RunRyder - Rapid clicking sound under tail rotor load!!!

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e-MS Composit Hornet > Rapid clicking sound under tail rotor load!!!

hoversmooth999
Heliman
Location: Jourdanton,TX United States

Hello to all,
Maybe someone can help me here. I have been flying my hornet x3d and it flies great. One thing that concerns me though is that in ground tests ,when full rudder was given in a particular direction, a high speed clicking sound would seem to come from the front of the helicopter. Naturally, I can figure that this sound is the product of something not meshing right between the main gear and tail rod pinion, but the gear mesh seems to be perfect with no gear slippage. The heli still does however fly perfectly and tracks great. I have experienced this with my big MA excell gasser with shaft driven tail in the past as well, but never figured out what it was. Can someone give me some info. Thanks

03-08-2007 Over year old.

DarkHorse1
Senior Heliman
Location: Gloucester UK

Yes your probably right, it's the conical and crown separating under load. Could be that there is some slop in the mesh and when the heli is hovering the weight of the heli is holding the main gear crown and conical pinion together. On the ground the gears slip more easy without the weight if the heli. I always run a tight mesh in this area to avoid this. A similar situation can occur when using a CF tail drive shaft that flexes and bows under load allowing the gear to separate. Sometimes this can help by taking mild gear damage several times before a critical gear tooth failure, as opposed to a ridged system that will just stip the conical pinion when the tail load is very high of tail rotor jams in a crash etc. So you may find that in fixing the gear mesh slop that demanding high tail loading does damage to the drive system instead of mild gear skip. Depends on the loads but take your pick.

See my tips page here for how I set the conical mesh (Ctrl+F search for flick or thumb).

Also, I avoid full rudder with large tail pitch commands on the ground.

03-08-2007 Over year old.

HOMEPAGE

Micro-Maniac
Elite Veteran
Location: Pasco,Washington Formerly: Captain Chaos

And make sure the main shaft collar is set well so theres no vertical play in the main shaft - That was the cause of one of my recent crashes - I set it down kinda hard and the collar slipped enough to let the conical gear slip/strip in flight.

03-08-2007 Over year old.

kiwidave1
Veteran
Location: Seattle, WA

are you sure nothing is hitting on the tail. Sounds like a a tail pitch arm is hitting on the housing somewhere. Have you checked this on the bench with full right deflection?

Never underestimate the power of stupid people in large groups.

03-08-2007 Over year old.

HOMEPAGE

hoversmooth999
Heliman
Location: Jourdanton,TX United States

Thanks to all,
You may be right kiwidave1 but I'm pretty sure I distinctly hear the clicking noise resenating from the front of the heli. To DarkHorse1, true, the only time this noise is heard is during ground testing, However, regarding the hovering and weight of the heli, I can hover the heli inverted and it still doesn't do this noise and this would be a situation where the weight issue would be vice versa. My shaft collar is snugged down but not to a point where the rotation is restricted. The ONLY time this noise is heard is during ground test. It may just be a trait of this heli. It definitely flies great and stable both upright and inverted. I just purchased another hornet kit with all the Pro mods. I'll see if this one does the same and report back. Any extra input would be appreciated. Thanks.

03-09-2007 Over year old.

Shoo
Heliman
Location: Eastern MA

I had the same clicking noise with my HII. The cf tail drive rod was partially delaminated and would only jump on high loads. I'm not sure how that would happen with the x3d steel rod but I'd say that it's a similar situation. Let us know if you figure it out.

Shawn

03-10-2007 Over year old.

hoversmooth999
Heliman
Location: Jourdanton,TX United States

Hello to all,
It's been while, but I never could figure the problem out, but what Shoo says may be what could have happened. Keep in mind, this situation only happened during hard tail loading.
My next problem, well maybe not a problem but definitely an annoyance, is another symptom I have found in other helicopters as well. I just purchased my second Hornet not too long ago. It is the Pro version with the metal parts in the head and tail. The problem is that I have balanced the tail rotor perfectly but I can still notice a bit of a shake in the main rotor which only happens in mid-range speeds. I have realized this small shake to happen during spooling up because of the blades straightening out in their grips, but when throttling down slowly there still is a small wobble in the mid-range speeds. It reminds me of when you have an unbalanced wheel on your vehicle. It may not be noticable at slow and high speeds, but somewhere in the middle is that special sweet spot that the wheel shakes. From a smooth landing and as I throttle down, that sweet spot comes in and causes my heli to do a little shimmy on the ground and then stop again. Why is this? Any info would be appreciated. This is such a great little heli. Thanks everyone.

03-23-2007 Over year old.

Micro-Maniac
Elite Veteran
Location: Pasco,Washington Formerly: Captain Chaos

This may sound unlikely to you but I'd say your spool up/down shakes are caused from the blade tracking being slightly out - Those shakes only go away when the blades are tracking perfectly or spinning past a certain speed.

03-23-2007 Over year old.

Shoo
Heliman
Location: Eastern MA

Tracking could be the issue. I know the hornet heads that I've had all seem to have issues staying in track at various pitches.

You said you balanced your tail but have you done the same for the head and blades, paddles, etc? A great resource for finding shakes is eric larson's site. http://www.ericlarsonrc.com/Heli/Eq...D/HornetX3D.htm Hope this helps.

Shoo

03-24-2007 Over year old.

hoversmooth999
Heliman
Location: Jourdanton,TX United States

Thanks,
Micro-Maniac and Shoo, the tracking issue sounds very likely. I found that sometimes it is even necessary to make the half turn on the ball link and install from the opposite side just to get the tracking close to perfect. This is kind of difficult as you would know because of ball links being open more on one side. I have check the tracking and adjusted it to almost perfect. Which resolved the wobble a bit, but it is still there. It just has that tiny jump from skid to skid. My first hornet with the plastic head does not have this wobble, however the blade tracking on it is perfect in all dimensions of flight. I'm using the Extreme Composits KO Propo Blades on my first Hornet and the MS Carbon Fiber blades on my pro version. Can this slight mistracking damage the heli? I don't think it should as I use to fly a Blade CP with this condition for a long time. I will see if there are any other possible causes to this. One being the aluminum swash. The outer race of the swash appears to move around oval-like as I slowly turn the main rotor by hand. Maybe it's just my eyes, for this, I think would cause a wobble throughout the whole rotor speed range. Thanks for all the help guys. I'll let you know if anything new comes up. It already is spinning up almost perfectly smooth. Any more adjustment would be for perfection.

03-24-2007 Over year old.

Micro-Maniac
Elite Veteran
Location: Pasco,Washington Formerly: Captain Chaos

I learned the tracking issue when I switched from the stock plastic head to the Duzi metal head - The virually slopless metal head is a lot more sensitive to tracking than the stock plastic head was - It really only reveals itself during spool up/down so it's not likely to do a lot of harm - It's sure smooth when it's perfect though,

03-24-2007 Over year old.

DarkHorse1
Senior Heliman
Location: Gloucester UK

There are a few other things to cause spool up and down wobbles (beyond bent shafts, bent blade grip head bolts and tracking). One I found resently was due to uneven head damping, that can be spotted at very low RPM looking across the rotor to observe one blade higher than the other. This is not tracking as the air speed at low RPM isn't a big enough factor effecting the blades.

Also the top box frame and radio tray are very soft and exagerate vibes particularly at higher RPMs. and require reinforcment. ...if I tweak the tail rotor and watch the response from the heli, the play in the top box frame and radio tray is pretty significant. For cruising around at stock 2500 RPM will probably be OK. Otherwise requires simple frame reinforcement triangulation, as the top box frame can easily twist relative to the main motor drive.
Will reduce spongy collective and cyclic inputs and stop the intermittent/variable resonant vibes at higher RPMs .

03-24-2007 Over year old.

HOMEPAGE

hoversmooth999
Heliman
Location: Jourdanton,TX United States

Hello to all,
Well I have some new discoveries. Unbelievably, The ball in the center race of my MS aluminum swash is not perfectly centered. I just bearly noticed this remarkable flaw yesterday as I watched the head closely on my hornet as it spooled down. I could distinctly see the swash move slightly back and forth during slow head speed. It is so crazy how this small deviance disappears at the flying head speeds. Micro-Maniac makes a good point and I definately agree with him. That extreme stiffness of the aluminum head does'nt have any give at all like with the plastic head which would indeed show more sensitivety to tracking and vibes. Shoo was definately right on the tracking issue. Another variant I have found is that this small shake pretty much disappears with perfect tracking. After tearing down the head I found that the bearings in one of the grips were bad causing a bind in that grip which did not allow it to move in unison with the other grip. This became very obvious when I decided to carefully spool up the heli holding it and watching the blades from the side. Perfect pitch was accomplished during positive ranges but went out of track during negative ranges. I connect this to the one grip binding at those points. As far as the dampening is concerned, this aluminum head is snug and tight and when the blades are perfectly straight in their grips, the height difference between blades disappears. Normally after spooling up the head the blades hit that perfect straightness in their grips, but when first straightening them out by hand and then running a slow head speed I saw this as well. I would definately not rule Darkhorse 1's symptom out though, but I Have checked the dampening and it's good with no height differences. All in all, one big cause I am sure by now is this wobbly swashplate. It already is running smooth even with this small flaw and anymore adjustment is just for perfection. I'll be back with an update. Thanks everyone.

03-26-2007 Over year old.

hoversmooth999
Heliman
Location: Jourdanton,TX United States

Hello all,
I just made a small mod that greatly improved my helis performance and took, yet a little more of the vibes away. I replaced the three blade grip bearings (2x6x2) with two Blade CP tail bearings (2x6x3) on each side. These bearing have a very smooth feeling to them and they fit perfectly. Also, I have a new swash on the way to replace the current one. I will let ya'll know how it goes. Thanks everyone.
P.S.
My apologies to Darkhorse, after reading my previous reply, it seemed to me that I may have been a tad harsh on your info. Sorry.
Again Thank-you and I appreciate all comments and help.

03-27-2007 Over year old.

DarkHorse1
Senior Heliman
Location: Gloucester UK

No worries, I just throw stuff out there, sometimes it's useful, sometimes it's not.

> I replaced the three blade grip bearings (2x6x2)
> with two Blade CP tail bearings (2x6x3) on each side.
Strange, your the second person today I heard that is swapping grip bearings. Wonder if there was a bad batch recently or if it's always been an issue.

03-27-2007 Over year old.

HOMEPAGE

hoversmooth999
Heliman
Location: Jourdanton,TX United States

Last update:

Hello to all,
After receiving my new metal swashplate yesterday (thanks to Henry at MS Comp. USA) I immediately replaced it and saw that the center ball was much better centered. With everything almost perfectly balanced and measured and the flybar paddles measured to within !!one-hundreths of a Millimeter!! I took the heli out to fly and she flew like a dream. The base loaded antenna sticking out off of the skid showed absolutely no wobble or vibes at all. "Did the helicopter still wobble around a bit on the ground during spool up and down?" YES, it did. In conclusion, I would like to report "in my own opinion and not fact" that this symptom may always reside with ALMOST every helicopter. Granted it has a rigid metal head. Due to the rigidity of the metal head (thanks to Micro-Maniac's input) the set-up is definitely more sensitive to ANYTHING including the TRACKING. And because of the minute deviances in DAMPENING (thanks to DarkHorse1's input) the slight blade height differences about the rotor disk would definitely cause a wobble at slower head speeds ie. spool up and down and naturally, at higher head speeds the blades would go into track overiding the dampening issue and thus elimination the wobble. I then went and did a close-up view of my second Hornet with the plastic head during spool up and down. Indeed, there was a wobble but it could only be seen visually as the plastic head parts did absorb most of the vibes and wobble thus eliminating the floor dance during spool up and down. My floor is hard tile thus not to absorbant toward shakes. At long last I can also conclude that these high spinning micro machines are prone to vibes from the numerous parts going around. These numerous parts in turn would also play a part in some of the issues I've encountered. They truly are mastermind puzzles that allow us to keep improving toward the perfect vibe free helicopter. Thank-you everyone for your help.

03-30-2007 Over year old.

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e-MS Composit Hornet > Rapid clicking sound under tail rotor load!!!

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