Tail belt walking off idler

[vburge]

I replaced both belts after the main belt failure and now my tail drive belt is walking off the non-tentioning idler pulley. It has happened on every flight and most of the time it is just partially off of the idler. The last time it had rolled all the way off the idler. I have tried tightening the belt more and it did not fix the issue. It came down pretty hard during the belt failure, but I don't see anything bent. I suspect it may be an issue with the new belt. Has anyone had a belt do this before?

[kumar2494]

How much tension is on the tail belt? Usually that happens if it is too loose or too tight. The tensioner should be able to swing in and out. It shouldn't be resting on the monoblock or pinned to the frame.

[vburge]

I have always followed the manual and have not had this issue till now. The tensioner arm would just be hitting the stopper screw and I would tighten it down. Not sure what you mean by "pinned to frame?"

From manual:
Pull the boom away from the frames very tightly. Make sure the tensioner arm is all the way open against the stopper screw.

[vburge]

I put the original tail drive belt on and it walked off the bottom of the idler also. It isn't the belt or tension, so I have ordered a new idler and the fixed post it mounts on.

[Andersonsmog]

Did that fix it?

[vburge]

I put the new idler, post, and old belt on and the first flight it still walked off. However, the next three flights it did not. During my 5th flight I had a boom strike and it demolished the boom and belt.

[highonhelis]

belt tension should be tight but not over tight. between 1 and 2mm from the frame and being fully tightened.

[Pitch-Itch]

Originally Posted by highonhelis

belt tension should be tight but not over tight. between 1 and 2mm from the frame and being fully tightened.

Sooo, why does the manual say the belt needs to be tight enough to put the idler pulley against the stop screw?

Is the manual wrong and just not updated?

[vmalpi]

Both of my Mostro have the belt tight to the point where is touching that stop screw. The important thing is not to over tight it.

[vburge]

Of course I had a major crash and replaced numerous parts, but I suspect the cause for the belt walking off was one of the intermediate shaft bearings was completely frozen. It is just a theory, but it is no longer walking off and I don't know what else could have caused the problem. The belt on there now is one that I had already tried and it was walking off before the crash. Here is my Mostro back in the air after being down for a month. The new Xnova motor has tons of power and runs much cooler than the scorpion.

Mostro 1-27-2015 (5 min 12 sec)

[FBLessOne]

Originally Posted by vburge

The new Xnova motor has tons of power and runs much cooler than the scorpion.

the heli sounds very quiet and smooth in that video.

[Razorback Flyer]

Originally Posted by vburge

Of course I had a major crash and replaced numerous parts, but I suspect the cause for the belt walking off was one of the intermediate shaft bearings was completely frozen. It is just a theory, but it is no longer walking off and I don't know what else could have caused the problem. The belt on there now is one that I had already tried and it was walking off before the crash. Here is my Mostro back in the air after being down for a month. The new Xnova motor has tons of power and runs much cooler than the scorpion.

Mostro 1-27-2015 - YouTube

Which Xnova Motor are you using? And What Blades?

[vburge]

Xnova XTS 4530-525kv motor with 695 mm cyclone blades. I am using the vbar governor at 2100 rpm.

[Razorback Flyer]

Originally Posted by vburge

Xnova XTS 4530-525kv motor with 695 mm cyclone blades. I am using the vbar governor at 2100 rpm.

Thank You, My Mostro is on the UPS truck today out for delivery! Thought Id like to give these motors a try.

[Pitch-Itch]

Very cool to see you back in the air!

[vburge]

Welcome to the Avant group Razorback flyer! Once you build and fly the Mostro, it is hard to even consider buying a different brand. The Xnova motor is awesome.. I didn't like how hot my scorpion motor got and believe it created additional wear on the drive belt. The Xnova with Cyclone blades is a very efficient combination and I am flying 4:50 min with 28% left in the batteries after most flights. Hope you have a "smooth" build and let us know if you need any help.

[Pitch-Itch]

Originally Posted by vburge

Welcome to the Avant group Razorback flyer! Once you build and fly the Mostro, it is hard to even consider buying a different brand. The Xnova motor is awesome.. I didn't like how hot my scorpion motor got and believe it created additional wear on the drive belt. The Xnova with Cyclone blades is a very efficient combination and I am flying 4:50 min with 28% left in the batteries after most flights. Hope you have a "smooth" build and let us know if you need any help.

What kind of wear were you seeing? I ask because the KDE motor I am running gets VERY hot even in cold weather. In the summer I can't imagine how hot it will get.

[kumar2494]

Originally Posted by DavisBladeWorks

What kind of wear were you seeing? I ask because the KDE motor I am running gets VERY hot even in cold weather. In the summer I can't imagine how hot it will get.

Which KDE motor are you running? I have the 700xf 505g3 in mine and it stays much cooler than the scorpion. What do you have set for timing?

[Pitch-Itch]

Originally Posted by kumar2494

Which KDE motor are you running? I have the 700xf 505g3 in mine and it stays much cooler than the scorpion. What do you have set for timing?

I'm running the same motor as you. Not sure about the timing at all. I just programmed mode 4 on the kosmik.

What's your timing setting? I will have a prog unit soon so I can play around with the parameters.

[kumar2494]

Timing is set to 18. Any idea exactly what temp yours is after a flight? Mine peaks at around 155-160 which is pretty normal. My scorpion used to peak over 200 sometimes.