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Synergy R/C Synergy N9 > Synergy Tail Failure ... Again!!!!!
 
 
chemHeliman - Location: Dijon - France -
Hello,

This afternoon, during my first flight of the day I crashed my Synergy because of a tail grip screw breaking.
Few weeks ago a friend of mine have had the same tail failure two times in a row.
Note that this screw wasn't overtighten, as writed in the manual.

Here's some pictures:







Someone had this kind of tail failure too?

What would the solution to solve this problem?

What type of screw must we use?

Chem
08-05-2007 08:24 PM
HOMEPAGE  
 
 
P.J.
Veteran
Location: Ireland

chem


Its looks like you over tightened it


P.J.

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YS
08-05-2007 08:54 PM
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ecosse2253
Senior Heliman
Location: n.ireland

I second that pj diffinatelty over tightened

climb-out uk
08-05-2007 08:56 PM
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bobc1
Senior Heliman
Location: Southern California

Just curious. How can you tell that the bolt was over tightened from the photo's?
08-05-2007 11:45 PM
 
 
j5coat
Veteran
Location: Phoenix

happened to me once, thankfully i hit the hold switch right away and landed with no damage. i just replaced the hub and put new screws in it and it has been fine.

Trex 700, Trex 600n
08-06-2007 12:20 AM
 
 
RCHELILOVER
Heliman
Location: in front of my computer

It was definitely overtightened, notice the missing part...


Charles
08-06-2007 03:59 AM
 
 
vitek
Key Veteran
Location: Corvallis, OR

Possibly overtightned, definitely overstressed. Were you guys using 105mm tail blades?

Travis
08-06-2007 04:17 AM
 
 
j5coat
Veteran
Location: Phoenix

i was using sab blades that came with the kit, but my bolt looked like it was defective. you could see when you looked at the bolt that only about 1/2 was a fresh break. The rest was a darker color that looked like it was cracked long before the blade was ejected.

Trex 700, Trex 600n
08-06-2007 05:18 AM
 
 
chem
Heliman
Location: Dijon - France

I use 105mm SAB tail blades that came with the kit.

Maybe the screw was overtighten... But then how tighten this one correctly, because I'm sure I didn't too much tightened it during assembly.

Chem
08-06-2007 07:04 AM
HOMEPAGE  
 
 
chem
Heliman
Location: Dijon - France

This 3mm screw seems to be very fragile and don't endure any over tighting.
Maybe it would be better and safer with 4mm screw...

Chem
08-06-2007 07:46 AM
HOMEPAGE  
 
 
Buzzin Brian
Elite Veteran
Location: College Station, Texas

The best practice I have found in this area is to turn the nut down until it just stops, and only tighten further to take out in and out play. The keeps the stress off of not only the bearings, but the point that fractured in the PICS. I am sorry, but I have to agree. It looks to have been overtightened to me as well.

Build it, fly it, crash it. Repeat as often as needed.
08-06-2007 08:16 AM
 
 
Scraptor
Heliman
Location: South East, England

I had exactly the same problem, bolt sheared in an identical way. Cost me £100 because the whole tail shaft twisted through 90 degrees stripping the crown gear, tail gears, tail blade tore off, tail output shaft bent...... Auto'd it down fine. Perhaps I too overtightened the bolt!

Speaking to others, this has happened once or twice before.

Paul
08-06-2007 12:57 PM
 
 
chem
Heliman
Location: Dijon - France

Maybe the good way would be that Synergy RC made a new Tail Rotor Hub with 4mm screw... What do you think about that?

Chem
08-06-2007 05:00 PM
HOMEPAGE  
 
 
Chuckie
Key Veteran
Location: Crofton Maryland, MHA member

Quote 
Maybe the good way would be that Synergy RC made a new Tail Rotor Hub with 4mm screw... What do you think about that?

Well then Synergy would have to replace the radial bearings, thrust bearings, and blade grips to fit the larger screw. I would not want to see less metal on the hub ends.

Charles

Please stand by for faster service!
08-06-2007 08:05 PM
 
 
UK Helinut
Senior Heliman
Location: Gloucestershire

I had the same fault with mine. I did not over tighten either. Same fracture, same tail blades ect.
08-06-2007 08:32 PM
 
 
RCHELILOVER
Heliman
Location: in front of my computer

Quote 
I would not want to see less metal on the hub ends.

Why would that be? Wouldn't it make it more reliable?

Charles
08-07-2007 03:07 AM
 
 
carzan
Senior Heliman
Location: The Lone Star State

had the same failure but mine was after a crash. I had repaired the heli and i obviously didn't dig deep enough. so one crash led to a stripped crown gear and a new tail hub.

Team Turd!!!
08-07-2007 03:42 AM
HOMEPAGE  
 
 
Mark C
Key Veteran
Location: Houston, TX - USA

chem I'm not here to tell you that you overtightned it or undertightend it. I'm just here to say that I feel your pain dude.

Been there and done that. Of course mine was "undertightened" and "uderlocktited" according to the powers that be.

This can likely be solved using a better grade bolt, a little less torque and a lot more locktite of the green variety.

Good luck on the rebuild. Get 'er flyin again ASAP.

Mark C.
08-07-2007 06:04 AM
 
 
vitek
Key Veteran
Location: Corvallis, OR

I was told by some of the Synergy guys to use 95mm tail blades to avoid this exact problem. They said the 105s make a very large tail disk and put a lot of stress on that bolt and the hub. The 95mm blades dont' appear to hurt performance any.

I realize the kit comes with 105s, and lots of guys use them, but that is just the information that I was given.

Travis
08-07-2007 06:54 AM
 
 
Revolution man
Heliman
Location: France

Me also I have crasher 2 times in one week because of Synergy Tail Failure.
I was equipped with 105mm Vblades
08-07-2007 10:47 AM
 
 
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Synergy R/C Synergy N9 > Synergy Tail Failure ... Again!!!!!
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