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Offline Earle Andrews  
#1 Posted : Friday, October 28, 2016 11:53:00 AM(UTC)
Earle Andrews

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For the past 4 seasons I've been running 2 receivers (Futaba 6014HS) in my Raven. Both are powered via dual batts thru a Wolverine switch. Plane is basically split down the middle control wise with 1 Rx commanding the Rudder & Kill, the other Rx has the Throttle.

Have not had any issues, although I've never had any issues with 1 Rx on previous planes.

Just curious as to other IMAC brethren's thoughts on this topic???? Smile
Offline Gil R. Major  
#2 Posted : Friday, October 28, 2016 1:45:00 PM(UTC)
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Originally Posted by: Earle Andrews Go to Quoted Post
For the past 4 seasons I've been running 2 receivers (Futaba 6014HS) in my Raven. Both are powered via dual batts thru a Wolverine switch. Plane is basically split down the middle control wise with 1 Rx commanding the Rudder & Kill, the other Rx has the Throttle.

Have not had any issues, although I've never had any issues with 1 Rx on previous planes.

Just curious as to other IMAC brethren's thoughts on this topic???? Smile


Earle, I also use two receivers, but one battery to one receiver and the 2nd battery to the other receiver creating true redundancy; no electronic sharing of any kind. The airplane, like you, is left receiver controls the left half and throttle; the right receiver controls the right half and optical kill. I have 2 rudder servos one on the left and one on the right receiver; the rudder is sluggish as hell on one servo, but it does work if the failure is due to a power failure. If the problem is a loss of signal to the receiver the rudder is really not usable.

Do we need it? That is a whole argument in itself. I will tell you I lost the left receiver a few years ago, early 2.4 (2008) (Futaba said it was a bad antenna segment). I ended up having to go to high rate on rudder and the throttle was stuck at a very high idle, but this allowed me to land and shut the engine down simultaneously. There was a little bit of a roll with the elevator, but it was easy to compensate.

Since then, I have the failsafe set at neutral controls and about 1/3 throttle. This allows me to fly the plane, clean my shorts, and shut the engine down (if it is the left receiver has failed) when in a good position to land.

I am looking at S.Bus, but I would run two receivers just like above, with one wire per side to the tail having one elevator half and one rudder servo per receiver.

I will always run two receivers with no electronic sharing of any kind on my big airplane. $150 of insurance!!

Edited by user Friday, October 28, 2016 1:56:39 PM(UTC)  | Reason: Spelling

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Offline Steve Sides  
#3 Posted : Friday, October 28, 2016 7:01:05 PM(UTC)
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Without a doubt I run 2 Rx, separate batts and switches for each. As both have said, the aircraft is split in half. Never had a failure but I sleep better !
Along the same redundancy lines, I'm looking very hard at Jeti for redundant transmitters. Also thinking about using a powerbox type setup so that the whole aircraft is still controllable with a Rx failure but that introduces electronics to control the Rx's so I'm still wrestling with that.
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Offline Chuck Edwards  
#4 Posted : Friday, October 28, 2016 8:09:00 PM(UTC)
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Earl,

I have to agree with all of the above. If your running sbus you can get away with using the small Futaba receivers with no issues, not that weight of the receivers is a big concern in our aircraft.
Charles Edwards
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Putting the Man in Unmanned.
It takes less time to do something right
than to explain why it was done wrong.
HWL.
Offline Paul Deppe  
#5 Posted : Friday, October 28, 2016 10:23:37 PM(UTC)
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My H9 Sukhoi also uses Steve's approach - two receivers, each powering one side of the plane and electrically isolated from the other side. The ailerons are split into outboard and inboard (flaps), and the inboard ailerons are crossed so each receiver has one aileron panel on each side. Ignition power and throttle servo are on opposite sides. The Smartfly ignition kill has inputs from both sides so if the ignition is powered but the throttle is failed, it is still possible to kill the motor. Each side has two batteries feeding the power box.

We had some discussions this summer about whether, in case of a failed side, the operating surfaces would have enough authority to control the plane if the failed surfaces were frozen. Several people thought that it might be necessary to switch to high rates to make up for the fact that only half of the control power would be available. It would be possible to set up a flight condition to test this idea, but I haven't been brave enough to try it yet.

IMG_5442.JPG (272kb) downloaded 11 time(s).
thanks 1 user thanked Paul Deppe for this useful post.
Gil R. Major on 2/16/2017(UTC)
Offline Michael Roxberry  
#6 Posted : Saturday, October 29, 2016 9:12:02 AM(UTC)
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Hi Paul:
I don't know whether I'm just a minimalist or adhere to the KISS principle, but I have always run just one receiver. Two bats with two switches, two regulators into one receiver. It has always worked flawlessly for me. My thoughts have been: the fewer points of failure-the better. I have used a Smart-Fly in one of my 30% airplanes basically because I won it at a contest. I have had no issues with the Smart-Fly either. You have a very nice and clean installation in your plane. That being said, I can actually see the belly pan in mine.Laugh
Offline Paul Deppe  
#7 Posted : Saturday, October 29, 2016 11:30:17 PM(UTC)
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Mike,
Over-engineering: What happens when you have a long Buffalo winter to put a plane together. BigGrin
Paul


Offline Earle Andrews  
#8 Posted : Sunday, October 30, 2016 7:00:31 PM(UTC)
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Is there a way to open a poll on this site? I looked around when i started this thread but didn't see one. Be interesting to just get that info (for more than the handful of guys who've responded here.
Offline Mike Karnes  
#9 Posted : Sunday, October 30, 2016 7:54:16 PM(UTC)
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Go back to your first post and click edit. Create Poll is in the top bar on the right.

Edited by user Sunday, October 30, 2016 10:26:28 PM(UTC)  | Reason: Not specified

Offline Earle Andrews  
#10 Posted : Sunday, October 30, 2016 11:13:14 PM(UTC)
Earle Andrews

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Originally Posted by: Mike Karnes Go to Quoted Post
Go back to your first post and click edit. Create Poll is in the top bar on the right.

Tried that.....Nothing there regarding a poll option for me?????
This is what I'm seeing on my edit screen;
Edit screenshot.jpg (183kb) downloaded 2 time(s).

Edited by user Monday, October 31, 2016 8:09:28 AM(UTC)  | Reason: Not specified

Offline rclad  
#11 Posted : Thursday, February 16, 2017 5:17:48 PM(UTC)
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I realize this is an old thread, but just thought I'd add my two cents.

I'm not an engineer, but I understand that a structural design that works for a .40 size plane will not work when scaled up as is to larger planes, say 50cc and up, without significant changes in material, structural layout, material dimensions, etc. The same applies to at least some aspects of the electrical design, as I'm finding out now with my first giant scale plane (that happens to be an electric as well). Wires that carry larger currents have to be thicker gauge, connectors have to be larger - both for the radio/server side and the power side (for electrics). New features have to be added that weren't necessary on smaller electrics, like anti-spark devices, and yes, redundancy.

Technically, a redundant system isn't necessary to make a working giant scale plane. But who would feel safe flying on a commercial airliner without redundant systems? A giant scale model won't be carrying any passengers, but the damage such a model could do, to either our wallets and/or nearby property and persons, is considerably greater than a small model. As many others have stated, redundant systems in large models provide some peace of mind that you have done your best to create a safe experience for everyone concerned. If you only fly by yourself in a rural area where the worst you might do is kill a cow - and the loss of a plane is not a big concern - then sure, keep it simple.

Anyway, this is what's going in my 3DHS 87" Extra:
- dual 7.4v Li-Ion 2800 mah Rx batteries (Booma RC Maxpacks)
- fail safe switch for dual batteries (Booma RC Smart Switch)
- redundancy bus that will isolate stalled servos and handle loss of signal (FrSky RB-10)
- dual receivers
If I lose a battery and/or receiver and/or one or more servos I will still have control of the plane. FrSky makes this very affordable to do.

BTW Earle, I am using your clever canopy latch design on my Extra, with one twist: instead of pressing a toothpick sticking out to release the hatch, the release button will be flush with the fuse.
Offline Gil R. Major  
#12 Posted : Thursday, February 16, 2017 8:12:06 PM(UTC)
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Originally Posted by: rclad Go to Quoted Post
I realize this is an old thread, but just thought I'd add my two cents.

Anyway, this is what's going in my 3DHS 87" Extra:
- dual 7.4v Li-Ion 2800 mah Rx batteries (Booma RC Maxpacks)
- fail safe switch for dual batteries (Booma RC Smart Switch)
- redundancy bus that will isolate stalled servos and handle loss of signal (FrSky RB-10)
- dual receivers
If I lose a battery and/or receiver and/or one or more servos I will still have control of the plane. FrSky makes this very affordable to do.

.


Sounds like your receivers are connected electronically, which is not true redundancy. If what ever in the middle fails what then.
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Offline rclad  
#13 Posted : Friday, February 17, 2017 7:43:41 AM(UTC)
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You're right. If in the middle of a dogfight the enemy puts a round through my RB10, I will be "shot down."
Offline Ron Graham  
#14 Posted : Friday, February 17, 2017 10:10:19 AM(UTC)
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I touched on this in an earlier article in the NC page last year. (http://www.mini-iac.org/Articles/Article/165/A123-UNCLOUDED)

In the 80's, my brother and I put together a Dura Stick plane from a bunch of worn out parts we had laying around the farm. We would flip a coin to see who would be throwing mud clods and who would be piloting. The pilot would see how many pass's he could make down the runway while the other would put together a whole pile of well packed mud clods. I think this stemmed from when, for the men in our family, it was kind of a "right of passage" when you were old enough and tough enough to get into a mud clod fight with dad. BigGrin

Unfortunately, for the Dura-Stick, it encountered many hits and rebuilds over the summer with any number of "upgrades" to make it more tough. I think we even had a V-tail on it for a while (way before computer radios BigGrin )
We had numerous control surface/servo/etc failures from those hits but had a very high success rate of safely landing unless it was the elevator. Many times we never new there was an issue until the plane was inspected.
thanks 1 user thanked Ron Graham for this useful post.
rclad on 2/17/2017(UTC)
Offline rclad  
#15 Posted : Friday, February 17, 2017 10:52:14 AM(UTC)
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Thanks for the link Ron. I had read it earlier, but just reviewed it again. Great article and helpful. I like the charger box set up shown at the end. I need something portable like that for charging all my 6s LiPos.

Your story about "shooting" each others plane down ("when ships were made of wood and men of iron") brought back memories of mischief my brother and I got into, but I better stop there.... Boys will be boys, right?
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