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No throttle on redundant receiver set up. Right?

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No throttle on redundant receiver set up. Right?

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Old 06-09-2003, 01:31 AM
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rustyrivet
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Default No throttle on redundant receiver set up. Right?

Ok Guys,

I'm wanting to use two receivers in a plane primarilly for the purpose of a sort of fail safe system. If I understand it right, redundant receiver systems are set up to work when you are using split up control surfaces that use two servos. For example the left aileron servo goes to one receiver, and the right aileron servo to the other receiver.

My question is:What about the throttle? You can only hook up the throttle servo to one receiver. Right? So am I right to assume, that it's a matter of luck which receiver goes bad...... and if it's the bad receiver which happens to have the throttle hooked up to it ,you end up dead sticking the plane home? Not such a great bargain if that's the case.
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Old 06-09-2003, 10:47 AM
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Default No throttle on redundant receiver set up. Right?

Randall,

Good reason to consider a single receiver with redundant batteries and switches. I know of no receiver failures that have not been caused by battery or switch failure. There are a number of back-up battery systems available that can do the job.

A better way to good, in my view.

Bedford
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Old 06-09-2003, 11:21 AM
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Default No throttle on redundant receiver set up. Right?

could somone post a diagram of how you hook up multiple switches and batteries to a single reciever?
Thanks!
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Old 06-09-2003, 07:33 PM
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Default No throttle on redundant receiver set up. Right?

I don't think you need a diagram. The second switch and battery is exactly like the first one. You plug it into the receiver into any extra slot. Now you have two switches, charge jacks, and batteries. Charge them both up, turn them both on, then go fly. Of course you can turn on one at a time for testing.

Tom
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Old 06-09-2003, 07:53 PM
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Default No throttle on redundant receiver set up. Right?

Go here http://www.rcbatteryclinic.com/ for great article and picture for two batteries with single receiver
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Old 06-10-2003, 12:20 AM
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Default No throttle on redundant receiver set up. Right?

Beepee,

Are you kidding me? You think I would be asking about a redundant receiver system, if I didn't already have redundant batteries and switches figured into the system to start with ?!!! Not to mention the Nelson glo driver, and a perry pump too. I also have a servo activated parachute which is automatically tiggered by a ground sensor. (OK, I was just making that one about the parachute.)

It's more a matter of personal preference as to whether one wishes to put two receivers to work, as the benefits can be debated. However, there are instances reported right here on rcuniverse about receivers OR the crystals going bad, and a redundant system saving the craft. I'm very fussy about planes that take me almost a year and a half to build, and so am hashing it over.


WOULD SOME ONE PLEASE CONFIRM THAT I AM RIGHT ABOUT THE THROTTLE QUESTION I STARTED THE THREAD WITH. Thanks.
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Old 06-10-2003, 01:37 AM
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Default No throttle on redundant receiver set up. Right?

Well, if your throttle receiver failed I guess you'd go dead stick, but wouldn't it be just as likely to fail at wide open throttle?

What would happen if you made a "Y" and connected your throttle to both receivers? Feedback and a lot of glitching?
Dennis-
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Old 06-10-2003, 01:56 AM
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Default No throttle on redundant receiver set up. Right?

Yep Dennis. That's a good question. For that matter I'm concerned that any of the servos on the dead receiver could fly your plane in a bad attitude. Seems I heard though, that coreless motors would return the servo arm back to zero.

But there's too many concerns that I need answered before I would go down this avenue!
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Old 06-10-2003, 10:57 AM
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Default No throttle on redundant receiver set up. Right?

Randall,

How about an airbag in the nose, did you think about that? :-)

There are mechanical couplers that take the output of two servos and deliver it to a single control. I have seen them used on rudders ... how are you dealing with the rudder in your arrangement? These consist of two servos, side-by-side, with a bar running across linked between two servo arms (fixed on one end and slide on the other). Somewhere in the middle of the bar is a single ball link clevice that connects to the control surface. No reason this could not be used on the throttle.

A year and a half to build your airplane? Heck, every airplane I build takes that long! See you at Scobee again anytime soon? I am still waiting to see your giant Hog.

Good luck!

Bedford
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Old 06-11-2003, 02:35 AM
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Default No throttle on redundant receiver set up. Right?

Beepee,

Well, in a redundant receiver system, the rudder control would not be a concern if it was on the dead receiver. You'd use the one aileron to make your turns and limp back home.

Anyway, I have yet to hear or be convinced by anyone that a dual receiver set-up can provide satisfactory returns, and is worth the trouble. Think I'll pass on that idea, and just stick with the every other fail-safe device I mentioned.

The grey primed Hog awaits its finish coat, and I have already been breaking in the 2.1 Moki engine on the test stand. Man, is that engine a stump puller. I was worried about the final finish weight of my plane at perhaps 19lbs being too heavy. Then, I stepped back to watch the test stand which is bolted to a milk crate and loaded up with bricks, take off and fly over my neighbors house. (Ok, I'm kidding about the box flying away. I only had to chase it accross the pavement.)


BTW, how do you prevent the air bag from knocking your plastic guy from out of your cockpit? Kill switch?
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Old 06-11-2003, 10:41 AM
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Default No throttle on redundant receiver set up. Right?

Somehow the thought of the airbag going off in the cockpit reminds me of that scene in "Six Days Seven Nights" when the raft inflates in the DH Beaver ... poor stupid girl. So far, I have not had my air bag inflate. By design it is to soften the aircraft contact with earth ... well that should be the theory, anyway. What makes even more sense is to build a garbage bag into the fuselage. Just think, when I go out to pick up the pieces, the container will be ready at hand!

You are assuming that the Rx will fail with the controls at center. I am not sure that is a good assumption, though I have no experience to call on. I have had a rudder servo fail (power failure) and it was mostly a non-event bringing the bird down, just could not taxi. If I had a failure causing the servo to go locked one way or the other, I would have needed the garbage bag.

Bedford
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Old 06-11-2003, 10:57 AM
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Default No throttle on redundant receiver set up. Right?

RandallM.,

I believe the dual receiver concept, originally was intended to relieve the electrical load of many servos. When split up wisely, it also provided a sort of backup system.

Many people seem to be going back to single receivers and using power distribution systems.
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Old 06-11-2003, 01:50 PM
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Default No throttle on redundant receiver set up. Right?

Yes gents,

I have been checking through A LOT of very TECHNICAL information on another thread I have going on the subject, (ssshhh...don't tell the redundant thread police)as well as in the rcuniverse archives.

Now that I have all the facts, I can arrive with my own conclusions, and agree that Jemo basically has it right. That being that the primary reason for redundant receiver systems is to handle excess servo loads. It poorly addresses fail-safe concerns.

The variables concerning the failure with one receiver in such a system can generate a multitude of scenerios and "what if" questions. (depending on how and where the failure occures)
For example; A receiver going dead and allowing a servo on a split elevator to become stuck in a full down elevator mode is no bargain, even if you can try to work the other elevator half in full up. You still may no safely be able to limp the plane back safely.

One has to ask, is it really worth the trouble? And would I not be increasing my chances of failure with the more stuff I put on board anyway?

Of course, there's always someone who recites an experience and says that having two receivers on board saved their expensive plane.But I feel that I'll be exposing myself to more pitfalls then the benefit that MAY be reaped in such a rare instance of receiver failure.
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Old 06-11-2003, 05:03 PM
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Default No throttle on redundant receiver set up. Right?

Randall,
That's a very important point that dual systems double the chance of a failure.

Tom
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Old 06-12-2003, 01:06 AM
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Default No throttle on redundant receiver set up. Right?

OK guys,

I think we put this one to rest. Thanks a bunch for the input.

Now let me see if I can go over to the radio forum where I have the similar subject going on to declare to them "The rain in Spain falls mainly on the Plain. By George I think I got it!" That's going to be a tough beast to slay though. I got all those pseudo pofessors and mad scientists arguing and debating amongst themselves on the topic. I don't think they'll hear me anyway.

My, my what have I created? Oh.....the horrrorrrr....
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Old 06-12-2003, 01:54 AM
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Default No throttle on redundant receiver set up. Right?

Randall,
The fact that you asked the question gives you no right to end a perfectly good argument. Some of us have nothing better to do and your attempt to declare a truce only makes us more stubborn.

Tom
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Old 06-12-2003, 02:20 PM
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Default No throttle on redundant receiver set up. Right?

An easy solution if you must have a dual system is to just put a second kill switch on the redundant receiver. this will at least let you kill the engine if required.
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