another wot4 crash caused by radio failure :(

[andyh]

just home from having crashed another wot4 foam-e due radio failure, having also crashed one on weds:

**LINK**

this time I was on my DS5e (no buddybox) & using an Orange R620 (I read on here somewhere that the R710 I had in previously might have had some range issues). brand new model with new ESC, etc. the model was range checked, Rx failsafe set (& tested) to fail back to neutral positions. the crash was almost exactly the same, model pitched nose down (possibly due to turbulence) & stopped resonding to Tx control inputs, before piling in & breaking all the same stuff as last time

I know this is a "how long is a piece of string questions?", but does anyone have any thoughts? I'm getting rather frustrated with this whizzy new 2.4GHz gear destroying my models plenty of other people at the club use Spekky Tx / Orange Rx combos without issue

[cymaz]

2.4 Rx aerials are very fussy on how they are positioned. I know with Futaba and FrSky the silver ends on the wires must not be covered at all and the two wires be at 90 degrees to each other.

My heart felt loss for the planes

Edited By cymaz on 11/08/2013 15:52:03

[Seraph]

It doesn't sound like a radio failure to me. Have you checked the elevator control linkage, especially the the screws which clamp the control rod to the servo arm. These can move and then jam if the screw isn't really tight.

[MattyAndJo]

Hello,

Sorry to hear about that, when I read your problems it reminded me of exactly the same problems I was having last month with my Spektrum DX7S, I lost 2 models in as many days (Wot 4 ARTF and a Calmato 40 Sports), lost all control and nothing responding. I range checked them both before flights, all fine, one had a AR400 "official" spektrum reciever in, the other an Orange RX615.

It was only after the second crash our club BMFA examiner came over and said "there's something wrong with that radio", it was only just 5 weeks old and was purchased from an official horizon hobby model shop (Phil Greeno models).

After much messing around we set up another model, range checked it AGAIN, this time though we tried "waggling" the antenna around, straight as I did that, nothing! Zippo! It lost connection, soon as I left it alone it connected again.

Took the antenna off (it just "clicks" off), and to everyone's shock and awe the antenna cable was freyed, I've taken a picture which I'll upload shortly, this was a BRAND NEW spektrum TX, it cost me 2 models! Emailed Spektrum very poilitely saying I wasn't after any compensation or anything like that, just wanted to "draw their attention" to this very serious problem, they very politely ignored my emails!

Anyway, check your antenna on your TX, make sure its not the same as mine!

[MattyAndJo]

Here is the picture of my Spektrum DX7S, 5 weeks after purchase, and after 2 totally smashed models...

[andyh]

thanks Matty. sorry to hear you lost two models, i'm not sure I would have been so polite with Spektrum if it was me! I don't think I can just pop the antenna off on the 5e to check; I'll have to dismantle the case this week & take a look

my thinking is that it's something on the model rather than the Tx though. the previous crash was with the 5e buddied as Slave to a 6i Master so, if I understand buddying correctly, the signal would have coming from the 6i antenna

thining about it, both issues have been with the model head-on, so potentially the Rx antenna could have been masked by the motor/ESC/battery

Seraph - the linkages are fine, I checked them after the crash

[MattyAndJo]

Yes your right, if your TX is just the slave attached then, like you, I believe it doesn't actually do any transmitting, worth a shot and didn't wan't you losing any more models like me.

[Erfolg]

I am not sure Cymaz that the comments with respect to Futaba 2.4 Rx aerials is correct, that the silver/metal bits mist not be covered.

I fly now in excess of 10 models, using a variety of Rxs, some are Futaba 617, HK-Orange Fasst, Frsky Rxs. All are covered, that is inside cotton wool bud tubes, drinking straws, snake outers. To-date I have not had a range issue, some have been flown at extreme ranges, in that they are gliders.

[andyh]

stupid questions:

1. is the full (~140mm) length of the Rx antenna "live", or just the uncovered end (~30mm) portion?

2. the Orange R620 & R710 Rx's each only have a single antenna. should I be using a satellite Rx with them (they both have satellite sockets)?

[cymaz]

Found this if it's any use

[Erfolg]

Cymaz, what is it were are looking for?

[Biggles' Elder Brother - Moderator]

Hi Cymaz - that covers Futaba stuff - and the "don't cover" advice relates to not swaddling the Rx box itself in foam - like we used to do in the good old days!

Like Erf I run my Futaba aerials in thin drinking straws - never had any problems with range or signal loss in the 3+ years I've been using 2.4. Not a single glitch, not even a hint of one. And I fly a lot!

OK, so let's have a look at Andy's problem.

Let's assume that it is a radio problem, as you say Andy other people use this kit with no problems. So I'm afraid you're going to have to face up to the possibility its something you are doing wrong. Let's go through the basics:

When you install your Rx are you making absolutely sure that that the aerials are fixed in an orientation at 90 degrees to each other - and I mean "Fixed" with a capital "F"! Not placed, or shoved in a gap that "might" hold them. I mean can't move. As I say above I do this by running the aerial in a small tube then gluing the tube to the airframe. In answer to your question - only the bare tips of the aerials are important - it is these that must be at right angles - the rest doesn't matter.

Second thing - are you 100% confident in the integrity and stability of your Rx power source? I assume this model is electric - are you running off the BEC in the ESC? If so what low cut off voltage is set? And what voltage is this supplying to the Rx - its probably around 5v - but its worth checking.

Third - stupid question but we need to eliminate all possible sources of error - when you are range checking are you alsolutely confident that you doing this with the Tx set to reduced power? Also are you going a good, generous, 30m away? A model shouldn't "just" pass this test, the test should present absolutely no problems or even hints of them. When you do your range check do you turn the model through 90 degree positions and so check the range from different directions?

I can't tell you if those receivers need a satellite as I don't use Specktrum gear! If they do then that could very well be a source of your problem.

Finally are you happy with your wiring? Is everything fully connected? Don't just nod! Believe me its very easy indeed to think that a plug is fully home in an Rx - but it isn't! Could there be any intermittant bad contacts? Have you given all your plug/socket combinations a jolly good wiggle and checked everything keeps on working?

Give us some feedback on that lot and we'll go from there. Its very frustrating to lose models and my heart goes out to you - but hopefully we can get you on the "straight and narrow" again!

BEB

[graham dewis]

Posted by andyh on 11/08/2013 17:06:48:

stupid questions:

1. is the full (~140mm) length of the Rx antenna "live", or just the uncovered end (~30mm) portion?

2. the Orange R620 & R710 Rx's each only have a single antenna. should I be using a satellite Rx with them (they both have satellite sockets)?

For 1. Just the end portion is live

For 2 Would be a good idea. (not gone on orange myself)

Graham

[cymaz]

I was thinking that the items covered in the link might have played a part however small. I have never covered up the silver end of the aerial wires but I know someone who did and suffered from poor range. It just means that I gave my honest opinion based on experience. Here is an article that doesn't cover the ends in an installation.

Has anyone thought of a switch problem?? However unlikely as the problem appeared in two separate models.

Someone once said to me in problem solving, work from one end right to the other.

Edited By cymaz on 11/08/2013 18:33:17

[Erfolg]

The ESC and Bec being the issue seems unlikely to me. If working as designed. All of my ESCs, just shut the motor off, or go to reduced power to the motor, never switching the power to the Bec part of the circuit. If this works, you should still have control, although it would not stop you stalling the model.

[Paul Marsh]

I don't like the 2.4 aerials where they are very fragile. Prefer the new DX9 and DX18 arrangement - fixed devices and not fussy on positioning, as there are two - in an "+" pattern - so no issue regarding positioning.

Broke my DX8 unit off again, as I've already done with the Futaba FF7 and the Spektrum Module on the JR set.
I don't think I would use your DX5 again.

(ps. I've got a brand new DX6i +DSM-X for sale...)

[Peter Beeney]

Andy, Assuming you mean a DX5e tx then it’s just possible the problem is with that. We had some Spektrum issues quite a while back which resulted in at least a couple of the lads going Futaba. One gentleman persisted with his Spektrum 5e though, but in his garage. The troubles had generally been a loss of signal but sometimes it would restore before the model actually crashed. By giving it a good trial he soon found the fault was in the tx switch, it appears it is a multi way device and it can switch off the rf output section without switching off the l.e.ds. He was able to demonstrate this at will by squeezing and/or griping the front of the transmitter; he took it all to pieces and, as an ex. motor engineer, (long retired), said he thought the switch could be politely described as ‘of dubious quality’. He banished the gremlins, though, by soldering a wire strap across the switch and turning it on and off by removing one cell. Now he often uses it to fly one of his ParkZone models, it’s never missed a beat since! Which, of course, completely proves the point.

I have an old DX5e too, it’s mostly as a buddy slave, and I also have a AR 500 rx. I’ve often tried to get this to fail in the same way but I can’t! Also I’ve just bundled the rx in a small powered glider, all tangled up with the ESC wiring, as you do, aerials curled up to boot, and flown it to the limit of visibility many times without the slightest cause for concern. We’ve also done long range ground checks, 600 metres, and we’ve never been able to orientate any of the aerials in any position that prevents the rx from faithfully relaying the signal to the servos. Every time. Personally I’ve always been a bit suspicious of the aerial theory, back from the days when I checked out 35 MHz, I’m long convinced that the range limiter is eyesight, not radio signal. If there’s a ‘situation’ of some sort, I tend to think it’s something else other than lack of range.

This is just as we found it, and maybe it’s not happened elsewhere; so it certainly might not be in anyway representative of your problem; bur it certainly might be well worth checking it out.

Hope this is of some use.

PB

[andyh]

Posted by Biggles' Elder Brother - Moderator on 11/08/2013 18:12:50:

When you install your Rx are you making absolutely sure that that the aerials are fixed in an orientation at 90 degrees to each other - and I mean "Fixed" with a capital "F"! Not placed, or shoved in a gap that "might" hold them. I mean can't move. As I say above I do this by running the aerial in a small tube then gluing the tube to the airframe. In answer to your question - only the bare tips of the aerials are important - it is these that must be at right angles - the rest doesn't matter.

Second thing - are you 100% confident in the integrity and stability of your Rx power source? I assume this model is electric - are you running off the BEC in the ESC? If so what low cut off voltage is set? And what voltage is this supplying to the Rx - its probably around 5v - but its worth checking.

Third - stupid question but we need to eliminate all possible sources of error - when you are range checking are you alsolutely confident that you doing this with the Tx set to reduced power? Also are you going a good, generous, 30m away? A model shouldn't "just" pass this test, the test should present absolutely no problems or even hints of them. When you do your range check do you turn the model through 90 degree positions and so check the range from different directions?

I can't tell you if those receivers need a satellite as I don't use Specktrum gear! If they do then that could very well be a source of your problem.

Finally are you happy with your wiring? Is everything fully connected? Don't just nod! Believe me its very easy indeed to think that a plug is fully home in an Rx - but it isn't! Could there be any intermittant bad contacts? Have you given all your plug/socket combinations a jolly good wiggle and checked everything keeps on working?

thanks BEB. it's highly possible I'm doing something wrong!

1, the two Orange Rx's ';ve been using only have a single aerial (hence my question about satellites). I've had it tucked into what I assume is the 35MHz aerial tube - ~3mm plastic tubing from the rear of the servo bay to mid-way between the wing & the stab on the top of the fus (although obviously it's only going in a couple of inches). since there's only yhe single aerial I wasn't too concerned; if I'd had two I would have secured them so they were 90 degrees apart

2. yes, running the Rx off the BEC in the ESC. I haven't programmed it in any way, I'm not sure if it even is programmable, it's the standard 40A ESC that comes with the model. on the ground, the Rx is getting 5v (between the black & red cables), although this is obviously not under any load

3. range check. hmm. I didn't know you could set the Tx power down. too much I don't know I don't know with this 2.4 gear we did a range check at ~50m, side on only, & everything seemed 100%

wiring - just gave everything a good wiggle & it all seems fine

Andy

[andyh]

Posted by Erfolg on 11/08/2013 18:37:00:

... although it would not stop you stalling the model.

are you an LMFC member by any chance?

[andyh]

Posted by cymaz on 11/08/2013 18:30:47:

Has anyone thought of a switch problem?? However unlikely as the problem appeared in two separate models.

no switch on either model

[andyh]

Posted by Paul Marsh on 11/08/2013 19:01:17:

I don't think I would use your DX5 again.

(ps. I've got a brand new DX6i +DSM-X for sale...)

I saw the problem on the previous model with the DX5e buddied as Slave to a DX6i as Master, so I don't think the tx is the issue

I have a DX7s on order already, not particularly for these problems, but the 5 is a bit basic, I only really bought it to mess around with a sim

[Erfolg]

An easy way to check what happens to your airborne pack when flying, is to charge the Lipo, run the motor until is shuts down, then check that the control surfaces still operate.

[andyh]

Posted by Peter Beeney on 11/08/2013 19:42:25:

Andy, Assuming you mean a DX5e tx...

Hope this is of some use.

PB

hi Peter,

yes, sorry, DX5e. thanks for the info. as per some of my above posts, I saw the same issue with the DX5e slaved to a DX6i master, so I'm still leaning somewhat towards the issue being something on the model. saying that, the DX6i is based on the same case as the 5e, so maybe the sswitch is the same. however the 6i is the club's buddyboxing Tx & I would have expected them to have seen the issue before now if that were the problem

Andy

[Peter Beeney]

Andy, Just a point of interest, do you know exactly which buddy lead you were using? Particularly if it was a genuine Spektrum lead, or not?

PB

[andyh]

Posted by Peter Beeney on 11/08/2013 20:37:02:

Andy, Just a point of interest, do you know exactly which buddy lead you were using? Particularly if it was a genuine Spektrum lead, or not?

not entirely sure, we just used the club one. 3.5mm headphone-type plugs on each end - stereo iirc - & some sort of box in the middle of the cable.  this has been used extensively by the club without issue as far as I'm aware

Edited By andyh on 11/08/2013 20:40:01