Rekon 5 HD - Caddx Nebula Pro - Naked GoPro - 2004 2600kv - 4s

By wrong17 on Aug 04, 2021

22  955  7

After building a Airblade Transformer 5” quad that is 6s with 1700kv motors, I am wondering if I should have used 4s motors instead. I feel that the low kv 6s motors does not have the power to lift 18650 4s batteries effectively. Sure, you can get off the ground with on 4s but I need to throttle over 50% to get it off the ground. I will need to do some comparison test to see which is the best route.
If you did not know already this is an open-source frame designed by Dave C FPV. He collaborated with HGLRC and came up with Rekon 5. However, the version I have was custom cut by CNC Madness because the Raken 5 frame kit were all sold out. In my opinion the purpose of these types of light weight builds are for long range flights that can capture cinematic videos with a naked GoPro. So, I plan to build it to be as light as possible and not worrying about the durability aspect.

:::::::::: The Build ::::::::::

I was debating if I wanted to use a AIO whoop board or a 20x20 stack because this frame only has hole for a 20x20 stack. If I were to use a AIO whoop board, I will need to 3D print an adapter. I went with the AIO whoop board because it was lighter even with the 3D printed adapter. I had to remix the adapter that Dave C FPV designed because the whoop board holes were too big for the m2 screws and there was no space to use a nut on all 4 corners.

I also found that the tolerance of arms is a bit off at the seams where the 2 arms touches. Because it is a tad too short, the arms can move a little, but I do not think it will affect the way it flies. My solution to this problem is to use a product called Fiber Grip. It is a gel specially designed to create friction and reduce slippage between carbon parts. By using this, it will eliminate the need to over tighten the chainring bolts.

Next, I remixed the GPS mount to accommodate a Matek M8Q-5883 GPS Module. I also had issues fitting the Caddx Nebula Pro camera because it was sitting too far inside the mount. So, I had to remix the mount by added a new hole that would move the camera forward. I like the idea of the rotating immortal T antenna mount that Dave C FPV created but I know I will forget to position it correctly before my flights. That is why I move the antenna mount to the front of the quad. I also added

If I had a choice, I would rather get a higher KV motor, but this was the only option I had because it was highest KV avalible during RDQ clearance sale. Like I said earlier I will need to do some more testing to see how it compares with the 1700kv motors on my other build.

:::::::::: Maiden Flight WTF ( Aug 05, 2021) ::::::::::

The maiden flight did not go as planned. I should have listened to the signs that it was a bad day to maiden the Rekon 5.

  1. Windy day ~22mph gusts
  2. Forgot the DJI Goggles (walked home to get it)
  3. Forgot the TBS radio (walked home again to get it)
  4. WTF.... the Naked GoPro mount is backwards??
  5. Sprinklers turned on mid-flight

I guess it was a good thing that the 3D printed Naked GoPro mount was mirrored and did not fit the camera, because I might have destroyed the GoPro when the sprinklers attacked. It is sad to say, that I did lose the Flywoo Goku GN745 2-6S AIO Whoop/Toothpick Flight Controller to the sprinklers. However, RDQ happen to have a sale on the same day, and I was able to pick up another AIO whoop board cheap. Here is the video clip of the crash, that took out my quad. Notice in the video that on my first pass over the trees, everything was dry, and the sprinklers were NOT on. Then when I did it again, the sprinklers magically turned on.

https://www.instagram.com/p/CSM9sHDl6FC/

:::::::::: Long Flight Time Test (BH 2100kv Motors) ::::::::::

  • 28 Minutes - VTC6 18650 4s Lithium Ion (Sony)

I wanted to see what kind of flight times I can get with 18650 lithium-ion batteries. My first attempted ended in a crash about 17 minutes in. On my second attempt, I was able to get 28 minutes with a home built 4s VTC6 18650 pack. I flew the quad until the voltage of each cell started to dip down to 2.7v and then I turn back and landed. I was flying in 100° F weather and the cells temp were about 110° F. According to the GPS, my cruising speeds is around 15 - 35 mph. You can see the full footage below.

  • 11 Minutes - GNB 1100mah 4s Lipo 50C

These are low C rating cells that would only work with low amp draw application, so this will pair perfectly with the Rekon 5 when criusing.

  • 11+ Minutes - GNB 850mah 4s Lipo 80C (Aug 26 2021)

I finially took out some brand new 850mah 4s lipos because the old Tattu 850mah (May 2018) are getting tired. The new lipos are GNB 850mah 4s 80C and it has been cycled a few time with the Cinelog 25 build I finished. With this lipo I was able to cruise around for about 11 and half minutes. That is kind of strange considering that is about the same as the GNB 1100mah lipo.

:::::::::: New Motors Rekon 2004 2600kv ::::::::::

The BH 2004 2100kv motors are great motors, especially for slow cinematic flights because of the low KV. But I want this quad to be an all-around quad that I would take with me everywhere and can take on all fly able conditions. I never encountered any situations where the 2100kv motors was not able to handle but when I push it, there are some instances when I had to peg the throttle to recover. That is why I do not have 100% confidence with the lower KV motors with a 4s lipo and Lithium-Ion setup.

Alt Tag
As I tore down the quad to install the Rekon 2004 2600kv motors, I noticed a few flaws with the 3D printed 20x20 to whoop board adapter. First, one of the 4 screws holding the adapter was missing. Then, the remaining screw were kind of loose. This time around, I added a nut to both the top and bottom so I hope it will hold better. I was relying on the friction grip from the TPU but that was not enough. I also printed the new mount with PLA+ so the adapter will be stiffer.

I think I will need to reprint all the 3D printed parts to match the new color theme because now motors are now red and black. Starting with the motors, I am slowly working my way in with the new color.

Since I am using higher KV motors, I will need to retest my max flight time results. If I had to guess, I would assume that I will get slightly reduced flight times compared to the 2100kv motors.

:::::::::: Updated Flight times with Rekon 2004 2600kv ::::::::::

  • 27 Minutes - VTC6 18650 4s Lithium Ion (Sony)

The flight times was only a little less with 27 minutes. Many thing may affected the flight times, especially how I flew the quad. According to UAV Forcast, it was 59F with 4mph Winds / 10mph Gust.


:::::::::: Test Flight Videos ::::::::::

Naked GoPro - Gemfan 5125 Props - GNB 850mah 4s


28 minute flight time - Naked GoPro - Gemfan 5125 Props - VTC6 18650 4s - 100° F Weather

Stay tuned for more updates....

Photos

Discussion

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Robert   6 days ago  

Just found you TPU's wish I had looked earlier as you solve the m8 gps, t-mount and make the video antenna fit better. Now I was wondering if you have thought of adapting these TPUs for the new DJI o3, as the action camera mount isnt really needed anymore, and we would need 2 video antennas

Escapereality428   Sep 23, 2022  

Great looking quad! What printer do you use for your 3D prints? The quality looks great.

wrong17   Sep 23, 2022 

Thanks! I am using a Sovol SV01 3D Printer. The best thing about this printer is that it is all ready to go and do not need to upgrade anything.

Junnicutt   Aug 07, 2021  

it looks like you copy and pasted your description but maybe there was an error cause part of it was repeated and part left out. great

Madcatmike3d   Aug 07, 2021  

God man, That looks so damn good. I've had one of these frames kicking around for a few months, but haven't built it. I did a bunch of custom multi color prints that I ended up not liking, and have been to lazy to print all new stuff. 1st world problems, I know.. lol

OptimaZe   Aug 04, 2021  
1

Awesome looking kwad.

wrong17   Aug 04, 2021 
1

Thanks!

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