Thread Tools
Oct 23, 2019, 12:28 AM
Fan of just about anything RC
SoloProFan's Avatar
Thread OP
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.




Without battery, but with receiver. the quad comes in at around 330g.



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; Dec 17, 2019 at 05:00 PM.
Sign up now
to remove ads between posts
Oct 23, 2019, 12:28 AM
Fan of just about anything RC
SoloProFan's Avatar
Thread OP
The "heart" of the Kopis 2 HDV version, is a special version of the Kakute F7 flight controller, that allows to directly connect the DJI Air Unit, without any soldering. Naturally this FC can be combined with the Tekko ESC, to create a low profile stack. Here's a picture of this combo:




Apart from the special connector to allow communication with the Air Unit, this FC has a few more directly visible differences with the regular Kakute F7. The gyro is no longer mounted on a gel (?) pad, but directly soldered onto the board. This is probably done to reduce the stack height. Also, there is no onboard OSD, because the DJI unit takes care of that.

The board also has plenty of free UARTs, a barometer, SD card slot for blackbox (supports up to 32GB size micro SD cards) and the option to connect external GPS/Magnometer.

For more discussion about this board, here's a special topic for it: https://www.rcgroups.com/forums/show...tal-FPV-System.


Anyway, back to the actual quadcopter, which is very similar to the regular Kopis 2 6S, same frame, same motors, same neat zipper case. The biggest obvious differences, apart from the flight controller, is de DJI Air Unit, which barely fits inside the low profile frame:




The Air Unit's antennas are neatly held by 3D printed brackets, which have a little "give", so the hit of a direct impact will be softened:





If you have a DJI transmitter that is compatible with the Air Unit, it's simply bind and fly. My sample didn't come with a transmitter, so I had to install a regular receiver in it. Since the F7 board has plenty of free UART ports, this wasn't too hard. For simplicity, the R-XSR was just wired up in SBUS connection:




I felt the best spot to install the R-XSR receiver, was below the camera, where it's not too close to the Air Unit, which can get hot, and also there is still some space left:

















(reserved for HD version. 373g without battery)
Last edited by SoloProFan; Jan 23, 2020 at 05:03 PM.
Oct 24, 2019, 12:25 AM
Fan of just about anything RC
SoloProFan's Avatar
Thread OP
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
SoloProFan's Avatar
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
SoloProFan's Avatar
Thread OP
Added new flying video.
Latest blog entry: For the love of the hobby!
Oct 27, 2019, 12:41 AM
Fan of just about anything RC
SoloProFan's Avatar
Thread OP
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
SoloProFan's Avatar
Thread OP
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.
Dec 14, 2019, 03:41 AM
Fan of just about anything RC
SoloProFan's Avatar
Thread OP
Quote:
Originally Posted by kydawg1
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.

I can try put in a good word for you. But no guarantuees it will yield anything.


Btw, I just noticed I didn't post the latest video I made, using an Rline battery, which has quite a bit less sag than the regular Tattu. Here's some footage:

Flying the Holybro Kopis 2 6S with better battery (4 min 16 sec)



What I like most about the Kopis 2 6S so far, is that it's smooth, but also very snappy. Often, when switching between 5 inch and 3 inch for instance, you feel the extra weight of the 5 inch, not just because it carries more momentum, but it feel less "connected". Part of that is physics, the extra weight, but part is also tuning, because a 5 inch can be very snappy too, without being twitchy, or over controlling. Even though Holybro said they didn't do much tuning, the Kopis 2 6S feels really nice, it can turn on a dime, but also does well when making large and smooth "figures" in the air. I just wish, like with the previous Kopis 2, that the FPV feed would be a little bit cleaner. Despite the large cap, still some motor noise is leaking into the FPV signal.
Latest blog entry: For the love of the hobby!
Dec 14, 2019, 11:26 AM
"Aircraftus Fragmentum"
kydawg1's Avatar
Thanks Solo.... no need to ask for products for me..I will buy it if I want it.

This also allows me to give my truthful impression about Good or Bad with no worry of any supplier's delicate feelings. I know you are good at telling the good and the Bad. That is greatly appreciated...as there are many reviewers out there that make all products seem excellent.

I seem to be half-good at tearing stuff up based on how the general overall BAD impression I have of most FPV products. Of the very few things that have impressed me.... they have proven bulletproof to me a my flying buddies with enjoy ripping.

Its all good.... nice rip on your 6S....seems you are liking it so far.

Have you found the Kakute Flaw in the Gyro yet? I found it on the very first Kopis2 release....Holybro seemed to ignore it when I sent them video and sent the first Kopis2 back to them (their so called TECH EXPERTS said it was an ESC issue and I told them that they were wrong). The second one had the fly away on first flight. Any other Kopis2 FCs (Kakute) the snappy maneuver flaw still is there (your drone will change directions randomly at end of a snappy move - as though the pad the gyro sits on is still moving which confuses the gyro input to the FC) ..... I have learned to fly around it. If you have not seen this, I can put up a video, it is a huge flaw in such a top end component.

I need to use a dab of hot glue on the gyro and see it it changes....I may be all washed up and just an idiot.... been known to happen.
Dec 14, 2019, 01:08 PM
Fan of just about anything RC
SoloProFan's Avatar
Thread OP
Quote:
Originally Posted by kydawg1
Thanks Solo.... no need to ask for products for me..I will buy it if I want it.

This also allows me to give my truthful impression about Good or Bad with no worry of any supplier's delicate feelings. I know you are good at telling the good and the Bad. That is greatly appreciated...as there are many reviewers out there that make all products seem excellent.

I seem to be half-good at tearing stuff up based on how the general overall BAD impression I have of most FPV products. Of the very few things that have impressed me.... they have proven bulletproof to me a my flying buddies with enjoy ripping.

Its all good.... nice rip on your 6S....seems you are liking it so far.

Have you found the Kakute Flaw in the Gyro yet? I found it on the very first Kopis2 release....Holybro seemed to ignore it when I sent them video and sent the first Kopis2 back to them (their so called TECH EXPERTS said it was an ESC issue and I told them that they were wrong). The second one had the fly away on first flight. Any other Kopis2 FCs (Kakute) the snappy maneuver flaw still is there (your drone will change directions randomly at end of a snappy move - as though the pad the gyro sits on is still moving which confuses the gyro input to the FC) ..... I have learned to fly around it. If you have not seen this, I can put up a video, it is a huge flaw in such a top end component.

I need to use a dab of hot glue on the gyro and see it it changes....I may be all washed up and just an idiot.... been known to happen.

Appreciate your comments about trying to form a true opinion, without any hidden commercially related motivations. It may not be the way to become very popular with many companies, and at times it can be tempting to shift some goal posts, but in the end there is no other choice than to keep things real.

I haven't experienced that gyro bug. While I did try some very hard and snappy moves, to see if I could trigger prop wash oscillations. Which is very hard with the Kopis 6S, you really have to deliberately fly it badly, to get some minor occasional shake. This quad does use the latest version of the Kakute F7, which has some changes over earlier revisions. I do remember the Kopis 2SE occasionally showing a little minor wobble during wide turns, which could be tuning, or a gyro bug. It's not very obvious though, and it doesn't show in all conditions.

Examples of this issue you mentioned are always welcome. Maybe it has been fixed in the latest version of the Kakute F7, but maybe it's still there, though I think I should have triggered it by now. Yet so far I only had an issue with radio signal, which is caused by the firmware on the R-XSR that it came with. Now with XSR it's been totally reliable.
Latest blog entry: For the love of the hobby!
Dec 24, 2019, 12:47 PM
Fan of just about anything RC
SoloProFan's Avatar
Thread OP
Short flight with the Kopis 2 6S:

Short flight with the Kopis 2 6S (1 min 59 sec)
Latest blog entry: For the love of the hobby!


Quick Reply
Message:

Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Mini-Review Holybro Kopis 2 SE - The new BnF 2xx class benchmark? (review) SoloProFan Mini Multirotor Drones 134 Oct 13, 2019 09:25 AM