CAUTION: E7 CRASH - Belt snapped - disappointing

[mstlc03]

 Well guys, the unthinkable happened to me this morning as I was taking my new E7 out to really begin flying her after some tuning sessions.  On the 2nd flight this morning, the heli went into a uncontrollable pyro and I was lucky that it wasn't a total loss.  After the crash, buddy and I went and examine the wreckage and noticed right away the belt snapped during flight.

This is a brand new E7 with only about 10 flights.  Most of those are to fine tune and adjust the BeastX.  The belt was setup according to what Matt had specified in the threads.  At this point, I can only guess there was a defect or a manufacturing flaw on the belt that caused premature failure.

I can say that I'm disappointed at what just transpired and wanted to caution others about visually inspecting your belts to ensure the samething doesn't happen to you.  What really gets to me the most is I had just bought a brand new pair of the Rail 696s blades and 106 tail blades and this was only the 2nd flight and now they are a total loss.

I'm attaching some pics so you guys can see what the damages looks like.  The canopy is pretty much done as well.  Going to take the heli apart and assess total damages.  Hoping the Synergy crew can chime in and comment on if there were any other belt failures during testing.  At this point, I'm trying to decide to rebuild this heli or wait for the *rumored* torque tube.   



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[Jerry Kovar]

Bobby... if you have not taken your tail apart yet, show some pictures (close ups) of your tail box..... Also of the section were the belt snapped and failed...

[Yanick Larouche]

Bad News !

TT is not a rumor . Matt test Tt in china now !

Thank's !

Yan

[mstlc03]

Hi Jerry, I shoot you some close up photos of the belt and of my tail assembly.

Anyone know timeframe for the TT setup??

[Yanick Larouche]

Matt said ASAP !!

[Kevin Feil]

Jerry,

 Do you have Pic's of mstlc's tail section and Belt? if so shoot them to me please sir. I would like to see as well. 


Kevin

[mstlc03]

Posting pics here to save time...



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[steffgiguere]

Super you are mistaken, Matt is not trying out the TT in China, he said he hopes to have a prototype for when he comes back.

[Kevin Feil]

I'm Drawing a straw on this one, a couple of Question.

1.) Does the Idler Pulley on the Tail Box Spin Free?

2.) Did You Lube The Tail And With What did you Lube it With?  "Which Product" ?

3.) Is There a Chance that the Belt Was Over Tighten? And If You could Explain How you Tighten it and determined it was Correct.

4.) Was the Belt twisted in the Boom. Instead of a 1/4 turn did you have a 1/2 turn in it?

****Keep In Mind That These Are Questions Only In Better Helping Determining The Cause. In NO Way Am I Asking These Questions To Doubt You..****  Myself And The Team Will Be asking These Questions and Probably More Just To Help Figure Out This Crash.  Kinda Like the NTSB if you will    Matt is Out of Pocket so we are fielding the Questions. It is Not Common at all for the belt To Break. The belts that failed in the Past were due to Set up issues.  Belt being Too Tight and Wrong Lube were Strong Factors.

 Keep us Posted with anything you can think of that might lend us a clue..  Sorry For your Crash Brother..

Kevin

[Kevin Feil]

Also check the Pulley buy the Tail Drive Gear. Do they move Freely.  I just Can't Get Past the "Belt Being To Tight" I could Be Wrong But these Belts just Don't Fail..  Matt and Mitch Are Proof in that Alone.  Just Keep us Posted if you think of anything.

Kevin

[seldred]

Hello mstlc03,

Sorry to hear about your misfortune.  Along with the questions Kevin asked, did you inspect your belt before you installed it? If there are any creases in the belt before installation it can cause a weak spot and could lead to failure. I've always looked at mine before I undo the zip tie, just to be sure it didn't get folded up from the factory. Also I make sure the zip tie did not cause any damage to the belt. Another thing that can lead to failure is too high of a tail gain. The harder the tail stops the more stress it puts on the belt. I run vbar, and had to lower my tail stop gain 5%. The tail is still very responsive and precise, but just decreasing the load on the belt. This is not a problem with the E6 or N5c, but with how long the belt is for the E7, it almost doubles the load on the belt.

I am not as skilled as Matt or Mitch, but I do fly hard 3D and I am rough on the tail. I have not had an issue with mine yet, and the tail on the E6 and N5c is bullet proof. I will always keep belt on those two helis, but on my E7 I will try the tt when Matt has some available.

Best Regards,
-Steve

[mstlc03]

Thanks Kevin for your help on this!

1. Yes, as far as I can tell the Pulley seems to be free rolling.  During initial build, I did have it too tight but losen it right before my first flight.

2. Not exactly sure what you mean by lubing the tail.  I only apply some oil on the tail shaft so the pitch slider would move more freely.

3. This is a hard one to answer.  I will say that it has been more on the lose side than on the tight side.  I would occasionally hear *ting* sounds coming from the heli during flight but it's only in very specific manuvers.  Definitely not all the time.  I've followed Matt's guide on this and have had other fellow fliers confirm tightness.

4. No, this was verified and was not twisted.  I would noticed this as I believe you'll definitely hear it.

I'm definitely trying to keep an open mind about this as I don't really understand how a belt can snap only after about 10 flights.  Also, we need to think about that manufacturing defects do happen so I just want to make sure we consider that as a possibilty as well.  In the end, it might be impossible for us to find out what really happened but I did want to raise awareness of this issue and hope we don't see anymore of these mishap to others.

[mstlc03]

Interesting comment about the gain and stops.  I run a BeastX and my tail gain is at 78% and my other tail values (on the dial) is the default setting.  I don't remember if I visually inspected the whole belt but I do remember that it folded from the factory and took me doing some light stretching to try and remove the bends.

Overall, I do believe the belt is of good quality and seems durable...just very sad to see one give out so early and causing me some pain.

[Chris Sexton]

At the end of the day, manufacturing mistakes happen and even new belts can break. I hope you are back in the air quickly.


Sent from my iPhone using Tapatalk

[seldred]

The belt is folded up, but it is done without completely creasing it. I don't try and stretch mine to get the bends out, Just simply install it and spray silicone on the inside and outside of the belt making sure it is nicely lubricated.

What kind of silicone or "lube" did you use on the belt before flying it? Spraying it with silicone is a MUST! I use Permatex 80070 Spray Lubricant.

Best Regards,
Steve