Welcome to our Syma Forum - Please click on topics to view comments.You have to be a member to post-Free to join. Enter correct email as password will be emailed to you- All Syma Helicopter help and advice here. NEW- you can now change color of forum, bottom of page!

A A A
Avatar

Please consider registering
guest

sp_LogInOut Log In sp_Registration Register

Register | Lost password?
Advanced Search

— Forum Scope —




— Match —





— Forum Options —





Minimum search word length is 3 characters - maximum search word length is 84 characters

sp_Feed Topic RSS sp_Related Related Topics sp_TopicIcon
Please Help Me Feed My Addiction!
Repair gone wrong - Help!
Tags: Syma X9
Avatar
Raddler
Guest
Guests
January 17, 2013 - 1:33 am

Hello all.  I received a Syma 107 for Christmas and was instantly hooked.  I probably had about 30 flights in the first week.  Then I crashed, as I often do, and my beloved Syma would shoot off to the side as soon as it was a millimeter off the ground.  Withdrawal started immediately.  I did some research and found out about the little "plastic nubs" that often shear off.  Sure enough, that was what had happened.  Well, I installed the new part using the video and it went fine.  I couldn't wait to get flying again.  Well, all is not well.  Now my heli will take off hover for about 3 seconds before it becomes incredibly unstable and begins a large sweeping toilet bowl dive.  Can anyone offer any suggestions??  Is there something often overlooked when a first timer does this repair?  There was a metal collar around the shaft that I just pushed down before I replaced the top blade apparatus...is this correct?  Could the shaft be so slightly bent that it doesn't even look bent?  I'm not sure I want to attempt a shaft replacement if it is unnecessary.  When I hold the heli and throttle up, everything appears fine.  There is some vibration in the tail but I never did this before so I don't know if it's normal or not.  Please help, I'm foaming at the mouth!  wink

Avatar
zedorda
Guest
Guests
January 17, 2013 - 3:15 am

When you replaced the flybar did you tighten it too much? The flybar has to be freely moving. Binding with the flybar causes TBE(toilet bowl effect). The blades also need to swing easily with near no resistance.

Avatar
Raddler
Guest
Guests
January 17, 2013 - 3:37 am

Thank you for this suggestion!  I was thinking "tighter is better" while I was putting everything back to together so I will check this out as soon as a have a chance and report back.  What do you mean by freely moving?  The flybar is bound to the top blades by the dog bones isn't it?

 

Avatar
zedorda
Guest
Guests
January 17, 2013 - 4:00 am

The flybar and the blades have an offset parallel pivot so as the flybar swings the blade deflect along their length. While all the parts are assembled the flybar should be able to swing easily without any resistance from pivot point where you put the screw. The blade moving should be the only resistance the dog bones should swivel on their ball socket easily also. TBE is caused when the flybar experiences any delay in its ability to react in its stabilization purposes. So binding/resistance is the enemy so make sure all the parts are assembled but move easily you will get used to what the "right" feeling is the more you repair it.

Over tightening can also cause deformation of the parts if your not careful. Remember these are made to be as light as possible so they are relatively fragile. It is a good rule of thumb to give everything a half turn after full contact when reassembling then during your first test flight take notice of excessive vibration because that is the first sign of something loose. Land and tighten where needed another half turn and retest. Again you will soon get the "feel" of it and not have to test flight so much.

Avatar
CPD
Guest
Guests
January 17, 2013 - 4:51 am

Could also be a bent main shaft. That's the most common cause of tbe, and very likely a problem, being that your pins were sheared off. Also, just a clarification, the lower screw where the top screws onto the main shaft should be snugly tight, (just enough to be snug and feel tight, but not enough that it cracks or strips.) while the one in the balance bar shouldn't be overly tight. You want that to move as freely as possable. If you can gently tap it with your finger, and the bladeset bounces a few times, you're good. The plastic is fairly elastic and will rebound if it's moving freely. (an added bennifit of these helis for if you're bored out of your mind)

If it's only minor tbe or minor drifting, I've noticed that it tends to go away with proper lubrication to the gears and where the main shaft goes through the plastic corpus. I have no idea why lubrication fixes minor tbe and why a lack of lubrication causes minor tbe, but it just does. I don't know if it's because the oil takes up just enough space to keep the shaft centered and gets rid of vibration, or if it's just a fluke, but it works on most minor cases. (just make sure to use plastics-grade oil or silicon grease. I use model train oil since it's plastics and electronics safe.)

Avatar
zedorda
Guest
Guests
January 17, 2013 - 6:03 am

Graphite is real good lubricant for plastic. You can take a number 2 pencil that is real sharp and color the gear teeth. Just another option to consider.

double-thumbs-up-thanks-smiley-emoticon CPD I over looked the pinch screws. If they are not tight the shaft can get damaged on the first flight.

Avatar
Raddler
Guest
Guests
January 17, 2013 - 6:28 am

Thanks for all the help!  I tried everything, I'm pretty sure it's a bent shaft.  I throttled up holding the heli with the top blade assembly removed and I could see a wobble in the shaft.  Is there a video of a shaft replacement somewhere?  I can't seem to find a link on the site.  I'm a little nervous about doing it, it looks like the whole thing is going to have to be taken apart.

 

Avatar
CPD
Guest
Guests
January 17, 2013 - 7:33 am

There's videos out there on youtube. I'm assuming when you bought the upper main shaft, you bought the whole main shaft, and it shouldn't be too hard. I haven't personally changed out a main shaft, but you probably have to dissasemble a fair bit. I'm sure you could pull out the old shaft with a multi tool or pair of pliers, and shove in the old one, but that's just asking for problems and for you to screw something up.

 

(looks on youtube)

http://www.youtube.com/watch?v.....b_u9Vuk6uQ
that's one option, but I'm not positive if it's the best way to do so. I'm leery about just pulling out the old one and putting a new one in. It could be that simple, but in my experience, when something that major sounds that simple to replace, you're usually doing it wrong and you'll usually run into a problem somewhere down the line. (and then hit an "Aha! Wait... DOH! Why didn't I just do that in the first place? It's soooo obvious!" moment somewhere along the lines, and really mess everything up.)

Avatar
Raddler
Guest
Guests
January 17, 2013 - 8:40 am

That idea freaks me out a little bit.  And that video doesn't say if it actually works in the end.  Is there anyone that has done this???

 

Avatar
Raddler
Guest
Guests
January 17, 2013 - 12:27 pm

So here's the current status.  I caved and attempted the pliars method.  It actually does work.  I had to pull a little harder than I was comfortable with, but it popped right out and the new one popped right in.  So, the vibration is gone.  But I'm still not flying.  It hovers a little longer, maybe 10 seconds, but eventually slowly heads into the toilet bowl.  At this point, I'm at a lost and frustrated. yell  So this Syma may be destined for the parts bin.  Might be time to buy a new one.

Avatar
CPD
Guest
Guests
January 17, 2013 - 12:46 pm

How bad of tbe are you experiencing? If it's a small ammount, then it might be from not lubricating the heli, you might not have put the shaft in perfectly,surgically stright, or it might just be a natural fluke flaw. I'd say as long as it goes away while you're flying it around, not just sitting still, and it's controlable, it's flyable. No use fixing something about it that's not broke.

Avatar
Raddler
Guest
Guests
January 18, 2013 - 12:27 am

Its bad, not flyable.  I'll try taking apart the top assembly and putting it back together again, maybe something isn't lined up correctly.  But after that, I'll be ordering a new one.  I did bang this one up quite a bit, so I'll chalk it up to a learning experience.  I'll be able to baby the next one a little more now that I know what I'm doing. 

 

Forum Timezone: Australia/Sydney

Most Users Ever Online: 84

Currently Online:
2 Guest(s)

Currently Browsing this Page:
1 Guest(s)

Top Posters:

MikeK: 178

SymaGuru: 32

nope: 5

cyclib: 2

groggy: 2

Shwan: 1

Member Stats:

Guest Posters: 726

Members: 914

Moderators: 0

Admins: 2

Forum Stats:

Groups: 7

Forums: 15

Topics: 1272

Posts: 8171

Newest Members:

NadejdaJogue, Toranja, JulianDreab, Januszek45Swido, Jamaalcag, nikagreimOnge

Administrators: Syma Freak: 1432, JamDJ: 255