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Ron’s HeliProz South . Century Helicopter . MTA Hobbies

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e-Align T-REX 250-450-500-600 > T-REX 450 T-REX battery or motor prob? help.....(please)
 
 
929freak
Heliman
Location: Warrington Pa

I have a rex all stock except for a couple aluminum upgrades.Here is my problem,after a about 1.5-2 minutes of flight time( I am a beginner so no 3d) I seem to lose power,and it seems like the tail won't hold.example,I fly a minute or two then put it down,when I go to lift off again it feels like it is gutless and sometimes it will spin on me like the tail lost its holding power.O.k. now for the weird part,it happens with all three of my batteries,as far as I know they have never been over discharged and they are balanced.so can anyone shed some light on this one?

p.s. no drag on geartrain
batteries not warm or puffed
motor around 140-165 degrees after flight
any other info needed to help just ask.

thanks in advance for the help
07-13-2008 03:43 AM
 
 
baby uh1
Senior Heliman
Location: St. James, Mo.

Might be your esc. It sounds like your losing a phase to the motor as your losing power and the motor is getting hot. Check the wiring between the motor and the esc also.
I had a problem with a heli, just like you describe and it was a bad esc.
Hope you just have a bad wire.
07-13-2008 04:25 AM
 
 
929freak
Heliman
Location: Warrington Pa

is losing tail control a sign of low voltage(assuming everything is setup correctly)I mean at first it holds fine,during hovering,hard climbouts etc...
07-13-2008 05:01 AM
 
 
baby uh1
Senior Heliman
Location: St. James, Mo.

It could be because the tail is driven by the main it could slow to the point of being inefective. Meanwhile the mains, since they have a large pitch range can still generate enough lift to take off.
I don't know if you have a spare esc or motor but swapping them out might be the only way to find out for sure.
07-13-2008 02:10 PM
 
 
Skarn
Senior Heliman
Location: Pasadena, MD

This happened to me as well. Then I saw on the ground the tail belt would occassionally ride to the left and bind in the tail casing. After many veteran flyers told me to remove my idler pulley, I did so and the probem went away. That was 7 months ago.

Skarn

It's better to burn out than to fade away...
07-14-2008 03:45 PM
 
 
929freak
Heliman
Location: Warrington Pa

Skarn can you be a little more specific?? I don't have the heli here
but want to check out what your saying when I get home. thanks!

07-14-2008 04:04 PM
 
 
nmrs
Senior Heliman
Location: Austin, TX

Skarn is talking about the bearing I have circled in yellow. Just remove it and see if it helps. If you do a search on "snubber pulley" or "idler pulley" you should find quite a few threads discussing the merits of this mod.



450 se v2
07-14-2008 04:39 PM
 
 
SSN Pru
Elite Veteran
Location: Massachusetts

Quote 
s losing tail control a sign of low voltage(assuming everything is setup correctly)I mean at first it holds fine,during hovering,hard climbouts etc...

that is because as you loose power and increase pitch to lift off, you also increase torque dramatically. Combine a HUGE torque increase with a low headspeed and a corresponding low tail rotor speed and you have a situation that is hopeless in terms of your tail holding!

And

It's not an IDLER PULLEY. It is a SNUBBER PULLEY.

It's purpose is to increase the wrap of the belt around the tail rotor pulley and thus increase it's ability to transfer power. In this application, it only F's up the whole system.
07-14-2008 04:59 PM
 
 
929freak
Heliman
Location: Warrington Pa

pssst Skarn,don't call it an idler pulley again..! I think he means business!! ha ha just joking umdpru... but seriously thanks for all the help soo far,I will keep updating my progress to possibly be-able to help someone else
07-16-2008 05:08 AM
 
 
702nitro
Key Veteran
Location: Las Vegas, NV

Another benefit to removing the pulley is it reduces overall drag in the belt system.

Vibe Fiddy
Atom 111110100
Trex 1001011000n
07-16-2008 05:13 AM
 
 
SSN Pru
Elite Veteran
Location: Massachusetts

SNUBBER DAMMIT!!!!!!


07-16-2008 01:12 PM
 
 
Skarn
Senior Heliman
Location: Pasadena, MD

Quote 
SNUBBER DAMMIT!!!!!!

Hmmm this could be fun

Dictionary definition of idler pulley: a guide or tightening pulley for a belt or chain

Pictures of idler pulleys:
http://farm3.static.flickr.com/2237...40c3c2d.jpg?v=0
http://www.daffysworld.info/pics/idler_pulley.jpg
http://www.kenlowe.com.au/_borders/Superc50.jpg
http://z.about.com/d/autorepair/1/0/R/F/91350183.gif

Oh and this one from viacopter.com where they recommend removing the IDLER PULLEY!!!!! http://vicacopter.com/idler_pulley01.jpg

But hey, if umdpru feels the need to call it something else....like snubber pulley.....go for it!

Skarn

It's better to burn out than to fade away...
07-16-2008 03:24 PM
 
 
dashpilot
Senior Heliman
Location: Norfolk, VA

make sure the belt is no TOO tight.. also...make sure nothing is binding in the head.. you should be able to move the head freely...

food for thought..

"what comes up must come down"....softly of course
07-16-2008 04:33 PM
 
 
SSN Pru
Elite Veteran
Location: Massachusetts

An idler pulley is generally used to ensure that the proper tension is applied to a belt by actively pressing against the belt using a torsion spring, as in the case of a serpentine belt, or to change the direction of a belt as is also the case in serpentine belt usage in vehicles.

A snubber pulley is generally used to increase the contact arc of belts around drive pulleys to enhance the power transmission capabilities of belts.

In the context of helicopter tail rotor drive systems, the pulley we are discussing is not an idler pulley as it really doesn't maintain tension on the belt or change it's direction. It does, however, slightly increase the contact arc of the pulley on the tail rotor drive pulley. In most instances, it only serves to aggrevate the tracking of the belt on the t/r drive pulley. I've removed mine because the rotational axis of the pulley was not perfectly perpendicular which cause the belt to ride to one side of the t/r drive pulley.

If you are going to include some sources, at least include reputable ones.
07-16-2008 05:52 PM
 
 
TRex888
Veteran
Location: Monmouth, UK

Sounds like BEC overloading. Servos drawing too much current will cause this without puffing your battery.

How may turns on the main blades can you get when you swing it by hand? Atleast 5 to 10 for a free running system. Mast collar too tight is a good place to check if you get less than 5.

Also pop the links off the swash and move the swash up and down by hand. The washout hub can get sticky from dirt, oil and even dust from worn ball links! Caused me two crashes this before I figured it out. Happened to a buddy also.
07-16-2008 05:54 PM
 
 
SSN Pru
Elite Veteran
Location: Massachusetts

Quote 
How may turns on the main blades can you get when you swing it by hand? Atleast 5 to 10 for a free running system.

That's a good point too.

I usually judge my rotor freewheel by spinning the boid up in Idleup1 which is close to 2900 rpm and then hitting throttle hold. My longest spool down time was about 22 seconds. When the drive system was less than optimal, I could see spool down times closer to or even under 15 seconds.
07-16-2008 05:56 PM
 
 
Skarn
Senior Heliman
Location: Pasadena, MD

Quote 
If you are going to include some sources, at least include reputable ones

LOL, what isn't reputable about a dictionary or the sites I posted?

And honestly I was must messing with you bro, that's why I said this could be fun! I could care less, I'm only going by what the many veterans that I learned from call it.

Ok how about a compromise/hybrid:
- Snubildler pulley
- Snidler pulley
- Idlenubber pulley

Or my favorite so far: Snubbler pulley

Skarn

It's better to burn out than to fade away...
07-16-2008 07:52 PM
 
 
SSN Pru
Elite Veteran
Location: Massachusetts

skarn,

sorry, i get worked up when i have too much coffee.

I like snidler pulley.
07-16-2008 08:11 PM
 
 
Skarn
Senior Heliman
Location: Pasadena, MD

Quote 
sorry, i get worked up when i have too much coffee

LOL! That's my line! Ok honestly, how many cups have you had so far today? I'm at 3 and a diet soda...

Skarn

It's better to burn out than to fade away...
07-16-2008 08:17 PM
 
 
baby uh1
Senior Heliman
Location: St. James, Mo.

OK I've been following this discussion and it looks to me that if I remove the snubbler pulley thing on my bird then the beltler will rubbler on the top of the inside of my boommler.

That can"t be good!
07-17-2008 02:30 AM
 
 
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Model Rectifier Corp . RCHover . RC-Direct

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e-Align T-REX 250-450-500-600 > T-REX 450 T-REX battery or motor prob? help.....(please)
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