Gemini V2 UAV Build Thread

[Derek]

I've been doing some researching and watching some videos. Based on what I've learned today, the TBS Crossfire Diversity rx is not going to suit my needs for the Gemini V2 UAV. That's really unfortunate. So, it will just go into the Parts Bin until I find a use for it. In the meantime, it looks like the FrSky X8R rx is going to do just fine. It will output 16 channels (1-8 via SBUS and 9-16 via the PWM pins). The X8R also has RSSI (which is never a bad thing) and the X8R will still reach out to about 2 miles-ish. That's still plenty far to suit my needs.

Let the progress continue....

EDIT....perhaps I could build a different type of plane and use the Crossfire Diversity rx with my 1.3ghz fpv system that's been in a box for a while. hmmmmmm.......

[Stambo]

Can you use an FRSKY L9R, that will give you a bit more range I believe but not sure if you can get the required channels with it.
It says 9/12 channel.

https://www.getfpv.com/frsky-l9r-long-r ... metry.html

[Derek]

Youre right, Stambo....the L9R would give me much more range. However, the X8R will give me the necessary channels (and a few extra) as well as RSSI. So, ive had to accept thia fact so that i can continue. Perhaps I'll find a long range setup at a later date.

[Derek]

WOW! I am about to explode!!! I began to install the Omnibus F4 v2 into the Gemini v2, along with the PDB. I got real curious about "would I actually get 16 channels from the X8R rx?" So, I followed a YouTube video.....that all seemed simple enough....a bit more daunting than my DX8 but I was able to get through the process of updating firmware and rx binding. That being done, I was curious if ALL 16 channels would show up in the Receiver Tab of the INAV Configurator.

Actually, I was gonna explain everything that I had done but that would be a LONG and drawn out story. The point it.....IT WORKS!!! All 16 channels are present in the INAV Configurator, lol. That's just too cool! I went so far as to assign several switches, in the Taranis, and everything, lol. Now, channels 1-8 are operated via SBUS and channels 9-16 are operated via the PWM pins on the X8R. I even tested it all by moving a servo from one set of pins to the next and flipping the switches......the servo actuated, lol.

Yes, I'm disappointed that I can't run the Crossfire system on the Gemini v2 due to lack of channel outputs but I am on Cloud 9 right now because the X8R is working with all 16 channels. So....I won't be able to fly as far as I had planned by using the Crossfire but I'm absolutely stoked that the X8R is doing exactly what it's suppose to do. I've talked with a few other people that run the X8R and they are still getting 3-5 miles out and back....and, the X8R has RSSI.

I'm a happy dude!!!

[Derek]

Finally something to report, lol. For the past few days, I've been trying to set up the air brakes on the Gemini v2 UAV. It was a surprisingly difficult process. Between trying to figure out the programming in the Taranis and getting the geometry right for the "air brake" doors, I was nearly pulling my hair out. I even called my Dad, yesterday, for his help. He came down and we built a setup that looked promising but just didn't work "quite right" using a single servo. I thought that using a single servo would simplify things. After completing a two servo setup, I almost think the two servo setup was easier. So anyway....Dad...thanks for your help!

Here is a bit of video showing the air brakes working....

https://youtu.be/dKe4tDayYjo

[Graham Lawrie]

Thats great Derek:) i feel your joy:) its always good when everything comes together and your effort is rewarded by something so simple:) excellent work:)

[Derek]

Thanks Graham! Yeah man...im so very pleased that the air brakes are hooked up and working. I think they may need a bit of tweaking but....they are working, lol. Too cool!

[Derek]

Rotten camera angle but, here is Makayla helping me install a pair of Castle Creations 50amp esc's into my Gemini V2 UAV. She's such a big helper!!!

https://www.youtube.com/watch?v=WzktPpf4l_Q

[Stambo]

So cute.
She is getting so big, what are you feeding her?

[Derek]

Hey guys...i have a question.

My Gemini is gonna have two control recievers, two fc's, and two GPS modules. Would there be any harm in having these 6 units within 6 inches of each other?

I'm using two receivers because I will be flying the plane and there will be a second control rx for an observer/co pilot on a second pan/tilt setup. I'm using a second fc and GPS module to allow OSD on the second fpv setup.

I know there should be separation between the vtx and control rx....ill have plenty of that. I was just wondering about the other parts.

[Graham Lawrie]

Cool video Derek:) Not sure about the separation, however i would think you would need it to stop one interfering with the other, especially on the same frequency?

[KevG]

should not cause an issue mate, both frequency hop on 2.4ghz so should be ok.

as for the 5.8ghz side make sure you have good channel separation and test it over distance on the ground before you test it in the air to see how bad your interference may be.

[Derek]

Thanks guys! There will be roughly 8 feet in between each vtx. There Will be about 6 feet in between each vtx and either 2.4ghz control rx. As for the channel separation, thats also quite easy to get. I can simply set one vtx to channel 1 and the other vtx to channel 8.

I'm making some decent progress on the Gemini v2 but there is still SO MUCH more to do lol. Some parts have become overwhelming, so I just step away from the build for a few days, here and there. I'm beginning to run servo wires from the tail to the fc. I'm trying to think ahead and route the wires so that they are semi cleanly installed and out of the way of other components.

[Derek]

I've been working on my Gemini v2 UAV more. Finally got the esc's calibrated properly. Time for a test taxi up the driveway. I've discovered that I need to get firmer wheels because of the weight of the Gemini.

Here is a bit of unstable video of the Gemini as I walk around it.

https://www.youtube.com/watch?v=bOpCGCrZMJk

[Derek]

In this video, we taxi the Gemini v2 UAV up the driveway. I also show the working air brakes and FPV pan and tilt. I wanted to show the cargo droppers working but I didn't have them connected and didn't realize it until after we turned off the video camera. Another video is coming that shows the cargo droppers working.

https://www.youtube.com/watch?v=oOBPvh0sfDw

[Derek]

ok, we have the proper connections made and the cargo droppers are working.

https://www.youtube.com/watch?v=538gQij7_AU

[DOG]

I am SPEECHLESS! That's one awesome build Derek. Can't wait til the maiden

[Derek]

Thanks man! It's been a fun, challenging, and exhausting project. There are still some changes to be made and more work to be done, but we're getting there.

[Derek]

I actually started this build about 2 years ago and just finished it. I got so engrossed in other projects that I simply put this build on the shelf and forgot about it. Then this Corona Virus came along and the Governor started the Stay At Home order. I decided to take this time at home to finish the Gemini v2 UAV.

Here is a list of the electronics used:

2 Eflight Power 15 motors
2 Castle Creations 50amp esc
1 Castle Creations 20amp BEC Pro
1 Matek F405wing flight controller (which also supplies OSD for the pan/tilt camera on the front for the pilot, me)
1 Omnibus F4 v2 Pro flight controller (which only supplies OSD for the pan/tilt camera on the belly for the co-pilot)
2 M8N Ublox GPS modules (one for each FC)
1 FrSky X8R receiver for the pilot
1 Spektrum AR600 rx for the co-pilot
7 Corona DS538HV servos (2 ailerons, 2 elevator, 2 rudder, 1 steerable nose gear)
2 smaller servos that operate the air brakes (i forget what brand they are)
2 HXT900 servos (wing mounted cargo droppers)
2 Runcam Eagle FPV cameras
2 Lumenier TX5G6R 5.8ghz vtx
6 3S 5000mah 45C lipo batteries
2 APC 13x8 two blade propellers

I think thats about it, lol. I just finished the build, to 100%, yesterday, so I haven't had a chance to fly it yet. Although I did list the batteries, above, I haven't ordered them yet. I need to wait until the Stay At Home order is lifted and local parks (and the local flying club) to open. Something that I've considered, to be sure that I have enough open area, I might just take the Gemini v2 UAV to the AMA Headquarters and use their WIDE open fields. I'm going to be so nervous flying this monster. I'm gonna want LOTS of open area until I get comfortable with it.

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[Graham Lawrie]

Thats looking great Derek, cant wait to see it in the air, stay safe:)