Wing servo lead plugs and sockets?

[Tim Flyer]

I would like to hear people’s ideas on servo lead tidying and connection in wings. Currently all my fleet have just plain servo leads in each wing . I colour code this with plastic tape to speed up connection when setting planes up at the field. Currently I’m assembling an 80 inch Hurricane with flaps and retracts etc and wondered whether I should take the plunge and buy proper wing plugs. The plugs and sockets seem to be about £20 for each side ( plug and socket required) so quite costly. I wondered what others do ?

[John Lee]

Multiplex green M6 plugs & sockets.

Use common +ve & -ve leaving 4 pins for the signal to up to 4 servos. I usually bond the plug into the fuselage & leave the socket free floating on the wing wiring harness. I only use the genuine items at about £1 each, for me it's not worth saving pennies on such a flight critical component.

[Martin McIntosh]

I had the same problem, with some wings having six servos. Connecting them all and fitting safe keepers took ages so I got some 10 and 12 way female plug shells from CPC. These are identical to JR/Hitech types so the male sockets fit. The parts in the wing consist of straight and 90deg. headers soldered to Vero board which is mounted with double sided tape.

Double ended 3 pin male sockets connect the 12 ways to the Rx.

I now use these on any model requiring more than two connections. They have cut the assembly time of my 96" Hurricane by three quarters.

If you look at some of my build blogs you will see what I mean.

[Biggles' Elder Brother - Moderator]

If your radio can handle it, use SBUS. Just one servo lead per wing then
BEB

[Tim Flyer]

Thank You guys very helpful ...and much appreciated . I will take a look and try to do a bit better on this model. 😊

[PatMc]

I've recently been considering using SBUS for an E-glider that will have a 3 piece wing with aileron (possibly 4) & flaps used as "crow" brakes but I'm a bit concerned at the thought of having a single point of major, potential failure.
An alternative to SBUS came to mind that doesn't have any wiring connection between wing & fuselage.
Why not use two Rx's bound to the same model in the Tx memory ? One in the fuselage powered from the ESC BEC & a second Rx sited in the wings fed by it's own dedicated battery.

Did a lash up yesterday evening using a pair of spare Rx's, some old Futaba 148's & a two 4.8v Nimh's. On the bench it proved to work fine. If further testing prove as successful, when done in earnest the plan will be to have a 2s LiFePo battery in the wings with the servos rated to take the higher voltage.

Main disadvantages I foresee is the need to maintain a second battery & loss of telemetry from one Rx.

 

Edited By PatMc on 30/08/2018 19:37:26

[Biggles' Elder Brother - Moderator]

Yes Pat, It's an ineresting solution, one I have seen before but not used personally.

However, surely you still have a single point of failure - ie the power supply lead to the in-wing Rx? So are we really any further forward?

BEB

[Martin McIntosh]

This should give you some idea.

Or this.

[Dane Crosby]

I have just completed my modern version of Swannee with ailerons and flaps.

Just before crimping normal servo connectors at the wing root I was lucky to discover that Purple Power / 4Max, are now supplying MaxLock connectors. They used to be called Ashlock.

They appear similar to normal servo crimp sockets and plugs and are from 6 to 12 way. The assembly is flat and has a locking latch. I have tested it out and all works nicely. I'll let you know how it all copes in the air after the maiden next Saturday.

The crimps outwardly look the same as normal servo connector crimps. They are totally opposite systems to each other. Normal servo crimps have a little square cut-out that engages with a tiny plastic tongue in the cover. The MaxLock crimps each have a small leaf spring that clicks into a slot in the cover. ( How did I find this out? Yup,I tried to use up my old servo lead crimps first. Had to cut them off and start again with the new type......Doh)

[PatMc]

Posted by Biggles' Elder Brother - Moderator on 30/08/2018 20:37:40:

Yes Pat, It's an ineresting solution, one I have seen before but not used personally.

However, surely you still have a single point of failure - ie the power supply lead to the in-wing Rx? So are we really any further forward?

BEB

I think on balance the risks of system or partial system failure will be substantially reduced using 2 Rx's instead of SBUS.

The power supply lead of a 2 Rx system does not need to be plugged in & out each flying session whereas with an SBUS the lead between fuselage & wing does. I don't think the plugs & sockets are really designed for constant plug/unplug.
Agreed that a failure of the in wing power supply of 2 Rx system would have the same result as a failure of an SBUS fuselage/wing lead. But the SBUS system would also have the same risk of failure of it's power supply only with complete loss rather than major control loss.
My intention will be keep telemetry with the wing Rx so that the battery can be monitored & assume that RSSI is similar at both Rx's. The BEC feeding the fuselage Rx will only have the load of 2 servos so is unlikely to suffer overloading or overheating.

[Biggles' Elder Brother - Moderator]

I love the idea that it is a "wireless" solution, that's a major plus for it. And its something I'd definitely have a go at in the right model, so let us know how it goes I'd be very interested. But I'm afraid I'm not convinced its a more reliable solution.

BEB

[Ron Gray]

I tend to agree with BEB, there is still a single point of failure for the twin Rx solution. With the SBUS setup this can more easily be reduced by adding in either power redundancy, eg Optipower Ultraguard or for full redundancy a redundancy bus, giving both power and Rx redundancy.

[The Wright Stuff]

I'm not really sure why we are focusing on the significance of a 'single point of failure' in this context. The transmitter is a single point of failure. The pilot is a single point of failure. Whatever you do, there will always be a weakest link somewhere. We should really be comparing the individual reliability of the various approaches (probability of failure), not the number of back-ups...

So, the corresponding question is: are there any failure modes when using the SBUS decoder system over and above the possibility of broken wires or contact resistance on the sockets (i.e. stuff that can equally well happen to a battery connection)?

[Chris Walby]

I am trying out JST-XH balance lead connectors, current model is using the 7 pin version for:

• Positive
• Throttle signal
• Aileron signal
• Flap signal
• Gear signal
• Wing lights (+3v)
• Negative

The additional advantage of making a loom up with male connector for port and female for starboard is that the gear (and others if needed) can be on different RX channels.

I use standard heavy duty servo leads from the RX to where the leads split Port and Starboard and then solder the connections to the JST-XH plug/sockets. The positive and negative are respectively combined so plenty of current available or you could connect directly and avoid servo supplies going through the RX, handy if you want retracts on a different supply.

 

 

 

Edited By Chris Walby on 31/08/2018 08:08:34

[Engine Doctor]

+1 for JST balance leads. I have used the 6s plugs and sockets on an FMS Zero for the wing as it has retacts, flaps,ailerons and lights, too many individual plugs ! Made a loom for the fuz and for wing. Simple couple of second job to assemble at field. Do make sure you get leads with decent wire as there are some rubbish leads on the net.

Edited By Engine Doctor on 31/08/2018 08:41:47

[Ron Gray]

@TWS - any failure that can happen to a ‘normal’ non SBUS installation can still happen to an SBUS one, with the same results!! However using power redundancy / Rx redundancy will significantly reduce such risks, in both types of installations. But the OP asked for replies with different wiring options, I’m with BEB, SBUS with redundancy for me.

[The Wright Stuff]

Posted by Ron Gray on 31/08/2018 09:13:39:

@TWS - any failure that can happen to a ‘normal’ non SBUS installation can still happen to an SBUS one, with the same results!! However using power redundancy / Rx redundancy will significantly reduce such risks, in both types of installations. But the OP asked for replies with different wiring options, I’m with BEB, SBUS with redundancy for me.

Exactly, I'm agreeing with you too. The SBUS presents a single point of failure, yes, but it does not introduce any new likely failure modes.

Edited By The Wright Stuff on 31/08/2018 09:18:24

[bert baker]

Are you going to use air or electric retracts

[Martin McIntosh]

The problem with XH is that they are designed to plug into a PCB header, not a free plug which has short solder pins making it difficult to support the wiring. The same applies to Multiplex connectors. I do, however, occasionally use the balance plugs on LiPo`s to tap in for a lower voltage to drive nav lights.

At least with my method you only lose one output in the event of a failure.

[Chris Walby]

Martin,

I use JST-XH balance lead extensions, correct me if I am wrong but aren't both ends (male and female) free plugs?

[Bob Cotsford]

I'm using both Sbus and MaxLock/Ashlok solutions in different models. With FrSky and XPS Sbus decoders I've found it best (essential!) to use digital servos but the Ashloks work with any type of servo or retract. Sbus is great if you need more than 8 channels, easy enough to find yourself in that situation with individual flap, aileron and retract channels taking up 6.

With Sbus setups I do like to use a second lead to supply a dedicated power supply if it's driving retracts too or high power servos.

I'm not sure that I like the idea of JST-XH, the ones I've seen all used soldered connections with small section pins, I have too many bad memories related to soldered connections on early radio systems!

I've thought about the second receiver solution but it would need a second battery to charge (or forget about) and a second switch, possibly the weakest link in the setup.

[Mike T]

Posted by Martin McIntosh on 31/08/2018 11:21:50:

The problem with XH is that they are designed to plug into a PCB header, not a free plug which has short solder pins making it difficult to support the wiring. The same applies to Multiplex connectors. I do, however, occasionally use the balance plugs on LiPo`s to tap in for a lower voltage to drive nav lights.

At least with my method you only lose one output in the event of a failure.

I use these on the Mpx connectors, which solve the support problem and also provide a good grip for making and breaking: http://www.nexusmodels.co.uk/emcotec-ecm-mpx-6-pins-without-connector-pcb-solder-wire-connector-5-pieces-a86008-830.html

Edited By Mike T on 31/08/2018 12:18:50

[Martin McIntosh]

Ah Chris, the male ends shown obviously use crimps instead of soldered joints which I have not seen before.

One end is a free plug, the other a free socket. (or slug, plocket, whatever you want to call them!)

[Martin Harris - Moderator]

Many of the suggested solutions have one glaring drawback, in my opinion. I have seen far too many soldered joints fail at the point where the solder finishes - any movement from connecting/disconnecting and/or vibration can quickly cause the strands to fail where they meet the solder.

For this reason, I prefer properly crimped joints which have strain relief built in.

If you do use soldered joints (the joints themselves are an excellent form of termination) then it is imperative to provide proper strain relief and support for the wires - a piece of heatshrink is unlikely to be sufficient as witnessed by many failures of JST leads using PCB headers as balance wire extension lead terminals.

See Chris Walby's last picture for an example of this "misuse".

Incidentally, JST stands for Japan Solderless Terminals!

Edited By Martin Harris on 31/08/2018 15:20:12

[eflightray]

On my Vulcan, I have elevator, aileron, and retract connections to make with the plug in outer wing panels.

To make life a little easier during assembly, I fixed the connectors (extension leads) to the inner wing panel, (ply strip and hot glue).

Then did something similar for the outer wing panel servo connectors, but left 'floating'.

I cut the outer servo connector housing in half ((normally only on the pin, male, side), glued them to a narrow piece of 1/6" ply, and then locked the servo lead connectors (female side) in the half housing so that they stuck out far enough to make a good connection.

The ply strip sticks out either end slightly to allow a finger to push/pull the connectors together and pull apart.

Using the existing servo and extension lead connectors means I can easily change a servo/retract without any need to de-solder.

Ray.