Tony Nijhuis 50" Vulcan EDF version

[TonyS]

I've built a few kits before, all have been balsa builds from pre-cut kits and plans and I'm getting comfortable with the basics.

This time I feel I've bitten off a bit more than I can chew.

Wiring 4 EDF motors, elevons and retractable tricycle landing gear (with a steerable nose wheel) to two batteries and a single transmitter is pretty daunting to say the least. I can see the wires multiplying before my eyes and there's not a lot of room and I can't see any instructions as to where to feed the wires from the nose wheel and steering servo through to where I think I'm going to have to squeeze in the Rx.

I have got as far as ensuring the landing gear works and steers which is something I guess - video here

[TonyS]

Just a quick question for all you veterans out there..,.

When wiring up tricycle landing gear do you use a 3 way harness or two Y harnesses. The way I've cobbled mine together with extensions and two Y harnesses means that there are lots of connections to go wrong. I don't want to clip them all as the weight is climbing all the time so.....?

[Craig Carr]

Hello Tony,

firstly the retracts, they normally come with a 3 way Y harness which is what I used. Im sure on mine the 2 mains went into the Y harness without an extension lead, but I may have had to extend the nose leg lead a little.

if I recall correctly I think the plan indicates the hole cut outs on the formers to feed nose wiring through (I made  them a little bigger than stated on plan for ease)

Secondly, your first post, yes its an absolute nightmare squeezing everything in. It’s doable though
here is my installation, it’s not pleasant but the best I could do.

The escs (turnigy 40amp) are along the middle of the fuz centre keel (2x) and down one side of the electronics bay opening. I braced them away (so not touching) the tubes as they were made from A3 laminating pouches and I was worried any heat from the escs may deform them

The rx is also in the centre keel. Had to extend the 3 phase motor wiring for some of them. It does all work though and the model does fly nicely but the fans should be 4s ideally.

have you seen this build thread here?

Craig

Edited By Craig Carr on 17/08/2020 06:36:57

[TonyS]

Thanks Craig,

I didn't get a three way harness with the retracts sadly.

The thread is really useful thanks. It's given me a few ideas. It was interesting to see that others had issues with the thrust tubes. That is what stalled the build in the first place. I did everything including building a tapered 'template' tube to wrap the acetate around. In the end I found it was as easy to stick the acetate in the fuse, the natural tendency for it to unroll and the fan in place held it together with the aid of some sellotape. I then glued using canopy glue which took several days to dry.

Anyway, once I'd managed to get over that hurdle I was back into balsa gluing which is where I'm most comfortable!

Can't see where you put the Rx? Was it accessible after the build?

I can't find a 4 way ESC connector block anywhere. If anyone has any ideas I'd be grateful to hear them.

Thanks

Tony

[Craig Carr]

Hi Tony,

I have my rx just towards the rear ... if you zoom in on the bit I’ve circled you should just see “futaba”

Regarding the escs “4 way connection” , I simply soldered the battery wires to make “two” sets of escs in parallel. (Ie bring the positives together as one leg of wiring and the negatives as another leg.). Then each of these parallel legs go each of the 2 battery bays. I had mine wired so one battery/esc combo powered the inner fans... the other battery /esc combo powered the outer fans.

you must though link all 4 esc servo leads together for your rx throttle channel BUT remove the red power wire in 3 of the escs (Ie so only 1 esc provides power to your rx)

I lift the tab and pull the red wire back and out of the servo plug.  Pop a little heat shrink over it so if at a later date you wish to use the esc in another model the red wire can be easily reinserted

Edited By Craig Carr on 17/08/2020 09:30:44

[Craig Carr]

Here’s a commercially produced 3 way lead for your retracts Tony,

but if they were the hobby king type you should have received one with the units

Click here

[TonyS]

Guys,

I’m now completely stumped.

I've created a 4 into 1 cable for my ESC leads with the red wire removed from three so the Rx only receives power from one.
So, two batteries. One battery powers the middle fans and the other the outside fans. Only one ESC is powering the Rx so the battery to that motor gets connected first. (This battery powers the outside motors). All the usual bleeps and I have control of retracts, rudder (for the nose-wheel) and elevrons. I then connect the second battery. I then have power to the inside motors (from the second battery) but no power to the outside motors.
no matter what I do I don’t seem to be able to get power to the outside two motors.

All suggestions welcome.

Thanks.

[PeterF]

I would start with a servo tester acting as the throttle signal and apply this one by one to each ESC (disconnected from the 4 into 1 wire), then connect the inner and outer ESCs and test as seperate pairs (one red wire removed). Also do a continuity or resistance check in your 4 into 1 wire.

I can not think of anything off hand. I have done several multis where the batteries are separate and the only connection is the throttle leads to the RX without issue.

[TonyS]

Thanks Peter,

I have a funny feeling that today is going to be one of those painstaking step-by-step testing days!

still, I can think of worse things on a dull BH Monday. 😀

[TonyS]

Thanks Peter,

I have a funny feeling that today is going to be one of those painstaking step-by-step testing days!

still, I can think of worse things on a dull BH Monday. 😀

[Craig Carr]

Hello Tony,

im the same as Peter, can’t think of anything offhand, if you’ve done it as described it will work. Did you remove the 3 x red wires directly from the escs rather than any servo y leads?

Edited By Craig Carr on 31/08/2020 08:55:58

[TonyS]

OK. So the fans, batteries and esc's are wired as per the diagram. Things to note.

1. Battery 1 powers the inside fans, Battery 2 the outside fans
2. All cables from the ESCs are intact. The 4 into one only carries the positive from ESC wire 3 to the Rx
3. Battery 1 is connected first to give Rx power

It doesn't work

When I power up only two fans ever work. Is this something to do with the arming sequence for the motors? Is it because having plugged the Rx in and this having 'set' the ESC's for the two motors powered by Battery 1, when I then connect Battery 2 the Rx isn't then shaking hands with the two additional ESC's?

[TonyS]

Posted by Craig Carr on 31/08/2020 08:32:01:

Hello Tony,

im the same as Peter, can’t think of anything offhand, if you’ve done it as described it will work. Did you remove the 3 x red wires directly from the escs rather than any servo y leads?

Edited By Craig Carr on 31/08/2020 08:55:58

No Craig I excluded the ‘live’ from the 4 into 1 on three of the sockets - same effect I’d have thought.

[Craig Carr]

Hello Tony

Was at the flying field today with my vulcan. It’s wired the same as your diagram.

my club mate/electric guru Brian Collins (Who had BRC hobbies) had a look at your diagram and said it all looks ok. He did mention though that he would have removed the red wire directly from 3 of the escs as well.

Might be worth a try ?

craig

[PeterF]

I had a 4 engine EDF, but I had both batteries connected together, then splitting to the 4 ESCs so first battery in armed all ESCs. Perhaps if you jury rig a cross connection between the batteries so you arm them all together to see, just do not power up the fans if the cross connection is lightweight.

The other thing I have thought about is have you calibrated each of your ESCs individually against your transmitter throttle range, is there something odd that once one lot of ESCs are properly armed, when the next battery is connected, those ESCs are not seeing a zero throttle, do you have any trim on your throttle.

[TonyS]

Thanks chaps.

some food for thought. First I’ll check the throttle settings then I think I’ll jury rig a cross connection to see if it’s an arming issue. I’ll tease out the live wires from three ESC connections but to be honest I can’t see that having any impact given the way it’s wired.

Frustrating.

[Nik Harrison]

Tony,

Simple test. What happens if you attach battery No2 first?

Nik

[Craig Carr]

Are you sorted with this now Tony?

Craig

[TonyS]

Hi Craig,

the simple answer is no but hopefully soon.
I never did work out why I couldn’t get all 4 motors to function but by a process of elimination it all seemed to come back to my 4 into 1 lead from the esc’s. I remade it but with no better results. I’ve now ordered one off eBay which is making its way from China as I type. Hopefully this will sort it out, if not, I’m at a complete loss and can’t proceed to finish the plane until I’m sure what the fix is.
fingers crossed and thanks for asking.
Tony

[PeterF]

Tony,

This has continued to puzzle me having done a 4 EDF that ran perfectly well, the only difference as stated above is I had the 2 batteries and 4 ESCs connected together. On my set up I used three 2 way leads to get to 4 ESC connections. My memory has just recalled reading reports a few years ago that some ESCs do not work well if too many are connected together. In these cases it is solved by adding the ESCs to separate channels on the RX and having mixers on the TX to mirror the throttle channel to the extra ESC channels. The cause was never diagnosed, but was thought to either be something like excessive current draw on the signal input to the ESCs causing loss of signal or noise from the ESCs corrupting the signal to the others. Keeping them on separate RX channels overcomes both of these issues.

My 4 EDF used HobbyWing platinum 40A ESCs, what is yours using.

Anyway, this suggests that you should test this by setting up a dummy model with 4 throttle outputs and try it with the ESC leads separate. If the works, then you could also try a test with two throttle outputs and with Y leads. The 2 outputs and Y leads may work.

I know this is clutching at straws time.

Peter.

Edited By PeterF on 11/09/2020 09:47:55

[TonyS]

Peter,

Thanks very much for that, it makes a lot of sense and I'd be over the moon to use two Y leads and two of the Rx channels which might well work, however the setting up of this is way beyond me at the minute ( I feel pretty good with myself if I manage to find the Delta wing setting on my Tx let alone mixing channels).

Also I have a Spektrum Dx7 Tx which may or may not be able to handle channel mixing, I'd have to do some research.

All worth doing though if I'm ever to get this thing to fly. I guess I'll add learning a bit about the proper use of my Tx to the list of processes needed to get this one finished..

Thanks again for the input.

Tony

[PeterF]

Some transmitters have the ability to specify that the model has 2 engines and the Tx then allocates 2 separate Rx channels for the 2 throttles without the need for any mixing. I do not use Spektrum so do not know your specific Tx programming details.

[TonyS]

Thanks again Peter - I'll dig into the manual over the weekend

[Nik Harrison]

Tony,

I've had a similar problem powering 4 ESC but from a Spektrum Rx. It turned out that the Rx could only power any 2 ESC at a time. The current drive from the Rx was insufficient. I used an op-amp to make a unity gain amp and the extra drive capability made it all work OK. Since found that there was no need to make one as I've now found a commercial product that does the same.

Try this

Cheers,

Nik

[TonyS]

Nick,

you’ve made my day.
Last night I tried what was my last idea and that was a proprietary 4 into 1 hoping it was my soldering that’s was defective. No joy, in fact, one of the retracts stopped working. This supports your idea that the current from only one ESC isn’t enough to drive signals to 4 motors and power three retracts and three servos.

I’ll be buying some of those beauties and will update later....

thanks again.

tony