I give up!

[winchweight]

The AR 6100 aerials were directly in line with one another, and the rx was positioned so that the aerials went left to right across the cabin. But isn't that how they're meant to be on this unit? It is a 6100 not a 6200 as previously reported.

[Chris Card]

Pass - I'm not going to pretend to know more about it than I do.  All my experience of 2.4 GHz receivers so far has been that the aerials should be perpendicular and this makes sense to my engineer's brain as one will always therefore be crossing the radiant field, irrespective of the orientation of the model.

 If there's something specific in the instructions for that receiver telling you to install them in line then that must be right.

[winchweight]

Yup, that makes sense to me too, but the aerials are short and I'd imagine they'd be prone to breaking if they were turned at right angles to each other.

[Tim Mackey]

Nope...you had them right.

[Yorkman]

is the 6100 a single receiver then? I assumed this talk of putting aerials at 90 to one another was referring to the 2 receivers as in the 6200?

[Lee Burke]

Perhaps I am not understanding the descriptions here, and my info refers to Futaba 2.4Ghz ,but the antennas should not be in line with each other but form as near as possible a right angle.  It doesn't much matter if they point up or down or across but they should be at 90 degrees to each other.  It is preferable if one of them points towards the rear of the aircraft but this is not vital.

[Chris Card]

Timbo - forum moderator wrote (see

Nope...you had them right.

I guess there must be another aerial internal within the case, providing the perpendicular component, otherwise with only 1 aerial it can get aligned directly away from the Tx.

[Lee Burke]

 This extract is rom the  6EX manual, I know, its not Spektrum but its the one I have.  They also mention that the Tx antenna should be perpendicular to the face of the Tx for best results.

----------

1. The two antennas must be kept as straight as possible. Otherwise it will  reduce the effective range.

(By antennas they mean the bits of bare wire, not the sheathed part)

2. The two antennas should be placed at 90 degrees to each other.  This is not a critical figure, but the most important thing is to keep the antennas away from each other as much as possible.  Larger models can have large metal objects that can attenuate the RF signal.  In this case the antennas should be placed at both sides of the model. Then the best RF signal condition is obtained at any flying attitude.

3. The antennas must be kept away from conductive materials, such as metal and carbon by at least a half inch. The coaxial part of the antennas does not need to follow these guidelines, but do not bend it in a small radius.

4. Keep the antennas away from the motor, ESC, and other noise sources as much as possible.

[Roger Wilco]

My understanding is that Futaba receivers definately state that the two 'sticky out' ariels should be bent at 90deg to each other.

Looking at the Horizon site it looks like any Spektrum receiver with  'DualLink' needs the same.

http://www.horizonhobby.co.uk/aeroonline/e6spektrum/e6receivers/e6receiversfs.html

also click on the 'glossary' tab.

Hope this helps it was just a quick browse ... I'm still flying 35Mhz. 

[Lee Burke]

But no doubt the Speccy has its antennas in a line as Timbo confirms.  Just good to know they are different. 

[Yorkman]

well the spektrum Ar6200 has two separate rx joined by about 6 inches of wire-and the two rx should be positioned at 9 to one another-definitely no talk of bending wires.

[winchweight]

Hi guys. The top end Spektrum systems have a satellite aerial unit which is indeed at right angles to the main unit. But the basic 6100 has two very short lengths of aerial wire (I guess actually one aerial stretching across the top of the module), and they point 3 o'clock and 9 o'clock or there abouts.

Counterintuitive I know, but it's what they say to do.

[winchweight]

You are obviously entitled to your opinion, but in point of fact, the model never entered a spin, it descended straight. And if it did, I have a rudder at my disposal. And you may be right the rx may not be at fault, but by the process of elimination (by replacing most of the major  components after crash 1), there are very few common factors.

Just because I can't reproduce it on the ground, doesn't mean I flew it into the ground. I have had a few crashes over the years and have never shied away from admitting fault. But in this case, I am adamant that unless there is a new set of principles of flight (I am a real, fullsize aircraft RAF flying instructor by the way), that only apply to electric models, then I did not crash this model myself.

The motor audibly wound down to idle, as heard by Frank and other witnesses. Now I definately didn't do that!

BTW I have taped up the fuselage and will reinstall the gear into the wreck for further testing, to try and reproduce the conditions tomorrow.

[Frank Skilbeck]

The fact that the motor when to the fail safe setting points to the Rx going to failsafe, this could be due to

i) Interference (but being 2.4 I'm surprised it lasted for 8-10 seconds)

ii) a component failure on the input side of the Rx

iii) a power supply issue, I'm guessing that if the ESC saw no output from the RX it would shut the motor off.

or a 

iii) TX fault

Hope your investigations show something tangible.

[Tim Mackey]

Right first of all, lets clear up the issue of aerial orientation. There is no suggestion, instruction, or illustration from HH that the "single" unit AR6100 that Shaun was using requires any bending of the 2 wire aerials whatosever.

They exit the case at opposite sides to each other, and bending them would be illogical - if they were meant to be at right angles to each other then Spektrum would  have designed the unit differently - as they have with the DSM1 AR6000 unit which DOES have the 2 wire lengths exiting in different orientation. I have lots of models fitted with 6100s and every one of them merely has the receiver placed "across the fuselage" with no bending of wires whatsoever. Several of them are actually buried within solid foam ( as in my 50" wildthing EPP sloper ) and this model flies a LONG way up and out over the sea...almost out of sight....with absolutely no issues at all. I personally have NEVER seen a 35Mhz so acalled park fly range receiver perform as well - they are simply stunning.

From Shauns description of the failure I have to say that brown out can be definately ruled out - he has confirmed that his reciver was QC enabled - and believe you me, the time taken to regain control following brown out is a split second at most. I am leaning towards one of the issues mentioned by Frank. Loss of signal ( but unknown reason as to why ) would exhibit all the signs mentioned - ESC shuts down the motor, all other controls assume last known good position with no visible response to stick inputs. 

Incidentally Shaun... when I suggested possible installation weakness of the UBEC I was thinking along the lines of dry / suspect joint of the connections / pins / etc - NOT that it had been wired up incorrectly.

[winchweight]

The point about me being a flying instructor is that I can recognise a stall or incipient spin, and as military aircrew we are all taught to be naturally self critical and to analyise our own performance before anything else. If I messed up, I'd hold my hand up, but unless I put it in a shallow dive, closed the throttle and made no effort to correct it, I didn't fly it into the deck. Fact!

As has also been said, any one of the components could fail, any solder joint could fail, any battery could fail. I am not saying the rx was definitely to blame, but at the moment I can't rule it out either, whether this is unpopular or not.

To assume that because your kit hasn't failed you it must be my fault, is as well thought out and balanced as the Mull of Kintyre Chinook BOI findings. That is to say, since no fault can be easily identified, the pilot did it.

Enough.

Timbo, you could be right, but wouldn't that have manifest itself on the first flight? Perhaps not. I'll have another look tomorow before I post off the rx to HH.

[Tim Mackey]

Hi Shaun, It may have ...it may have not ! Dry joints and the like have ( as you surely know ) a nasty habit of being very intermittent and notoriously diffficult to spot. I doubt we will ever really know - and its a bummer when you lose a model for no known reason ! I understand what you mean about the unlikelihood of pilot error from your desciption of events - and like you....will readily admit when dumb thumbs are to blame, but get equally frustrated when no cause is known. Reception loss may also not have occured on previous flights, but again, I am at a loss as to explain why ( if indeed it did ) it happened.

Now...I am off to beddy byes, and David is away, so please assure me that you guys will not go upsetting the normally smooth waters of this place as you are now un- supervised

As I remember being told by David many posts ago... " be nice gentlemen!" night night zzzzzzzzzzzzzz

[BB]

Got to be the rx, its the only common thread through the events. ESC is working as  it sent the right signal at the right time and voltage. Servos free. and as you were flying figure of 8's the rx antenna would have orientated more than once in the same direction torward the tx. Same applies to the doughnut of death.

Feel for you Shaun, Sounds like a real mare !!

[winchweight]

It is frustrating. I'll do a few more tests before posting the rx to HH, after that we'll never know.... or will we?

Nice ! Nice! I'll give you ni..........

[Tim Mackey]

Oy... I am up and alert I will have you know

[DH1950]

Hi Shaun

 Very sorry to see and hear of your 'problem'.

I wrecked 2 models earlier this year, the lead up to each crash being very similar to yours - a couple of full length flights with no problems, then sudden failure (with possible failsafe) and no response to Tx control input.  In my own defence, the first crash was put down to pilot error being too far down wind at dusk(!), the second was well within our site, at a sensible altitude, and clearly indicated something seriously wrong.

To cut a very long story short, involving hours of bench testing, swapping bits of known reliable kit with bits of the offending airborne set, it turned out to be the switch harness. This had been a new item just prior to the first crash. What I found was that with a fresh fully charged battery showing 5.4v, only 4.8v came out of the other side of the switch harness. Putting a part used battery showing 4.9v in the system resulted in 4.3v coming out the other side of the switch harness. With this set up, I could get the sytem to firstly glitch, then failsafe, then come back on line, then glitch etc etc. Swapping the switch harness showed a 0.1v drop across the replacement.

This was all on 35meg, i.c. power, so it may not relate directly to your problem but its worth a check.

Cheers

Derek

[Tim Mackey]

As I said earlier, it could be down to any one of the many items involved in the whole installation, or indeed be a duff receiver. As also said....we shall probably never know - and I think it will go down as another undetermined reason resulting in a crash.

I still believe the Spekky system is far superior in several ways to 35Mhz - but no-one - not even me as hige fan of the system - has ever said it makes flying radio control aircraft 100% safe - that is impossible.

I know Shaun, and know also that he will put it down to bad luck, but he knows that we are all pretty much stalling the inevitable outcome of almost every model we ever own...and that is ...its final funeral flight

PS I doubt that a switch harness was deployed in this model - one less thing we leccy brigade have to worry about

[Yorkman]

Following this thread with interest, as pretty relevant to my concerns with the York (if you've seen my thread 'any thoughts'), just to say, fiddling around with it on the table last night, i discovered that 'wiggling' the elevator servo lead near the rx would occasionally cause the servo to move..disconnected, 'thinned' the plug on some wet and dry, reconnected, won't do it now.

Just to reinforce Timbo's line about 'dry' connections-electrics can do funny things-maybe Shaun the ubec/rx plug was just that little bit dodgy...and decided at that moment to quit?

[Tim Mackey]

You know.... we all usually just hurl our beloved guided missiles skyward with barely a thought for just what the heck is involved in getting it all back down in one piece again. Literally thousands of delicate and sensitive electronic components all switching away millions of times a second in perfect co-ordination, chemical cells generating electricity for it all, yards of wires and cables, endless tiny little plugs hopefully staying perfectly still in equally tiny and fragile little sockets,switch leafs gently held under minimum spring contact with one another, and all in an environment of huge voltage spikes and back EMF flying around all over the palce, not to mention all the other external signals trying to muscle in on everything..... and so on.

Its nothing short of a bloomin' miracle that we all get away with it as often as we do !

Makes you think doesnt it

[Myron Beaumont]

Watch the for sale columns .Fed up with modern technology & nightmares --NO LONGER FUN