I give up!

[winchweight]

Timbo - forum moderator wrote (see)

PPS I still like you

Scott Cuppello wrote (see)

 Timbo....still like you too.....!

Oh hello sailor!

Did someone say - "I am free!"

This thread is getting more camp than a row of pink tents....

[Keiran Arnold]

Its all your fault Shaun you started it 

[Bravedan]

No wonder many RC pilots stand right on the edge of a field to fly............................... 

This is another run and run, just like "to UBEC or not" on another forum............me,from lots of use I think they work and help avoid the ESC shutdown then Rx reboot time risk with 2.4GHz gear.......................others say they CAUSE interference and are rubbish...............Hey Ho.............

[scott cuppello]

Camp?....hmmm, see your point!

We advise UBEC for 2.4ghz, voltage regulator for 35mghz users [UBEC's switch at 40mghz, hence, sometimes, glitch problems].

[Tim Mackey]

Camp indeed LOL

[Myron Beaumont]

Whats all this camp rubbish ??  When I lived down Cornwall we said  "  Not fed up with the real thing yet ""  I'll get mi coat & go and feed my new hedgehog who comes around every night now . Another prickly aquaintance  but a little beauty . Sorry  Off any thread   Thought  Timbo was away    (probably got a PC in his pocket)

[Tim Mackey]

no... just happy to not see you !

[Myron Beaumont]

[Tim Mackey]

only jokin of course

[Chris Bott - Moderator]

I agree UBEC is best these days, I did used to have glitch issues with them myself. I've only just spotted this thread and have skimmed through so sorry if I'm repeating something. It seems to me that Shauns crash could have been caused by an overheating BEC?? It could have got warm on one flight, hot on a second and eventually too hot and it shut down. This would give no volts to Rx, ESC would shut down power to motor and there would be no control. It's important that the BEC will handle all the servos on board. Here's where I assume a lot - did the model have small servos? they usually take more current that standard ones. did the model have many servos? I have in the past connected up an external BEC (early UBEC, linear type) and sat waggling sticks for 10 mins. Eventually the BEC overheated and shut down. 1/2 hour later it was fine again, it had cooled.

[winchweight]

Interesting theory Chris. The model had 6 mini servos during the flight. You could be onto something here.

[Bravedan]

Shaun, it only takes a servo to be "dragging" at some point in it's travel (not just end of movement stall) to start loading the BEC up. If it was close anyway............

I have just set up a stupid little foamie wing with only two servos...............one (new) Titch servo kept sometimes buzzing at neutral position despite hinge being free and OK, etc, etc, etc......now wiser, I changed it......people (me included!) tend to ignore the "only sometimes" buzz we get from servos................maybe we should not!!!

[Tim Mackey]

It wasnt a digital was it? cos these buzz "normally"

[Martin Roberts]

Hi Shaun,

Sorry to read this thread today, been busy, at least the fury wasn't large scale job, but I feel real bad 4 u anyway.

Getting back to what happened, with the DX6 series the stock Tx bat will pull down real quick, mainly because some idiot used the wrong transistor when designing the Voltage regulator. The DX6 voltage regulator is 9V which is why the TX beeps that the battery is getting low after about one hour of flying time, that said, I haven't seen any where that the TX had low volts, I designed a VR to run 5 Volts in my DX6, but bought a VR that is 3.3Volts, the DX6 actually needs only 3.0 volts in its highest voltage line, so its dissipating any other over voltage as heat, quite silly isn't it, having the warning at 9.0 volts when you only need 3.0 volts. I am not sure whether or not they changed the VR in the later DX7 series.

Also the Tx has a stock 9.6 volt 600 mah bat, which I have changed 4 a 2500 mah 11.1 Lipo, which tends to last all weekend, I fitted a Lipo Saver to mine to keep the cells in good order, and the auw is less than stock, but the low voltage circuit still warns you at that critical 9.0 volts - yippee.

I note that the retracts were up so in theory not using volts, once up the servo should just stop unless there was some resistance caused by poor setup therefore not cming to full end travel, beside one or two servo's sticking out of end point would draw some amps but not enough, so I am sure this is not the case.

[Martin Roberts]

Next would be to look at the total number of servo'sif you were flying 3d, that might be enough to cause a shut down, but in your fury I assume one elevator, two retracts,one rudder, two ailerons, and they would all be small servos in a relatively small foamy, so the amps should not be a problem.

If the Ubec was a problem it would be because you use a 5 volt bec with 6 volt servo's, and I imagine that is not the case but worth a check, e.g. pulling more volts than supply.

[winchweight]

Hi Martin. As you say the retracts were up and certainly not binding during the preflight checks. That left 4 servos (elevator, rudder and 2 ailerons).

The radio was a DX7 with (IIRC) a 1500mah NiMh, so I don't think that is an issue.

As for the UBEC, it was a 5v, but the servos are all rated for 4.8v and 6v I believe (JP mini servos).

Timbo did a series of tests to investigate brown out and loss of signal. Well worth a read as this is probably the most significant factor.

[Martin Roberts]

I think the biggest clue would be that the RX from your description went to fail safe, but then flew into the deck.

You have not stated whether the RX went out of bind indicated by a need to rebind, or whether the speedy had switched off and back on, which would be evident if your speedy has a musical tone on start up, if it has then you would have heard jingle bells at one mistake of altitude.

Hope that makes sense to you so far.

As for all the necessary seperations of wires etc... the DX6 in my stryker, is jammed between the 2200 3cell, a 30 amp speedy, and a 3100kv motor, with two 9 gram servo's, if you know a stryker fus, there is no room, so its spaghetti central, and a few carbon spars to boot. The standard DX6 rx antennae are just long enough to clear the canopy, I do glue on a smallish heat sink to the speedy, and have ported air tubes for the Bat but not the speedy or rx. Nothing gets past warm, even when high speed runs are made, and this plane goes vert from take off to about 'can't see it' same set up in my 900 span foam cessna.

For my money I reckon its not volts or amps, neither is it heat, i reckon its a bad connection or a dry solder joint, then it could only ever be a faulty RX, as in if the speedy didn't switch off, and the tune didn't play, and the rx didn't need a re bind, but the motor went dead, and you lost signal, then in she goes.

Whether the solder joint is in the TX or the Rx is anybodies guess, but as a hint, most speedies will play a tune or beep if switched on without a signal or if you switch TX off, so for my money, if there was no melody or beeps, and the RX gets power from the speedy, and this is not the original speedy, it is a FAULTY RX, there is no other plausible explanation. 

Gotta love little magic boxes - p.s. it doesn't really matter what you do with the antennae, as long as you don't cut them........

Marty

[Martin Roberts]

Hey Shaun and Timbo, yes I viewed the Vids, very enlightening.

I have not been so enthused to go so far as that, but I have a fair understanding, and our Flying Club secretary is a sparky (retired). We have some very interesting discussions, and both 'teach' the newbies as much as they really need to know.

I must say that even with the DX6, there seems to be at out site 3 distinct places where my planes 'glitch', and there is no explanation, even the pres and one of the other lads, whom both have JR 9xxx with the ducks guts fully adjustable frequencies etc 'glitch' in the same 3 places, but only (for all of us) intermitently, usually on the half hour. And those guys are in the top % of RC pilots flying 2.5 metre katana's etc...

 Anyway I look forward as always to seeing more of your build pics, I spent today fixing my sons car, so I am off to bed, so I can wake up to another glorious sunny morning on the Gold Coast

Marty

[Martin McIntosh]

Hi Shaun, only saw this thread recently and have only read some of the earlier posts but I remember measuring the current drain on a popular 9g servo and it was found to be 250mA with the motor disconnected from the gearbox and free running. Just what they draw in normal use I hate to think. A typical 3A UBEC should be OK but if you use slightly larger servos the drain is usually much less.

With regard to Rx positioning, I deliberately velcrod a futaba 2.4gHz Rx to an ESC running at 500W and there were no adverse effects whatsoever!

[Doug Ireland]

Hi Martin R,

I've heard of flying sites having blind spots before. It might be that your field is in line with a microwave data link, sending out burst transmissions every half hour. I work offsore and have actually seen seagulls dip below the line of these things!

[winchweight]

Hi Martin,

The rx remained bound to the tx. The only clue was the model flew normally, then without any intervention from me , the throttle closed and the model flew straight as a die, into the deck, refusing to respond to any inputs on the tx. Subsequent checking found everything working as advertised.

After crash no1, the rx went back and was replaced by Horizon Hobbies (HH) for an updated rx with the newer software and brownout detection. I was then burgled and the tx was stolen leaving me with a loan set from my LHS. I changed the esc to a higher rated unit and added a 5v UBEC.

So the second crash did not have a common rx, battery, tx, ESC, and had a UBEC fitted. The only common components was the model, the motor and the servos. All of which are currently giving fine service in other models.

After crash 2 the rx went back to HH who tested it and could find no fault. They replaced it again FOC. Great service from HH.

On both occasions the lipo (3S 2200mah, 25C) was tested and found to have used less than half the capacity.

However, as Tims test showed, signal loss was the likely cause, but what brought about the loss of voltage to cause the loss of signal, will alway be a mystery.

Datalinks? Now there's a new train of thought.

[Martin Roberts]

Hi there Doug,

Yes, we have had a look at MC bursts, and we are sure that the offending party sends a short packet on the 1/2 hour, will affect one plane on a particular lap, but the next plane through (maybe 45 seconds later) will get nil effect, sometimes 2-3 craft will come through and be affected, we instigated a major upheaval due to what is known as a Q100 rain event which effects the flood water level, which resulted in our clubroom being moved to the far side (higher side) of our site which puts our pit area below the glitch zone, and our run way is another 30 metres out, that killed two birds (pun).

We did have the site checked for transmissions,  but the fellow who came and measured, was unfortunately rather short legged. In fact he was only about 6 foot, and the glitch is usually found by planes flying at about 100 feet, which is supported by what you say about the seagulls...Wife has just called for dinner... there's a thought, if you get the seagulls to fly into the MC burst instead of below, could be lunch on the wing...do they come out all crisp or are they under done?????????

Marty

[Martin Roberts]

Shaun,

I am absolutely positive that there was no heat/voltage problem, otherwise there would have been some proper indication (all my speedies (cheapies) will beep if no signal from the TX, and play the selected melody when re-arming etc.....) I truely believe it is signal reception whether that is because of either a particular vibration frequency (harmonic) at the particular lower throttle (different harmonic at higher throttle) .....hey Timbo, now thats something you could try to sort with Shauns RX and motor/prop combo ... the other bits would be totally irrelevant, having no bearing on the harmonic e.g. ailerons level elevator level, rudder straight, wheels up.

Or again maybe MC bursts as you said you were within about a mile of crash 1 site. MC does not have large wave length, but is more line of sight from origin to target, are there any signs of transmitter towers in the area, MC antennae should be easy to spot.

Marty

[Tim Mackey]

Shaun Chant wrote (see)

However, as Tims test showed, signal loss was the likely cause, but what brought about the loss of voltage to cause the loss of signal, will alway be a mystery.

I for one am not assumning that the signal loss was caused by a loss of voltage.

The idea of it being a failing battery / BEC voltage has been pretty much discounted due to my tests proving the recovery time from a conventiona l"brown out" is milliseconds only - most pilots would not even know a brown out had occured - one of the reasons HH implemented the flash of the led to indicate that such a thing had happened.

The theory of the BEC shutdown due to overheating / simple malfunction is an interesting and possible option.

This though could not really be classed as true brown out, more a complete radio power supply failure - black out! 

Also, if the BEC unit did shut down - for whatever reason - remember that using a 6V PSU instead of 5V would NOT have mnade any difference.... more evidence that simply using a 6V supply is NOT a guarantee of success. All components in the chain must still be correctly specified for the job in hand, installation must still be excellent, and so on.

[Martin Roberts]

Hey there Timbo, not sure where to put this ......no don't be rude!!!!!!

I note in the review section for motors there is only for 2 stroke or 4 stroke..... but its not a review section for IC engines, so where should one post reviews for electric motors.

Also a lot of newbies would not know what size props for ICs, or what revs the particular IC would pull with a given prop, maybe the vet IC flyers could set up a forum/thread with results of IC type/size, fuel, glow plug?, prop size, and measured (not guessed) revs obtained.

Maybe start with the oldies like Cox 0.49 and 0.25 as they easily relate to small park size models.

Marty