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CanoMod . Futaba-RC . A Main Hobbies

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Synergy R/C Synergy N9 > Torque tube failure!
 
 
Droid
Elite Veteran
Location: Deep down in the Southwest- UK

I know i'm gonna get some grief thrown at me, but, to save anyone else the carnage i've got sitting on my bench read if your interested.

Beautiful clear skies...

Engine has had 2 gallons through and i've upped to 15%

Canopy off and dial in the needle settings.. i'm grinning!

Fly of into some gentle circuits, figure 8's

Model passes at 30 ft bank to its right and on the exit (knife edge)violent tail movement.. tail control gone..damn must be the servo! The rest was a blur heli piroeuttes franticly , instintively i flick TH but too low to recover headspeed gone.

Nose in to the ground...game over

Bottom line is hexagon drive has spun in torque tube, no i wouldn't believe it either after the grief i had trying to get it in there!

All i'm gonna say is when i reassemble it i'm drilling through and bolting it.

Quotes may have been changed for my own amusement
09-12-2006 06:15 PM
 
 
hansking12
Senior Heliman
Location: irvine, ca

sorry to hear droid

that's a real bummer! i had a tail hub shear on my fury and experienced the same scenario.

those 4 setscrews in the collar to the hex drive pinching the tube--were they locktited and still secure?

hope the rest of the model came out relatively well. i can say that i was impressed after my crash with its survivability. did the main gear get damaged? or the crown (pretty much impossible with no tail drive forces going through it)?

hope you get it back in the air soon!

hans
09-12-2006 07:05 PM
 
 
Droid
Elite Veteran
Location: Deep down in the Southwest- UK

Yeah everything was tight, collar still is!! Seems like the splines spun inside the tube. While assembling it i thought it was that tight you could have got away without the collar!!

Done the servo tray, frames, boom, feathering spindle, flybar, tail shaft, wrecked the gyro and servo! Everthing else looks ok but will scrutinise 2night. Definately no gear damage.

Only consulation was canopy was off for final shake down!

I'll be pinning the couplings when i rebuild it!

I'll post some pics later to show the coupling( and the carnage)

To be fair it went in HARD and was surprised more wasn't damaged

Quotes may have been changed for my own amusement
09-12-2006 07:15 PM
 
 
Scooterpilot
Key Veteran
Location: Southern, California

Droid,

Could you post a picture of the splines that spun inside the tube. I’d like to see how smooth they are?

Thanks

Two N-9's,600N, MagnumFuel Rep, YS Rep
09-12-2006 07:42 PM
 
 
hansking12
Senior Heliman
Location: irvine, ca

splines

wow, i'd like to see whether you have any more splines left after spinning in the tube like that.

i have noticed that the 4 setscrews which hold the pinion gear onto the end of the drive assy on mine were loose--have you checked those also? are they still tight?

and did you notice any hints of failure on flights prior to the final one? any signs of slippage or weak tail response?

hope you get it sorted quickly,

hans
09-12-2006 07:42 PM
 
 
Droid
Elite Veteran
Location: Deep down in the Southwest- UK

Yes in hindsight the heli was telling me the last flight i had on sunday but i dialled in the fan etc yesterday and put it down to rich running. What probably killed it was a tank full of full power climb-outs!!

Hindsight is a wonderful thing!!

Quotes may have been changed for my own amusement
09-12-2006 08:00 PM
 
 
DroidElite Veteran - Location: Deep down in the Southwest- UK -
Here are some photos notice the polished are where the grub screws clamp the tube, the collar is still solid on the tube!!



Quotes may have been changed for my own amusement
09-12-2006 08:14 PM
 
 
Spookyeng
Heliman
Location: Gulf Breeze, FL USA

Droid,
Sorry to hear about the crash. I know what you mean, very difficult getting the couplers into the torque tube. I am intersted though, both my front/rear couplers and collars were powder coated black and not natural alluminum. It took me about 1 1/2 hours of heating up the tube and beating the couplers in to get them in. Take it easy.
09-12-2006 09:19 PM
 
 
hansking12
Senior Heliman
Location: irvine, ca

grub screws

are those the stock 3x4 grub screws that came with the kit? if so, i am pretty sure mine are screwed in quite a bit further than that. i'll try and pull my torque tube later tonight to see if they are indeed. nonetheless, you can see where there was some force applied from the abrasion and corresponding smoothing of the splines. i'll post later to let you know what i find.

regards,

hans
09-12-2006 09:47 PM
 
 
Droid
Elite Veteran
Location: Deep down in the Southwest- UK

Yes stock screws tighten in as far as i dared!!

Quotes may have been changed for my own amusement
09-12-2006 10:25 PM
 
 
JitsuGuy
Veteran
Location: Tulsa, Oklahoma

This is definitely the negative side of a torque tube.
09-12-2006 10:34 PM
 
 
inkspot1967
rrProfessor
Location: cranston ri.

Droid

you have the collor part 115-217 on backwards the manual shows it that way but i was told to flip it the other way set screws more to the front

Trex700e outrage 12s Solid-G Tyler Bonta Flybarless
Next-D Rave Flybarless vbar
WENZEL CANOPYS
09-13-2006 12:01 AM
 
 
hansking12
Senior Heliman
Location: irvine, ca

checked mine

i pulled my torque tube out and my grub screws are screwed in more so that the ones in your pictures. i also took the opportunity to tighten them tighter, just in case. the pinching effect needs to bend the aluminum torque tube, so i cranked on those poor grub screws to make sure that happens. hard to say what torque spec i used since i don't have a micro torque wrench.

i hammered on my tail on saturday with repeated full left/instant full right tail commands and if it were going to let go, i thought for sure it would have been then. my fury crown gear would have stripped instantly for sure with that kind of abuses. now a disclaimer--i'm running 95mm tail blades and programmed the delay into the 611 which has been detailed in another thread on this forum.

once again, sorry to hear of your misfortune.

regards,

hans
09-13-2006 12:42 AM
 
 
Scooterpilot
Key Veteran
Location: Southern, California

Inkspot1967,

You told Droid:

"you have the collar part 115-217 on backwards the manual shows it that way but i was told to flip it the other way set screws more to the front"

Where did you hear the collar should be flipped the other direction?

Thanks

Two N-9's,600N, MagnumFuel Rep, YS Rep
09-13-2006 01:01 AM
 
 
Droid
Elite Veteran
Location: Deep down in the Southwest- UK

Well like i said hans i think i'll epoxy this back in and probably swap out two of the grub screws for longer studs and positively lock the collar to the tube to the drive hex on both ends!!

Not sure of the benefit of turning the collar around though the marks on the spline correspond to half the length of the insert, maybe i didn't tighten them enough, dunno.

Like i said earlier the trouble i had getting them in i was surprised it required any external mechanical lock, not half as surprised mind when it let go

Oh well better dig through the manual for some part numbers

Receiver was destroyed after i unpacked it from the foam padding!

I think its gonna cost more in radio gear than parts, glad i haven't put the lipo and regulator on yet!! Might even just stick with the NiMhs.

Quotes may have been changed for my own amusement
09-13-2006 01:20 AM
 
 
inkspot1967
rrProfessor
Location: cranston ri.

todd bennet told me that at ircha

Trex700e outrage 12s Solid-G Tyler Bonta Flybarless
Next-D Rave Flybarless vbar
WENZEL CANOPYS
09-13-2006 01:22 AM
 
 
Droid
Elite Veteran
Location: Deep down in the Southwest- UK

Be nice if they could keep their forum up to date.

So are you saying that the instruction manual is incorrect?

Please elaborate.......

Quotes may have been changed for my own amusement
09-13-2006 01:27 AM
 
 
Chuckie
Key Veteran
Location: Crofton Maryland, MHA member

I've got a call into the TB/JK for clarification on this. I've not heard of reversing the collars either and I wouldn't think it would make a difference. I've been using the gy delays and have been hitting full right then left then right again without issues.

Charles

Please stand by for faster service!
09-13-2006 05:26 PM
 
 
inkspot1967
rrProfessor
Location: cranston ri.

thx chuckie

let me know because this is what todd told when i was building mine at ircha he said to flip them the other way so i did

Trex700e outrage 12s Solid-G Tyler Bonta Flybarless
Next-D Rave Flybarless vbar
WENZEL CANOPYS
09-13-2006 05:40 PM
 
 
Chuckie
Key Veteran
Location: Crofton Maryland, MHA member

inkspot1967,

I talked to Todd about the TT assembly when I got my kit a week before IRCHA. We discussed many things but he never mentioned reversing the collars. If this is new then I'd like to find out but as I stated before I really don't think it will make a difference. The set screws are still on the teeth in either direction. At OC Bob's on Sunday I was banging the snot out of the tail were I was getting chirps from the hard starts and stops. Mine are the silver ends so I've got nothing special.

Were you discussing something else perhaps? It was a few weeks a go!

Charles

Please stand by for faster service!
09-13-2006 05:54 PM
 
 
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Synergy R/C Synergy N9 > Torque tube failure!
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