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KYTEN


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I used it a couple of times but as there is no rudder I found ground handling an issue, I was going to fit steering controlled by a separate Rx, much the same way I had the glider dolly setup but found hand launching was so easy I never got round to it - gathering dust now!

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Thanks for the info Ron. I noticed another one for safe where the air scoops are at the front of the fuselage and quite a bit bigger which may well have allowed a lot more air to pass over the ESC. Do you think with the airflow over the wing and the position of your scoops that there may have been reduced air flow + a lot of trapped and disturbed air in the fuselage that cooked the ESC?

 

You could try powering off the RX with the servos attached and see if one servo moves into a repeatable position (may have been bound like that) but I suspect you may get a random twitch and with Elevrons any movement will cause roll and pitch at the same time.

 

As you say you could have a separate RX battery or UBEC or any number of complexities, but in my book that just adds up to more things that could go wrong at a cost of more weight.

 

PS Can't say I have ever had a lot of success with dollies of the steering and non steering type, but then again some models you just can't hand launch even if the props don't get in the way!

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Always a relief which it drops its winch line...and retrieve the dolly!

Edited by Chris Walby
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I don't think cooling for the ESC was a problem Chris as it had never got hot when I checked it in its early life (20 flights ago?). I had also recently fitted 2 NACA ducts either side of the fuse primarily to cool the battery and after its first flight last Thursday I did check to make sure that the battery was cool, which it was. In that flight I was pushing the 'plane around a lot so it would have been peaking at approx 60A but in the terminal flight I hadn't  'got going' so it wouldn't have drawn anywhere near that.

 

Will check the surviving electrics tomorrow.

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Ron,

 

When you post the pics please could you include one or two showing the three (probably now only two) leads coming out of the motor end plate?

 

The burnt wire attached to your esc is one of the motor wires, all of the esc wires themselves look undamaged; also the burnt wire is only burnt at one end, which suggests to me that it was a result of arcing at a break or poor joint rather than overheating of the whole wire. For a fault current to run down that wire it would have had to return via one or both of the others, hence my above request.

 

It would be interesting to test the esc (cold tests using a meter, then if all appears ok, a live test with a fuse in the supply). I'm not suggesting this as a route to reusing any of these items but merely as a point of interest to try to ascertain what has happened.

 

Looking at the pattern of the melted wiring in the motor my initial feeling is that the motor itself is the culprit here.

 

Brian.

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Well Ron, the esc and two remaining motor wires look nice and shiny and don't appear to have overheated. The third motor wire has clearly come off where it is (or was) attached to the motor windings just inside the motor casing.

 

The esc may have become damaged at that point if the loose end shorted to one of the other phases, only testing the esc itself would verify if that were the case. However there is no obvious damage to the outside of the esc (apart from a bit of a scuff on one corner).

 

The motor was in my opinion the original cause of the problem, going by the photos. As it was a pusher model the motor may have overheated due to lack of airflow.

 

Brian.

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Interesting....and the Vulcan take off...

 

In one of your pictures it shows the battery, as a matter of interest, how did the white outer wrapper become split please ?

 

Still looking and learning about electric propulsion...

 

Interesting the motor windings are not "epoxied" or taped ?

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@RottenRowthanks Brian. The ESC is dead, no life in it when connected to another battery, hence why I’ve cut the wires. Motor overheating - totally exposed motor and in all  flights, including this one, the motor has always felt cool to the touch, I tend to give it the finger touch after flights, especially those when I’ve been giving it full throttle for a high % of the flight. But I agree with your opinion that it was the motor that failed quote how that destroyed the ESC and why that affected the control surfaces?

 

@Rich Griffthe outer wrapper has split due to the battery getting squashed out of shape when it connected with terra firma!

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