Landing gear mount breaking screws.

[troasb]

On the front mount of the landing gear I have broken, first one mounting screw, then fixing the mount temporarily with a strip, only to shredding the other mounting screw. What is wrong here?

[Danny Dugger]

Got pics? I'm not positive I follow what you have going on here. Is the screw not threading all the way into the hole? Are the threads in the aluminum mount ok? Do you have an M3 tap?

[Mike Spano]

if this is a nitro, you need to look into your rear bearing. if its a nitro, and/or electric, look at all bearings from the front trans back. high frequency vibs can do this. its very common in gasser helis to have this happen...

[troasb]

Yes, this is a N7. Sorry, i do not have pictures of this as I have managed to get the remains of the screws out by cutting a slice in them and got the remains out and have remounted the landing gear.

The mounting screws were cutted of at the base of the landing gear mount, leaving the remains of the screw in the landing gear mount.

I guess this is a vibration issue, or alignment incorretion of the frames. When I mount the landing gear, I have to put a little pressure on the frame to align the mounting holes

[Roger]

Try loosening the screws that hold the landing gear mount to the frame.  Then attach the struts to the gear mount snugging them up in a back and forth pattern.  Just snug them up.......do not completely tighten them yet.  Once they are snugged up tighten the screws holding the gear mount to the frame securely in a back and forth pattern until completely tight.  Then go back and finish tightening the screws holding the struts to the gear mount.  Remember that you are mounting a plastic piece to an aluminum piece so don't go hog wild on them.  Let the thread lock do its job!!

You should not need any pressure to line holes up!!

ROG

[troasb]

I have a suspicion that the split frames on the N7 are not stiff enough. I have broken the landing gear mount screws twice, throttle servo mounting lug has broken, and my second clutchliner gone in less than 50 flights. Ok, I stop the engine by cutting off the fuel line and that puts a litte extra strain on the clutch, but so do serveral of my fellow fliers to on other helicopters with no trouble. I cannot adjust more on my radio and really don't know how to set it up otherwise to cut the engine with the radio. But this should not be the problem. I have flown my Align Trex 600 Nitro since 2010 without changing the clutch and stopping the enginge by cutting the fuel.

[Jason Cummings]

I have a suspicion that the split frames on the N7 are not stiff enough. I have broken the landing gear mount screws twice, throttle servo mounting lug has broken, and my second clutchliner gone in less than 50 flights. Ok, I stop the engine by cutting off the fuel line and that puts a litte extra strain on the clutch, but so do serveral of my fellow fliers to on other helicopters with no trouble. I cannot adjust more on my radio and really don't know how to set it up otherwise to cut the engine with the radio. But this should not be the problem. I have flown my Align Trex 600 Nitro since 2010 without changing the clutch and stopping the enginge by cutting the fuel.

I'm sure if you look hard enough you'll find the source of your problem is a high frequency vibration. Where do you live? If you have a team member in your area they would be more than happy to meet up and help you sort out your problem

[troasb]

Hi Jason!

I live in Norway, and I do not know about anybody else that
fly Synergy in my vicinty. Nobody stocks Synergy in Norway,
so I have to order parts from the U.K. or Synergy store in U.S.

I have been told by a very experienced pilot here that attended
the IHRCA this summer that several fliers had problems with
the split frame not being stiff enough. And I beleive this may
be true. I have to push the frame a bit to mount the landing
gear, giving the same expression.

Best regards
Trond
Norway

[Danny Dugger]

Hi Trond, I'm sorry to hear you're having trouble. I agree that you could have a vibration problem. To be breaking so many fasteners and running through clutches maybe the engine is not running smoothly? It may be worth double checking if there could possibly be an alignment problem between your frame sections as well if your skids fit poorly. When assembling the frames it is recommended to first leave ALL of the fasteners that secure the frames loose. Place the frame (without skids) on a very flat surface (I use a precision granite surface plate, but a nice counter top, dinner table, or pane of glass or similar will do) and square the frame to the flat surface with a square, or a large precision parallel, etc. With the frames now properly aligned and square the frame spacers, boom holder, tail transmission, front battery plate, and FBL tray can all be tightened. Before tightening the three main shaft bearing blocks make sure the main shaft slides through all three bearings freely without binding at all. Alignment of the bearing blocks may change slightly when tightening so tighten the screws slowly, alternately, and double check alignment with the shaft as you go. When you're done the shaft should be able to fall through the bearings under its own weight. If it doesn't, they're not aligned. Once the bearing blocks are secure and aligned I like to mount the engine using the surface plate for alignment as well, and lastly align the clutch stack to the clutch bearing. I would also check over the engine bearings while it's out to see if they could be contributing to a vibration issue. I attend a good number of events including IRCHA, have met and talked to a lot of folks with N7s, and have not heard complaints about the structural integrity of the frames or general service life of parts. If parts are failing there is certainly a reason, we just have to find it. It is typically a very low maintenance airframe.

[troasb]

Hi Danny!

Thank you for your useful information.
I did check the alignment of the frames on
a flat surface when I assembled them, but it may
seem like I should to it again. Nice to hear from you
that it is not a common problem with the frames
beeing too flexible.

[Kevin Feil]

Hello Trond,

 I agree 100% with Mike,Jason, Danny, I am trying to honestly figure out why your having so many issues with your N7. I can assure you with the exception of yours, this has never been any issues with any of the Synergy Models available today. Furthermore the split frame design isn't an issue either. I have personally owned 8 N7's  3 of which where pre-production and with countless hours flown and I'm fortunate enough to live close to Matt and hang out and fly with him a lot and have never seen anything like this on his machine. The only thing that I can even come close to maybe the issue is possibly over torquing the Mounting hardware, with that being said if you have a high frequency vibe in the machine this could in fact prematurely lead to snapped hardware, especially the landing gear mount bolts going along with Jason's post. Keep us posted on your findings. Also keep in mind if your running a OS 105 or YS engine they produce even more torque especially if you let the engine run with the fuel cut off, your enduring a "Lean Condition" on your motor that will eventually wear the clutch liner, I would get someone to help you sort out your mechanical set-up that would allow you to shut the engine down with your Tx. Another question I have is how is your flying style and do you do a lot of Auto Rotation Practice? My final question is has this machine been involved in any crashes and if so how many and how bad?

Best Regards,

K

[troasb]

Hello Kevin

Thank you for your information.
I run a O.S. 105 HZ-R engine in my N7.
My flying style is sport and a little mild 3D with some tic tocks trying to learn more 3D. Until now I only auto rotate for landings. My N7 has gone through 3 relatively mild crashes.

Best regards
Trond
Norway

[Kevin Feil]

Thank you Trond for the responce. Keep us posted moving forward..

BR,

K