QuadStarDrones ARX-R 6"

By HK-AERIAL VTOL on May 26, 2019

18  424  4

This is (I believe the first on Rotorbuilds.com) the QuadStarDrones 6" ARX-R (edit: I was wrong =]). This is the most challenging build I have had to date. This quad is like no other in that it has a less "restricted" feel in the air. It is fast, and even my first few attempts at "going real fast" illustrate the capabilitiy this quad has in comparison to traditional designs. First off, lets discuss take-off. It is nearly vertical. I do it out of a little box that is big enough for my battery to sit in, but smaller than the motor footprint (kinda like a football tee). What Ryan at QuadStarDrones says is accurate: the direction the arms are in makes this quad RISE with speed. That is a HUGE plus because at speed you do not want to be low. Slowing down and turning around can be disorienting the first few times (because it occurs very sharply you may have a time getting your rates set right). I should probably not advertise that Ryan has some great PIDS to start out tuning with (hey Ryan... maybe for just this quad you should publicly post the somewhere). I ended up nearly halving my I and D's from what Ryan gave me. With a little more adjusting I think I can get this one close to 200MPH. I fly kind of like a fixed wing pilot might (big inverted-S turns that almost scrape the ground), and I find that style gets me into the high 160-170 range with ease. I don't think the 6" can get into the 220MPH area like Ryan does with the 5", and so I am now building one of those with the 2722KV 2207.5 Hyperlites right now (high RPM you say Ryan?... Look out!). This frame can be the illest race quad, but it is at its heart, a drag frame that aims to satiate the speed lust that most pilots crave. I see many pilots asking "where do you mount the battery?", and so I have posed mine illustrating how that is done. My FC and ESC are the new HGLRC FD445 stack, which was rushed to me by the great folks at the factory (can't say enough about how much I love HGLRC micro stacks). VTX is the AKK FX-2 Ultimate (and yes.... those three parts can make quite a bit of heat under the canopy). The F60 Pro III's are smoother versions of the II, and though they posses just a wee bit less thrust as their older counterparts I do think they are a perfect fit for this application. I also chose lower KV versions, which work well for me, but might not have been the optimum selection (I fly this on 4 or 6S, but prefer 4 as the heat in the canopy is a bit frightening on 6 (HADOUKEN!). The F60 Pro II's are very, very powerful and could be a lot harder to tune for this quad because of that.

Edit: I've had issues tuning this beast, and that was my fault. HQ 6040 (6x4x3) are the absolute shizznit! I added a capacitor, but adding these props (V1S) has been lately turning my quads into absolutely hawks. The 6040's might be even better than the 5" 4.8's. I just took this one back out on them and pushed the throttle to eleven and BOY-OH-BOY. How fast was I going? I don't know. It was the fastest I've ever flown before. And smooooothly. You won't get fast with your quad shuttering like a leaf... lots of wasted energy going on in that situation. I will admit that until I got these new rotors I didn't think I liked the Pro III's as much as I like the Pro II's (grrr.... broke a motor on my Pro II rig). Now all is right with the world and in the air. I also switched to a 30MM canopy, and though I built with a 20MM set I just need the extra room (and you might too!).The AKK FX2 was not the optimum choice the FX3 is for this particular configuration. The close shot of the right side shows how one might arrange antennas and capacitor; this is the kind of build that will make you get creative as you will desire to keep the profile as minimal as possible.

Edit 2: I've now flown this monster on APC 6045's and 5S Venom and THAT is the configuration I prefer with the 6" ARX-R. This provides the massive requisite CLEAN power that the APC's cause the Pro III's to draw. The flight time is still way more than I need to make drag runs, and when all is said and done (4-5 minutes) the motors come down cold! The flights are as smooth as they have been from V1S to APC. Coming out of (huge fixed wing style) inverted-S turns helps get this vulture way faster than I've experienced before. It's fun in a whole different respect.

Edit 3: I destroyed this quad. I have a near KM track of open farmland to fly, and when this quad broke a prop at full throttle it hit the only 10-15' of pavement it could. It was my fault. Strictly speaking... it was my ignorance. What made it happen? I first thought it had to do with a prop, but now I suspect the quad vibrated a motor screw loose. I checked my other ARX and sure enough it had a few that were plenty loose. I need to use LocTite. Do you? I don't know... I never used it before. I'm going to have to research it.



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ThumbzFPV   May 27, 2019  

Technically the first yes. My very first ARX build on here was a 6" prototype, but I didn't have any 6" props XD

HK-AERIAL VTOL   May 28, 2019 

I'll concede to you then sir! I personally go by wheelbase before prop, and so you are correct. You were the first!

QuadStar Drones   May 27, 2019  

After doing a lot of testing, it seems that milder motors do just fine on BF 4.0.2 default PIDs. The more powerful motors need to have the P and D lowered about 15%. So far, I haven't had to touch d_min at all.

HK-AERIAL VTOL   May 28, 2019 

Huh... well I'm building my 5" now and I did just flash it in 3.5.7 (cause you know, I'm the "worst PID tuner in the world"...lol). Waiting on some XM+'s, but I gotta say these Hyperlite's feel great on the bench. I've been getting some nice speed out of my 6" but I think I might cooked one motor (a couple real good full thottle blasts on 6S). I haven't taken it out since, so I could be wrong.

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