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e-Align T-REX 250-450-500-600 > T-REX 450 help vibration
 
 
joecass
Senior Heliman
Location: NJ

my heli was flying really well up intill i crashed it. the tab for the red wire broke off of my battery when inverted i manged to land on the skids but it landed hard here are the parts i replaced

R/S and L/S lower frames
lower bootm plate
whent from 500th on 13t to scorpe 8 on 15t love the power now
here are the parts that i replaced to try and fix vibration

all shafts
main blades


vibration is very noticable. the landing skids are vibrating like crazy and it gets worse when i go into idle up
10-04-2008 04:33 PM
 
 
Heli 770
Elite Veteran
Location: Lemon Grove, Ca. USA.

I'd check dampers and blade balance.
10-04-2008 05:51 PM
 
 
Flint325
Senior Heliman
Location: Albany, New York

When you say "all shafts" did you replace the tail rotor guide shaft?

I learned to fly inverted, I just stand on my head
10-04-2008 07:32 PM
 
 
joecass
Senior Heliman
Location: NJ

i balance the blades and replaced them. i also balanced the hole head
assembly. i will try new dampers. yes the tail shaft was replaced
10-04-2008 08:11 PM
 
 
Heli 770
Elite Veteran
Location: Lemon Grove, Ca. USA.

You may have damaged the main shaft bearings.
10-04-2008 08:19 PM
 
 
joecass
Senior Heliman
Location: NJ

ok im going to check the bearings out thanks
10-04-2008 08:22 PM
 
 
TomRex
Elite Veteran
Location: West Palm Beach Fl.

Joe, I had some issues once upon a time after a tree jumped in the way,changed out the usual shafts and a bearing etc. What I wound up doing was remove the mains then the tail blades, after a big ta doo I removed the head again and spooled up to check the tail shaft and hub and grips, I removed the grips and wha-la the grip screw was bent. spoold up again with the grips and were smooth, then the head was installed minus the mains, spooled and found the flybar/paddles were out, taped one paddle then the other and found the prob, removed the tape and just screwed the one paddle in one turn spooled to to balance, then added the tail blades and taped one then the other to find the prob,removed the tape and sanded the one blade till it was smooth when spooling up, then added the mains and added a snot of tape to balance and BAM the mo fo was perfict, yea it took some time but it flys like a Singer Sewing Machine and after I siliconed the gears and belt the noise ceased to exist, so the moral of my story is, you get back what you put into it and then again you don't, if you don't!

The AMA is way better than what you belong to!
10-04-2008 11:54 PM
HOMEPAGE  
 
 
joecass
Senior Heliman
Location: NJ

i found the top main bearing to be rough (not smooth) i hope this fixes the problem the vibration is very bad i hope one bearing can cause all of this.
10-05-2008 03:31 AM
 
 
Heli 770
Elite Veteran
Location: Lemon Grove, Ca. USA.

I've seen a lot of guys rebuild and take it apart again because they didn't check bearings.
10-05-2008 03:47 AM
 
 
joecass
Senior Heliman
Location: NJ

the main bearing help the vibration a lot. there still is a small
vibration what else can i check

thanks for the help so far
10-16-2008 09:23 PM
 
 
Heli 770
Elite Veteran
Location: Lemon Grove, Ca. USA.

I hate to tell you this, but did you check the bottom bearing also?
10-16-2008 09:29 PM
 
 
joecass
Senior Heliman
Location: NJ

i replaced both
10-16-2008 10:20 PM
 
 
Heli 770
Elite Veteran
Location: Lemon Grove, Ca. USA.

On the ground and in the air, what is vibrating?
10-16-2008 10:25 PM
 
 
joecass
Senior Heliman
Location: NJ

in the air the skids and tail box fin
10-16-2008 10:28 PM
 
 
Heli 770
Elite Veteran
Location: Lemon Grove, Ca. USA.

Here we go again, check the bearings in the tail housing and see if the bearings in the tail grips are good. It should be the tail housing bearings, is my guess.
10-16-2008 10:41 PM
 
 
joecass
Senior Heliman
Location: NJ

ok the tail case bearings are new but i will check the rest
10-16-2008 11:19 PM
 
 
7379df
Senior Heliman
Location: Branson,USA

Im having same problem as you are. Have you found out what it was??
I was going to start a new thread until i seen this one. I dont want to be a thread stealer.....hope you dont mind me chimming in. Anyway this is what I have:
TREX 450, all metal head, tail and ccpm frame.

This is what has been replaced so far:NEW,Advanced pro ccpm frame with motor on top
NEW,Bearings
NEW,main shaft
NEW,upper head
NEW,feathering shaft and dampers
NEW,flybar
NEW,Boom
NEW,Belt
NEW,gear set,main and tail
NEW,output shaft for belt drive off lower gear and bearings
NEW,tail output shaft
NEW,tail rotor shaft
NEW,tail blades
NEW,Scorpion 8 < this thing is SICK !

This is what has NOT been replaced:
EXISTING,grips
EXISTING,carbon fiber blades,(not balanced)
EXISTING,see saw, swash, linkage ect.
EXISTING,tail output shaft bearings

Still have vibration at higher rpms. I can fly at 40 to 50 on throttle curve. Any thing higher it will vibrate. This is the crazy thing....when ran on faster rpm (60 on curve) it might fly for a while before it starts vibrating....it doesnt start the vibration everytime. Once it starts i have to sit it down, slow down rpms until vibration stops, then spool back up and again, sometimes its ok and sometimes i cant start it without setting throttle curve back down to 40 again.
Does anybody run these little things on say 80 to 100% when doing 3d. It absolutely sounds like this thing is going to fly apart... it spins REALLY fast. I have a predator gasser and spin this around 1850 rpm... it sounds like this little thing is WAY faster than that.
How fast do you want these to spin ? Can they spin to fast ??

Well now i can build a second rex with all these parts Ive went through. O well. Thank you for any help you can give me. Darren

10-20-2008 02:48 AM
 
 
Heli 770
Elite Veteran
Location: Lemon Grove, Ca. USA.

Make sure your links are not loose and see if the blades need to be balanced, Can't believe you got all those parts without checking blade balance. Anyway try that first, links and balance.
10-20-2008 02:57 AM
 
 
7379df
Senior Heliman
Location: Branson,USA

I use the V-blades (Vic Campbell) on my larger helis and have never needed to balance. I guess it makes sense these smaller ones turn a whole lot faster. Im not positive but before the crash, (has anyone besides me forgot to pick the correct model?) they seemed to be fine.... but im not sure if i was turning them as fast. So yeah, I will be balancing them or getting V blades.
10-20-2008 03:06 AM
 
 
Heli 770
Elite Veteran
Location: Lemon Grove, Ca. USA.

Your head speed should be around 1000rpm faster than your gasser.
10-20-2008 03:20 AM
 
 
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e-Align T-REX 250-450-500-600 > T-REX 450 help vibration
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