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**Nutter** · 27-08-2012, 05:56 PM

Ian

I noticed that there is the tiniest amount of vertical play in my tail drive shaft, but when I took the tail box to bits, there was none at all. So thanks for the info and will check the alignment of the bolts in the frame later.

Cheers!

**Nick B** · 27-08-2012, 06:00 PM

Had exactly the same prob on a 500efl a few months ago,found it while chasing a vbar vibe,i filed the holes out abit and 'voila'...vibe gone

**Nutter** · 27-08-2012, 06:02 PM

Ian

Forgot to ask you, but did you just simply elongate the hole in the side frame with the Dremel then?

**coolice** · 27-08-2012, 08:26 PM

Originally posted by Nutter View Post

Ian

I noticed that there is the tiniest amount of vertical play in my tail drive shaft, but when I took the tail box to bits, there was none at all. So thanks for the info and will check the alignment of the bolts in the frame later.

Cheers!

Originally posted by Nutter View Post

Ian

Forgot to ask you, but did you just simply elongate the hole in the side frame with the Dremel then?

Hey.

Well I was alerted to the possability of play here, but on taking the assembly out of the model it went away. So I left it, then saw it again and then realised it must be an inaccuracy in the carbon frame holes and sure enough it was.

Yes, I all did was using a dremmel and a small engraving bit is elongate the holes upwards. I didn't want to remove the assembly again, so very carefully plunged the cutter into the frame hole and worked my way around until it was right.
Popped the screws back in and the play has gone, will test fly tomorrow. But I'm guessing the bearings would not have lasted too long either, as they will have had excess side load placed on them with the vertical shaft being twisted almost.
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**Nutter** · 27-08-2012, 08:41 PM

Thanks Ian

I may take out the tail box altogether so I don't foul the tail gear box.

Cheers for the info!

**dszabo** · 27-08-2012, 10:14 PM

Good shout Ian, just checked mine and it's the same.

**Jamin_00** · 27-08-2012, 10:27 PM

Originally posted by coolice View Post

Hey All.

I remember a topic recently about the vertical tail output shaft play, but could not easily find it so thought I'd start a dedicated topic.

After taking my boom block out of the model and finding no vertical play in the shaft, I fitted back into the model. It was then seen that play was evident again, so I turned my attention to a possible tolerance issue on the drilled frame holes through which the boom block is secured.
On taking out the two lower securing screws it soon became evident why I didn't see any play with the assembly out, the lower boom block holes do not match the natural position of the plastic boom block. On adding the screws the boom block twists to accomodate them and the gap between the ball races is opened up and play is introduced.

A quick whizz on both sides with the dremmel and voila, no more play

Pictures show it better.
.

Nice find Ian, is this the V3??

**coolice** · 27-08-2012, 11:11 PM

Originally posted by Jamin_00 View Post

Nice find Ian, is this the V3??

Hey.

Yes it is on the V3. I thought it was originally a tolerance issue with the shaft, but then removed the two screws and it was obvious then the hole inaccuracy is spreading the bearings apart.

I'm going to forward the pictures onto Keith@Robbe to pass onto Align I think.
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**dszabo** · 28-08-2012, 06:38 PM

All done, no more play...

**Nutter** · 28-08-2012, 08:00 PM

Just done mine as well!!!

There was the tiniest amount of play with the tail gear box fixed into the side frames, but none when the tail box removed. Now elongated the hole in the side frames as per Ian's photos and now the play has gone!!!

**coolice** · 28-08-2012, 08:24 PM

Hey Guys.

Brilliant, glad you've managed to fix your play to.
As to what problems may have arisen if it was left I don't know, but I would imagine the bearings would fail quicker than normal with the constant pounding as the shaft banged up & down with tail rotor torque changes.
It's good my model wasn't to only one to be suffering from alignment problems, but a shame it's apparant on others to.

Flew mine today and it seemed to sound better during piro reversals, I need some shims now for the tail output shaft as well, which I'll order tomorrow.
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**Nutter** · 05-09-2012, 09:14 PM

Ian

Flew my 700E DFC tonight for the first time after doing the frame mod like you suggested and guess what?

Yep. The vibration noise has completely gone!!!

Many thanks for the info again!!!

**lee mister** · 30-09-2012, 07:15 PM

Just built my new kit and had to do this mod.
I had about 3mm of play, tiny bit of dremal work on the front two holes on both sides and now it's perfect

Thanks for this tip

**coolice** · 30-09-2012, 07:41 PM

Originally posted by Nutter View Post

Ian

Flew my 700E DFC tonight for the first time after doing the frame mod like you suggested and guess what?

Yep. The vibration noise has completely gone!!!

Many thanks for the info again!!!

Originally posted by lee mister View Post

Just built my new kit and had to do this mod.
I had about 3mm of play, tiny bit of dremal work on the front two holes on both sides and now it's perfect

Thanks for this tip

Hey Guys.

Brilliant news, glad it's been useful to you and helped cure any funny noises.

Another thing to add int othe mix is that I've switched to the plain aluminium boom and mine has quietened down fully now, I cannot hear the tail buzz I was hearing before. The testing continues but the ali boom seems more stiffer than the carbon/ali type.
.

Announcement

700E DFC Vertical Tail Shaft Play Cause Found

700E DFC Vertical Tail Shaft Play Cause Found

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