DKjens

My Feedback: (50)

Did you read my post, or did you not understand it? I lost two planes because I had failsafe set to what would have been a level glide, if the plane was level at the time of failure. Since the plane was doing 3D at the time of failure (no airspeed) it became a lawndart and did a vertical glide to the ground. I didn't say setting 3D rates as failsafe, I said full up elevator and all else neutral, which will slow any plane more, than a more non-3D setting, and would have saved much of my equipment in my planes. You sound rather narrow minded to my, bud.

I know personally of a guy, who has two Futaba PCM Rx's hooked up to one emcotek power box. He lost one RX a few weeks ago, was able to land safely, replaced it with another new RX. Two weeks later, the other original RX failed, again was able to land safely with one RX. What I'm getting at, does running two RX's so close to each other, and with their signals running into the same power distributing box (although controlling separate channels/controls) have an adverse effect on the RX's? Who knows exactly what kind of high frequency vibrations etc. takes place in the Rx's, and can they affect/damage each other if located to close to each other, or if their control signals are to close. So, if running two RX's, should we run two power boxes.

I run a single Futaba PCM RX on a Smart-Fly powerbox to six aileron servos, four elevator servos (all 9152), a throttle servo, and a smoke pump, and just signal to a Seiko PS050. The powerbox is powered by two 4400 mAh Li-Ions and the Seiko by a three cell 2400 mAh Li-Ion. If running two RX's and no powerbox, I would have to split one channel in three and another in two on each RX, and I would not feal safe doing that. I could easily mount two RX's on the powerbox, but if they have an adverse effect on each other, I'm better of with a single RX like now.

I just believe that if the warranty has expired, nothing in the world is going to save your plane. You can have all the "so called" redundancy in the world, some idiot will turn on, on you, and that's all she wrote. It is disconcerting, and some times, especially right after having a bad/expensive day at the field, it even makes you doubt this hobby. All our equipment is manufactured with compromises, or it would be more expensive than we are willing to pay, and with compromises come raised failure rates.
DKjens

JettPilot

My Feedback: (6)

Dual systems protect me from ANY failure in either radio system, INCLUDING SERVO failure. If a servo fails, no problem, Dual elevators, dual ailerons, dual everything. When I lost one battery, I lost HALF the servos in the plane [X(] and I still was able to fly and land it without a scratch.

Matt Merciez

My Feedback: (34)

Loosing a battery or switch on a dual receiver system would appear to put you in a worse condition than running a single receiver/dual battery-switch setup, simply because you have now lost half control of the plane. If you are running only one throttle servo off of one of your two recievers, you now have a 50% chance of losing throttle control when one of your two receivers die (assuming a single engine plane ).

So far, of all the cases of lost receivers, the receivers would appear to be predominately Futaba 149s. Has anyone seen a JR 945 or 955 receiver fail? Is there any history of high end JR receivers failing? I might be more inclinded to consider a dual receiver setup if the high end JR receivers show a history of failure.

Hammbone

My Feedback: (309)

O.K. Matt, Now I understand what you mean by the single RX having an advantage in that stuation (loosing a battery or switch on a single receiver/dual battery-switch setup).

It's really not a big deal to land a plane on 1/2 the controls though, and I'm sure we all have practice landing dead stick (in case you loose the throttle servo).

Still, I say do what you want. One way is not wrong and the other way right. It's just a matter of personal preference.

I say there is less risk loosing your plane if you fly it with 2 RX's. If someone wants to fly with one RX they can and they will have fun doing so (that's why we participate in this hobby right?). They will have more of a risk of loosing their plane with only one RX, but we all risk loosing our planes every time we fly no matter what set-up we use.

Our set-ups should be a personal prefererence based on our tolereance of risk vs the amount of money spent on an airplane. I say this because setting your plane up with more reliability costs more money.

I usually try to stay out of these discussions, but have to chime in when I see someone say " there is no benefit to having a 2 RX system". I don't like to see people get confused or misinformed.


Jim

gixxer01

So then I take it nobody has taken the plunge and purchased a DPSI twin... For those that do not remember what the Twin does, it automatically switches from Rx1 to Rx2 in the event the DPSI senses that Rx1 is not working properly. So... when it makes the switch you still have 100% control, not 50% because Rx2 is wired to all surfaces and such just like Rx1. Almost forgot the built in regulator and dual battery support. Of course if your frequency is really getting bombed, it does not matter if you have 2 Rx in your plane or 100, it still is not gonna work. Only drawback is the unit does have some weight to it. Enough of the tech lesson. Why is nobody using it?


Tim

sillyness

My Feedback: (25)

I hate these discussions too, BUT.

We aren't thinking outside the box Matt!!!

Take those 2 RX and make a jumper that goes between the an empty socket on each (pos and neg wire ONLY). Put a 5-7 Amp fuse in the positive lead. NOW... in your 1000 flights you will lose half of the airplane twice due to RX failure, where with 1 RX you would lose the entire airplane twice. If a battery or switch fails you keep the entire plane. If something SHORTS OUT, you lose half the plane. With the single RX you would lose the entire plane. And since I have mad skills on the sticks, chances are I would get the plane down with minimal damage[X(] Also, I run throttle servo on 1 RX and a choke servo on the other... I can kill the engine and glide her home if I lose throttle control.

My brick house is built on pontoons, and it contains enough booze to last me 40 days and 40 nights

MarkShapiro

My Feedback: (52)

Sillyness,
Are you saying that on the jumper wire, the center wire is seperated and ommitted from the other two? For example if using JR servo wire, the brown and red wires are all that I will use and the orange wire is ommitted?

sillyness

My Feedback: (25)

Yes, remove the signal wire... that would be very bad to have that connected. Keep Brown and Red, discard the orange wire. The center wire is actually the red one... you don't want to get rid of that. The orange should be on one side.

MarkShapiro

My Feedback: (52)

Thanks sillyness. I'll try it.

JettPilot

My Feedback: (6)

You just cant beat 2 complete reciever systems to protect against failure.

In my setup, when I loose a system, I loose half my flight controls, BIG DEAL.... The plane flys just fine on one half elevator, and one aileron. I also loose control of one engine, BIG DEAL... I just fly till it runs out of gas... If it quits at idle, thats even better, I just land. With a single engine airplane, losing the engine is a common occurance and you just land.

With a singel reciever, there are still many SINGLE things that can fail and cause you to lose control of your airplane.
If the CRYSTAL
ELEVATOR CONNECTOR TO RECIEVER
AILERON CONNECTION TO RECIEVER
POWER CONNECTION TO THE SYSTEM
SWITCH
BROKEN WIRE

Any of those things will cause you to crash with a single reciever. With my double setup, no type of radio, battery, servo, or any of the other failures will cause me to lose control of my airplane. This is a no brainer, it shouldnt be that hard to figure out....

In airliners we have several SEPERATE systems to power the flight controls, SAME IDEA, so that no one failure of any system will render the airplane unflyable. No one biatches about only having half the flight controls when it happens, we just land... Its a proven design philosophy that is in use in EVERY large airplane made.

BlueMax3

My Feedback: (1)

If you don't mind my asking, what brand and model receivers were those?

Travis

rtigg

My Feedback: (7)

i have read all post on this dual receiver idea, i hava few questions??
if you have two recivers on the same channel, wont both receivers receive the same input and move accordingly? i need some hepl, please????

shakes268

Not if set up correctly. You should cross your elevator servos so that the right receiver controls the left elevator and the left receiver controls the right elevator. In the event of a failure, this helps stabilize and keeps you from going into a full roll in a turn (if both sides are connected and end up creating drag on one side, the plane WILL roll). You do not lose control of the plane with only half a plane. With the setup crossed as I described above you can maintain control however it will react sluggishly so be ready to fly on super low rates - thats how it will act.

Sillyness also mentions running choke and throttle off of different receivers - good idea because it gives you two ways to shut off the engine and both receivers would have to fail simultaneously. Now, if you are running some kind of other engine cut off - make sure that it can handle two receivers like the Smart-Fly optical ignition cut-off. You may or may not want the engine to quit. If you have throttle control the Smart-Fly will still power the ignition whichever receiver fails. If its the receiver with throttle, just kill the engine via the smart-fly or the choke and dead stick it.

Rcpilot

My Feedback: (78)

Sillyness:

Can you show me a pic of your jumper set up with the in line 5-7amp fuse?

I'm about to start a dual RX plane. I'm using PPM Hitec 8ch Supreme RXs. I like the idea of using a jumper incase of a battery failure. I'll only be using 1 battery per RX with a SmartFly super Switch. 18ga leads going in and dual 22ga leads coming out.

It would be nice to have the jumper in there if I loose a switch or battery.

I've never actually lost a switch or a battery. I replace them every season. Cheap insurance.

This is the first time I've ever read that you should run your antennas in different configurations. I was planning on just running 1 antenna down the left side and 1 down the right side. Now I'm confused. I don't see how I can run an antenna out on the wing--it's a removable wing. How are you going to secure the antenna to the wing everytime you put the plane together?

Can I run 1 antenna down the left side and secure it to the tip of the left side horiz. stab--then run the other antenna out the right side and secure it to the right side of the horiz. stab?

Or do the antennas need to be on a different plane (level) completely?

Somebody suggested running them at 90 degrees to each other.

shakes268

If you can, run the antenna for each receiver as far away from each other as possible. If inside the fuse, a good 45 degree angle works. pretty good on one while the other runs along the bottom of the inside of the fuse.

So when looking through the back of the fuse, the right side goes up at a 45 degree angle while the left side runs down at an angle or straight out. That will make sure the point where the antennae are closest together is at the receivers.

sillyness

My Feedback: (25)

I run one ant on the bottom outside of the plane, toward the back, taped to the belly, angled so it goes from one side of the plane at the front to the other side of the plane at the back. The other is either through the turtle deck, angled opposite compared to the bottom one, or out the turtle deck and to the tip of the vertical stab (Chip Hyde style).

Remember that you have 3 dimensions to build angles betweent he ant's, not just 2.

Sorry... don't have any pics. Just go to Radio Shack and pick up a mini-automotive fuse holder. It should be pretty obvious.

OnTheEdge

Yes they will. In theory, you can have ten thousand receivers all on the same channel and they'll all do the same thing at the same time with the signal from one transmitter. It's a good question as I recall wondering the same thing as I researched dual reciever use a few years ago.

"... i hava few questions??..."

What's you next question? [sm=thumbup.gif]

.........Mark

karl540

Does anybody have a wiring diagram for the proper plug in of all servos when running 2 recivers? This is new to me and I can get everything to work only if I use mixing. If using 2 recievers you have 2 channel 1 2 channel 2 ect. Where do you plug everything into? Any help would be appreciated. Thanks

DKjens

My Feedback: (50)

Just buy a Weatronic receiver, true dual receiver redundancy and very easy to work with.

karl540

Im running 2 2.4 recivers and as far as I know Weatronics is PPM

OnTheEdge

Not sure if I follow your question, but while you have two "slots" to plug into channel #1, both slots will received the exact same signal, so yes, you would still need some mixing on all but a simple 4 channel set-up (i.e. one aileron and one elevator servo).

For instance on a Futaba, channel #2 is your elevator channel. If your plane will have two elevator servos (one for each elevator half) you will most likely need to mix another channel as a slave (let's say channel 5) to you channel 2 elevator channel. Then you will plug your right elevator servo in to channel #2 on Receiver A , and then plug your left elevator servo into channel #5 on Receiver B. The mix is still required so you can adjust for servo centering, reversal, and end points.

You would most likely do the same for your ailerons and rudder servos.

They only way to avoid the use of mixing would be to use programmable servos and program the servo for reversal, center and endpoints.

If this doesn't make sense, let me know. I'll try to explain further.

......Mark

mogman

I put 2 rx's in my 1/2 scale Spacewalker. Each side of the plane has it's own rx, batt. switch. Throttle servo on one rx, kill sw. on the other. If anything happens I can still either throttle down or kill the motor. System has worked great for over 3 yrs. now. Both antenna's run parallel down either side of the fuse(about 8-10 in. apart.

Cheers, Dave.

karl540

Thanks Mark that is what I thought. I have several 30 and 35% planes but run them with duel batteries but to only 1 receiver. On this 40% it is my first time running duel recievers. I wanted to run it on 2.4 radio system and just wanted to be sure.

OnTheEdge

Glad to help. Best of luck with your new 40% plane.