Tail problem on T500

[cd5]

my mates t500 was wagging up and down and it was too low of a headspeed. Could this be a issue for you?

[PiccoZ06]

I tryed the not GOV mode but ofc it still wags.
I'm looking for a shop close by with berlings to try not trust berlings.

EDIT:
I just put in 3x8x3 bearings but guess what....

It still bounces from left to right.

I also noiticed higher head speed increases the bounceing....

[eldoubleu]

Hi Bob, Let me reiterate what everyone is saying……….GREAT JOB on all the videos they are so helpful. Thank you so much!

OK, I just spooled up for the first time and before any positive pitch the tail twitched fast to the right about 45 degrees (my knees were trembling) then stopped, and then just before lift off it started making small twitches.

So what you’re saying about the thrust bearings, are you suggesting reaming out the blade holders just another so the end race fits loosely?

My set up 401 and S9650

Larry

[eldoubleu]

OK, I just removed the tail grips and bearings. Reassembled making sure the thrust bearings were installed properly. The inner race (larger ID) does have to be pressed into the grip but upon finish assembly every thing moves very smooth and free.

Same problem, but this time I lifted off into a hover and the tail just constantly wagged like the gain was set to high. I tried 0 to 100 percent on the sensitivity, no difference, Normal Mode and AVC, no difference. HELP I want to FLY!!!!

Larry

[Mercuriell]

Futaba have a good basic tail rotor setup 101 for the 401 gyro and it might help people having trouble to run through this checklist http://www.futaba-rc.com/team/team-tip-002.html On the T600 we had lots of tail wag stories - common problems were the thrust vearings binding in the grips as Bob points out - the T600 is also sensitive to blades - some blades make it wag some don't and there doesn't seem to be any rhyme or reason to this so try different makes of blades and make sure they're loose in the grips - just tight enough to remove side-side rock in the grips but loose enough so they hang free in mid position.

[hopntod]

Thanks for the link John,I had not seen that,
todd

[eldoubleu]

John thanks for the link. I reviewed it and that’s the way mine is set up.
I have the same 401/S9650 setup on my 450SE so I’m familiar with the setup.
Now on this thrust bearing issue, on mine the inner race (the first race to be inserted into the blade holder) fits very tight into the blade holder. It has to be snapped into place with a bit of pressure. Should this race be loose fitting? In other words when you hold the blade grip upside down should it fall out? I hate to ream out the holder unless I’m sure this is what’s needed.

Larry

[Finless]

Thats my theory but I am not going to grind the grips I am going to file the outside of the race. It wont take much I don't think. Some 600 guys did this and it worked for them. Same symptom by the way.

Bob

[rcmarty]

I know when i get my hands on mine i'm going to do the same thing i've done to all my 600's.

Dual radials and a thrust set. Just like quk stuff but only $5

My 600e wagged so bad i could barely hover it. Modded it and it was gone, no changes at all to the settings. Didn't even bother flying the 600n without modding it so i can't say there.

What i did wasn't that hard to do, about 10-15 mins.

i took a longer bolt (3mm x 15mm for the 600's) sanded it down to fit ( bottomed out on the hub before it binded up the bearings , end threads of the bolt needed the threads sanded off a bit as the hub isn't threaded right to the bottom) Then assembled with the extra bearing. The cap (all i had at the time - mushroom if you got it) bolt needed a slight sanding to clear the radiax tail blades. I also sanded the seam of the blades , this allowed the blades to kick back 90 degrees if needed. The 600n plastic blades didn't need anything done.

last post has a few pics
https://www.helifreak.com/showthread...highlight=tail

On the 600e i put a spacer in the thrust set but on the 600n i didn't bother, there not going anywhere.

My take on the single radial and the thrust. This system depends on headspeed, you need the headspeed to keep the radial centered , if the speed isn't there then there is even more of a chance of binding, making things even worse. I know when i screw up i loose alot of headspeed !

With the dual setup the radials are taking all the loads reguardless of headspeed (someone say fast piro stops ?) and the thrust set just does thrust. As a bonus i think the thrust pack being not so deep in the grip helps to prevent binding.

I'm sure quk ,kasma, etc will come out with a dual setup eventually (just like the 600) but untill then we'll need a solution. Myself , i like bling but try to keep to the improvment/safety bling. The stock tail grips align has been making lately are beefy.

Martin

[Finless]

Well I have another take on it too....

Look at the main head thrust bearing setup. There is a large ID spacer ring that goes between the thrust bearing and the radial bearing.
OK what that does is cause the thrust bearing inner race to apply force to the OUTSIDE race of the radial bearing. Without this the inner thrust race will apply pressure to BOTH the radial outer race and inner race thus not allowing the radial to turn!!! Now with that and the inner thrust race having to be forced into the grip I think is causing the problem. Under load the system is sticking and make the grips hard to turn.

I need to find a spacer ring that is the right OD but has a large enough ID to not touch the inner race of the radial bearing.

Fireup! Got anything?

Bob

[fireup]

Originally Posted by Finless

Well I have another take on it too....

Look at the main head thrust bearing setup. There is a large ID spacer ring that goes between the thrust bearing and the radial bearing.
OK what that does is cause the thrust bearing inner race to apply force to the OUTSIDE race of the radial bearing. Without this the inner thrust race will apply pressure to BOTH the radial outer race and inner race thus not allowing the radial to turn!!! Now with that and the inner thrust race having to be forced into the grip I think is causing the problem. Under load the system is sticking and make the grips hard to turn.

I need to find a spacer ring that is the right OD but has a large enough ID to not touch the inner race of the radial bearing.

Fireup! Got anything?
Bob

Ok, now you're getting me to take apart my perfectly working tail and look at it... be back shortly.

[eldoubleu]

OK .........solved my problem with the twist of the dial (on my transmitter).
I feel like such a dork, My GYRO SENS was in the INHibit mode. Set it to ACTivate ............ when out in the dark and hovered by a spotlight in my driveway. The tail was solid at 50% not one bit of a twitch.
I probably won't be able to do anything more than a hover until next friday when I get to fly it indoors. So until then?

[fireup]

Originally Posted by Finless

Well I have another take on it too....

Look at the main head thrust bearing setup. There is a large ID spacer ring that goes between the thrust bearing and the radial bearing.
OK what that does is cause the thrust bearing inner race to apply force to the OUTSIDE race of the radial bearing. Without this the inner thrust race will apply pressure to BOTH the radial outer race and inner race thus not allowing the radial to turn!!! Now with that and the inner thrust race having to be forced into the grip I think is causing the problem. Under load the system is sticking and make the grips hard to turn.

I need to find a spacer ring that is the right OD but has a large enough ID to not touch the inner race of the radial bearing.

Fireup! Got anything?

Bob

Ok, took apart my tail and looked at it. It dosn't need a washer because there's only one radial bearing on the outside. The thrust bearing "In" part of the race just rest on the blade grips inner flange. Adding a washer here makes no difference. The "Out" part of the thrust bearing should have a smaller OD and not touch the blade grips at all. Sanding down the "Out" race OD to make it small may help.

Bob, maybe we can try swapping tail assembly and see if I get your problem. Or install the Solid-G on my heli.

[Finless]

Lets do that Kevin. Try putting the solid G on yours etc....

Bob

[rcmarty]

Originally Posted by Finless

Well I have another take on it too....

Look at the main head thrust bearing setup. There is a large ID spacer ring that goes between the thrust bearing and the radial bearing.
OK what that does is cause the thrust bearing inner race to apply force to the OUTSIDE race of the radial bearing. Without this the inner thrust race will apply pressure to BOTH the radial outer race and inner race thus not allowing the radial to turn!!! Now with that and the inner thrust race having to be forced into the grip I think is causing the problem. Under load the system is sticking and make the grips hard to turn.

I need to find a spacer ring that is the right OD but has a large enough ID to not touch the inner race of the radial bearing.

Fireup! Got anything?

Bob

I see what you mean. I wanted to put the thin washer in my 600 tails but i didn't have the right size. One would say ideally you would put the washer in there but in my case it wasn't available and i tried my luck without it. Fortunately it worked out fine for me, i'd venture to say it is due to the lighter blades in the tail.

I don't have my hands on one of these baby's yet. Does anone have any info on the tail bearing sizes ? I'm thinking a 8mm od should be plenty for the 500 , but who know's what align came up with. If it is 8mm then the spacer washers from the 450 v2 head will be a good source.

Martin

[HeliBurns]

you da man, edoubleu......

you solved your prob and had the intestinal fortitude to explain how it ocurred...

good job....^5

[RobertAbles]

Bob, Kevin,

This is the exact same problem Align had on the Thrusted "upgrade" tail for the 600 back early this year.

The slow wag IS caused by the outer thrust washer/race binding under load with the plastc grip.

I used a dremel and ground down and polished the outer edge of the outer race and this fixed the issue.

The only problem after this is that there was a lot more side play if you will at rest that did show up in flight with real fast rudder inputs or stops, it almost had a popping jerking sound to it if you had it in close and went full rudder input quickly.

I flew this for months with no problems other than hearing and feeling something not tight or right in the way the tail felt in flight.

I upgraded to the Quick UK tail hub and this made the tail feel very nice and smooth...

Hope this helps... Looks like we already need some better or metal tail grips...

[eldoubleu]

Not so fast with the high 5’s HeliBurns, Yes I solved the wicked tail wag but now………….

OK Just hovered for six and half minuets, at first it was rock solid, then I started doing some pirouettes. First slow then faster. Well now I think I’m seeing the tail problems others are seeing. It’s not wagging; it’s making fast 20 to 40 degree rotations to a solid stop and not returning to original heading. I think they were all nose to the right. Can’t say for sure I was really getting nervous. I think I’ll let her sit until I decide to make a modification to the thrust bearings or something else someone might come up with for a cure. Darn, I want to fly her so bad. It was such a rush just hovering………..until it started doing its own thing that is!

One other thing I noticed, it was quite tail heavy even with the WATTS UP meter I had strapped to the front skid. Of course I’m using Thunder Power Prolites 2100mAh, so that may be part of it.

Larry

[rcmarty]

larry.

My tail ( talking 600 here as i don't have the 500 yet) would wag back and forth once spooled up would wag back and forth about 8" or so.

If your heading is changing on you then it might be deeper than we think. I'm leaning towards gyro due to the heading changes.

Do you have another gyro to try ? Or a bad / going bad servo.

Is the tail servo proven ? new or one you know is good ?

Martin

[carlos]

No probs with my 500.
After reading these posts I pulled the tail assembaly appart to check anyway.
Everything was as per instructions except for the lack of grease on the thrust bearing.
There is plenty of play between the outer thrust cap and the blade grips as well.
Gyro 401 with 9257 mounted as per bob's video.
9257 is brand new and the 401 has done a million miles with plenty of crashes along the way.