gregoryshock

In all the years I have flown RC planes, I've never installed more than one receiver. In one article in Model Aviation a guy talked about using redundant switches, servos, recievers, and battery packs. Meaning: He liked to have 2 of everything for a backup. Obviously, not every airplane is big enough to carry 2 of everything. Last summer, Ihad a scare. I went to give my airplane a pre flight test, and found out that my receiver was dead! The scary part was the fact there was no warning. Meaning it could have just died in the air, causing a crash! I'm curious how does one wire in 2 receievers? I fly with a 72 Mhz system.

TFF

Most split the left and right servos and have left and right receivers to run them. Separate batteries and switches.

tschuy

My Feedback: (1)

Ditto...

I did this with my BTEModels Super Flying King without issue. It worked great.

Given the newer 2.4GHz radio's and their binding requirement, has anyone been succesful with it?


Cheers,

Villa

If you split it left/right, then when one receiver fails, you will probably still crash anyway.Or not.

jetmech05

Here's the way I have seen it done.....Battery, switch and receiver 1...left aileron servo, rt elevator servo, rudder....then battery number 2 switch 2, receiver 2 with rt aileron left elevator and throttle......if you have 2 aileron servos per wing and and 2 elevator servos then split accordingly

TFF

You crash if you cant overcome the opposite side. Airliners can segregate side to side if something jams. It is called a fighting chance.

tschuy

My Feedback: (1)

Chances are (and my personal experience) the servo's will either hold their last position if deflected or will remain streamlined. I had one receiver drop and was lucky to get the bird down without damage.

Reason the receiver drop? Unknown. Changed battery pack first and it was no help. Tossed the receiver and replaced with a new one and everything went back to normal.... Didn't bother with sending the failed receiver in for repair. It was cheaper and easier for me to just toss it...

Cheers,

K-Bob

My Feedback: (1)

That's just, at best, silly.

Most planes will be very flyable with one half out. I've done it and it just seemed a little sluggish.

jetmech05

I have never had a receiver fail....but I did have an aileron servo fail on a dual aileron servo airplane...It was sluggish but it got home with no problems...The guys flying two receivers have very expensive aircraft like the carbon fiber fuselages...I fly with a gent whose airplane is 13 grand....If you want an example the CARF Corsair and a Moki radial are 8000 bucks...now start adding everything else...I 'll never have to worry about that outta my price range

Gray Beard

My Feedback: (-1)

I haven't seen it done in years. I was still wearing a bow tie and high button shoes last time I saw anyone install two RXs. The norm today is two batteries and two switches.
Most of my planes have two aileron servos and two elevator servos though and I do run two batteries {6volt} and two switches, heavy duty JR switches.
My set up isn't about being redundant as much as ease of set up. The redundant thing has saved a plane or two though when servo controls have failed. I use a 9-ch. TX so I use ch. 1 & 7 for aileron and ch 2 & 8 for elevator. My TX defaults to 6 or 7 for the second aileron servo and 8 for the second elevator servo. I only use two batteries on favorite 60 size planes or bigger. If it isn't a favorite or it's a smaller plane, then it has to take the single battery and switch risk.

Luchnia

My Feedback: (21)

It sort of makes no sense because you only fly with ONE radio! I always get a kick out of redundant this and redundant that, yet no one uses redundant radios? I mean you could certainly do it, but no one I know does. The radio is a single point of failure no matter how you look at it. If it is your number, it is your number Just how much redundancy can you build it to a system? So what if you have redundant receivers and your radio battery chokes one day? Or what if you have two receivers and a servo or two smokes that is vital?

Of all the folks I fly with, I have yet to see anyone with redundant receivers. I did see one that had a very nice Smart Fly Power setup with quite a bit of redundancy built it. An amazing setup. He still only had one radio to fly the plane with. With 2.4, if you have an extra receiver and you want to go for it, then you just bind to both receivers and you are done.

The cool thing about RC is happy flying and, "To each his own."

BarracudaHockey

My Feedback: (11)

You can bind more than one reciever to one transmitter (or tx/model memory with model match).

You can't bind more than one transmitter to a reciever.

In the case with Spektrum/JR the recievers need to be the same modulation and resolution.

jetmech05

Luchnia...I'm glad you're not an aircraft enginner.....redundancy is paramount.....I hear what your saying about a single point of failure.......what the guys that fly redundant systems are elminating is as many single point of failures as possible....
I fly gasser most of time anymore...my latest has dual battery switches and dual batteries.....Once each flight day I check to make sure that either battery is capable of powering the system alone....no I have never had a switch or battery failure in flight....
I also use an optic kill switch.....besides giving me an extra way to kill the engine...in case of system loss of power the iginition shuts down...no I have never had a runaway either..
I'm eleminating possible problems.....
But you are correct about single point of failure...the DC-10 in Souix City had 3 seperate hydraulic systems..all three were taken out by the engine....But we try to eleminate problems.....thats all they are doing

gene6029

Years ago we ran two recievers & two batteries & two switches. At that time we were interested in takeing the load off one reciever bus. Some of us were running 3& 4 servos on the rudder and anywhere from 2-4 on the ailerons, not to mention two on each elevator half. ...Gene

GerKonig

Well, yes, you still have "one" radio on the ground, but if you could eliminate most failures from the receiver onwards, you might eliminate most of the failures "except" the radio. And the day you use 2 radios you can have a stroke and crash anyway because there is only one pilot...

Being one piece, not subject to vibration, and impacts (landings), the radio transmitter most likely will create the least "issues" in the first place. Most people's concern (rightfully) is with the "onboard" part of the equation.

My 2 cents

Gerry

Gray Beard

My Feedback: (-1)

I have had two switches go bad and one battery short out on me. One of the switches was just dirt build up and it has worked fine after flushing it with electrical cleaner. {as an ignition switch} The other switch was a small one that came with cheap flight packs and I haven't used that type in decades. The battery pack was a bad wire. These things can happen and do. If you go to enough IMAA events you will see two people flying one plane with two radios and the plane will have two RXs. Flying the plane together is stretching it a bit though. One person is flying the plane and one person is operating things like lights, bombs, smoke and other systems. Last one I saw with two people at the controls was a huge BV-29.
Back in the days of people using two RXs was when giant scale was just getting going and people were experimenting with how to do things. It can work but we do have a lot better gear on the market today. Just look at the JR 9 channel 2.4 RX. It comes set up for two battery packs and has four antennas. This stuff wasn't even dreamed of a few decades ago.
Extra RXs you don't see these days but ganged servos operating one control surface is the norm if you go to any IMAC event. Almost all my planes have two aileron and two elevator servos. It's just how I like to set up my planes.

Luchnia

My Feedback: (21)

Thanks for the post jetmech.

I do agree and am certainly not against redundancy it just seems overkill sometimes with some RC planes, especially when you know guys that have been flying for 30+ years and rarely have an issue. I have even seen guys with all the fancy smancy stuff and watch an old timer come out with a plane he has been flying for a millenia and not have as many problems as the guy with the fancy stuff.

I try to put as much redundancy as I can possibly afford. For me at some point it is more than the plane is worth to me. I am more cautious with my more expensive models. I do think two switches and two batteries are not a bad suggestion. However I have seen when more complexity is added then more variable points are there to cause an issue.

I certainly understand the value in certain situations much like redundancy in hydraulics and such. It is good to eliminate as many SPOFs as possible. There is so much more at stake when people's lives are on the line than with a model airplane and with people's lives that is certainly where redundancy is paramount as you stated. No matter how good all our redundancy is, if the variable falls on the wrong point we pick up the pieces.

rgburrill

What, pray tell, airliners do this? Airlines usually have 3 systems, not 2. And they all control both sides. They vote in that if one disagrees with the other 2 it s taken off-line.

There may be some aircraftwith dual redundancy but these are partial control and summing systems such that if one fails it cannot overcome the other and the mechnical system as well - these are fault-tolerant systems. But fly-by-wire, full authority systems (and that is after-all what we fly) for airliners are at least triple redundant. fail-safesystems.

rgburrill

Possibly the best answer to receiver failure is a PA-1 (or whatever number they are at now).  Program it to put the plane in a large descending spiral with power off or low.  Should be a lot cheaper than trying to add full redundancy.

Some years ago I programmed my 72MHz PCM receiver to do just that - never had to use it so don't know if it worked.  (Didn't have the guts to turn off the transmitter [X(])

Prop_Washer2

My Feedback: (26)

Heck 2 receivers, 2 switches and 2 battery packs is twice as much schit to go wrong on you..!! I fly with 1/2 of a receiver, 1/2 a switch and 1/2 a battery, half as much crap to go bad inflight...

rgburrill

Cool idea - then you can fly two in formationat the same time

VF84sluggo

My Feedback: (55)

The Lockheed L-1011.

It's been a while since I flew it (13 years), but I remember we could separate the control columns in the event of a jam. In theory this would allow identification of the jammed control path, thus allowing basic control through the non-jammed side. We would practice this in the simulator.

Sluggo

jetmech05

MD-90 will split the columns as well

RBACONS

My Feedback: (3)

Two receivers is definitely an added margin of safety and is worth it in the larger, more expensive planes. I have a 100cc Carden that has 2 receivers, switches and batteries splitting the left and right sides of the plane. I did have 1 receiver fail in flight and was able to bring the plane in safely with just the right hand side working. The plane is still flying today and it sure as heck wouldn't have been without the dual receivers.

gregoryshock

I think your kill switch idea is excellent! Is there anyway to make a remote kill switch for a glo engine?