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Oct 23, 2019, 12:28 AM
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Mini-Review

Holybro Kopis 2 evolved: New 6S and DJI HD FPV versions released (review, wip)


Holybro continues to develop the Kopis series of 5 inch FPV quadcopters. After the Kopis 2 SE, a real special edition (wonder what the SE with the regular Kopis 2 would stand for... ? ) was released, as the Rotor Riot version, with different camera and motors as the most prominent changes.

Now Holybro made a "few" other changes, and is releasing a HV version, with lower KV motors, optimized for running 6S, as well as a version using the new DJI HD FPV system. In this review I hope to tell more about these, and show what to expect.


Disclaimer: I don't get paid, or in any other way make money with reviews like these. Product specifications and quality may vary at the manufacturer's discretion, and are beyond my influence. I cannot guarantee you will get a product that performs exactly the same as seen and described in this review. There is always room for a general discussion on the reviewed item, feel free to comment, but if you are planning to add a long written review, instead of some summarizing remarks or a single video, it would be appreciated to put these in a new review topic or on your RCG blog page. And please, no affiliate links!

Note: When clicking a link that is posted in this review, some text or numbers might be added to the link, making it appear to be an affiliate link. However, all links I post in the review are clean, and this addition is done automatically by your browser and forum software, so sadly beyond my influence. If you don’t want this to happen, copy the link, then paste this in an address line of a fresh browser window/tab.



For easy navigation, here's a list of contents:

1: Specifications (posting #1)
2: Unboxing (posting #1)
3: Preparing for 1st Flight (posting #1)
4: Flying Performance (posting #1)
5: Camera & FPV Performance (posting #1)
6: Suitable for a Beginner? (posting #1)
7: Preliminary Verdict (posting #1)
8: Additional Tuning, Modifications & Other Info (posting #2)
9: Suggestions for Improvements (posting #2)




1 - Specifications:


First, let's start with a picture and a link:





2 - Unboxing:

Like all other quads in the "Kopis family" the Kopis 2 "HV" comes in a sleek zipper case, inside a sealed cardboard box, listing the specs.


Inside the box we find the quad, strapped to the inside of the case with a battery strap, and all other hardware in a wirenet bag that is part of the top cover. Here we find another change, apart from the motor KV, the props are no longer Dalprop T5046C type, but from T-motor, and 5147, in "clear gray" color. I really like the 5046 with a great mix of power and efficiency, as well as sound, so I'm hoping these different props will be at least as good as the Dalprop. Time will tell...




At first sight the frame seems unchanged from the Kopis 2 SE, but when looking closer, the arms are now full carbon, instead of the lighter and more expensive carbon composite material. I haven't asked for the reason for this yet, might just be purely because full carbon is cheaper, but could also be mostly because people thought the carbon composite in the arms of the 2 SE was the same materials as the cheap stuff that some Furibee and Eachine quads have been using, and which would often shatter upon first impact. Where life crash testing on the Kopis has showed that composite to be at least as strong as full carbon, maybe even more durable. But for those who didn't see these videos, the perception would still be "Oh no, why did they use that weak sandwich core carbon? I am not going to buy one of these with that crap material!" or similar.

Those people will be pleased to hear the arms are 5mm thick carbon, and can be replaced individually. The bottom plate is 4mm carbon and the top plate is 2mm.




The VTX antenna is the Foxeer Lollipop 3, and has a shorter "stem", bringing it closer to the frame. In theory this could make the frame be blocking the signal more, but a flight test will have to reveal if this is really an issue or just a theoretical one. Btw, these most of these pictures were taken after replacing the receiver, so you don't see the stock R-XSR but the larger XSR being fitted, making it look a bit less "clean" than it originally did.

The overall build quality is nice, all screws are well tightened, and wiring looks neat. Just a few points of criticism though. The VTX antenna wire still almost blocks the USB port on the FC, and the wire harness between FC and ESC partially blocks access to the micro SD card slot for the included black box.




And there is no card present from the factory. So if you insert one, you will have to remove this wire, and then put back, not very convenient, and the harness could be damaged during the process. On the positive side, once a micro SD card is present, you won't have to worry about it getting ejected very easily, since the wires are blocking that. It should be possible to re-route the wires, and fully clear the micro SD card slot but that would probably require a longer harness, and would require partially taking apart the FC to replace a harness that was damaged in a crash.

The FPV camera is still made by RunCam, but has been changed to the Robin series, a CMOS camera with 2.1mm lens. If this is an improvement, we'll see in chapter 5, where FPV flight will be demonstrated and commented upon.

Overall, the quad looks sleek and neat, with a low profile center, and apart from the 35v 1000uF cap that is attached right above the battery leads, the R-XSR antennas and the VTX antenna there are no bits sticking out from the sides, asking to get ripped off in a crash.





3 – Preparing for 1st Flight:

When connected to BetaFlight Configurator, the FC is identified as Kakute F7, as to be expected, and flashed with BF 4.0.4 firmware. It seems Holybro did a full setup, Airmode is permanently on by default, the receiver has been setup, and also the OSD looks organized and pretty clean. a full dump of stock settings will be attached to this message, for future reference, in case you need a backup, or simply are just curious.

I didn't have to change many things, just a few preferences, like OSD, Motor Stop, which I prefer to be on, and Air Mode on a switch, as well as other Modes preferences, that I have gotten used to.

I did encounter one annoying thing, when arming the quad, but still at zero throttle, the beeper would sound all the time, and only be silent when raising throttle or having Air Mode on. This turned out to be the "Armed Beeper" being on as well, so after the arming beeps, this one takes over, to warn the pilot and bystanders the quad is armed, but not running yet. Since I mostly fly alone, and don't want too much beeping to disturb the peace, I de-activated this beeper setting. Btw, if you keep Air Mode permanently on, you won't notice it, which is probably why HolyBro never bothered or thought about unchecking the box for this beeper setting.

So (apart from the receiver already having been replaced before this picture was taken) this is how the quad looked, when fully ready for it's maiden flights:








4 - Flying Performance:


[no Line of Sight tests done yet, please go straight to the next chapter, for FPV performance]



5 - Camera & FPV Performance:

As mentioned earlier, the RunCam Robin is now being used instead of the Micro Swift. CMOS micro cameras tend to be a bit like, you love 'm or you hate 'm. Love because of the higher level of detail, hate because of the not always too great low light performance, and many of these struggle with reddish colors, making these into fluor pink instead. The Robin however, tries to combine the best of both worlds, and the color balance, based upon the tests so far, seems pretty neutral. More testing is needed though, to be able to have a full verdict.

Due to lack of 6S batteries, and sometimes even struggling to get any bigger batteries here, without costing their weight in gold, the first FPV flight was done with a 4S 1300mAh battery, in this case a regular Tattu 75C. In my personal experience, and those of others, the regular 75C series from Tattu are not that great, often usable, but with a bit more voltage sag than you'd like to see. If you need to get batteries for a quad like this, GNB or the R-Line series would be a much better, but more expensive choice.

Anyway, this was the first flight, short, but (mostly) sweet:

First flight with the Holybro Kopis 2 6S edition, ending in a crash (2 min 21 sec)



So what happened, I'm not entirely sure. I did hear a few "signal low" warnings, but these were at the beginning of the flight, not later on, and I even got mostly to the other end of the field without and problems. Then suddenly it disarmed and dropped like a brick...

Luckily the ground was soft, and the props started to free wheel during the fall, slowing it down. It seems that apart from some dirt, and the buzzer popping loose from where it was attached, there is no real damage. It appears the arms/props took the first impact, and then if rolled over, before coming to full stop. Even the battery doesn't have a dent, and was only a bit wet/dirty on the outside.


To rule out the receiver as possible cause, I swapped out the R-XSR with the bigger XSR, and secured the buzzer. The next flights no more mishaps, and I can say that even on a somewhat lower spec 4S, like the Tattu 75C 1300mAh, it performs very nice. Here's one of the next flights, after replacing the receiver:

Kopis 2 6S - sunset Flight, stock PIDs, 4S 1300mAh Tattu 75C (3 min 37 sec)






6 - Suitable for a beginner?


5 inch and beginner are no great match, as most will probably agree. A small quad, with prop guards, 1S, or maybe 2S, will be a better platform, most likely. However, the level of detail on the Kopis 2 6S, and it's apparent durability, do make it more likely to withstand the treatment a beginner pilot may make it be subjected to. So it's not totally unsuitable, but supervision from an experienced pilot would be much recommended.




7 - Preliminary Verdict:


Based upon the few flights so far, the Kopis 2 6S has impressed me in quite a few ways. Mostly the almost impeccable handling. When you want to fly smooth and gentle, it does that, if you want to rip around, and move fast, it does that just as easily. The control is instant, and direct, without ever becoming twitchy. Whether this is the tuning, the "feel" of BetaFlight 4.0.x, the hardware, or the combination of these, it does again feel nicer to fly than the Kopis 2 SE.

On the negative side, apart from being more expensive than average, I did encounter issues with the R-XSR receiver, which are likely not caused by HolyBro though, and the VTX still doesn't give a very clean image. Which can only be partially blamed on the antenna being so close to the frame. The noise that you see as soon as motors are running, is almost trademark for the Atlatl VTX, as it was also visible on the Kopis 2 SE, with antenna being on a bit more favorable position, and it's also present when nothing is blocking the signal to your goggles.

It doesn't detract much from the great flying experience, due to the superb handling in the air, but if you compare to some other, sometimes even older quads, with nice and clean FPV image, this is clearly something that HolyBro could improve upon.



Pros:

- Well tuned
- Neatly built
- 5mm strong carbon frame and arms
- Smooth motors
- Comes with 2 full sets of props


Cons:

- Wires blocking Micro SD card slot
- VTX wire sticking out from the side, could be vulnerable in a crash
- Some motor noise visible in FPV feed, despite big capacitator on battery leads



(to be continued)
Last edited by SoloProFan; Oct 27, 2019 at 12:44 AM.
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Oct 23, 2019, 12:28 AM
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(reserved for HD version)
Latest blog entry: For the love of the hobby!
Oct 23, 2019, 12:28 AM
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(reserved for additional information)
Last edited by SoloProFan; Oct 26, 2019 at 03:13 PM.
Oct 24, 2019, 12:25 AM
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Added some more information, first video coming soon.
Latest blog entry: For the love of the hobby!
Oct 24, 2019, 01:51 PM
Fan of just about anything RC
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Thread OP
Added first flying video.
Latest blog entry: For the love of the hobby!
Oct 26, 2019, 12:58 PM
Fan of just about anything RC
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Thread OP
Added new flying video.
Latest blog entry: For the love of the hobby!
Oct 27, 2019, 12:41 AM
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Added more pictures and info.
Latest blog entry: For the love of the hobby!
Nov 05, 2019, 12:25 PM
"Aircraftus Fragmentum"
kydawg1's Avatar
Solo - Have you torn up the sky yet on 6S?
Nov 05, 2019, 12:34 PM
Fan of just about anything RC
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Quote:
Originally Posted by kydawg1
Solo - Have you torn up the sky yet on 6S?

Still waiting for suitable batteries, without breaking the bank. Tattu 75C is relatively cheap, but don't perform. Rline and GNB are better, but the latter isn't locally available, and the first is, but at about double the price of what these cost from China webshops.
Latest blog entry: For the love of the hobby!
Nov 05, 2019, 03:57 PM
"Aircraftus Fragmentum"
kydawg1's Avatar
Tell those Holybro guys to send some models over here....I am glad to wring them out to show all the good, bad and ugly.


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