500 ALZRC Devil 420 FAST - build log

I would be willing to bet, that the Goblin shaft and bearing blocks would fit it. Something to think about when the time comes to change the main shaft.
 
Geena said:
I would be willing to bet, that the Goblin shaft and bearing blocks would fit it. Something to think about when the time comes to change the main shaft.
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Yes, for sure it would. The Alzrc Devil 380 which has been in production for a while originally used the exact same design as the Goblin, basically a direct copy of the Goblin. Alzrc say that they changed to this new design to make changing the shaft easier. I suspect that the flanged shaft may have been expensive to produce, which probably had something to do with it.

They did put a shallow groove in the shaft for the locking screws to seat into, so i dont think it will come loose, time will tell.
 
Smoggie said:
Here's the devil 420 built except for electronics installation. Other than the fit of the boom and a bit of confusion over the difference between the main shaft design supplied vs that shown in the manual, it was all a very straightforward and enjoyable built. The quality and fit of all parts was first class. I think she looks great too:

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Cant wait for the electronics to arrive...
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Very nice. Looks Good, I like it :D

Can't wait to see her fly :)
 
Someone pointed out that it didn't look right tilted back and resting on it's tail fin... so i suck a battery in to get it sitting right on it's skids:

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No more build progress to report as I'm still waiting on the electronics.
 
Hey Smoggie, I've notice that there's no servo linkage adjustment. I take it you must be dead on to get the swashplate and everything else to zero out.
 
Yes, you have to adjust your servos to exactly center and check full positive and negative pitch. If you have more negative, then your swash is too low and you need to raise all of the arms. If you have more positive, then your swash is too high. On the Goblin (not sure about this one) there are marks on the head to show 0 pitch which helps out a lot.
 
Yep, as explained by Tony, the servo to swash links are fixed length. This is a good thing IMHO as it means they are all precisely the same length. The fully symmetrical servo layout with servos all on their sides means that adjustment of link length is not required regardless of the type of servo you use. This makes swash levelling a breeze, all you do is precisely centre the servo arms using the trim function in the FBL (best done before mounting the servos), and that's it, you know that the swash is level.
 
The ALZRC motor arrived today, it looks very much like a Scorpion! here is is installed and the drive belt fitted too:
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Unless you want some work, do not try to shorten those leads. I have seen hard epoxy coatings, but this thing, holy crap. I wish I hadn't shortened mine because now I'm worried about a cold join in the bullets which is why I really do not want to fly the goblin. These things suck at auto's.
 
Tony said:
Unless you want some work, do not try to shorten those leads. I have seen hard epoxy coatings, but this thing, holy crap. I wish I hadn't shortened mine because now I'm worried about a cold join in the bullets which is why I really do not want to fly the goblin. These things suck at auto's.
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I always advise anyone never to attempt to shorten motor wires, for at least the majority of motors that have multistrand wingdings. It's almost impossible to remove the lacquer on all the hair like strands and if you dont get it off all of them you end up with only some of the wires conducting, which is a recipe for a burned out motor. I've heard that if you put the ends of the wires on an Aspirin tablet and heat with a soldering iron there is a strong acid given off that takes off the lacquer, but I've not tried it (the fumes are very nasty apparently).

vyrnguy said:
The 420 blades should make it a bit more floaty compared to a 380???
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Yes, it should be a lot 'floatier' than the 380. This got me thinking about weight of the 420.

The complete air-frame and motor with battery tray/straps weighs in at 980g

The components missing for a ready to fly weight are:
  • Battery (6S 2200mAh): 380g
  • ESC: 50g
  • Swash servos: 3 x 20g = 60g
  • Tail Servo: 40g
  • Vbar: 11g
  • Sat receivers: 5g
  • Odds and ends: 10g

Predicted RTF weight = 1536g

That's not bad when you think that a Trex 500 Pro that has the same rotor size (within 5mm) weighs in in the 1900-2000g range. I've also seen reports of Goblin 380 builds well over 1600g.
 
Yea, soldering flux will do the same thing, but I'm completely out and we were in the middle of a live stream when I did it. Just another reason why I really don't want to do any more builds on live stream. Things can and will go wrong, like the motor wires.

Speaking of that motor, I was very surprised at the small gauge of wire in these motors. Very small.
 
It will remove some of it at a high enough temp. And I'm not talking about the nice stuff in 60/40 either, I'm talking acid flux :biggrin:
 
Yeah, i was thinking about acid flux but I've never heard of it being effective in removing magnet wire lacquer, maybe the very strong types would have some effect? Please let me know if you experiment with it and how it works out. I'd like to have a reliable way of removing that lacquer. I'll try the Aspirin trick on some spare magnet wire and see how that works. If either method does work reliably I might try shortening the motor wires on the 420 because they are much longer than they need to be so there is a few grams to be saved if nothing else.

here's the Aspirin trick, seems to work ok in the video:
 
Some good news, my servos and ESC arrived in the UK so should be with me tomorrow. Today I also ordered the batteries from the Hobbyking UK warehouse (6S 2200mAh 45C Nanos).. So with a little luck i could be set for a maiden flight this week. I'll get the video camera charged up!
 
PS... I tried the Aspirin trick to remove the lacquer on some motor wire.. it didn't work:(

The wire I was using was off an old Align motor. The Aspirin melted just like in the photo and produced lots of smoke and a sticky gunge just like in the video, but it had no effect at all on the lacquer. I'm guessing that it depends on the type of lacquer used, the high temperature stuff used on decent quality motors these days seems to be immune to the Aspirin trick. So back to the drawing board as to a way of shifting the stuff!

What I will try next is to burn the lacquer off with the flame off a lighter. I know from past experience that this leaves a black charred deposit that's just about as hard to shift as the lacquer was, but possibly the Aspirin will work better on that stuff?

PS......I used a spay painting face mask for the fumes which seemed to do a great job of filtering out the smoke.
 
I'm thinking best bet is harsh chemical attack. Something like MEK, Acetone, toluene, xilene and the like. Nasty crap that I used to haul. Not something that I would want to advertise on video because of the health risks.
 
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