"OH NO" I have the "WAG"

[Zoobie]

If we all agree on a set distance from the front pulley for each heli - say about 30mm or so on the hurri.( think that this could be universal) it would be easy to standardize. BTW the scales for trout fishing are really tiny - perhaps we are not as optimistic!

[mjdee14]

I'm thinking the best way to adjust it is to place Both feet on the frame....put a 2 x 4 trhough if needed....and pull on the tail until the belt stretches 1 inch... (lol)

Seriously...I think as someone mentioned above....the belt must stretch over time and as bearwood mentioned it might go into resonance.....think how fast the tail blades are turning....that belt is running pretty fast.

I would suggest the next person to get the "wag" do nothing else but tightenend the heck out of the belt....if it doesn't fix it...then we have other problems.

[Zoobie]

Well I get a weird vibe during intial spool up so I was going to just tighten my belt a little more. In the "tail vid" finless recommends running a fairly loose belt, perhaps that is why we are running into trouble? Surely other helis with longer booms should have the same problem? Are the "waggers" running the longer boom or shorter one. Mine is the shorter one and so far no probs except for the noise/vibe on spool up.

[istandalone]

maybe different on yours, but i set my belt looser then bob suggested and it just got worse, but with added tail kick to go along with the wag.

[bearwood]

I took the Heli to work this morning to see if the other Engineers could come up with any ideas for standardising the tension of the belt. The universal answer was it will be just a feel thing, when you get it right, feel the tension and remember it.

I had a bit of a trim problem and did a trimming run in the front yard and I touched the tail rotor on the grass. Wouldn't you know it the wag/kick returned. ##!!.**^^ Tried tightening, no change, loosened the belt, no change. Took it in the workshop and had a really good look at all the teeth on the belt and they didn't look as sharp as the spare belt I had. I removed the belt and the new belt was a lot sharper and is possibly from a different manufacturer as it has different markings. So I fitted the new belt (firmer that original but not really tight, I marked the boom at both ends previously) and ran one pack through with no wag again. Hopefully this is the fix for me although I have said that once already!

[Cralis]

Interesting post, bearwood. On my very first attempt to fly the 550, I had the gyro reveresed... Spun up, but as it was on grass, I didn't notice a problem, until it got a bight light on the skids... Chopper spun around, but didn't go over or anything - caught it just in time. However, a tail blade DID hit the stabiliser, and chip a bott off the stabiliser. Blade was fine though...

However... maybe it's not fine... Maybe the shaft is a bit bent? Your post has reminded me of that...

I also hear the 'tick, tick' sound when land... Is that the belt hitting the inside of the boom?

[bearwood]

Cralis, I just came in a little to nose high and stuck the stab in and the blades cut a nice track in the grass. Didn't think it was too bad but it upset something.
On my second flight ever I had a tail blade seperation complete with holder, that smashed the stab and I replaced it with a fibreglass homemade one. Since then I have fitted a new gaui tailhub/holders and slider and more recently a CNC tail unit complete. The output shaft is still the original but I checked it when fitting the CNC tail.
After fitting the CNC tail I forgot to check the gyro reversing and the heli spun like a spinning top on hard packed sand, something I won't forget in a hurry:oops:

I hope to get a few flights in early tommorow morning to see if the wag/kick is gone.

I only get the tick sound if I shake the Heli, I don't get a tick when it is running or spooling up or down. I'd say there is a far chance that the belt may hit the boom during spoolup/down due to the length of the belt and the whipping that probably occurs whilst spooling up or down.

[Zoobie]

Cralis, I also get that noise on spooldown. I am convinced it is the belt. I have tightened mine, so I will see how it goes now.

[Cralis]

Look forward to hearing if it has an effect. I'm taking off the boom for the heli to be shipped to Australia, so it's pintless me doing much now... :(

But once there, I'll rejoin the trouble shooting. :)

[xfaega]

I will have to agree on the belt being the cause of the wag. The reason is being that my Trex450 SE had the same problem and when I tightened the belt that wag was gone. Also make sure your tail blades are balanced and somewhat loose.

[istandalone]

this issue might even come down to the belt, not so much the tension. thinking on this last night, i deduced that in theory if you've got a belt that's been installed but not flown, and sat on the shelf for a long time and have taken "shape", kind of curved/creased around the pulley's then when you go to spin the heli up, it would cause a vib. this of course would go away when a new belt is installed. also would go away if the creased belt was really tight. maybe some of the belts that got sent out with the hurri's are made of an inferior material?

[bearwood]

istandalone,
The belt I removed has a twist(wierd looking bit) in it. Kind of hard to discribe, I will try to post a picture tommorrow, I'm at work right now. I hooked the belt in the handle of the vice and applied 25KG (bit over 50 pounds) pull on the belt and the twist did not pull out.
When I post tommorrow I will also give the name on the new belt and the name of the old belt.

[Zoobie]

Bearwood, that sounds like the culprit, and by tightening so much we are partially overcoming the effect of the "twist". I will try inspect my in situ on my heli. Really dont feel like removing the belt.

[bearwood]

I took a photo, but the twist (for want of a better word) is not easy to photograph. It runs run about the 3 cm mark to around 23cm. The bottom edge is dead straight but the top side twists away a small amount. In my case it is where the writing is on the belt. I don't think you would see this whilst the belt is installed.
The belt I took off has the following markings :T Force Do Not Crimp Antistatic resistance 572XL 088 D007 6378E778.
The belt I put on has the following: PIN BELT TIMING BELT 572XL DO NOT CRIMP 06, all the writing is very bold.
If someone wants to do the maths, the tail rotates at 4.5:1 to the main rotor and the belt does on revolution to 7.5 main rotor revolutions. So I guess this equates to a "glitch" every so often (I'm too tired to try and work it out).

[bpd964]

I flew a little today and now I see what "wag" you guys are talking about. I guess the first thing I am going to do is tighten the belt. I have the Align 75A esc but i will leave that alone until I tighten up the belt and try again..

[Cralis]

It's contagous!!! Save yourselves!! :lol:

[Wazzer]

ok guys

how do you differentiate this tail wag from a wag caused by an incorrectly set up gyro?

cheers

ben

[mjdee14]

ok guys

how do you differentiate this tail wag from a wag caused by an incorrectly set up gyro?

cheers

ben

You will difinately be able to tell the difference....the gyro is a "hunting" type of movement....and the wag is is very quick side to side kick...mine had the sound to go along with it...you will also see no movement on the servo...or very little. it is also very repetitive at a certain head speed.

I kept reading about it...but when it happeded it was very obvious it was a "wag" and not a gyro hunt.

Mine would also go away while spooling up then when the rpm stabilized it would wag, it did this at several different spots on the spool up wherever I stopped the throttle.

If you have tighten the heck out of the belt....and see if it goes away.

Mike D

[bpd964]

OK.. the tail hum/wag/growl/vibration thing is a belt tension issue for sure...(at least it was in my case) :)

I don't have the cnc tail or any of that and the only thing I did was tighten the belt.

[bpd964]

The tail fin belt tension wag is like a giant humming bird wing on steroids.. Your gyro wag it's similar to the movement of balancing your blades.. it has a slow leveling feel/look to it..

That's the only way I can explain it...:smokin:

[istandalone]

you hit it right on the head, bdp! the vertical tail fin will look like a hummingbird's wing fluttering. gyro wag is more of a slower hunt, and really only noticable in forward flight. i can have my gain at 100 and hovering it won't wag.

[bpd964]

Got the wag fixed but NOW, I have a stripped gear.. Didn't even crash.. Just spooled up and It started clicking.. WTH!?

Where should I get gears and what tooth do you guys recommend? I want to replace the whole set.. I knew I should have ordered them prior..

[bbagle1]

I don't mean to muddy the waters even more on this issue but lately my hurri has been wagging whenever hard cyclic or collective inputs. Found out today my gyro mount on the Gaui CF frame was loose and twisting/sliding. Tacked it in place with CA and strapped it down tighter with velcro. Problem solved

[jackjakosalem]

Hi guys, this is my first post here after seeing this is the best forum for the GAUI 550! Just got mine few days ago, test flew it... perfect hovering even with all trims centered and no more trimming needed, then after around 2 minutes of very stable forward flight and hovering.... THE WAG! it currently has the RTF servos with Maxwell 831MG tail servo and Futaba 240 gyro. tried all gain adjustments with the gyro but the wag remains. But it only occurs after 1 to 2 minutes of hovering. i didnt want to risk losing tail control so i stopped after 2 sets of batteries. Tommorow i swap the 240 gyro with the 401 i have on my esky belt CP and put on the extra 9650 servo i have kept. then after reading all your posts ---- tighten the belt. Hopefully the DREADED WAG dissapears! Have a great weekend of flying everyone!

[skydude]

Could the tail wag be that the heli is happy to see you?

(Coudn't stop myself from making that post)

My bird is painted and ready to go cept for the rx. Ordered the futaba 606fs 3 weeks ago. Kept asking the lhs when it was coming. They finally checked and it turns out that rx has been discontinued. Replaced with the 607. Should be here soon.

Glad I read through this thread. Good stuff regarding belt tension. Thanks.

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