Redundancy 101

Originally Posted by camss69

Redundancy 101

I like No. 5.

Bobby aka TDD

BTW, I also like the town's name as it's he same as mine!!

I figure maybe if I have a pic people will understand it better....

#4 is the true winner ! lose the regs and go HV use a 922 or better Rx

Originally Posted by airboss/oc

#4 is the true winner ! lose the regs and go HV use a 922 or better Rx

True winner in what regard? In terms of cost? #4 is a compromise between cost and redundancy. In terms of redundancy #5 can't be beat.

Ha! Just noticed that there are only 4 options, 2 and 3 are one option, got carried away with the numbers.

I must be missing something as i can't see how you turn the battery's on and off. You have a s/w in the circuit, out of the receiver, but what is it actually doing? How do you charge the battery's? Do you unplug them to charge? Running without switches would be good as it removes another potential failure point but to plug/unplug power packs, at the receiver, to charge isn't practical. Like I said, I must be missing something- please explain

Originally Posted by rdgreen

I must be missing something as i can't see how you turn the battery's on and off. You have a s/w in the circuit, out of the receiver, but what is it actually doing? How do you charge the battery's? Do you unplug them to charge? Running without switches would be good as it removes another potential failure point but to plug/unplug power packs, at the receiver, to charge isn't practical. Like I said, I must be missing something- please explain

No problem.
I use JR/Spektrum "power safe" receivers, they have "fail safe" switches and the battery power does not flow through the switch, so it is shown differently (off to the side of the receiver) on the drawing. The fail safe switch setup constantly draws a small amount of current and in the manual it recommends you unplug the batteries when you are not going to use them for extended periods of time. (between flying sessions) So when charging yes I unplug the batteries but I unplug them anyway. They are also lipo batteries so they are charged through the balancing connector anyway and not he main power leads. The receiver has leads that come off it for the batteries and they are unplugged at the leads not directly at the receiver. I agree that wouldn't be practical to unplug the batts directly from the RX every time.

If you think about option number 5 for a minute, think about the most practical failure you are going to have. I think the most common are battery and switch.

A battery failure in this setup should go un-noticed until you go to check your batteries or recharge. The batteries are "Y" harnessed and each battery feeds each receiver. The key is to make sure if you go to a single battery that one battery is enough to support the entire load of your plane.

Switch failures should virtually be eliminated from this setup but if a switch can fail open (which would cause the system to come on) why couldn't it fail closed? (causing the system to go or remain off) In this system it would still be redundant in the fact that the second receiver would still function.

I just setup my 35% Yak similar to #5 (did you see the pic's?). But I had only 1 big rudder servo (Hitec 7980). I wouldn't split the rudder servos like that. Also better to put throttle on one and ig kill on the other. Mine also has no cross-connection between the batt's and rx's. I can tell you that my batt draw is not even. The rudder being on one and not ther other makes one drain faster that the other. Not a big deal though. I have enough for 4-5 flights on 2x2300 A123's. Have another 2300 A123 on ignition.

Originally Posted by JoeAirPort

I just setup my 35% Yak similar to #5 (did you see the pic's?). But I had only 1 big rudder servo (Hitec 7980). I wouldn't split the rudder servos like that. Also better to put throttle on one and ig kill on the other. Mine also has no cross-connection between the batt's and rx's. I can tell you that my batt draw is not even. The rudder being on one and not ther other makes one drain faster that the other. Not a big deal though. I have enough for 4-5 flights on 2x2300 A123's. Have another 2300 A123 on ignition.

Ahhh the rudder servos, so what are the two possible problems that could happen?

1. One servo goes dead for whatever reason, the second servo being on the other system still has control of the rudder and will overcome the drag of the dead servo.
2. One servo locks, either the second servo overcomes it or it can't. If the working servo can overcome the locked servo, you are doing ok, (this would be no different if they were on the same side) if it can't you are about in the same situation as if they were both on the same side.

In the case where the servo simply goes dead due to loosing one side and the working side still works, you are better off than if they were both on the same side. For example you loose one RX, the second RX is still working and your rudder is still working at half power. (probably slightly less)

Soo... I split the rudder servos.

The ignition kill, I'm using the smart fly ignition kill and it is setup to work with a dual RX setup, it plugs into both receivers and as long as one RX is powered up it continues to work normally. If both RX's drop it will drop the ignition. Can't get much better than that! Notice in the drawing it shows the Ign kill on both RX's.

The cross connection on the power to the RX's, the power safe receivers have the ability to isolate a bad battery. (according to the documentation that comes with the RX's) So if one battery goes bad both RX's can isolate from it.

In my setup the batteries recharge within 100 mA of each other every time.

screw the failsafe switch! i use a bind plug in my r1222, soon to be r1222x, my 3w150ts(twin spark) has two ignitiongs, two regs, two batteries, and the equivalanet of 2 switches for each battery! now thats redudant, now only if i could afford two RX's

Originally Posted by INFINITE-FOAMIES

screw the failsafe switch! i use a bind plug in my r1222, soon to be r1222x, my 3w150ts(twin spark) has two ignitiongs, two regs, two batteries, and the equivalanet of 2 switches for each battery! now thats redudant, now only if i could afford two RX's

The bind plug trick works ok, I've used it before myself, freeks people out when there is a bind plug sticking out the side of your plane.

lol yea i know, i sued an ern101 plug from horizon(female recptor takes extension from the switch port and mounts it on the side of the plane, pulled the bind plug apart and took the silly 'bind plug' ribbon off and put one on that says 'remove before flight'

Use two power safe receivers (you pick JR or spektrum) and a "Y" harness for each battery to connect each battery to each receiver. The receivers have the ability to isolate a shorted battery (according to the instructions included with them) and in the case of a dead or failed battery the RX's will run off the one that is still good. As long as you have one good battery you are still flying and even a shorted battery won't stop the rx's from working. IMO this is the best most reliable setup going right now. Minimal points of failure, maximum redundancy. The key is of course using batteries that if you loose one the other has the capability to support the plane in flight (current and capacity wise). With this setup you shouldn't even notice a single battery failure until you check the batteries before your next flight.