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A lot like Lot, or When it rains it pours, ESC.

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A lot like Lot, or When it rains it pours, ESC.

Old 09-22-2010, 10:02 AM
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Default A lot like Lot, or When it rains it pours, ESC.

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Some kind of dreadful week I'm having. Although it's a little bit off-topic, to set the scene I am forced to mention that my Dad passed during the early hours of last Saturday. Although it had been some time coming, you can never really prepare yourself and it was/is still a shocking event. For the last eight years he has required pretty constant care and I have been living here and looking-after him so, apart from the personal loss, I suddenly find myself without an occupation.</p>

Enter the TRex...</p>

I thought to myself that, since the weather is pretty fair at the moment, I would spend every hour I could out with my TRex 450 Sport and try to avoid moping about the house which now seems very empty.</p>

This was a good call and it had been going quite well. All the while I was out I was able to keep my mind off of things and of course get plenty of practice at the same time. I've only got 3 lipo's at present so there has been a lot of sitting around waiting to get a re-charge from my car but that was ok... at least I wasn't at home.</p>

I've had the 450 Sport for a few months now. It's my first CP heli and I am clearly still a noob. I can hover tail-in and hover/fly left/right side-on, move backwards and forwards at a fair-lick anything really, so long as I don't end-up nose in. It's frustrating because with the sim, I can do a lot more including nose-in, stall-turns, inverted, piro's, loops, etc. I've even started practicing tic-toc's, and the like. In real life though, as soon as I get anywhere near to nose-in orientation, my nerve goes and I'm all over the place. So that being said, I'm pretty cautious when flying for real and so far I haven't had any crashes at all.</p>

So on Monday afternoon I'm at my favourite quiet spot in the New Forest practicing hovering, orientation and forwards/backwards/ side-on flight. Now, at this particular place there is a small clump of bushes and stunted trees right in the middle where I usually set-up my bags and other kit. I suppose it is about 6-8 feet in diameter. On this day I had the thought that, if I fly forwards quite slowly (4-5 mph), I could make a pass behind this clump, come to a hover at the other side and then reverse back to where I was standing. It would mean that the heli was out of sight for about 1 - 2 seconds, in level flight at a height of about 3 - 4 feet. It didn't feel too risky. So I gave it a (hestitant) try and guess what, I made it around the back of the clump! I saw the heli appear at the other side, still going nice and slow, at the same height as before BUT the orientation had changed (or rather... I had changed the orientation) so that I was now nose in.</p>

If I had been trying to do a full 360-degree circuit it would have been perfect. The heli came-out from behind the clump facing straight towards me. And if (another if) I had been on the sim I would have had no problem flying back, either forwards or backwards, to where I was standing? But of course I panicked, made some stupid speculative stick-input (I couldn't even say now exactly what I was trying to do?) and the next thing I know my 450 is rolling-over sideways on the ground.</p>

As crashes go it could have been more dramatic. I was only a few feet from the ground and going no more than 5mph but it completely recked my head: main rotor housing, washout block &amp; control arms, link rods, main shaft, flybar, etc. The parts list, inlcuding a ball-link reaming tool &amp; shipping costs came to 70-quid. I have ended-up with a few more spares but jeez! What a time for it to happen. Fortunately I got the order in to Fast Lads by (actually just after) 3:00pm and those good guys managed to dispatch the same day.</p>

So, last night I sat up until about 2:00am rebuilding the head and setting-up again. I finally did a servo test then spun-up the motor without rotors to check for oscillation... all ok. Then tried again with rotors on and everything looked and sounded great... flat rotor disk at around 30% throttle. I couldn't go any further cause this was in my kitchen.</p>

In some ways I was quite pleased. This degree of rebuild was more than I would have had to do if I had built from kit in the first place (I didn't, but will if I ever manage to afford another heli in the future) so I felt good about having made the repairs and only losing a day's flying to the crash.</p>

So, this morning the weather continued fair and by 10:00am I had loaded the car, and me and Oscar, my black labrador, set-off for the day.</p>

As I arrived I noticed that there were a few New Forest ponies in my usual place so I had to sit around for half-an-hour or so while they munched the grass until they finally got fed-up and moved along. I still had my first pack loaded (but not connected) from the motor-test the night before. Having used about 5-10% during testing, I had also topped-up the pack before going to bed so it had a full charge.</p>

I set the heli down at my usual spot, switched-on the Tx, straddled the model to connect the battery to the ESC and...</p>

SMOKE!!! LOT'S and LOT'S of SMOKE!!!</p>

I just managed to pull-away the leads which spontaneously un-soldered themselves from the ESC but the damage was already done. I won't bother to post a photo but if you can imagine the ESC heat shrink well-toasted at one-end and the two main cap's separated from the board then you'll get the picture. I just stood there stunned! I still can't believe it's happend... now of all times! Imean, the crash, well obviously that was my own fault and even though I couldn't really afford the repair I was living with it. But this...? When it was fine last night in the kitchen. I feel like Lot!</p>

For those interested it was a stock Align RCE-BL35X running a stock Align 450M motor. The pack was a Turnegy nano-tech 2.2 35-70C which has had between 10 and 20 cycles through it.</p>

Since I got home I've tested the other electronics and they all seem fine, Rx and servos still function. Can't say for sure about the motor except that I have measured a small resistance between each of the leads, in the order of 1 to 3 ohms (crappy multimeter!). Does that mean it's ok? I'm not sure but I think so.</p>

I will be contacting Align about the ESC. I don't relish the idea of dealing with the retailer since I have no confidence in them but I'm guessing that Align may help. But in the short term I want a new ESC and I'm reluctant to buy another Alignmodel. Some people say they're fine, others say they are rubbish? Having watched one go up in smoke I can only imagine how much worse it would have been (in terms of cost) if this had happened in the air! As it is, in addition to another bill for replacement parts I now have some nasty burn marks on my frame and skids.</p>

QUESTION:Can anyone recommend an alternative ESC/BEC combo which will run the Align brushless and which will suit the pocket of an unwaged front-line carer!? A tall order I know. I've been looking but there are so many to choose from. I know what I need in terms of raw spec, i.e. 35A constant load, 45A peak. I've got a futaba 9257 and 3 Acer D12-MG's with a Spektrum AR6200 Rx(and DX6i Tx) and a Futaba 401 gyro so the BEC has to cope with these and assuming the 450M is still ok the ESC has to work with the Align motor<font size="2" face="Arial"><font size="2" face="Arial">If I really clenchboth cheeks I can maybe stretch to 70-80 quid but would rather spend 40-60.
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I've seen a super-cheap KDS 40A / 2A BEC for under 30-quid, also looked at both 35A &amp; 45A Scorpion Commander or Thunder Power Smart Guide 40Amp Programmable Brushless ESC or Flighttech ESC 40A 2-6S Lipo With Bec or WHAT?</p>



Any suggestions appreciated but I've got to order very soon for reasons stated above... I MUST GET BACKOUT!!

Is there anybody out there!!??

Many Ta's

Rich</p></p></font>
Old 10-10-2010, 04:21 AM
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Default RE: A lot like Lot, or When it rains it pours, ESC.

Hi Rich,

Sorry about your father.. nothing could prepare you for that..

But what week with your TREX.. My Blade 400 had a few days like that..

A brand new Carbon fibre blade seperated mid flight, - rebuild - elevator servo failed resulting in spectacular but unintentional inverted flight - rebuild - new servos - then the tail rotor drive belt failed mid flight - heli totalled..

Ran the Blade 400 motor in another heli for 2 flights and it seized rock solid..

I know how you feel..

Have you considered a hobbywing 40amp ESC?  Pentium or Platinum models are good..

I also understand how you feel with nose in hovering..

I was the same and finally just plucked up the courage to Force myself to do it..

Then I spent the next 3 batteries doing nothing BUT nose in hovering and then stopped for the day..

The next day it was just such an anti climax and my flying confidence improved massively..

Now I alway terminate from forward flight with it coming towards me and ending up in a nose in hover, and it feels nice to just take off, do an immediate 180 and just hover nose in for a few seconds then off you go...

Now that I faced that fear I am actually really enjoying every flight much more.

Jump back on the horse and face those nerves and you'll never look back... 

Hope your luck changes and here is best wishes for you..


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