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I give up!


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http://i94.photobucket.com/albums/l92/winchweight/FuryRepairs.jpg

Speaks for itself really. I'll give more details later, but despite changing the following:

25a BEC ESC to 60a Opto ESC with UBEC

Battery Pack (just to  be safe 2250 mah 3S Loong Max pack for a  2200mah 3S Electrolite pack)

Spektrum DX7 tx (mine was stolen)

Flying 1km from site of original crash

Having the AR6200 rx checked and updated by Horizon

My Sea Fury rekitted itself in an identical way. Locked out in a gentle turn probably due to the rx entering failsafe (the throttle audibly closed and the wings levelled). Despite being at approx 150' when it locked out, at no point during the lengthy (probably 8 - 10 secs) did control restore.

I am going to bench test the rig this afternoon. Intiial post crash analysis - the model flew 2 successful 5 minute flights yesterday, and was 3 minutes into a gentle lazy flight today. The battery pack was cool to the touch, showed 12,3v and took just 400mah on charge after the crash. The ESC was not hot and appears intact. All the servos are free moving, and at the time of the crash, the gear was up and throttle was set at approx 1/3.

More later

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Good grief, I'm gutted for you Shaun .

If the  Spifire flys OK with no problems then it sounds like no external interference is present.

Do  the fusalage/ wings have any carbon fibre present, could this be masking the arials in the Sea Fury  long enough to cause the Rx to go failsafe??  

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Hi guys. The rx sits fairly clear of all wires etc and the aerial goes side to side. There is a carbon spar, but it's well forward of the rx. And besides, why would if fly so well twice yesterday and fly repeated figure 8s in the same bit of sky without fault, and then crash?

Anyway, I set the wing up on my bench, with the tail servos, esc, battery motor etc. The motor was clamped on the end and a Wattmeter added to the soup. I then put the same battery pack on, freshly charged and ran it at full power, without let up, waggling the servos etc, watching the rx light and noting the amps, watts and volts every minute. I did this until the motor powered down. At this point I still had full control of the servos etc. The only thing that changed was the prop, because I only had a 10x7 APC-E as opposed to the 10x8 it had this morning. Remember these are static figures, and I was noting them and writing etc at the same time.

Power Up-

Rx bind light on, no flashes. Tx volts 11.1v Battery volts 12.5v

Full Power -

11.4v / 30a / 340w

1minute -

11v / 23.9a / 267w

2 mins -

10.8v / 23a / 250w

3 mins -

10.6v / 23a / 240w

4 mins -

10.5v / 22a / 232w

5 mins -

10.28v / 21.7a / 216w

6mins 10secs - Motor cut out - 8.5v remaining. Full control retained throughout!

Post run examination = esc cool, battery comfortably hand warm, motor red hot.

Battery checked off a voltmeter = 10.5v

Observation, the motor was running happily with no odd noises etc, despite being run over it's nominal power (noticed too late, but seems happy enough). Could this cause a lock out? Surely the UBEC would kick in as the volts drop anyway.

Once the battery cools I'll recharge it and note what it takes.

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What a swine!  Bad luck, Shuan.  Where is the Rx located?  I see that Futaba recommend housing it as far as possible from any other elements that might warm it up .  They also suggest fixing it on its narrow edge to promote cooling.  When you ran your tests did you put the cockpit back on and try to recreate the actual temperature of the flight?  Do you think it could have been the Rx heating up?
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Hi Lee. The rx is a Spektrum AR6200, and unfortunately there is nowhere to put it inside the fuselage that is well away from the servos etc, as it's a very smal model. However, it was clear of the esc, motor, battery etc and I tried to keep it clear of wires too. However, the wires come from all directions and obviouslyterminate at the rx, so whilst I tried to keep from covering the rx, it's nigh on impossible.

Sadly there isn't enough left to fit the cockpit to as the nose fell apart as I removed the esc etc, so short of putting it inside a styrofoam box (there's an idea) I can't really do that. But with the exception of the motor, nothing really got above slightly warm, and there's a reasonable airflow through the fuselage. Besides, it's flew beautifully twice yesterday under similar environmental conditions, and if anything it was flown a little more aggressively, doing aeros etc. Today was just a few lazy figure 8's and circuits to start the day.

The bench run was conducted in full sunshine, if that makes any difference.

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Shaun I know yours is not Futaba but what's good for the Goose might well be good for the Gander.  You have probably read this stuff from Futaba, but just maybe you haven't.  As you say you can't always get thr Rx very far from the other stuff, but, just maybe it was getting too hot. 

Don't wrap your FASST receiver in foam.

Protecting your receiver from vibration by wrapping it in foam used to be a "must". Not so with 2.4GHz FASST receivers. Unlike 72MHz equipment, they're not as vulnerable to vibration. Using less foam lets them operate cooler - which is a plus for all electronics.

Tip: To keep the receiver cooler use small foam blocks (like standoffs) so that there is an air channel around the receiver.

2. Shade your model from sunlight when not flying.

Clear canopies expose the radio compartment to direct sunlight which results in additional heat in the model interior. This causes no problems during flight, but makes shading your model on the ground very important. Cover the canopy with a white towel; or better yet, park your airplanes in the shade. This will help keep the electronic components cool.

Tip: It is important to note that lighter covering colors will absorb less heat whereas darker colors will absorb more heat.

3. Mount your FASST receiver away from heat sources.

We had to avoid mounting 72MHz receivers near anything that might produce RF noise. That's not as much of a concern with 2.4GHz FASST receivers - you should instead make sure that you're mounting the unit in the coolest part of the radio compartment.

Stay away from the muffler exhaust, battery packs, regulators or any other heat source. We also recommend that you use the receiver's long, narrow side as its base (rather than mounting it with the bottom flat against the radio compartment floor). Secure the receiver using a Velcro® strap or gel tape.

--------------

 If it wasn't over-heating,  then maybe the power was dropping out.  The fact that you were not demanding much from the battery today might have meant that the UBEC was having to dissipate more heat than yesterday in its attempt to step down the volts for the Rx.  I think I read something like that about BECs somewhere.  Hopefully the experts will be able to exclude that idea in short order.

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Doesn't it go on & on & on & on Here is me after nearly 3 Yes 3 years of building what I call quality home designs 9 in all having returned to the "hobby" & still cant programme all this digital stuff ! Every time I read a thread I think ,What can I do to make it work like it used to ? What should I buy next to improve my (what used to be fun) hobby ? I now have lots of bits & bobs (you name 'em & dont enjoy it as from now!) Have been modelling for 50 'ish years & am now (having returned after a life of doing all I wanted to do)p---- d off with life as it now is IE money orientated/ the latest gear (this month next month etc ) Not my style .Look out for the "for sale adds" shortly.
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Well..... there's not much I can really do. The model is the model. The rx was placed in the only open space, as far away as lead lengths permit, mounted on a velcro pad, and not wrapped up. The model has reasonable ventilation, with air channels in the cowl which cross over the rx to an exit behind the wing and rx.

The model was flown straight from the van and it was still very cool with the last remnants of fog clearing. If anything it was cooler than last night.

I'm just so frustrated. I have changed everything here, except the model (other people aren't having any problems with it), the motor (which seems to run fine and doesn't draw too much current), the servos (which all functioned perfectly in the bench test) and the rx itself (which Horizon tested and certified as fully serviceable).

What the hell does it take?

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Hi, hope you have had a good day flying.

The ESC doesn't have a switch. the tx is a loan from Martin as mine was stolen, so considering the last crash was on mine and this was on Martin's, I guess that eliminates the tx.

I didn't fiddle with the plugs but maybe I can try that too.

The test rig

http://i94.photobucket.com/albums/l92/winchweight/FuryRepairs018.jpg

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Shaun

Don't know if it helps, but I've had several flights this weekend with my Dx6i and 6200 and 6100 Rx's in several diffent models, some Balsa and some Foam and never a glitch, I hadn't done anything special with respect to Rx mounting, just used some velcro to attach it to the side on the fus (inside) near the ESC and battery.

The 6100 also worked really well in my Alfa Mig 15 EDF which is very Rx sensitive on 35 mhz, so I can't see it's anything you've done related to the above and i'd suspect a bad connection somewhere. 

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All the components were brand new for the build and all appear to be working fine, even now.

Tim - the tx battery is a 1500mah NiMh 9.6v pack.

I don't mind the crash, but I wish I at least knew what caused it. The rx is the prime suspect for me, so it'll go back to Horizon once again, with a plea to check it over thoroughly.

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Hi guys. The model definately refused to respond to the tx, all the way into the deck. The descent was quite slow (easily about 10 secs) so I had plenty of time to try to recover, but no amount of stick waggling would illicit any response. Also, the model had power applied (1/3rd throttle approx) and was in a gentle turn at the north end of a lazy figure 8.

As for the tx tray, I don't use one.

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Yorkman: pointing the aerial  at the model is more critical with 2.4 than 35mg. With early 2.4 the aerial was fixed vertically when the problem was noticed they fitted a hinge at the bottom so the aerial could be bent over parallel to the ground. Signal radiates from an aerial along its length around the whole length like a toriod, no effective signal raidates from the end. A shorter aerial means the height of the toroid is shorter (squashed down) thus the hole in the middle is larger.
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 Unless they are unusually thorough, the people you return the Rx to will run a simple test on it and probably find it works okay, just as you did.  That leaves you in the dark.

 In your place I would attempt to recreate the same conditions that ocurred during the flight to get to the bottom of this.  The setup needs to be enclosed in the same (or similar ) way it was during flight.  Then you need to be in an open area where you get some distance between you and the setup and run it under as close to the same power conditions as just prior to the crash.  If you can repeat the event in this way you can probably isolate the culprit.  I'd say it was worth the effort.  The set-up as shown in your photo looks too open to replicate the real conditions.

 Best of luck, anyway, Shaun.

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I can certainly box the battery, esc, rx and tail servos in and try to run it. But given that the lock out happened at low power after just a few mins, and the only high power function was take off, I can't see that there would be much heat built up at all.

As for the rx, you are probably right. I have emailed HH today and will wait to see what they say.

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I intend doing some more checks today. If I can find a suitable box, I'll dummy a fuselage and put all the components inside an nice box with no cooling air flow on anything except the motor. If that doesn't overheat it, nothing will.

As for the volts, the UBEC is a 5v device so the voltage should never have gotton that low, and as my bench test showed, the UBEC did it's job just fine.

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