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View Full Version : crash report: xmseller/generic mt cnc head/tail


crabfu
02-19-2008, 03:28 AM
It started as a wonderful day, no winds what so ever. Everything was working perfectly, doing my usual flips, loops, rolls, fff, backwards circuits, and held an inverted hover down to maybe 4 feet above the ground.... which was a milestone for me :) Tail was holding completely solid - I recently took the 2100t out of it to test another heli, and replaced it with a gy401.

3rd pack in, and in my zen like state, something happened that I can only describe as a "moment of unclarity"... I was doing some low backwards upright circuits, and my mind must have wondered off to never never land. Events leading up to a crash is often fuzzy at best, all that I know is that, all of the sudden, confusion set it, followed by paralyzing panic, and down she goes. I hit throttle hold when I knew it was a gonner, which was just a fraction of a millisecond before it met mother earth. Luckily it was pretty level and the landing gear absorbed most of the impact. How the.... what the.... oh &#*$@(! I could only look at the pieces and laugh, and curse at my stupid thumbs again.

So.... I've been raving about the xmseller cnc parts ( http://www.helifreak.com/showthread.php?t=54741 ), which I guess is marketed as just generic cnc metal head and tail in a variety of places on the web. And I've been asked about how they hold up in a crash, up until now I could not respond with first hand experience. So here is the result of the crash:

Damage report:

bent feathering shaft
bent main shaft
lost both align CF main blades
bend tail boom
broke the landing gear in many pieces
broke the bottom chassis
broke the battery tray mount
stripped main gear
bent flybar
lost both canopy mounts
tiny crack on the bottom of the canopy, but still good!
broke align carbon linkage rod for the tail
broke the align plastic tail fin in half
broke the tail boom support
broke/lost a few align linkage rods on the head

xmseller cnc head and tail.... all good! Head parts on a new main shaft feels silky still, doesn't look like anything is bent, or cracked or anything. Surprisingly the K&B tail blades, and the belt survived. The bearings feel ok, electronics are still all good whew. Real test is when I get the replacement parts in and rebuild it to be sure... but carefully examining the cnc head and tail, doesn't appear to have any problems :)

Again, the impact was luckily mostly on the bottom, but cnc parts seemed to have survived without issue.

Just thought I'd keep you guys updated :)

-Crabfu

fretbuzz85
02-19-2008, 12:12 PM
Ah, the topic i was looking for a couple of weeks back. :YeaBaby:

Right now, im using the Xmseller head, some tail parts and the Fiberglass body.
Have crashed a total of 3 times in various ways.

I have to say that the parts hold up pretty well in the crashes. No bent parts so far.
After the 1st crash, as Crabfu said, everything on the head unit was still silky. After the 2nd and 3rd however, i start to feel the bearings loosing the smoothness, particularly in the blade grips, but still no bent parts, and still mostly smooth.

Im not sure if the bearings can be changed out, they seem to be pressed fit on pretty tight. Would be perfect if i could find replacement bearings.

Lastly, the fiberglass body, in my opinion isnt good. Its much heavier than the stock body, which kinda defeats the purpose, and some parts of the desgin is a step back from the original MT plastic body. Bad placement of certain key items, and most of all, the tail unit is now NOT removable.
Its a hassle now to change belts.

Blackrat
02-19-2008, 12:19 PM
why cant you get the tail off ?

im 90% sure the bearings are the same as the original MT ones .. so you could use the ones out of your plastic head

crabfu
02-19-2008, 01:09 PM
Im not sure if the bearings can be changed out, they seem to be pressed fit on pretty tight. Would be perfect if i could find replacement bearings.

Lastly, the fiberglass body, in my opinion isnt good. Its much heavier than the stock body, which kinda defeats the purpose, and some parts of the desgin is a step back from the original MT plastic body. Bad placement of certain key items, and most of all, the tail unit is now NOT removable.
Its a hassle now to change belts.

I'm sure the bearings can come out with a bit of heat to loosen/melt the thread lock. I haven't had to do it for this heli yet, bearing still feel smooth :)

I didn't know they made a fiberglass frame, seen some carbon before but not fiberglass. Plastic body works fine for me so far, i like the layout and ease of working on, and yeah the removable tail unit is one of the coolest features...I'll keep sticking with the plastic frame :)

-Crabfu

fretbuzz85
02-20-2008, 10:47 AM
The plastic frame is definitely the way to go...im actually thinking of switching back to it, and upgrade the key parts to metal.

And, will try the bearings from the plastic ones, hehe. Thanks

crabfu
02-23-2008, 02:17 PM
Well just took the mt up, and my initial evaluation of the cnc parts were correct... absolutely no damage, everything is silky smooth once again, and I am STOKED once again about how this thing is flying! I went through only 2 packs before it started raining, but man it is a tight machine, there is nothing else that I can ask for, just a perfectly flying machine :)

-Crabfu

Blackrat
02-24-2008, 06:29 PM
im going thru a crashing phase, i hope .. crashed twice last weekend and again today .. the metal bits are fine just need blades and mainshaft .. pity im too slow with throttle hold so gotta replace the main gear this time :(

paintballkidz
02-27-2008, 09:54 PM
can an align metal head work with the titan?

Blackrat
03-03-2008, 10:05 AM
yea but you gotta use the mini titan swash