Futaba 2.4 radio issue?

[Tim Morton]

Apologies for the long story - but it's needed to give the full picture...

I lost a brand new plane to radio failure last Friday (15th April). It was a Great Planes Big Stick with a nice new shiny 75AX upfront on it's second flight. The Rx was a Futaba 606FS bound to my 8FG with a new battery pack and servo's. The entire lot was brand new (the 606 was old but unused). Range check etc. was al fine - basically the system was all brand new and shouldve been 100%. I took off and flew around a bit and passed the Tx to a flying mate of mine (a B cert. - so a pretty good pilot) and asked him how it compared to his Wot4. He proceeded to fly it and at the top of a Cuban 8 the radio died - the plane went in at full chat from about 150ft. Dug an 18" hole and broke the engine in half. Failsafe was set to idle but this never occured. When he lost it I was standing with him and watched the furious stick twiddling having zero effect. Gutted is not the word - but it wasnt his fault!!!

Now about two months ago I lost my hot EasyStar (with a fast brushless) with the same radio setup under almost identical circumstances. I must've had a few hundred flights with the Easystar with no problems and wham - top of a loop and no control whatsoever. At the time when I extracted the remnants the elevator servo had stripped its gears - I put the crash down to unexplained and /or pilot error.

There was a third instance involving the same Rx in Egypt about 3 years ago - this time a homebuild Big Stick (I really like them) when again I had total radio failure - when I pulled the wreckage up the tbg on the elevator clevis was missing - so I put it down to me not checking the model (it had already had quite a few flight s though - say 40-50), and pilot error and panicking at the time.

However there is a common theme here of the 606FS Rx. Could this be the problem? In the meantime I've grounded all aeroplanes with that Rx (I bought a bunch of them when they first came out) - until I can afford to replace all the recivevers.

Edited By Tim Morton on 18/04/2011 13:18:33

[leccyflyer]

Bad luck. The worst thing is that it knocks your faith in the entire radio system.

 

You've just described pretty well the problem that we encountered yesterday with a Spektrum AR500 -the most puzzling aspect being why, since the failsafe was set to throttle off - the loss of radio control was not accompanied by the motor switching off. It was still under power at impact. Puzzling, to say the least.

[David Ashby - Moderator]

Really sorry to hear that Tim. I assume the Rx wasn't the one that crashed in earlier models?

I've had a few 606s and they've been fine but if I have a model crash and I can't see the fault then the Rx stays grounded. It doesn't get a second chance.

 

How's that battery? Was it new new? Had it been cycled? Have you tested it since?

[Tim Morton]

 

Thats what happened to me - the failsafe didnt work.

Not sure what to make of it though - if it lost signal then it would've gone to idle but they all went in at full power.

 

Is it possible something else causing the problem - the Tx maybe (2 x 8FG here and the Big Stick in Egypt was with a Futaba 2.4 6EX - American edition).

 

The 606FS is now discontinued with no seeming explanation - is there something wrong with it? If so why wouldn't Futaba say something on their website about it?

 

Guess the only poistive is that no-one got hurt. A Big Stick with the OS 75AX is quite a large aeroplane and to break the engine in half in long grass and soft soil - well it was going some. So a big cost to me but no-one hurt and no damage to property.

Edited By Tim Morton on 18/04/2011 14:23:34

[Tim Morton]

David - it was all brand new.

This Rx was a few years old but unused and still wrapped in it's box when I installed it.

I have another few all wrapped up still - think they going to be hammer targets for me!!!

The battery was new but is now destroyed too (the cells broke apart) - the plane took a real thumping.

The only salvagable bits are the wheels and main U/C...

[Tom Wright 2]

Tim Had you checked the the motor fail safe setting was working prior to the flight ?

 

TW2.

[David Ashby - Moderator]

It's bad enough but worse not knowing, ouch that sound slike it really did go in!

 

Well' I'm still using 606s that are 4 years old now and they've never missed a beat. You coudl perhaps send them back to Ripmax to get them checked?

[Tim Morton]

yes -Tom I'd had some problems setting it up for some reason (servo's reversing with the throttle cut) - I'd checked it again just before the maiden and it was fine

 

[Tom Wright 2]

Tim i am not current on I/C setups ,EP only, but it sounds more like a receiver power supply problem ?

 

TW2.

Edited By Tim Mackey - Administrator on 18/04/2011 22:30:56

[Tim Morton]

I did the only thing one can under the circumstances - went home phoned my pal Mike at West Wales Models after hours and ordered a complete new one. Plane, engine, Rx (the 8channel), 5 servo's (digital this time), prop, switch etc. Hopefully will arrive Wednesday.

 

Then I poured the biggest G&T I've had for a very long time - swiftly followed by another equally large G&T.

After that I felt quite alright - almost philosophical about it l!!!

 

Edited By Tim Morton on 18/04/2011 15:23:56

[Tom Wright 2]

That should do the trick Tim , it eliminates the problem and any guilt about spending the cash.

 

TW2.

[simon burch]

If you had absolutely no control, and the failsafe (which I guess you checked on the ground before flying ??) did not kick in, it sounds like you've had a power failure of some kind to the rx.

[Biggles' Elder Brother - Moderator]

Interesting, we had a very similar incident at our patch yesterday.

 

The model concerned was a Seagull PC9, a well proven model with several flights under its belt. Pilot took off got an almost immediate dead stick on climb out. He struggled a bit with the resulting straight ahead landing and the model went in quite hard - but on examination no immediately obvious damage.

 

Gathering his wits he decided to "have another go". Started the engine, fettled it a bit, then lined up for a second take off. After a short run the model took off and proceeded to go into a large loop at full throttle. It went right round the loop and completely buried itself in the middle of the strip. The impact was at maximum force and the cowl and spinner are still in the ground!

 

Again he had no control and the failsafe didn't step in, the model stayed at full throttle and the elevator was obviously stuck "up". On examining what was left (not very much) we concluded that the following was at least one possible explanation of the fact such as we had them:

 

1. the first heavy dead stick landing must have loosened the connection to the Rx battery pack. The battery pack may have even come loose at this point.

 

2. on taking off the second time the jiggling caused by running down the strip had completed the job. Just at the point of rotation the battery became disconnected somehow from the Rx.

 

3. Without on board power the servos would of course stay in their last commanded postion - ie full throttle, slight up-elevator. The failsafe would not activate because it is only intended to protect against loss of signal. If there is no on-board power the Rx cannot implement the failsafe baecause its not powered-up and there is no power to the servos.

 

What happened here sounds very like what happen to you Tom. I would not suspect the Tx. Beacuse if the Tx failed in some respect, but the Rx was still functional, then the failsafe would kick in. The fact that it didn't would indicate to me total loss of operation of the Rx. Now that could happen because of an Rx failure or disconnection of the power to the Rx. Either way, not nice, but unlikely to be the Tx's fault.

 

BEB

[Biggles' Elder Brother - Moderator]

Simon - two minds with a single thought! But you said in a lot fewer words!

 

BEB

[Tim Morton]

Simon / BEB

The Rx power failure does indeed sound like it could be a problem - would explain a lot and yes Simon I did check it on the ground before the first flight.

But its still a little strange - I agree with power failure on the 1st Big Stick (in Egypt) and the one that went in on Friday as a possibility but with the the Easystar no - that had an ESC and if one lost power the whole thing would shut down servo's, motor and all - surely?

 

[Tim Morton]

I guess my concern is I don't really know what it was, which makes me nervous for other planes.

I've got a 7C 35Mhz set which I can use - perfectly good setup so may just go back to that. Keep the 2.4 and 606's for the park flyers and indoor stuff.

But that’s not really the answer is it? Something happened and assuming it was radio failure (Rx) then that's at least identified the problem.

But what if it was something else - like a Tx problem - unlikely I suppose but still a question?

And it was at the end of the day - just a model aeroplane and they all crash sooner or later (well mine do) but what if it had gone in elsewhere like that?

I dunno - but I'm deeply suspicious of all things 606FS just now....

 

 

 

 

 

[Chris Channon]

Hi Tim, i also lost two aeroplanes using Futaba 2.4 gear, no reason just did not respond to the Tx, the Super Air did not go into fail-safe, just stopped and went in.

For me i have gone back to 35 megs , it always worked well in the past.

Saw a heli go in a couple of weeks ago, very competent pilot, and he just had no control, two weekends ago another guy lost his aeroplane on climb out, again no control, for me, 2.4 is not reliable enough to fly a model aeroplane around, we have been lucky, no-one was hurt, i honestly can see the day when something bad happens.

I wonder, just as an aside, how many more incidents ( claims) have arisen on our BMFA insurance since 2.4 became available?

Really no point in flying a model if you are not sure that you will be able to fly the whole tank out without a problem, as i say, i have gone back to 35, a few more have followed.

regards

Chjris.

[Biggles' Elder Brother - Moderator]

Well, Chris all I can say to that is I've been on 2.4 for just over a year, and I've not had a single problem, not the slightest glich. I don't think I ever had a single year on 35MHz I could say that.

 

Tim an 8FG is an awful nice Tx to confine to park fliers - there is no real evidence to implicate the Tx.

 

BEB

[Tim Mackey]

Mostly been said, but I agree that it does NOT sound like a loss of signal, as the failsafe did not activate. That suggests to me the Tx and Rx are probably fine, and you suffered radio power supply failure.

On the IC model - could be battery, wiring, plugs switch etc, and on the leccy model, maybe the BEC / BEC overheated / failed?

Not wanting to tempt fate, but I also have a fair few numbers of AR500s, and all performed great.

[Tim Morton]

Another option on the power failure just occurred to me - what about the switch?

On the Big Stick it was a Futaba heavy duty switch BUT if it failed it would have exactly the same symptoms...

[Biggles' Elder Brother - Moderator]

Yes indeed Tim. As Tim M has said, it could be anything that would result in a loss of power to the Rx; battery wiring itself, switch fault, broken wire, bad connection between a wire and a plug/socket, faulty plug/socket, fault in the Rx itself. Any of them would do this.

 

Makes you think doesn't it about just how many things could go wrong!

 

BEB

Edited By Biggles' Elder Brother - Moderator on 18/04/2011 21:28:21

[Tim Mackey]

And factually speaking - none actually "radio failures"

[Tim Morton]

Agreed it isn't radio failure if it was the switch or similar. But at present it falls into the realm of unknown.

 

The worrying thing to me is I've been flying 35Mhz alongside these disasters and (looking for some wood to touch) never had a radio problem. Not one!!

So is it purely circumstantial that all the battery /switch / power supply failures have happened with the 2.4 setups?

Guess its feasible but is it probable?

I really don't know - but for sure i'll be only putting in the most rugged system I can.

I'll try the 2.4 again in the new Stick - but with the latest 8 channel receiver and digital servos (probably what it's really meant for).

I agree the 8FG is an awful lot of Tx to use on indoor planes but I'm wary to the extreme now.

 

 

 

 

 

[Martin Harris - Moderator]

Oddly enough, I had a deadstick last week at the top of a loop. Nothing unusual here but it was an electric foamy (my Bearcat) with a fairly freshly charged battery.

 

I still had control and tried shutting and opening the throttle to "re-arm" the ESC - nothing so headed it back towards my feet (I'm lazy) but at 50 feet or so there was a massive glitch (I'm still using 35 MHz for my "minor" models ) but I was able to land under control.

 

Picked up the model and turned it upside down to look at the battery connector - no motor response...and now no control response either - must be the battery then - but hang on, what's this silver thing on top of the inverted fuselage?

 

The crystal had fallen out!!!

 

It must have come half out in flight , confused the ESC and caused the glitch - putting it back in (after disconnecting the battery) immediately restored normal function.
 

The point here is that had it splattered in, I would have assumed interference, intermittent receiver problems, battery, ESC/BEC failure or similar rather than the crystal - which I'd have assumed had popped out in the crash so you need to keep an open mind in any investigation.

Edited By Martin Harris on 19/04/2011 00:13:46

[Biggles' Elder Brother - Moderator]

Spot on Martin. I find that usually you might be able to eliminate certain causes of the accident but its often difficult to home in the actual cause. You can just say vague things like "for some reason the rx stopped working and that could be for a number of possible reasons".

 

BEB