefy O-rings that attach to the bottom of the quad and hold it against a TPU battery pad. I didn't have them in the pictures because the quad doesn't sit flat after they're on XD It's very secure though, I haven't had it so much as budge in any of my crashes

catSupremacy   Apr 04, 2019 

Also what battery do you use?

ThumbzFPV   Apr 04, 2019 
1

I race on Thunder Power Adrenaline V2 1300mah 4S. I'm able to get dealer pricing so they're not too hard on my wallet. Those bits of DVR were both recorded with nearly two year old Tattu 45C packs though.

Zakre256   Apr 02, 2019  
1

very nice man, I get my arx-r v2 in the mail today. what batteries are you using with this frame? I have alot of 6s batteries but I feel like this would be a good 4s frame to keep it light as possible.

Show 5 more comments
Zakre256   Apr 03, 2019 
1

I have a mockup page of it right now, I have to add all the parts I ordered for it today. but theres a few pictures of the progress so far! https://rotorbuilds.com/build/17140

ThumbzFPV   Apr 03, 2019 

That thing's gonna haul butt with those motors on there. The distressed silver looks dope as well

Zakre256   Apr 04, 2019 
1

that's what I'm going for with those new BMS T-Motors. thank you man! all the parts should be in Saturday!

maplechill   Apr 02, 2019  

looks great! wish i hadnt got the first version,... cant even give that thing away

ThumbzFPV   Apr 02, 2019 

This one is awesome. I was one of the few that got the first ARX-R to work very well. But the ARX 5R 4S was a nightmare for most people. This is its redemption

P0operMcWank   Apr 02, 2019  
4

That pod looks like frosting from a cake at a wedding i went to. I like soft foods sometimes like cottton candy or porridge

Iamhugo01   Apr 02, 2019  
1

EXCELLENT WORK MY FRIEND!

ThumbzFPV   Apr 02, 2019 
2

Thank you very much! This build was tough but I'm really proud of it. The flight feel is definitely worth the time and planning it took to build it!

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