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View Full Version : How to eliminate tail slop?


Steve Joblin
10-19-2010, 09:54 AM
Still suffering from CWS (Cronic Wag Syndrome) :(

I've been focusing so much on making sure my tail isn't binding, that I didn't pay close attention to how much slop I had and if that was the culprit of my waggy tail...

As you can see in this video, I don't have much play in the tail grips, but there is a fair amount of play if I pitch (or twist) the blades... Is this normal? If not, how do I eliminate it? It seems to be in the slider and connecting linkages...

7LWwBngBXrA

Cadjocky
10-19-2010, 11:41 AM
Steve, that pretty much normal for the 250. I have the "slop" and the stock tail works fine. Remember that you are judging things in the static state, the dynamic state is much different. The forces are pretty high when spinning @ HS 4600 rpm the tail is around 19k rpm putting about 60lbs of rotational force on the hub to grip screw heads and it takes about 3-4lbs of lateral force to make the grips rock on the head of the screw "slop" Just something to consider.

dbennettya
10-19-2010, 01:40 PM
Steve,

I just check my 250se and the blades move about the same as yours do when twisted. There is one difference I see from your video, it appears that your tail shaft is sliding about 3-4x as much side to side as mine does. My tail shaft only moves a few thousands of an inch sideways inside the housing. Maybe try shimming between the belt pulley and bearing on one or both sides. This movement translates into a pitch change and dead zone.

Good Luck, Don

Steve Joblin
10-19-2010, 02:08 PM
Yeh, I noticed that little bit of play of the tail shaft inside of the housing... I just checked it very closely, and the amount of play is the thickness of a piece of paper. If I work hard enough, I can just about slip a piece of paper in between the belt pully and the bearing... the video makes it look like there is much more play then there actually is... I would say that mine is a few thousands of an inch just like yours.

toys2cars2toys
10-19-2010, 04:35 PM
Hi have you seen this?
http://www.helifreak.com/showpost.php?p=1033279&postcount=111


So far I have zero tail wag....... then again, I've not had time to finish mine, so fingers crossed when I do

RyuuChi
10-19-2010, 05:00 PM
i got a set of aluminum pitch slider links from helidirect and that seemed to cut a lot of the slop from my se tail...

BTB
10-19-2010, 05:50 PM
Yeh, I noticed that little bit of play of the tail shaft inside of the housing... I just checked it very closely, and the amount of play is the thickness of a piece of paper. If I work hard enough, I can just about slip a piece of paper in between the belt pully and the bearing... the video makes it look like there is much more play then there actually is... I would say that mine is a few thousands of an inch just like yours.

I noticed after my first rebuild that if the four screws in the back of the tail case are screwed in before the front two there would be excessive movement in the tail shaft. But if you tighten each screw in a pattern like you would do with a main gear the shaft doesn't move as much.

Steve Joblin
10-19-2010, 06:01 PM
Interesting posts guys!

That is a great link Toys2Cars... actually it is a great thread that I will read through in detail!

I might have to give a set of those aluminum pitch slider links a try with my next order of parts, RyuuChi.

Bob - I'm a bit confused... I only have three screws on my tail case... are you talking about the two black plates that hold the bearings for the Metal Tail Rotor Shaft?

BTB
10-19-2010, 06:15 PM
YUP:thumbup:

pitchp
10-19-2010, 08:39 PM
ohh man steve, that's slop. on the blade grip, that is slop. I adjusted my blade grip so it doesn't have that play (this is on my hk250 plastic), by sanding down the hub. As for my tarot(which is metal), I took out the blades grip screws and rethreadlocked them, and tightened the screw so there is minimal movement, but not much binding, there is a little, but I can live with that(better with a slight bind than slop). As for the movement on the slider, I had that too, same amount of movement. I put a dab of CA on the ball holder to make it tighter(this I find wears out over time, so I check it (this requires TLC, as you can't put too much CA or there is total bind, I only put just enough CA, one coat until there is no play, I allow the CA to completely dry out, then I put a drop of oil before reinserting the ball back in, once this is done by hand i move the slider about 20 times and it gets a little bit loose, I apply another drop of oil while the ball is still in the holder and repeat the tail slider movement). I also put an extra washer in the gear to stop it from moving(So that gear movement in the gearbox is very minimal,but yours is a different gear to mine, so you would have to adjust differently). I hope this helps. good luck dude


Also for the tail blades holder screw, i've replaced them with nuts and bolts( I had to make the holes bigger), and threadlocked them. I check this everytime because of my High HS, things get loose over time. So I adjust it accordingly

dze
10-19-2010, 08:47 PM
Still suffering from CWS (Cronic Wag Syndrome) :(

I've been focusing so much on making sure my tail isn't binding, that I didn't pay close attention to how much slop I had and if that was the culprit of my waggy tail...

As you can see in this video, I don't have much play in the tail grips, but there is a fair amount of play if I pitch (or twist) the blades... Is this normal? If not, how do I eliminate it? It seems to be in the slider and connecting linkages...

7LWwBngBXrA

for one thing i can tell you positively that if there is a wag problem your tail assmbly from the slider-grips looks alot tighter than mine .. what i did notice is the belt gear moving quite a bit and i would probably try to eliminate some of that myself by sanding lightly on the rear post or tightening up the housing screws ... but not to the point there is zero play there needs to be some .. anyways ... my advice is look elsewhere to eliminate wag - gyro mounting, gyro settings, mechanical gain, heli vibration ... try differnt blades if you have them .. headspeed has a pronounced affect so have it set up to have a headspeed that is producing the power level you desire and tune it from that point ... again .. i have helis with twice as much slop in the tail .. thats not where to look .. take it or leave it :thumbup:
.. another point i can tell you that will affect the overall setup is the belt .. those kevlar belts are stiff and i would strive to get a belt tension as loose as possible .. not sloppy but definitely not tight ..
.. also to keep adding to this post heheh, what i found on the 250 i fly almost daily, is that eliminating all slop ( which i tried to do) actually results in a situation where i have to run less gain and experience even MORE of a problem with wag, especially flying in a stiff wind .. just a thought .. i wouldnt waste time trying to tighten the bejeebus out of the tail action .. your linkage and control arm looks tight and thats the main worry on slop ..

Viet-Lama
10-20-2010, 12:54 AM
I put a dab of CA on the ball holder to make it tighter(this I find wears out over time, so I check it, and place another dab of CA in the ball holder until it's tight again(this requires TLC, as you can't put too much CA or there is total bind, I only put just enough CA, one coat until there is no play,

I had similar play which was happening at the pitch slider ball (just like in your video) and used the CA trick. Just smoothed a coat around the ball and when it dried the play was totally gone! I didnt think it would work but its perfect now.