ARX-R

By QuadStar Drones on Oct 09, 2018

28  1,010  9

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The Customizable Race Frame

AIO: A drag frame one day, a technical racer the next:
It went against my instincts to make the frame configurable since I'm always talking about balance and speed, but after getting some feedback, I decided to make it configurable to not only the racing situation, but the desired feel. I don't have every configuration shown, but it can be top or bottom battery mount; horizontal or vertical battery mount; upright, inverted, or a mix of inverted and upright motor mounting. I have already flown it as a vertical mount battery style (and love it), so it should be interesting to see how it feels tomorrow...

Available Versions

Choose between 5” (207mm) and 6” (230mm); and between 1.5mm and 2.0mm arm versions:

  • 1.5mm arm pieces with 2.0mm clamping plates, for those that are more focused on light weight and speed
  • 5” base is 47g, 49.5g with reinfoced screws, and 40g in “lite” configuration
  • 6” base is 49.4g, 51.9g with reinfoced screws, and 42.4g in “lite” configuration
  • 2.0mm version: 2.0mm arm pieces with 2.5mm clamping plates, provides the best combination of strength and speed (just 0.5mm adds a significant amount of strength)
  • 5” is 54g, 56.5g with reinfoced screws, and 47g in “lite” configuration
  • 6” is 57.5g, 60g with reinfoced screws, and 50.5g in “lite” configuration

Features and Improvements

More Beef... and Less Weight:
The standard version is a little beefier with 2mm thick arms. Attachment to the center plate has been strengthened and the clamping plates are now held in with 8 screws instead of 4 (the 4 extra screws are included but optional during assembly). Since there are many ways to configure it, you can still build an ultralight frame.

Vertical arms:
Using a patent pending* design, the ARX-R is constructed using a method that reduces the amount of material needed that retains a high level of strength while keeping cross section low:
Re-engineered to provide the strongest vertical arm form

  • During crashes, impact forces are efficiently transferred to the clamping plates
  • Shear stress points have been removed and impact forces are distributed over a larger area
  • Yaw axis is much stiffer – no more sensitive yaw tuning
    Vertical arms allow the props to breathe freely and thrust to flow smoothly
  • Quicker throttle response
  • More thrust
  • More efficient
  • Quieter due to less pressure interaction between the prop and arm
    Broken arms can quickly be replaced
    In combination with magnet wire (for
    ESC to motor wiring), the cross section of the arms is as small as 3mm

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Versatility:
Whether you are drag racing or zig-zagging around a technical track, the ARX-R can be configured to handle it.

  • Slow it down: The ARX-R has the ability to accelerate like a rocket, but how does it handle a technical track? How well does it decelerate
    into a corner? This is where battery layout comes in and how the ARX-R gives you the best of both worlds. For technical racing, laying the battery horizontal is recommended. When laying the battery horizontally, more surface area is created to act as an air brake when entering a corner… Wait a second… then why not use a conventional race frame??? The ARX-R still has the advantage: since the increased surface area of the battery doesn’t block any thrust, you still get explosive acceleration.
  • Just the way you like it: Not only can you go from a vertical to horizontal battery layout, you can further customize the frame to have the feel you are looking for: horizontal/vertical battery, top mount or bottom mount battery, and you can further customize the feel by inverting the motors – or maybe invert the front motors only? The ARX-R gives you the ability to get exactly the feel you are looking for.

Battery cage:
Re-engineered
Vertical battery provides a low cross section in the direction of movement
Battery placement optimizes CG/CT alignment

  • Higher angular acceleration
  • More efficient use of thrust
    O-rings provide a quick and easy way to change batteries
    Accommodates a large range of 4S-6S lipos without the need to reconfigure anything
    The mentally insane can fit a 8S in the cage if they desire (not recommended)

True X Layout:
Why??? The ARX-R design eliminates the need for a stretch layout. It allows for a high camera angle (high pitch angle) and eliminates the need to stretch out the frame to avoid front prop wash affecting the rear props.
How is this accomplished??? Unlike conventional designs, the ARX-R doesn’t have large amounts of horizontal area that create lots of downforce:

  • When pitching forward, quads with large horizontal surfaces deflect airflow like a tail on a race car and pushes the quad down
  • This creates an awkward feedback in which more thrust is required to offset this downward force
  • Quads with large horizontal surfaces require a larger range of pitch angle throughout the throttle range
  • Since the ARX-R lacks this downforce, altitude control is easier

The ARX-R frame can fly at a higher angle (higher camera angle) without the need for too much throttle

  • Slow speeds can still be obtained with high pitch angles
  • Instead of creating downforce (due to horizontal arms/surfaces), the arms create a lifting force
  • A higher angle provides a more natural feel
  • A higher angle eliminates the need to stretch the frame to avoid prop wash

The true X has a more compact design

  • Less chance of hitting gates
  • Lower MOI (moment of inertia)
  • Quicker pitch response

Miscellaneous:
Room in the center of the arm plates provide a secure place for smaller electronics such as rx or vtx
Slotted motor mounts can accommodate 16-19mm hole patterns
Designed for 20mm wide FPV cameras, although spacers can be used to increase this distance
Optional HD camera plate provides a secure platform for HD fpv cams such as the split or turtle
Protective braided mesh tubing included in the kit to protect FPV camera wires

Tuning Tunnel Vision and Filters
I have had speed run tunnel vision for so long that I never realized how bad my speed run tuning was for "regular" flying, I just thought I was a really bad pilot :/ With that said, it was no surprise when I found out that a good tune for regular flying is bad for speed runs.

However, before I could tune it, filters had to be adjusted. The default filters on BF work well on "conventional" frames, not this one. Once this was understood, all was good to work on tuning.Alt Tag

Video with my latest tuning (I'm not quite there yet still learning, still got a little prop wash):

Drag race set up speed run with (roughly) the same tuning to show how bumpy "regular" tuning is for speed runs - maybe this is still lack of skills(?):

Photos

Discussion

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wiytboi   13 days ago  
1

speed run looks fantastic.. the ground is moving so fast.. but the second video.. doesnt look like it handles for shit when its not going in straight light.. my opinion,, but still fast fuck... great job bud.

QuadStar Drones   13 days ago 

Thanks! Totally agree, long story on the tuning but it is completely my fault. I updated the description above (the last section titled "Tuning Tunnel Vision and Filters") which explains a little more. I also updated the videos with the latest tune I have (still have a little prop wash, video is boring) and a different speed run that shows how bad a "normal" tune is for speed runs - it's a special kind of shit on 6S :O Gotta mention about the speed: it was VERY windy!

maplechill   Oct 10, 2018  

can you toilet tank top mount the battery?

QuadStar Drones   Oct 10, 2018 
1

Yes.

maplechill   Oct 10, 2018 
1

ordered

QuadConnect   Oct 09, 2018  
3

Damn.
This is some quality shit.

QuadStar Drones   Oct 09, 2018 
1

After I fly it, you can chuck out the word quality - it's gonna look like shit :O

P0operMcWank   Oct 09, 2018 
1

Thats how I roll too. I make that tootsee roll in more ways than one but I'd rather not talk about it anymore.

thumbtwiddler   Oct 09, 2018  
2

dude every time i see one of your builds in my feed my day gets better

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