SELF DESTRUCTION: Tail Belt Snapped 150' UP! (PICS!)

[gagi]

Well the destruction is not that bad.

The tail started squeeling for about five seconds and then wam! The bird started spinning out of control at full blast! I did my best to save it and luckily it missed a fence and landed in some tallish grass!

I just wish I would have made the mistake, not my tail belt failure. Now I want to know what happened!

To me it seems like the tail belt ran off the rear pully, got jammed in the tail gearbox, and then snapped.

HOW CAN I AVOID THIS IN THE FUTURE! : (

Here are pics to show the damage!

-Gagi

[Holeshot114]

OUCH! you came in hard! Hey, can you put a picture up of how you set up your 9650 if you get a chance.

I can't tell why your belt is off the pulley by your pix. Was everything tight and 90 degrees?

[gagi]

Yea everything was tight as far as I could tell. I leveled my tail so that was at 90, but im guessing my tail belt stretched out a bit and it was too loose? IM not sure how thats possible.

I think the servo had nothing to do with the problem as there is no binding and the link was totaly in tact after the crash!

GRRR BELT GRRRR BELT!


Here is a pic of the tail servo before the accident.

IT has not changed position!

https://www.helifreak.com/album_mod/...69c6eb8f87.jpg

[Finless]

The boom is known to slip in the SE boom blocks. I always wrap the end of the boom with one wrap of scotch tape and that stops it from slipping.

Bob

[gagi]

Hmm I had a feeling that was happening, especally when I could hear the tail belt tiwink against the Alu shaft. Oh well almost done repairing the head ; /. I will have to do the scotch tape thing!

Good looking out Bob.

[gagi]

Just took off the tail shaft! It too is bent!

Not much but will never fly again!



Thanks guys for taking all my venting!

[Coop]

I mostly only hover my 450xl and have made at least 20 flights maybe more without a problem. However the last flight I was about 3 feet up when I too heard the squealing sound followed by a rapid descent and hard, but no damage landing. The belt was wedged against the frame off the pulley, not broken. I rotated the gear and got the belt back on the pulley. And yup it was looser than I had previously adjusted. I'm going to follow Finless' advise with the tape. Seems like loose is what causes it. I have a plastic tail assy..thought maybe that was the problem, but I see yours is metal!

[cdyckes]

A failing belt caused a similar problem in a hover but I was able to set it down with no damage. The belt had frayed at the edges and a thin strand of whatever thead (kevlar?) they use in the belts was wrapped around the tail frive gear in the main frame. Belt had broken the rubber at one point and just held together by the threads.

The belt looked fine in a visual examination in the heli, but on disassembly it was obviously knackered.

[Paul_C]

Been there done that got the bag of broken parts, but only realized what was going on when it happened the second time – replace the idler pulley with an mx400 idler, it is flanged and it is impossible for the belt to slip off.

[ukgroucho]

I had one do this but luckily noticed the reduced tail response and was close enough to land and investigate.. that was down to the belt tension being a little too loose. I have though about getting some MX400 idlers though - they have teh shoulders/flanges so would help prevent the belt actually slipping off the side. However, at the end of the day correct belt tension and a locked boom are essential.

[gaeric]

What is the advantage of the long belt vs. standard belt in any of the above problems? I would think the stanard belt w/ keep more of the tail boom in the frame and more secure.

-Eric

[gagi]

Where can I get some MX400 idlers, and I too wonder about the longer belt?

[gagi]

Quick summary of what was trashed in the out of control crash!

1x Main Shaft $2.50
1x Tail Boom $12.00 (Upgraded to CF)
1x Feathering Shaft $1.50
1x Tail Belt $8.00
1x Tail Fin $7.00
2x Landing Skid $8.00
2x Main Blades $13
1x Flybar $2
1x Main Gear $5.00

Thats a gran total of $60 With an upgrad to the tail boom!

You are forced to buy more than one part at a time, so you spend more per crash if you dont have parts lying around, but from the calculations it is clear that even a fairly heavy crash wont eat your wallit.

Cool!

-Gagi

[EKIM]

I too use the mx400 pulley. My belt used to wander until I put this in. Its a direct replacement part and works wonders! But its not a cure all solution. You still have watch for boom slippage and what not.

here's the pulley:

http://grandrc.com/inc/sdetail/12433

[gagi]

Thanks Mike!

I will have to order that guy!

I was a bit pissed when I saw the belt guid align put in! NO SIDES! Who are they effin with. :wink:

-Gagi

[Rick Rotorhead]

I think I read somewhere on HF that you can dispense with that idle roller altogether - yes?

[Finless]

I dont run one on mine! I dumped it the minute I realized it was contributing to belt tracking issues AND drags the belt down aking the motor work a tiny bit harder....

Why have something that really does absolutly nothing sitting there running on a belt that can wear because of it?

Bob

[gagi]

Hmmm that sounds interesting. So you just put the little stand off thingy where the usless roller was. I kind of liked the roller me like shiney! No but seriously how could that thing that does nothing contribute to the tail belt sliding off of the tail shaft drive gear?

[ormandj]

My tail unit only has one of those little metal things on it. No roller at all. I just put that metal pipe looking thing on the very rear of the tail and that's it. No problems at all!