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Old Jun 30, 2012, 01:12 AM
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The silicone 'ring' won't really stop a clevis coming off... but it would need to either not be clicked home, or the 'click fit' thingy to be worn and not clicking solidly anymore.
Or an in-flight Gremlin (I think I saw one of those on a plane in the Twilight Zone movie) removed it - and it might have been him that is falling off at 1:10, mission accomplished.....
Unlikely to come off (if it was in fine clicking condition) in a crash that didn't hurt the elevators... though shock waves could probably achieve anything - just very unlikely..... and not if the clevis still has a solid 'click fit'.

And it looks 'closed' now..... so that jsut adds another mystery of how could that happen too!
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Old Jun 30, 2012, 05:34 AM
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I think it went off during the crash - very easy for elevator on this plane. A couple of times after crashes I found snapped-off connectors and they were definitely on in the air. Although the behavior in last 5 sec is strange - either something mechanically went very wrong or the pilot did a rough move.
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Old Jun 30, 2012, 10:38 AM
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Gremlins
Well I didn't see Will Shatner jump into frame to stop the gremlin but after running the vid thru the HAL9000 in the infraRed band .... Clearly its a gremlin jumping off and going to his next assignment .....

The small object in frame top side at 1:10 is there. But like Pete said its hard to pin point what it may have been. The battery hatch is bigger, the canopy was still on etc. Could have been a bird yelling, "look out" for all we know.
But it being top side and the aileron and stabs remaining intact indicates the flight surfaces were still there in any of the "sequences" so not sure how the "object" would have played a role in a control failure in the last 3 seconds.

But ya .... Pete we finally have a matching theory, Gremlin!

I agree with Sockrat's observation re linkage coming detatched. It happens enough with belly landers such that some comment to put the Z bend on the horn rather than the clevis so that the grass doesn't pull them off even if a protective cover is being used.
The lower Yaw fin should have offered some protection but it happens... Grass catches the control as it cart wheels on impact.
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Old Jun 30, 2012, 10:58 AM
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It must be a Microsoft gremlin because I still can't see it on my apple device.
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Old Jun 30, 2012, 11:07 AM
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Double post some how... this must have been a gremlin also since I was already in the car down the road when this second post showed up..........
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Old Jun 30, 2012, 01:27 PM
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Max is in shock, please someone help him!

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Old Jun 30, 2012, 03:01 PM
Should've, Would've, Could've
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Originally Posted by Maxthrottle View Post
but after running the vid thru the HAL9000 in the infraRed band .... Clearly its a gremlin jumping off and going to his next assignment .....
lmao! Classic!
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Old Jun 30, 2012, 03:02 PM
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Anyone know if if the fans are still together? He was doing a high speed pass and could have blew one out causing a momentary upset such has the bits hitting the VT making it move for an instant. In the RAF we had a Tornado do this with an object strike that shattered some blades and the instant vibration caused a severe change in direction for a second or two till it spun down. Also being unfamiliar with the model a twitch like what happened could cause him to over control and hit terrafirma. In the desert we have lost a few planes similar to how this happen by simply flying through a dust devil that is sometimes invisible. I was landing one aircraft and five feet off the deck on a perfect approach it popped into a snap roll before I could react and smashed in.
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Old Jun 30, 2012, 06:29 PM
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Su-Down

Well I lost my Su today. I'm a bit puzzled at what was going on with it. This is the second flight in a row that a motor smoked about a min into flight. First one had enough altitude and was able to get back but unfortunately this time was different. Plane was faily low and when motor went it rolled to one side pretty quickly and nosed in. I was hoping it was the same side so I could at least narrow down problem but it was opposite side so I'm not sure.
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Old Jun 30, 2012, 09:10 PM
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Anyone know if if the fans are still together? He was doing a high speed pass and could have blew one out causing a momentary upset such has the bits hitting the VT making it move for an instant.....
I'm thinking not likely. Why? at speed the flight surfaces have much more control force than the TV can offer. On my other TV models I set up the radio slider to control the thrust line independent of all the other controls. When slower the TV has a greater effect but once the model was above ~80 km/h I could hard pitch the nozzles with little effect. This has been shared comments from others trying to knife edge on TV in YAW or looking for faster roll rates etc.

Too the duct at the end of the vid looks like its intact. If the fan let go I would expect shards chewing up the duct. I would also expect a sharp tone change if either one of the fan grenaded. Most likely too Urrl would have mentioned it.
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Old Jun 30, 2012, 09:18 PM
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Originally Posted by DamonH View Post
.... motor smoked about a min into flight. ....
Sorry to hear that you too have gremlins. What's your setup because a motor smoking can be a lot of different things.
Battery
Connectors
ESC
ESC placement
Wire connection to motor
Fan/Motor

Were the ESC settings ever mod'd.
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Old Jun 30, 2012, 09:23 PM
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Originally Posted by Maxthrottle View Post
Sorry to hear that you too have gremlins. What's your setup because a motor smoking can be a lot of different things.
Battery
Connectors
ESC
ESC placement
Wire connection to motor
Fan/Motor

Were the ESC settings ever mod'd.
Everything is stock except for the esc's which are castle ice 75a and are placed in the stock location. Timing on esc's are set to medium. Motors/fans are stock purple can. My last flight the right motor smoked this time it was the left one. Battery is gens ace 6s 5300mah. Connectors are EC5's.
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Old Jun 30, 2012, 09:32 PM
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Originally Posted by DamonH View Post
Everything is stock except for the esc's which are castle ice 75a and are placed in the stock location. Timing on esc's are set to medium. Motors/fans are stock purple can. My last flight the right motor smoked this time it was the left one. Battery is gens ace 6s 5300mah. Connectors are EC5's.
What does the data logger show on the ICE75. That may show any fault conditions that may have happened in or outside the ESC. Otherwise Gremlin.
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Old Jun 30, 2012, 09:54 PM
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Originally Posted by Maxthrottle View Post
What does the data logger show on the ICE75. That may show any fault conditions that may have happened in or outside the ESC. Otherwise Gremlin.
Havent checked data yet. Pieces parts are all in a big pile. I just didn't feel like messing with it right now, still frustrated with the situation.
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Old Jun 30, 2012, 09:59 PM
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I was testing the remaining 'good' motor I took out of the Su - the whole fan/motor combo. I think I had tested it on the bench back when I did take them out, but couldn't find records of that. So I ran it up on 6S and it only gives out 600g thrust !! Pretty well exactly what the 'faulty' motor/fan had done!
I think it is 4 pole, but maybe not, so the RPM readout is not trustworthy, but the sound was 'high RPM' to me.

I threw in another fan/motor (same ESC) and it worked fine, so the scales and every other test setup aspect were fine still.
But it is very weird that BOTH the gold Su fan/motors ended up at that same output result - drawing 32Amps for that.
But both had been fine in the initial in-plane tests, until that first one floundered and had me remove it to test on the bench - for that initial approx 600g result.

I tried every combo of ESC timing/PWM and it was 600g at low timing (1deg) and just got a bit weaker and weaker as the timing was moved upwards (7,15,30).

It seems to run perfectly smooth, but the result seems like what I would think if a winding 'died'. Though both motors look fine when checking in through the ends - I will have to open them to check properly soon.
So either both are now faulty.... or something else is causing it. But I can't see what that could be. It would be nice if it was some quirk that meant they are both really ok.

This test came about as I was working out what to change into my Dynam Meteor... the remaining good Su fan/motor combo on 6S. But not to be.
And I have a Lander 70mm 2550kv "6S" combo, that I never even tried or used in 6 months since buying it (!!), and that gives all but 2.0Kg thrust for 51Amps!!! (1.98Kg recorded). That is an awesome output for 51Amps!!
If the stupid thing was not so heavy - and costly at $82 - it would be good for in the Su !!
I have never even looked at it in detail but it is just fantastic design and construction, with a very good 60mm can Inrunner - it looks like an ARC (due to the holes in its ends), and is not a Leopard/Tacon/TurnigyXK, but is basically of HET level of ability by the looks - in power and efficiency. And being alloy and running at 55k RPM (5 blade) it actually sounds far better than a plastic housed (eg stock Su) low blade count fan. Something like half way to a CS10 sound.
But at 51A X 2 = 104Amps at WOT, for 4.0Kg out of plane(!!!) that should be over 3.0Kg in-plane total still.
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