Boom broke in flight?

tombo242 · Posted: Fri Jul 23, 2010 12:29 am Post subject:

Commiserations DT,

That's one expensive lesson that you'll never forget. I think that I would rather not learn that way, but it does happen to us all.

I hope after all that work it was the swash causing the vibration problem. Be awful if it's still there.

Dumb Thumbs · Posted: Fri Jul 23, 2010 4:21 am Post subject:

P.S.
Looks like the motor bearings are shot and may also have been causing the vibration. After pulling the motor there is some not so funny play in the shaft. Guess that's what I get for trying to save a $ and recycling old parts from other birds. Come to think of it... For what I've put into this Hobby King 450, I would have been way better buying an Align 450 Sport kit.
On the bright side, after the crash I did get in four great flights on the other 450 (Align) and one more with the 250 (also Align) Very Happy

I would have tried the J3 Cub foamey too, but the wind was even pushing the 450 around a lot by then so I decided to play it safe and save the cub for another day.

tombo242 · Posted: Fri Jul 23, 2010 5:05 am Post subject:

That's a good decision there DT,

I've always had a great respect for the weather, Ocean sailing teaches you that in spades. Your life is on the line then not just a model!

Crashagain · Posted: Fri Jul 23, 2010 7:42 am Post subject:

That sucks DT.. I did the same thing a year ago with my 450...
Only did it once...

Dumb Thumbs · Posted: Fri Jul 23, 2010 8:14 am Post subject:

Oh well, at least I didn't crash into the lake nearby. Smile

I opened up the battery hoping it was something broke that was easy to fix, but couldn't find anything that jumped right out at me. So that pack is now in the salt bath Crying or Very sad

Aside from the battery and frames the rest of the heli came out better then one would expect. Main mast is bent, but the feathering shaft is fine and so are the blades. Didn't even bend the skid pipes or break the struts. Go figure???
And besides, that field was in need of a little rotor tilling anyway Very Happy

Dumb Thumbs · Posted: Thu Jul 29, 2010 8:20 am Post subject:

Well I got it rebuilt but still have problems. I replaced the Align 430XL motor because of bad bearings in it with a Scorpion 2221-6 motor. Tested it out and the Align 35 Amp ESC came down HOT (140+ deg). Motor and battery were very hot too. I played around with motor timing on the ESC but it still got super hot. Guess the ESC can't keep up with this new motor so I have a Castle Ice 50A on order. That's what I have on my SEv2 and it's fantastic, so I'm sure that will put that issue to bed.
Other problem that still plagued this heli from day 1 was blade tracking. Could never get it perfect, close enough but never 100% right.
Turns out the prebuilt head from the factory had a wrong sized thrust bearing plate on one side.
I replaced it with the proper part, but I'm waiting till I get the new ESC before I go any futher. Don't want to risk smoaking a new motor with a ESC that is getting so hot after short tests.

Dumb Thumbs · Posted: Mon Aug 02, 2010 3:55 am Post subject: SUCCESSS!

Everything is super smooth now. No vibration, new motor and ESC are not getting super hot and blade tracking is dead on Very Happy

Still going to make some tweeks to the Castle Ice50 ESC to see if I can get a bit more run time, but all in all I'd say this heli ready to do anything I may ask of it.
This HK 450 sure didn't turn out to be a cheap build like I'd planned on and took a lot of time & frustration, but at least I got it nailed down in the end.
Come to think of it, there isn't too much left on this HK heli that still has it's Hobby King parts.

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tombo242 · Posted: Mon Aug 02, 2010 6:33 am Post subject:

That seems to kill my thoughts of a HK 450 DT, I've been looking at what I might build from scratch in the 450 line.

However. it's great that you've got it sorted and in the air Cool

.