Fighter VTOL 4+1 fixed wing

Hi Christian,

I wanted to notify you about a design flaw in the VIFLY 2. If you let it sit for months without use, like I did over the winter months, it appears to be dead when you try to use it. It will no longer charge either. Apparently, the device draws a tiny amount of current just sitting around and then latches in a bad state.

The fix is to remove the shrink wrap, and touch a 5v supply (regulator or rx. pack) across the on-board battery tabs. This brings it back to life and you can then recharge it for use. I went a step further after recharging it and soldered an additional 150mAh pack in parallel to the on-board pack. This provides a much longer period before the batteries are drained.

Hi Jed,

Thanks for the detailed introduction and information on your 12s setup. I am curious to hear about your 4.1.0 Beta testing results so please give us a summary when you are finished. Our flying season here in Upstate NY has been poor this summer with lots of storms, rain, humidity, and wind. It feels like an extended spring season.

I compared our 6s and 12s current numbers and the differences appeared to be reasonable. My hover current was 60A on 6s and yours was 37A on 12s (or 74A on 6s). You have a heavier setup. My FF current was 17.5A at 19m/s and yours was 7A on 12s (or 14A on 6s) at 17m/s. You were flying slower on a more efficient setup. So the numbers seem to be in the same ballpark.

I see that you went with a black nose. It was a nice upgrade to the appearance! :grinning:

Cheers!

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Hi Jed,

Very nice setup! thanks for sharing the detail. I think the slower motors turning large props, especially on 12S makes for a very efficient VTOL. I have seen a video of Ben (3DXR) briefly mentioning the trend towards this as a preferred setup over higher KV and smaller props. He seems to live and breathe this stuff and appears to be very knowledgeable.

Can I ask about the connection that you have from your EMLID base to laptop? Do you use the RS2’s wifi hotspot to connect to the computer and then send the corrections out from the RF Designs radio base plugged straight in to the laptop USB with persistent connection to the airside RFD? Or is the RS2 cable connected physically to the laptop?

Combined with the Herelink which has a good control range also, that’s a very nice solution to to have long range control, FPV on the controller monitor, telemetry and NTRIP corrected data sent to the M2 onboard and no need for an EMLID LORA radio in the mix! Only using 1 of the RFD868 antenna’s or is the second one inside the fuselage?

Does the M2 connect to the CUBE carrier board, or is it just connected to the RFD868 and used independent of the FC and purely for data camera hotshoe logging?

And also what size battery are you using to independently power your sensors for your hour of flight?

7 amps in cruise seems amazingly good.

Finally - Do you fly your believers as 6S setup? I assume they are configured as belly landers? I am not far off building my first Believer which has sadly been sitting in its box for a very long time. Are you able to provide similar detail on how you have yours setup? It would be very helpful.

I like the video - very quick up and transition.

Apologies in advance for the barrage of questions…but I am very interested in the setup detail.

Cheers

Jeff

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Hi Jeff

We use the Hotspot to connect the RS2 then RFD on USB

There is one external antenna and a stubby in the fuselage just incase someone forgets to connect the external

The M2 is connected to GPS1 and is used for Nav I know they don’t advise it but we do have a Here2 as backup it has never caused us any issues we get on average 24 Sats on the M2 and 17 on the Here2 GPS_AUTO_SWITCH is set to 1 choose best

We use Panasonic 3.7v 3200mah 18650 Li-ion cells 7 in total

The Believers are setup exactly the same but on 6S and we only carry one sensor we still get a reasonable 7/8 Amps in cruise

No problem anytime, we have quite a few hours on the fighter its a very good aircraft I cant think of anything else on the market at the moment that could replace it

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Thanks for the tip Greg. I have some small 1s batteries (160mAh) that I will plan to hookup to the VIFLY so that I don’t have to worry about the primary depleting.

Cheers!

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I have a gut feeling but I won’t venture a guess because I do not know for sure and it’s been a while since my electrical engineering for physics courses. @rolf might be able to answer definitively. This is something you want to make sure is wired up correctly unless you want to risk some “magic smoke.” :sunglasses:

I have XT90 connectors for the VTOL LiPo battery hookups with everything else downstream soldered. The Li-Ion battery hookups are XT60 and should never reach 60 Amps so I should be ok there plus the XT90 plugs come at the expense of extra weight. The anti-spark connectors are a nice option, I might swap out later this fall.

Cheers,
Christian

Welcome Jed!

Your setup is very similar to what I am working on (MTOW 11.4 kg). I’m glad to hear that it is working out for you thus far. I do find it curious that you use the same motor model for all of the motors on board. The MN605 is significantly lighter than the AT4130 that I am using but not nearly as powerful (mine is overbuilt intentionally). In hindsight, I would have gone for the integrated arm kits to save the hassle of installation on the VTOL motors.

How has your range been with the Herelink? Has it dropped out on any of your missions or have you pushed that limit? How was initial tuning on the heavy bird? Which parameter set do you use?

Photos of your build are much appreciated if you’re willing to share.

Cheers,
Christian

It’s very common for electronic systems to have multiple voltages. As others have said, you need a common ground.

Generally connecting the grounds of the batteries is a safe way to connect the grounds. It is certainly possible to connect grounds in a way which will burn out components. I learned this about 7 years ago when I destroyed a microcontroller by connecting the ground from a motor controller to a ground connection which wasn’t near where the motor was receiving its power. I described my problem in this thread on the Parallax forums. (It’s embarrassing to read my old comments. Those guys were so patient with me.)

My mistake would be like connecting the ground of the power connection to a UART ground on the flight controller. As long as you have the return grounds from large power items return to the same power junction used by the positive line, you should be fine.

Here’s how Phil Pilgrim explained it:

A lot may hinge upon how and where things are grounded. Since you are using high-current devices, it’s important that the ground currents from them do not traverse through the logic portion of your circuit. IOW, the ground returns of all devices should be connected at a single point in such a way that that the currents from high-current devices do not return to the logic ground terminal but directly to the high-current ground return. High ground currents through your logic circuit could easily fry the Prop.

His comment applies to protecting flight controllers as much as it applies to protecting a Propeller microcontroller.

If you’re not sure about your particular setup, you could always post a diagram and photo of your planned wiring and someone here can take a look at it to make sure you’re not going to fry any components.

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Hi Jed

Thanks for the great information - it is very useful to have details of other members working examples.

Just a couple more questions…if i may?

Are you using the EMLID Tallysman antenna for the M2? I assume it is inside the fuse somewhere? Do you mount it on the recommended 100mm ground plane? Where do you mount it in relation to the camera position?

Have you ever used the Hex Here+ RTK ground base to send corrections to your Here 2/Here 3 - in addition to the EMLID RTK system?

If you were just powering the single sony camera and no other sensors - what in your opinion should be the Li-Ion configuration of the separate battery pack ie S and P configuration for V and mAh etc to ensure that it runs for at least the entire mission?

Are you able of give me the specification of the motors, esc’s and props that you use in the Believers that you are using?

Thanks again

Cheers

Jeff

Hi Duane

Thanks for your great information and links to follow up with my Common Ground question.

It is something that needs to be right otherwise yes there will potentially be $$ going up in smoke…

I checked out the freeman after your suggestion, but didn’t end up going down that route - instead just ordered a MFE Striver as my first Quadplane build - and rather than trying to covert my believer - set that up as a belly lander…I like the 4+1 configuration and at 7Kg the Striver should be ideal for my 6S setup…I will probably order a Fighter as well…and would set that up as a 12S to take advantage of all that it offers.

Thanks again.

Cheers

Jeff

Hi Christian,

Thanks again for your great information with regards to the common ground question.

I have some good suggestions too from Duane and should seek Rolf’s advice as well…yes Magic Smoke can be expensive and very alarming to watch! I have fried some LED’s by over voltage, in the past but thankfully no expensive components - Yet! I always use a Smoke Stopper when I first plug in so hopefully that will at least catch some problems…

Thanks for the info on the connectors - I have XT-60’s and Deans etc on most of my Lipo’s so I was going to replace these all with XT-90 so I have consistent connections and so I don’t need to use adaptors on these…soldering downstream is a good idea to reduce points of failure and weight…it all adds up! anti-spark connectors would be good too.

Thanks again

Cheers

Jeff

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Jeff, no worries. I’m happy to try and help save the head banging on the desk/wall of others if possible. I’ve been down many rabbit holes on this adventure.

Consistent connector size makes the charging easy.

I am using the stock connector size on the batteries since my battery circuits are in series (double voltage, same capacity, same current). If I were to connect in parallel then I’d consider upgrading the connections to handle the increase in current (i.e., if expecting constant flow at 60 Amps then I’d upgrade to XT90).

Just be sure to not cross the battery cables when removing and adding a new connector- it’s a quick lesson that you only need once! ha

Cheers,
Christian

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If it was the EMLID M2 kit, it comes with a helical antenna and doesn’t require a ground plane. In the video, it appears to be mounted at the rear GPS spot by the tail which is where I have mounted mine. Fits nicely there.

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Hi Christian

Yes that is a nicer solution than the Tallysman antenna…

Cheers

Jeff

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Share an introduction and video of Striver mini VTOL.
Striver mini VTOL

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Hi Christian, I ordered an EMLID helical antenna - thanks for the inspiration - it definitely will be a nicer installation and no ground plane required! It still works with the M+ but only L1 and it is in then in place for when I upgrade to M2.

It will be nice to see some more photos of your overall component installation.

I have switched camps for now and will build a Striver first, as I figured that as a 6S system, I can build it out nicely to almost MTOW capacity - and then when I re-visit my Fighter build, I can do so without interrupting my working machine - and I will come back to the mixed battery idea, but all as 12S.

Actually as I mentioned earlier - I will probably also build a hack VTOL platform using a Volantex Ranger EX - massive fuse but probably not much in the way of payload capacity - but a good test bed for VTOL ideas…3D printed camera mounts and 1/2 axis gimbals etc…it doesn’t need to be built for endurance - just proof of concept and if it crashes - well, so be it… I might just use a cheaper FC than the Orange Cube though…

Cheers

Jeff

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Hi Jeff

I use the helical antenna that came with the M2 and I do use a ground plane it states that its optional but it made a big difference

I did try it and it was a bit disappointing I think I had a fixed lock on about 3 occasions I tried for about 3 months to get it to work reliably but gave up in the end

The RX1R Mk II needs 3.7v so 1s I have 1S 3P the batteries are 3200Mah

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Hi Christian

The Herelink is an excellent piece of kit it has never dropped out and the video transmission has been faultless although we have only tested it out to 500m

I used the default Plane parameters the tuning was quite easy

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Hi Jed,

Thanks for your responses.

That’s very disappointing about the Here+ RTK but I guess if the EMLID system serves as the primary and reliable RTK component in the system, then it doesn’t matter. I have the M+ still in its box, but don’t know if I will bother with it at all, given your experience with it.

How big did you need to make the ground plane to make the helical antenna work properly for you? How did you end up mounting this assembly on the aircraft - you mentioned in your post that it required some work to get it optimised… any photos that you don’t mind sharing? I have been using plain copper clad fibreglass PCB sheet that I use for my tallysman antenna - do you use something like that for your groundplane?

With regards to the physical connection between the M2 and the Pixhawk, do you use the M2’s S1 port plugged into the Pixhawk 2.1 (CUBE) carrier board via the 6 pin cable to GPS 2 port to receive the RTK corrections through the system with the RFD radio plugged into the telemetry port of the Pixhawk - or do you need to have a feed directly from the RFD radio to the M2? Some more detailed information on this setup would be most appreciated.

Cheers

Jeff

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Hi Christian

Well I only switched to the Striver idea temporarily - Changed my mind and changed the order - I now have a Fighter on the way…The Striver seemed like a good idea (and looks like a great airframe) but I was going to run out of space and would have been at MTOW very easily…So the fighter it is, as it will allow more options for payload…I have a whole lot of bits and pieces for a conversion too - and I think I might turn my attention to my believer and see if I can keep it setup as a twin tractor and add VTOL…options…options…Ranger Ex will still get the VTOL treatment…

I bought a T-motor AT4120 KV500 and have an 80amp ESC - so obviously a 6S setup but I thought I will still set the fighter up 6S for the cruise with two 12500 mAh Li-Ion batteries in parallel for 25000 mAh capacity and a 12S VTOL System maybe with two 4000mAh Lipo’s in series. This 12500 Foxtech Li-Ion idea comes from reading one of your earlier posts but I am doubling it up parallel 6S and more flight time potential. I am very interested in hearing about your spilt battery system performance once you get operational.

Cheers

Jeff

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@Jed_Freeman

I can give you a report on range once I get the Herelink buttons working for the VTOL modes.

Did you have any issues getting Q_* modes to activate using the Herelink remote? Do you mind sharing your parameter file? At a minimum I’d like to compare values for the FLTMODE_* to see if that is what the problem is.

Cheers,
Christian