Top Banana 6 a.k.a Satan's Turd(RuxusUltimateEvolutionFinalForm)

By zaamii on Dec 11, 2018

17  668  5

I tried to avoid posting this build because I didn't wan't to know how much I spent on it, but I now feel obligated after all the questions people have asked about it. I'm still going to avoid looking at the total price and when I inevitably glance at it, I will squint my eyes harder than someone who got sprayed directly in the face with mace... Now on to good stuff.
The build started as a desire to see how fast a 6" quad could be when optimized(Also becuase I freaking love 6 inch quads). I was tired of hearing the "experts" claim that 5 inchers were the only size that could go fast (above 110-120mph) and that anything even slightly larger would require a copious amount of power that current battery technology could not provide. I knew 6" had potential to reach high speeds, but a suitable high pitch propeller didn't exist at the time. That changed when APC released a reverse rotation version of their 6x6 airplane propeller last year.
I originally planned to use my own base frame design, but I discovered the ruxus v2 right before I was about to get the carbon cut. The ruxus was almost identical to my idea with the most important similarity being the very thin arms. I then chose the FPVAF 2507 2200kv (made by hawksky) due to the fact that the hawsky 2207 was very close to the cobra cp2207 based on thrust data from miniquadtestbench. That means a 2507 using the same construction would be really powerful!
The first tests on 3s yielded speeds over 90mph. My theory about a high pitch 6" prop was correct. The apc 6x6 was literally 25-30mph faster than any other 6inch prop(and more efficient at high speed too). 5s runs consistently hit 150mph, but the first 6s tests were a little disapointing with most being under 160mph. I could have stopped at that point. Those speeds are right up there with the fastest conventional 5" quads (not including Ryan's fast crazy machines).

The experiment gave me an addiction to speed and I wanted to go faster. So I started learning as much as I could about streamlining. I studied everything from NACA aerodynamic research to velomobile forums lol.... If aero matters for a freaking bicycle, It definitely matters for a 160mph quadcopter!
Given my lack of rescorces and the fact that my "workshop" Is also my bedroom floor, the resulting abomination made from cardboard and vinyl tape isn't suprising.
Anyways, the streamlined shell completely transformed the machine. The 5s runs now reached average speeds over 160mph and the 6s speeds were over 170mph. One run with an improved, less wrinkly shell and a LiHV lipo actually hit 188mph(I'm almost certain this was caused by a tail wind) I estimate the actual top speed would have been around 180mph. Most impressive was the dramatic increase in effciency at moderate speeds. This thing can comfortably cruise at 100mph drawing only 20-26 amps on 6s.

Despite my disdane for 5 inch props, I also tested the apc 5150 and 5260. The top speed was the same or a little slower than the 6x6, but the acceleration and low speed efficiency was worse.
The biggest downside is that the bodywork must be destroyed in order to change the battery or accsess the internals. This meant that every rebuild performed a bit differently and every flight produced inconsistent speeds that eventually drove me insane. Also, landings frequently deformed the tail which produced strong lift forces that would cause violent yawing at high speed.



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QuadStar Drones   Dec 14, 2018  

I admire this: "my "workshop" Is also my bedroom floor". Adverse conditions bring out creativity and resourcefulness; it creates an in depth connection to the problem at hand that $ and computers cannot replicate. Among the small 5' x 6' corner workshop in my apartment you'll find a coping saw, files, sandpaper, electical tape, and Easter eggs - not exactly high tech.

lepricrashfpv   Dec 12, 2018  

This is the fun part of the hobby, pushing the limits. Showing people they dont have all the answers.

I think unpolished builds that push the limits bring more to the table than showroom quads.  it shows the ingenuity, the grit and determination that you put into it.  
I like it.

recon   Dec 12, 2018  

This is incredible. The flying banana slug. This would gain some traction in Santa Cruz, CA.

P0operMcWank   Dec 12, 2018  

Turd reminds me of my fb friend named Kaka Tang. I feel bad cuz his name sounds like the spanish word for a turd. The guy is a mongolian so I don't think he cares but I do because thats the kind of fb friend I am. Turd also reminds me of a story butt thats sort of embarrassing so i'll stop now

Showusflight   Dec 11, 2018  

Satans turd squited out pretty fast.

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