Two servo or Y lead for your ailerons ?

[Brian Cooper]

Meanwhile, back with "Y" leads... Nope, use separate channels. 

They are easier to set up and also gives a greater level of security in the event of servo failure. 

[jeff2wings]

19 minutes ago, Brian Cooper said:

Meanwhile, back with "Y" leads... Nope, use separate channels. 

They are easier to set up and also gives a greater level of security in the event of servo failure. 

Never quite understand this statement, if one servo on a Y lead fails the other one will continue working

[Brian Cooper]

8 hours ago, jeff2wings said:

Never quite understand this statement, if one servo on a Y lead fails the other one will continue working

Why risk connecting a good servo to a faulty one..

[jeff2wings]

So all those people using S.Bus...?........... 

[Brian Cooper]

2 hours ago, jeff2wings said:

So all those people using S.Bus...?........... 

Good point. . . Let's hope they stay lucky.

[Simon Chaddock]

Sure;y it depends on how a servo fails.

Fail to "dead" then no problem whether on a Y lead or not.

Fail to short circuit or gets stuck then there is a risk that the resulting voltage drop can cause an Rx brown out.

 

[RottenRow]

It’s not just S.Bus connected servos that share common connections. All of the servos on most models have their supply connections connected to the same point, the receiver output connector block. The effect on the other servos caused by one going short-circuit would be much the same irrespective of whether they are connected via a Y-lead or separate channels.

 

A short-circuit servo (pretty unlikely) would pull down the supply due to the excessive current probably sufficiently for the receiver to switch off (as Simon says). That’s if the insulation on the wiring doesn’t melt in the meantime.

 

Brian.

[Martin Harris - Moderator]

1 hour ago, RottenRow said:

A short-circuit servo (pretty unlikely) would pull down the supply due to the excessive current probably sufficiently for the receiver to switch off (as Simon says). That’s if the insulation on the wiring doesn’t melt in the meantime.

 

Brian.

I've witnessed such an incident.  I also had it happen to me when an aileron servo failed, but I was using a proprietry powerbox style device designed to trip the channel at 15A and only noticed a slight lack of response in roll.

[jeff2wings]

Exactly, so the 'safer with separate channels 'is nonsense ,most models using duel servos ( something first done in the 60's) can get by with a Y lead unless you have a need for differential/flap mix 

[Martin Harris - Moderator]

I'm not so sure Jeff - I can't recall the exact details but my friend's model survived the servo burn out, although it was considerably scorched around the wiring exit.

[GrumpyGnome]

Well, I use separate channels whenever I can..... I've never had an extension lead cause issues, but I have had several Y leads do so.  I'm sure others will have diametrically opposite experiences 🙂

 

As well as allowing all sorts of nice mixes, dual servos allows me to match speed and throw of different servos..... 

 

I think the only reason anyone has posted FOR using Y-leads is to save an output channel. Which I think is perfectly reasonable. In which case, it's really a question of "why woudn't you use a servo per channel?"

[Dickw]

2 hours ago, Martin Harris - Moderator said:

I'm not so sure Jeff - I can't recall the exact details but my friend's model survived the servo burn out, although it was considerably scorched around the wiring exit.

I think Martin may be referring to my Sebart Pitts biplane. It had 4 wing servos each on its own channel from the Rx. One of the wing servos failed and the wiring insulation on that servo lead melted into the wing covering. I landed because it felt sluggish, but I landed safely.

It did have a decent 6A (12A peak) BEC which obviously helped.

 

Dick