FPV in Roban MD-500E 700 Build

[PawPaw]

I didn’t intend to take on a new hobby, but sfcfury saw to that shortcoming when he sent me a vid of some guy flying his helicopter FPV. I’ve mounted cams in 2 of my Roban helis but only for DVR. So, being absolutely new to FPV and seriously ignorant, thought I would pass on my experiences and hopefully garner a few tips from those folks who really do know what they are doing! Here’s my setup…

Roban MD-500E 700 Conversion Kit
PhoenixTech 600 Mechanics stretched to 700 size (6s)
Scorpion Tribunus 120 ESC
Beast X FBL
Futaba 3008SB/T10J Radio
BAG Gimbal
Caddx (Dji version) Cam and Air Unit
Dji V2 goggles
Motionsic Head Tracker

So, after watching several vids of guys flying FPV in planes, I started looking at FPV equipment. It’s confusing. Ok, I just decided to go with Dji because it looked to be the easiest setup and so far that assumption has been correct. Not the cheapest…but less stressful. So far. My initial goal was to purchase the BAG gimbal unit and Caddx cam/air unit first simply because I needed those in hand to plan out the MD-500E build, then buy the pricey goggles later.

[PawPaw]

Here’s the first lesson I learned: The BAG gimbal has 2 Savox micro servos that are 6v. Well, my helis are 7.2v, so I looked for a HV micro servo to replace the Savox ones. It appears those guys designed the BAG around those 257MGs because there is no room for a larger tilt servo in the frame, and I couldn’t find same size HV ones. So, I reset the ESC to 6.1v. Second lesson: The Caddx air unit needs 7.4v minimum by spec, so not wanting to add a separate battery pack, I ordered a BEC just for that. Still not concentrating, which is my normal method, I bought a 9v Castle BEC. It works, but 12v would have been better. Here’s the BAG mount I made for the copilot seat in the MD cockpit…

[PawPaw]

I used all 4 of the hard foam spacers to mount the BAG to help with vibration plus I needed extra height to get the proper pilot eye level position anyway.

[PawPaw]

My next step was to couple the BAG tilt and pan servos to the heli’s elevator and rudder servos just to have movement, and fly it like that awhile to check out any operability or video issues. A “Y” wouldn’t work because the BAG servos were reversed, so I just set them up on aux channels with a P-Mix, and set the max pan/tilt travels that way. BAG works great! Third lesson: The Caddx air unit works just like any receiver….must be linked to operate. So much for my “just fly it first in DVR mode” idea. Ok, Dji goggles purchased (much earlier than planned). Ordered the Motionsic “Tallyho” head tracker also.
Got the goggles’ software downloaded and registered ok. Lesson four: The head tracker comes with a 3.5mm mono trainer cord which fits anything else but what I have (Futaba). The instructions state “Futaba adapter sold serarately”. Where? Emails to vendor unanswered. No phone number listed for Motionsic. So, as of this date, still no reply. I did find a 3.5mm mono-to-Futaba square mini cord at Helidirect which may work, if it doesn’t require a stereo mono plug. Motionsic didn’t specify…
Good news is once I linked the goggles and air unit, the video signal looked great through the MD windshield. Couldn’t record as my SD micros haven’t arrived yet. I did see a popup message in the goggles “Recording unavailable in low power mode” so don’t know if that’s due to no installed SD cards or my 9v BEC needs to be a higher rated one. Manual says 7.4v min. We’ll see…

[PawPaw]

Forgot to mention another BAG item: I had originally planned to use my RunCam Split 3 Nano in the BAG. The BAG includes a thin metal strip meant to adapt one hole mounted cameras but it’s very flimsy and doesn’t work well. This mount is really designed for 21mm cameras that have 2 mounting holes on each side. Any smaller camera that needs a silicone adapter to fit within the mounting arms will just drag on those arms when the camera tilts, also.

[sfcfury]

I didn’t intend to take on a new hobby, but sfcfury saw to that shortcoming when he sent me a vid of some guy flying his helicopter FPV. I’ve mounted cams in 2 of my Roban helis but only for DVR. So, being absolutely new to FPV and seriously ignorant, thought I would pass on my experiences and hopefully garner a few tips from those folks who really do know what they are doing! Here’s my setup…

Roban MD-500E 700 Conversion Kit
PhoenixTech 600 Mechanics stretched to 700 size (6s)
Scorpion Tribunus 120 ESC
Beast X FBL
Futaba 3008SB/T10J Radio
BAG Gimbal
Caddx (Dji version) Cam and Air Unit
Dji V2 goggles
Motionsic Head Tracker

So, after watching several vids of guys flying FPV in planes, I started looking at FPV equipment. It’s confusing. Ok, I just decided to go with Dji because it looked to be the easiest setup and so far that assumption has been correct. Not the cheapest…but less stressful. So far. My initial goal was to purchase the BAG gimbal unit and Caddx cam/air unit first simply because I needed those in hand to plan out the MD-500E build, then buy the pricey goggles later.

I appreciate you throwing me under the bus right out the gate!!!

[Gravythe clown]

Dude pawpaw you nuts. Lol
ive done lots of FPV, even a 120 mph F-16. I don’t think I would feel safe enough to o FPV a helicopter. I thinks it’s cool as hell, but I’m sure I would end up doing so carnage.

Gravy

[PawPaw]

You’re right. I shoulda waited to the second paragraph, at least.

[PawPaw]

Dude pawpaw you nuts. Lol
ive done lots of FPV, even a 120 mph F-16. I don’t think I would feel safe enough to o FPV a helicopter. I thinks it’s cool as hell, but I’m sure I would end up doing so carnage.

Gravy

Tell that to sfcfury! He made me do it!

[Gravythe clown]

Yeah I blame DCORSAIR on stuff like this. Always good to have someone to blame.

Gravy

[sfcfury]

You’re right. I shoulda waited to the second paragraph, at least.

At least! Now hurry up and get it figured out for me!

[PawPaw]

Making progress, I think? Motionsic finally replied to my email re Futaba trainer cord adapter. They now have those added to their products online, so it’s ordered. They did say a standard 3.5mm mono-to- Futaba mini square adapter, as commonly available, will work only if you open up the mini square plug and resolder the PPM out pin to the PPM in pin. I did order one of those a few days ago and will try that….much later, I’m guessing.

[PawPaw]

Answered the “low power” no recording question. The air unit goes into low power mode when it overheats, as stated in the manual, but I didn’t realize it gets hot that quickly. It certainly does if no air is flowing, which will be an issue in a heli setup vs fixed wing, so gotta figure out a good cooling fan setup.

[lwright292]

Hey PawPaw!

I've been flying FPV helicopters for a while now. I use a Puma flight control system with Cyclic, Collective, and anti torque control along with DJI FPV. Just added the BAG and working on anti vibration measures.

https://www.youtube.com/watch?v=DPJlQ1NitDc

[PawPaw]

Outstanding, sir! That’s the vid sfcfury sent me that started me on this path, in fact. I’m getting closer to test phase and just need the Futaba trainer cord adapter to arrive for my vibration tests. On yeah….need to finish painting the MD-500E also.

[lwright292]

Cool!

I first built my rig in 2018 and it's been a science project ever since. I'm about to adapt everything to a Roban UH1 800.

[PawPaw]

Thanks for joining us on Hobbysquawk, and particularly this thread, lwright. As I stated earlier, this FPV effort is new to me and so far the learning curve has been reasonable. My cooling fans are due to arrive today and that will start my effort to design and build a simple bracket to get the fan(s) mounted. My goal is to determine if this FPV will work inside the MD-500E’s cockpit without removing any of the front windshield panels either for visibility or cooling. Your input will be much appreciated, sir!

[PawPaw]

Painting ‘posed to be relaxing. It ain’t, for me anyway. I’m doing a camo scheme per the Chilean military mostly because the MD-530F Defender is an export version and my other option was the Afghan Air Force which is now owned and operated by the Taliban. Couldn’t find a Taliban pilot figure.

[PawPaw]

First cooling test looks pretty good. I bought 2 Yeah Racing “Tornado Plus” aluminum case 25mmx25mmx10mm fans from AMain that are rated at 5.1cfm each, and are good from 5-7.2v. I cut a square of .060 polystyrene the size of the Caddx air unit mounting cradle and cut a hole in the middle for one fan to match the fan blade OD. Taped that assembly to the Caddx cradle and powered everything up as before. This time, after 15 minutes, the unit was only warm. Before, it kicked into low power mode after less than 5 minutes without any air flow. That’s encouraging, but summers in coastal Texas are miserable so the final design may need both fans. I will post a pic when the fan install is complete.

[PawPaw]

Here’s the “dirty” setup I am testing. So far, so good. The Caddx mounting cradle allows 1/8-3/16” clearance between the unit and fan base that’s not visible in the pics.