Wiped my n7 twice in a row [emoji29]

[ktmdiesel]

I don't know what is going on. I set it up the first time with ikon and got the viberations down to minimal. When trying to get rescue to work without shooting to the left, I accidently activated close to the ground and it planted in the dirt. I finally got parts and ordered an axon fbl because I'm scared of the ikon now. Had it flying very nice haven't had a chance to check vibes yet. Decided to try rescue for the first time and it flips upside and shoots into the ground.. I'm losing hope on this n7. I did hear a vibrating noise in the tail both times, but have set up everything perfect. I have built many helis before. I guess I am missing something on this heli or in the fbl programming. Has anyone had these issues?

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[Chuck Bole]

 Sorry you're having problems man. Was the vibration noise the same both times you heard it?  I don't have any experience with either of those FBL units, so not sure what to say there. Any chance a bent or tweaked shaft or hub or maybe grip might have been missed. I know i've missed things like that a time or two.

 It's been awhile since i had a N7 but after getting the engine tuned it was very smooth.

chuck

[Chris Sexton]

Hello!

Sorry to hear you are having issues, vibs and questionable trust in the FBL can haunt any airframe for sure!

Reading through your post, sounds like the heli was flying well both times, just bail out caused issues.  Now the thing to keep in mind here, all rescue, bailout, pick your term, systems use accelerometers to control the auto level portion, not the gyros.  These Accelerometers are EXTREMELY sensitive to vibrations, of any kind. Even the smallest vibration that you and I would consider normal gear train can wreck these systems if the FBL isn't properly isolated from them.  Nitros add to that issue by default with the addition of the engine and it's normal vibs.  Even the best tuned, balanced, and broken in engine/drive train on a nitro will make more nominal vibrations than an electric.

That said, the noise in the tail could be a clue too.  Was this frame used?  Could the tail have been touched to the dirt at any time? Even a 0.001mm tweak on a shaft, really hard to see by eye, will cause the tail to buzz or vibrate at 9,500+ RPM. 

I know you are frustrated, and I know this post doesn't help much. But I encourage you to tune the heli to the FBL make it fly well, then consult your FBL OEM suggestions for vibration dampening on a nitro. Every FBL recommends something different.

[Steve Graham]

I have had very good luck with the MSH/IKON2 flight controllers.  Still, I do not use rescue with my N7.  I spent an entire day trying different mounting pads and methodologies and looking at the logged vibrations.  The only pad that ended up dulling a well running N7's native vibrations to the point below the line in the FBL unit's software that would allow for reliable self level was the Futaba soft foam mount.  That worked for awhile until the pad got oil soaked and started to deteriorate causing bad control wobbles.  I went back to the 3M grey tape and disabled the rescue feature.

As others have said the vibrations coming from even a well tuned glow engine are severe and challenge even the best flight controllers.  Perhaps a generation or two down the road with these sensors and we will have reliable systems for this purpose but for now I won't even try it.  Otherwise the MSH/IKON units have performed flawlessly for me in all applications.  The engaged and forward looking engineering team allows me to easily recommend them.

[Al Tulone]

First I would try changing the tail shaft just to eliminate that question.  Like Chirs said even a slight bend will generate high frequency vibes.  Then I would look at the tail box bearings around the mushroom tail bevel gear.  Chasing a vibe is very frustrating but unfortunately it's a process of elimination.

[Gabriel Sandoval]

Pull the entire boom off as an assembly rotate by hand and feel for any abnormalities then remove the tail box and twist again for anything ( rocking of TT etc. ). Then check the tail box for smoothness then isolate each individual part ( bearings, shafts, grips ) and inspect for smoothness and straightness on a flat plate. something is causing the buzz in the tail so I would start from the mid point and check all parts.