vertical grimmace

My Feedback: (1)

So, I am back here with another crash story. At the Warbirds over the Rockies I lost my old beloved Fokker DR1. I had 2, fully charged 2600 mah RX batteries, running in two heavy duty smart switches with the light meters, I was flying a DLE 30 Gas engine with a 200o mah ignition battery. No optical kill, just a smart switch on the ignition.
Everything checked out fine and I took off and flew for about 3-4 minutes. Then out of the blue I had no radio control. The aircraft made about 2 circuits of the field free flight and thankfully pitched down and crashed in the downwind section of the pattern in our dirt field. Plane was completely destroyed.
When I arrived at the crash, all of my switches were glowing green and the batteries were still over 6.5 volts. The RX was going from red to green. Like it was searching. Then later at the shop, I held the little button in and it bound right up, glowed green and all servos worked fine.

Question...What would cause a RX to just unbind like that? It never lost battery. Could it have been vibration? I just want to try to avoid this again. Pretty scary when you consider this thing easily could have hit a bunch of spectators on this day. This was a Futaba, and it was one of the R117 RX I think. The full range 7 channel they sell.

Silent-AV8R

Flashing green/red is the indication of an internal error. The receivers either link or not, they do not search. Under normal circumstances you see a solid red = no signals seen, flashing green = FASST TX seen but not linked to that RX, solid green = Linked to a FASST TX.

Vibration can certainly be a cause. While being somewhat less sensitive than our previous 72 MHz RXs to vibration, they are not immune.

I would absolutely send the RX in to be looked at. BTW - low power will not do this, FASST does not "brown out" It works down to about 2.8 volts and then stops until it sees greater than 2.8 volts. It will not lose link due to low voltage.

BTW - I think you mean R617FS for the receiver name.

rmh

FAAST wont brown out?
all of em will quit if voltage drops low enough. any brand 2.4.
anyway - loosing bind is certainly a strange one - never saw that happen.

vertical grimmace

My Feedback: (1)

I am thinking vibration as it was pretty bad until I got the engine tuned in. I had many flights before this happened though. I will be sending it in. Yes, that was the number 617

Silent-AV8R

Dick - you know perfectly well what I am speaking of. Your favorite brand coined the term "brown out" meaning a loss of control due to a long time to re-boot after a low voltage event. In addition, when that term was coined the threshold was fairly high. Later models addressed that issue to some degree.

But I stand by what I said. FASST will not "brown out" in the popular use of the term because by the time you reach the voltage that turns off the RX your servos are very likely no longer moving. Beyond that, FASST has a low voltage failsafe that warns of voltage below 3.8 volts (well above the loss of power voltage) and in teh event of a loss of power turns back on almost instantly with no worries about loss of binding.

rmh

All rx will quit when the voltage falls below operating threshold
Favorite radios or not
Futaba is no exception
The reason for this type failure -in case you never noted -is not a fault of the rx. The battery is typically involved but other devices such as regs- special switching arrangements esc/bec overworked servo -on n on can be the culprit.
the power falls below operating voltage - for whatever reason
Unbinding is a completely different matter.
I have never seen it happen except in cases of rx which are not in operation.
no safety issue there .

vertical grimmace

My Feedback: (1)

Yes, the point of my post was to determine what would cause the RX to unbind. Battery was no where near the issue here.

Capt Cash

My Feedback: (1)

It's unfortunatewhen the cause of a 'loss ofradio control' goes undetermined. I fly 2.4 Futaba radios and receivers with mostly dual battery setups on my larger gas planes just as you have so this post caught my attention. No problems for me so far. I have various 617's, the 608, and 614 rx's.

I very much hope that if you send the receiver in Futaba will find a fault with it, but as history shows in these cases I'm willing to bet they will say it's working perfectly.

Do keep us posted with your findings.

MinnFlyer

My Feedback: (4)

How was it attached in the plane? Was there any shock mounting, like foam or velcro?

TimBle

vert grim,

A flashing red/green LED means it was not propery bound in the first place. I have seen this twice previously

First case occured when the Rx was bound to the Tx at an airfield with other FASST Tx powered up and operating. My club mate realised his mistake when his plane was responding to both my Tx and his. Somehow the Rx accepted both TX ID's.

The second time was in my workshop when I bound an Rx while it was powered by battery with almost no remaining capacity.

If the bind instructions in the manual are followed then there will be zero issues of unbind or "brown out'

Also, with a FASST TX/RX bind, it only ever needs to be done once and once only. As long as you are using the same Tx with the same Rx, it never has to be rebound. Even if you remove it from the plane, change the servo's fit additional devices, it never has to be rebound.

Incidnets with FASST where RC pilots have complained about link security can IME, betraced back to pilots not reading the manual and understanding the bind procudure. In all cases when questioning the pilot they had at some point fiddled with binding at the airfield.

DougV

That right there was a recall from Futaba about 4 years ago with the ZERO GUID issue when using the 6 or 7 channel tx's or the TM-7 module.

Tim, What model radio and receivers where in use here?

Doug.

rmh

The two issues are NOT the same thing.
A bit of history
The original 2.4 spread spectrum systyems by SPEKTRUM, had a low voltage threshhold of about 3.5 volts- even a spike drop to this point would loose th link to the tx- BUT the identification between the tx and rx still existed
these early rx (first generation) took a long time to reconnect.
The fact that a number of modelers simply did not understand the fact that computer radios were much like home computers in this respect, caused a fair bit of complaining.
Some never figured it out.
The Futaba 2.4, which came later on - changed their operating low cutof to slightly lower setting by about .5 volt and they had a faster reconnect .
BUT the "brownout" or shutdown due to low voltage could (and still can ) interrupt operation.
This issue still exists with all the 2.4 systems
the reconnect on ALL of the newer rx is much better-from all mfgrs - simply because the sorting out of common user problems showed where the failures were.
One radio mfgr even went as far as to recommend NOT using switches if at all possible - due to rx shutdown resulting from switch failure.
NON OF THIS has to do with loss of bind - that is a completely different issue but- typically the radio has to loose original connection (loss of signal) for the bind to be lost.
The original comment was that the radio flew for a while then quit.
Typically this means
1- power was lost or
2- signal was lost .
Why this occurred is a question which must be sorted out with the system and associated components used and all connections and installation.

Batteries which still show adequate voltage after a crash may still be part of the problem. I have tested this premis over n over . It is easy to proove.
some batts fail under loads and when load is removed - readings are good
This is again not peculiar to Futaba - they all can have this happen
It is said by most radio mfgrs - the majority of problems are user caused -Having seen this - I agree with them
the problems which are user induced are never done intentionally BUT they still are - user problems-
I have seen this since the first 2.4 radios(SPEKTRUM) and I expect to still see it for some time to come - with all of em.
If anyone thinks their favorite system is bulletproof - guess again.

AndyKunz

Bill,

That is EXACTLY the definition of a brown-out!

ALL electronics can be browned-out, your favorite brand included.

Maybe living in CA you're more familiar with black-outs but those are different - power goes to 0. A brown-out on the AC grid is below 85VAC (we call it "low-line").

Andy

vertical grimmace

My Feedback: (1)

I have been using this RX for the last 4 years. It only was used with one TX/module. In fact I only have 2 Futaba 2.4 RX right now. I am moving all of my stuff over to Hitec. Mainly because I prefer that TX. I had one of the first generation Module/ RX combos. Could that have been an issue with a recall?
I had it zip tied to a former in the fuse wrapped in foam. Maybe it needed more?

Silent-AV8R

Still missing the point. The term brown out came to be used to explain the crashes experienced by people using the early Spektrum/JR equipment that lost link when power dropped too low. The long recovery time resulted in many crashes.

My point is that while all equipment has a certain voltage below which they will not work, the term brown out has a very unique meaning. However, I understand why you would want to see it used in a broader manner.

Unless the system voltage is so low that even the servos are not working then Futaba owners can be confident that low power is not going to cause a crash unless it is sudden (battery unplugs) or the pilot ignores the failsafe. In addition, Futaba FASST systems provide a built in low voltage failsafe which activates at 3.8 volts warning of a possible voltage issue. Since the OP did not mention that his throttle dropped to idle prior to the crash we can assume that it was not voltage related. Given the alternating red/green flashing LED he observed it appears he had some sort of RX failure which I suggested may be due to vibration from his engine.

rmh

FWIW -the term Brown Out preceeds Spektrum by many years
Notwithstanding Futabas' warning of low throttle as a device to preclude low voltage problems- -it is just a warning that can happen at the same time (during a sudden rush to low voltage) as power failure occurs. This would effectively cancel the warning system.
The low voltage warning system is NOT failsafe-it assumes power is gradually dropping and has reached a point.
It does NOT take into account the sad fact that some batteries and regs and ESC/BEC reach a levle then quickly shutoff.
If you have ever done load tests on cells such as A123-you would see a power shutdown curve (under load) that goes from a working current to effectively dead in seconds.
again- power failure could be the problem- and again not directly due to the battery going to low voltage. A high load will cause effective low and disastrous low voltage at the rx.
This would set the stage for signal disconnect -at that time failure to reconnect (for whatever internal rx failure). could take place.
I am not picking on Futaba-the systems work well .
Unravelling the cause of failure can present some surprises.
I spent years working professionally, at trying to establish real cause in industrial machinery accidents . The claimed and proposed causes were often not even close to the real cause.

crash1ace

Gee, guess you just cant beat those good ol 72Mhz radios cant' ya? In all the years Ive been using 72, I've never experienced not even one issue with my setups. Seems to me, with everything I keep hearing about/reading about these 2.4 systems seem more trouble than its worth. Guess I will keep on using my good old trusty radio gear for ever and ever ;-)

GerKonig

Not really, we had a lot of problems with the old systems, just that people did not come on the board to discuss them. Seems to me you are wrong, very wrong.

Gerry

rmh

Good ol 72 - if there is no frequency conflict -they are hard to beat-

MinnFlyer

My Feedback: (4)

While you're at it, replace your car with a horse and your refrigerator with an ice box

rmh

I have LED tvs- fibre optics computer feed into the house -for quad core stuff etc..
As a kid we had oil lamps, a spring house for cooling food and horses plus one ratty ol car for long trips otherwise -we walked .
We never felt we needed anything else
Would I trade back?
naw -just trading one set of problems for another -

chris923

My Feedback: (53)

I had it zip tied to a former in the fuse wrapped in foam. Maybe it needed more?

I was told NEVER to wrap 2.4 receivers in foam. They will get hot, they only need to be velcroed or straped in.

Chris923

4u2nv-RCU

My Feedback: (28)

quote:

ORIGINAL: crash1ace

Gee, guess you just cant beat those good ol 72Mhz radios cant' ya? In all the years Ive been using 72, I've never experienced not even one issue with my setups. Seems to me, with everything I keep hearing about/reading about these 2.4 systems seem more trouble than its worth. Guess I will keep on using my good old trusty radio gear for ever and ever ;-)

While you're at it, replace your car with a horse and your refrigerator with an ice box

++++++++++++++++

My car doesnt go out of control by itself. My refigerator runs just fine. 72MHZ is just as good as it has ever been and with all the folks buying into the hype of how good 2.4 is I have fewer frequency conflicts. Bad battery management has caused crashes since we have been flying RC. It seems the 2.4 stuff is, at best, more sensitive to battery problems so I will come to the conclusion that 72MHZ is better, for now.


Peace!!

rmh

Your rx would get hot ?
Perhaps -I thought Futaba resolved that problem-which applied to certain series .
some shock mounting is always desireable and there is always the possibility of loose wires attached to a vibrating rx , could wriggle loose or loose continuity.
The non genuine wiring which is very inexpensive, can do this -also it definately will not carry current as well as genuine HD Futaba or JR HD wiring.
This problem is often very difficult to detect!
Loosing power -as I mentioned earlier is not simply "battery going dead." a poor connection will heat -and cause even further power losses
It is pretty tricky to see .
Using a commonly availabe watt meter - placed in each connection point - will sometimes show the offending connection
Another really ugly one to spot -is a servo driven to it's end and held there
here is a typical example:
Let's say you have flaps - the flap servo seems weak-so you replace with a nice higher torque model
you install it and adjust so that it firmly locks the flap in up position.
If you install the wattmeter in the batt to rx connection - you may find that as the flap locks into the UP position - the voltage drops and the current draw instantly shoots up.
You may not hear the servo straining but some of them really draw current when stalled
In this example - the plane may fly normally for a while -but the batt is rapidly draining.
finally (time is unknown) you reach low voltage warning - and the voltage keeps right on dropping -fast -you won't even detect any warning.
This may not be what happened in your case- but it has happened- the type/and rating of batteries can be very different.
In these cases it is not uncommon to read the unloaded voltage of the battery as being good after the problem occurs
back when using 72 only we had far less current draw (servos simply would not draw a lot except for the special ones) and the radio would keep right on truckin and just got slower n slower.- The 2.4 will not do that.

jeffEE

My Feedback: (5)

Vertical Grim. I hope you find the cause. I am sorry to hear the DRI is gone. It was a classy bird.