THIS is why I run TWO Receivers!!!!

[KrisW]

So, there I am on the 2nd flight of the day with my Big Bunny WH Extra 300. Radio equipment is 2 5955 Hitecs per wing, one per elevator, two 5735's for rudder, the same for both receivers, with the throttle being handled by the left receiver.

Receivers are a well-proven 649s JR on the right side of the plane, left side is controlled by a year old R2100 JR synthesized single conversion 10-channel unit. Power is from dual A123 2300ma packs through a single Fromeco Wolverine switch, split form 14 gauge into 4 JR connectors out of each half of the switch, then routed directly to the receivers, with one pigtail going directly to each aileron to help spread the current out across the receiver buss connectors and keep current through the buss to a minimum.

So, per receiver. . 3 power inlets on empty channels, 3 power outputs on the right side (elevator, aileron, rudder) with a 4th external power feed source to the ailerons, and the same on the other side with an extra channel for the throttle. Simple, dependable, bulletproof. . .

RIGHT????

Not so fast Jose. Doing lots of slow rolls, points, 8 points, just feeling the plane out after too many weeks of no flying. About 10 minutes into the 2nd flight (preflight voltage from each A123 pack was 6.64 volts) I'm pulling the plane through a lazy reverse half cuban with 1 1/2 positive snaps on the 45 upline, throttled back to idle on the 5/8 loop, level off and increase the throttle at the same time and NOTHING happens. . . plane just coasts. Rock the wings. . VERY sluggish, and have a tail wind as plane glides toward center field at about 10' of altitude. Not enough speed to turn back, too fast for the runway, can't really skid with rudder bacause it's barely working, I manage to gently bank the plane so the LG is running WITH the rows of 6" stubble in the cotton field that surrounds the runway, and gently ease her down onto the dirt. Hit a divot, plane pitches forward and the still turning prop kills the motor as it digs in.

Get to the plane do a control check. . no left side at all, with all the servos locked at center controls and throttle locked at idle (failsafe settings). $$$$ Biela 29-12 3-blade is broken (*&^%*$%&%)(*^_!!!!!!!!!!!!!!!!!), and we carry the plane back to the runway.

Take the canopy off, the blue LED is glowing on the receiver. Try to reset the channel but the LED just blinks fast as it goes into search mode, then slowly as it can't find anything transmitting that it can lock on to.

I called Horizon when I got home .. their standard answer is . .4.8-6 volts for the receivers .. . but we all know better since 5-cell packs have the same voltage range as the A123's .. top out at about 7.4, nominalize at about 6.7-6.8 and then plateau at about 6.5.

Well. . the plane is one piece. Gerhard is glad for my business with ordering a replacement prop, and Horizon is getting my receiver back to repair it. And in a few days I'll be flying again after installing a spare receiver in place of the R2100.

And THAT is why I run TWO receivers. If the R2100 had been my only receiver in the plane, I'd be telling everyone how many pieces I had to pick up. Instead, I get to complain about having to replace the prop. A $190 receiver is CHEAP insurance against losing a $6000 plane due to receiver failure. I've never had one fail in flight before .. . in 9 years back intot he hobby. . . but today proved that there is always a first time. All these years preaching the advice for 2 receivers. . just in case. . . and looky here. . it actually saved my plane today.

I told you so!!!

[Simpleton]

How would the flight have gone if the 649 was the only RX?

[Edge 540]

I've never considered two different types of receivers...
Was that just what you had available?

[3-d flyer]

But Kris, if you used Futaba Recievers you would not even have to buy a prop or replace a reciever, you would still be flying today! LOL


Alright, Alright.... I'm only kidding of course!!!! Could not resist

[KrisW]

	Quote: Originally Posted by Edge 540
	I've never considered two different types of receivers... Was that just what you had available?

Actually, I was using dual R945s at one point, but I kept having lockout or weak reception problems for some reason, and eventually kept changing out receivers until the problem went away, which resulted in having the R2100 and 649s in the plane. Not by choice, but it just happened that way. I went through quite a few ideas to get rid of the problem, since I was also having problems with some of the servos at the same time (which were replaced by HiTec), and had to sort that out as well until I got all questionable items isolated and replaced.

The setup has been rock solid for 10 months now, which is why todays incident is kind of bothersome.

[KrisW]

	Quote: Originally Posted by Simpleton
	How would the flight have gone if the 649 was the only RX?

Not sure if this is a serious question. but losing the receiver in a single receiver setup means good bye airplane. . . and even with dual 649's, losing one would have resulted in the same scenario.

[RollingHarrier]

Thanks for sharing Kris. This is why I use two also.

[Simpleton]

	Quote: Originally Posted by KrisW
	Not sure if this is a serious question. but losing the receiver in a single receiver setup means good bye airplane. . . and even with dual 649's, losing one would have resulted in the same scenario.

It was serious. You said, "If the R2100 had been my only receiver in the plane, I'd be telling everyone how many pieces I had to pick up." If the 649 had of been the only RX (in this particular instance), you'd saved the cost of a prop. I understand the 2 RX reasoning, it's just that (in this particular instance) having 2 RXs this time put you in a field. I know, better than losing the entire plane and all that.

[Mithrandir]

Now all I need is a Dual Tx Module... one on 50 MHz and one on 2.4 GHz

[exeter_acres]

you mentioned that you tried multiple receivers....

have you sent your TX in recently to have it checked?


glad the plane was OK

[bodywerks]

This whole shpeal only has merit if Horizon says they found a problem with the receiver.

[krayzc]

i hope my receivers contunie to treat me good only one of my many planes as 2 rec. but they are smaller jobs anyway....

[Mithrandir]

Well.. he said something about a flashing light thingy... that means the Rx isn't making the connection right?? And the Other Rx was happily functioning....

It is the Rx

[Judge]

So in summary, you were running the RX at a higher than recommended voltage and in a configuration that Horizon does not recommend (dual RX's). But why lsiten to them. They only make and service the things, no reason they should know better than us how their equipment works.

You had previous issues with poor reception using a similar dual receiver set up. (Which is one of the reasons Horizon does not recommend dual receivers in the first place).

Oh and the added twist was two different models of receiver. Not sure if that makes a difference, but I cannot imagine that it makes it better.

And yet, dual receivers saved the day??

OK.


You skills as a pilot surely saved the day flying half a plane. Of that there is no doubt. But what would have happened if it had locked off center??

[KrisW]

	Quote: Originally Posted by exeter_acres
	you mentioned that you tried multiple receivers.... have you sent your TX in recently to have it checked? glad the plane was OK

When you are chasing a receiver glitch, you try every avenue, from different TX modules, to synthesized pieces, to connecting and disconnecting parts of the plane to see if teh servosthemselves are causing a problem. What I was running into was a disparity in receptivity strength between the two sides of the plane, not total loss of range that affected both receivers, so it was a matter of figuring out what was causing the issues. In this case, I found that the servos in the wings were causing a feedback problem of some sort when they were plugged in. I could do an antenna-out range check and see a 600-700 foot range with the wings not attached, and have that reduced to 200 feet with the wings plugged into the circuit. I eventually found that at least one servo per wing was going causing an issue from time to time, but not always. At the time I was using the 5945's, three per wing, so I installed dual 5955's, which seemed to fix the problem, except that even though they had all been given a clean bill of health after a crash, 2 of them were going into shut down or becoming intermittent.

So, I was going after first. . a feedback problem, which I resolved, only to run into an intermittance problem, which I then resolved with yet more servos (HiTec replaced all problematic servos for free, btw) and THEN I had a receiver or two that was "weak" and had to be swapped out. Eventually I woud up sending in every receiver I owned for re-tuning, buying some R2100s that now reside in some planes as well as this one, and then experimenting with the R790 7-channel receivers which are also synthesized (and work extremely well). So, over a 3-4 month period last year I chased a number of component problems, solved them, got a lot of equipment sent in and realigned and tuned, and bought some brand new stuff as well.

In the end I wound up with a totally reliable set up, 6 "spare" receivers in my field box, 8 spare servos (5955's and 5945's)on the shelf. Since then, and until today, the plane has been totally reliable.

Oh, yeah, every TX module I have has been tuned and aligned, as well getting a "Synth" TX module, just in case, and the TX went in last year for a checkover and lithium battery replacement. Sometimes you just run into a string of problems that you need to resolve. In 9-10 months, though, I have not had a radio related problem, up until today that is. . .