S.Bus2

S.Bus2 is a newish method of connecting servos from Futaba. The new R7008sb RX from Futaba has a separate S.Bus2 connector on it. Serial Bus has been around for years, what it means is that two heavy duty battery wires run around the aircraft with a third signal wire. The signal itself comprises a Start bit, a series of information bits and a stop bit. To be honest the string of info from your TX is exactly that! The RX merely separates out the channel information and places it on separate sockets for your own use. What Futaba have done is made the serial stream from the TX available to you in the aircraft, this means you can run a 3 wire main around the aircraft and plug S.Bus servos into it. The down side is cost, and the fact that you have to plug the servo into the back of your TX to program it, before you fix it in the aircraft. You can program things like, channel number, speed, dead band, end point and neutral, to name but a few. I believe that a separate programmer is also available to do this.
Why would you do this one asks? Well, suppose you have a 4 servo wing, not that unusual I understand. You could run the Bus out into the wing and have 2 S.Bus servos set to Aileron1 (Channel 1) and the other wing half servos set to Aileron2 (Channel 6) Preset all your info and the servos do the rest, no more servos fighting one another!
Once you've done this you would have to remember that Channels 1 & 6 can no longer be used on the RX itself, unless, of course you want to split the ailerons and use standard analogue servos on the split section. Many full size gliders use this system when you don't want too much throw out towards the wing tip.
Beware, you can't mix S.Bus2 and S.Bus servos on the same Bus system!

For the record, I don't mind banter, just remember, if you can't take it, don't dish it!
If you can shed some light, please feel free.

Exactly right Phil, I imagine Futaba now have a proprietary chip that they can throw into servos and hubs, costs them just a few cents. You can also buy a hub that gives you 3 standard servo outputs.

Short of reducing the amount of wiring the S.Bus servos can have a lot of local programming. You can also now have extra battery packs anywhere in the plane. Think about a complex glider that can have up to 8 servos in each wing, camber changing, ailerons, spoilers, reduced travel on the outboard ailerons, all on only three wires!

This Sbus system sounds very like the DCC system now being used in model railways, where one controller can operate up to 60 loco's - individually, because each loco has it's own decoder chip with it's own address.

You will probably find that the same three wires will turn lights on and off, operate sound effects, and anything else that the gadgeteers can dream up.

alan cantwell wrote: only jesting, i use similar, i use JR Matchboxes, these can let me plug in several servos, and set them individually, i can also use programmable servos with my HI-TEC programmer, these i can set up individually for each control surface, is this similar to this futaba thing?

Exactly Alan, one of the reasons I'm doing this overview is because 10years from now all our radio stuff is going to be done this way. Not too long ago somebody on RCM&E did a future cast of what people would be doing 20years from now, Looking back over the last 20years, he wasn't far wrong!
Yes Eric, exactly like the DCC system, except that we don't get so many channels outgoing, we do however have 31 channels incoming!
Unfortunately Phil if we use a ring system we won't have the advantage of being able to distribute additional batteries around the plane. Also don't make the mistake of being egocentric! The Heli boys use quite a few functions, and use the S.Bus to connect their gyros. And, we haven't even touched ships!
The 14SG has a Roll function you can press, and yes it does exactly that!
Yes Simon it is eyewateringly expensive, but then many of us remember how expensive (as a proportion of income) a 4 channel set was 30 years ago! 5 years from now Analogue servos will be both expensive and only a small part of the market, the rest will all be programmable digital connected to an RX that does the channel distribution or to the S.Bus! And, by todays standards, cheap!